libpng: Update to 1.6.47

thirdparty/README.md

@@ -530,14 +530,13 @@ Files extracted from upstream source:
 ## libpng
 
 - Upstream: http://libpng.org/pub/png/libpng.html
-- Version: 1.6.45 (51f5bd68b9b806d2c92b4318164d28b49357da31, 2024)
+- Version: 1.6.47 (872555f4ba910252783af1507f9e7fe1653be252, 2025)
 - License: libpng/zlib
 
 Files extracted from upstream source:
 
-- All `.c` and `.h` files of the main directory, apart from `example.c` and
-  `pngtest.c`
-- `arm/` (minus `filter_neon.S`), `intel/`, `loongarch/`, and `powerpc/` (minus `.editorconfig`) folders
+- All `.c` and `.h` files of the main directory, apart from `example.c` and `pngtest.c`
+- `arm/`, `intel/`, `loongarch/`, and `powerpc/` folders, except `arm/filter_neon.S` and `.editorconfig` files
 - `scripts/pnglibconf.h.prebuilt` as `pnglibconf.h`
 - `LICENSE`
 

thirdparty/libpng/png.h

@@ -1,6 +1,6 @@
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.6.45
+ * libpng version 1.6.47
  *
  * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
@@ -14,7 +14,7 @@
  *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
  *   libpng versions 0.97, January 1998, through 1.6.35, July 2018:
  *     Glenn Randers-Pehrson
- *   libpng versions 1.6.36, December 2018, through 1.6.45, January 2025:
+ *   libpng versions 1.6.36, December 2018, through 1.6.47, February 2025:
  *     Cosmin Truta
  *   See also "Contributing Authors", below.
  */
@@ -238,7 +238,7 @@
  *    ...
  *    1.5.30                  15    10530  15.so.15.30[.0]
  *    ...
- *    1.6.45                  16    10645  16.so.16.45[.0]
+ *    1.6.47                  16    10647  16.so.16.47[.0]
  *
  *    Henceforth the source version will match the shared-library major and
  *    minor numbers; the shared-library major version number will be used for
@@ -274,7 +274,7 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.45"
+#define PNG_LIBPNG_VER_STRING "1.6.47"
 #define PNG_HEADER_VERSION_STRING " libpng version " PNG_LIBPNG_VER_STRING "\n"
 
 /* The versions of shared library builds should stay in sync, going forward */
@@ -285,7 +285,7 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 45
+#define PNG_LIBPNG_VER_RELEASE 47
 
 /* This should be zero for a public release, or non-zero for a
  * development version.
@@ -316,7 +316,7 @@
  * From version 1.0.1 it is:
  * XXYYZZ, where XX=major, YY=minor, ZZ=release
  */
-#define PNG_LIBPNG_VER 10645 /* 1.6.45 */
+#define PNG_LIBPNG_VER 10647 /* 1.6.47 */
 
 /* Library configuration: these options cannot be changed after
  * the library has been built.
@@ -426,7 +426,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef char* png_libpng_version_1_6_45;
+typedef char* png_libpng_version_1_6_47;
 
 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
  *
@@ -744,7 +744,21 @@ typedef png_unknown_chunk * * png_unknown_chunkpp;
 #define PNG_INFO_sCAL 0x4000U  /* ESR, 1.0.6 */
 #define PNG_INFO_IDAT 0x8000U  /* ESR, 1.0.6 */
 #define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
-#define PNG_INFO_cICP 0x20000U
+#define PNG_INFO_cICP 0x20000U /* PNGv3: 1.6.45 */
+#define PNG_INFO_cLLI 0x40000U /* PNGv3: 1.6.45 */
+#define PNG_INFO_mDCV 0x80000U /* PNGv3: 1.6.45 */
+/* APNG: these chunks are stored as unknown, these flags are never set
+ * however they are provided as a convenience for implementors of APNG and
+ * avoids any merge conflicts.
+ *
+ * Private chunks: these chunk names violate the chunk name recommendations
+ * because the chunk definitions have no signature and because the private
+ * chunks with these names have been reserved.  Private definitions should
+ * avoid them.
+ */
+#define PNG_INFO_acTL 0x100000U /* PNGv3: 1.6.45: unknown */
+#define PNG_INFO_fcTL 0x200000U /* PNGv3: 1.6.45: unknown */
+#define PNG_INFO_fdAT 0x400000U /* PNGv3: 1.6.45: unknown */
 
 /* This is used for the transformation routines, as some of them
  * change these values for the row.  It also should enable using
@@ -1976,15 +1990,44 @@ PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
 
 #ifdef PNG_cICP_SUPPORTED
 PNG_EXPORT(250, png_uint_32, png_get_cICP, (png_const_structrp png_ptr,
-    png_inforp info_ptr, png_bytep colour_primaries,
+    png_const_inforp info_ptr, png_bytep colour_primaries,
     png_bytep transfer_function, png_bytep matrix_coefficients,
     png_bytep video_full_range_flag));
+#endif
+
+#ifdef PNG_cICP_SUPPORTED
 PNG_EXPORT(251, void, png_set_cICP, (png_const_structrp png_ptr,
     png_inforp info_ptr, png_byte colour_primaries,
     png_byte transfer_function, png_byte matrix_coefficients,
     png_byte video_full_range_flag));
 #endif
 
+#ifdef PNG_cLLI_SUPPORTED
+PNG_FP_EXPORT(252, png_uint_32, png_get_cLLI, (png_const_structrp png_ptr,
+         png_const_inforp info_ptr, double *maximum_content_light_level,
+         double *maximum_frame_average_light_level))
+PNG_FIXED_EXPORT(253, png_uint_32, png_get_cLLI_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr,
+    /* The values below are in cd/m2 (nits) and are scaled by 10,000; not
+     * 100,000 as in the case of png_fixed_point.
+     */
+    png_uint_32p maximum_content_light_level_scaled_by_10000,
+    png_uint_32p maximum_frame_average_light_level_scaled_by_10000))
+#endif
+
+#ifdef PNG_cLLI_SUPPORTED
+PNG_FP_EXPORT(254, void, png_set_cLLI, (png_const_structrp png_ptr,
+         png_inforp info_ptr, double maximum_content_light_level,
+         double maximum_frame_average_light_level))
+PNG_FIXED_EXPORT(255, void, png_set_cLLI_fixed, (png_const_structrp png_ptr,
+    png_inforp info_ptr,
+    /* The values below are in cd/m2 (nits) and are scaled by 10,000; not
+     * 100,000 as in the case of png_fixed_point.
+     */
+    png_uint_32 maximum_content_light_level_scaled_by_10000,
+    png_uint_32 maximum_frame_average_light_level_scaled_by_10000))
+#endif
+
 #ifdef PNG_eXIf_SUPPORTED
 PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr,
     png_inforp info_ptr, png_bytep *exif));
@@ -2029,6 +2072,60 @@ PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
     int color_type, int interlace_method, int compression_method,
     int filter_method));
 
+#ifdef PNG_mDCV_SUPPORTED
+PNG_FP_EXPORT(256, png_uint_32, png_get_mDCV, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr,
+    /* The chromaticities of the mastering display.  As cHRM, but independent of
+     * the encoding endpoints in cHRM, or cICP, or iCCP.  These values will
+     * always be in the range 0 to 1.3107.
+     */
+    double *white_x, double *white_y, double *red_x, double *red_y,
+    double *green_x, double *green_y, double *blue_x, double *blue_y,
+    /* Mastering display luminance in cd/m2 (nits). */
+    double *mastering_display_maximum_luminance,
+    double *mastering_display_minimum_luminance))
+
+PNG_FIXED_EXPORT(257, png_uint_32, png_get_mDCV_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_white_x, png_fixed_point *int_white_y,
+    png_fixed_point *int_red_x, png_fixed_point *int_red_y,
+    png_fixed_point *int_green_x, png_fixed_point *int_green_y,
+    png_fixed_point *int_blue_x, png_fixed_point *int_blue_y,
+    /* Mastering display luminance in cd/m2 (nits) multiplied (scaled) by
+     * 10,000.
+     */
+    png_uint_32p mastering_display_maximum_luminance_scaled_by_10000,
+    png_uint_32p mastering_display_minimum_luminance_scaled_by_10000))
+#endif
+
+#ifdef PNG_mDCV_SUPPORTED
+PNG_FP_EXPORT(258, void, png_set_mDCV, (png_const_structrp png_ptr,
+    png_inforp info_ptr,
+    /* The chromaticities of the mastering display.  As cHRM, but independent of
+     * the encoding endpoints in cHRM, or cICP, or iCCP.
+     */
+    double white_x, double white_y, double red_x, double red_y, double green_x,
+    double green_y, double blue_x, double blue_y,
+    /* Mastering display luminance in cd/m2 (nits). */
+    double mastering_display_maximum_luminance,
+    double mastering_display_minimum_luminance))
+
+PNG_FIXED_EXPORT(259, void, png_set_mDCV_fixed, (png_const_structrp png_ptr,
+    png_inforp info_ptr,
+    /* The admissible range of these values is not the full range of a PNG
+     * fixed point value.  Negative values cannot be encoded and the maximum
+     * value is about 1.3 */
+    png_fixed_point int_white_x, png_fixed_point int_white_y,
+    png_fixed_point int_red_x, png_fixed_point int_red_y,
+    png_fixed_point int_green_x, png_fixed_point int_green_y,
+    png_fixed_point int_blue_x, png_fixed_point int_blue_y,
+    /* These are PNG unsigned 4 byte values: 31-bit unsigned values.  The MSB
+     * must be zero.
+     */
+    png_uint_32 mastering_display_maximum_luminance_scaled_by_10000,
+    png_uint_32 mastering_display_minimum_luminance_scaled_by_10000))
+#endif
+
 #ifdef PNG_oFFs_SUPPORTED
 PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
    png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
@@ -3249,7 +3346,7 @@ PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
  * one to use is one more than this.)
  */
 #ifdef PNG_EXPORT_LAST_ORDINAL
-  PNG_EXPORT_LAST_ORDINAL(251);
+  PNG_EXPORT_LAST_ORDINAL(259);
 #endif
 
 #ifdef __cplusplus

thirdparty/libpng/pngconf.h

@@ -1,6 +1,6 @@
 /* pngconf.h - machine-configurable file for libpng
  *
- * libpng version 1.6.45
+ * libpng version 1.6.47
  *
  * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson

thirdparty/libpng/pngerror.c

@@ -935,23 +935,37 @@ png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message)
 int /* PRIVATE */
 png_safe_execute(png_imagep image, int (*function)(png_voidp), png_voidp arg)
 {
-   png_voidp saved_error_buf = image->opaque->error_buf;
+   const png_voidp saved_error_buf = image->opaque->error_buf;
    jmp_buf safe_jmpbuf;
-   int result;
 
    /* Safely execute function(arg), with png_error returning back here. */
    if (setjmp(safe_jmpbuf) == 0)
    {
+      int result;
+
       image->opaque->error_buf = safe_jmpbuf;
       result = function(arg);
       image->opaque->error_buf = saved_error_buf;
-      return result;
+
+      if (result)
+         return 1; /* success */
    }
 
-   /* On png_error, return via longjmp, pop the jmpbuf, and free the image. */
+   /* The function failed either because of a caught png_error and a regular
+    * return of false above or because of an uncaught png_error from the
+    * function itself.  Ensure that the error_buf is always set back to the
+    * value saved above:
+    */
    image->opaque->error_buf = saved_error_buf;
-   png_image_free(image);
-   return 0;
+
+   /* On the final false return, when about to return control to the caller, the
+    * image is freed (png_image_free does this check but it is duplicated here
+    * for clarity:
+    */
+   if (saved_error_buf == NULL)
+      png_image_free(image);
+
+   return 0; /* failure */
 }
 #endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
 #endif /* READ || WRITE */

thirdparty/libpng/pngget.c

@@ -380,7 +380,13 @@ png_fixed_inches_from_microns(png_const_structrp png_ptr, png_int_32 microns)
     * Notice that this can overflow - a warning is output and 0 is
     * returned.
     */
-   return png_muldiv_warn(png_ptr, microns, 500, 127);
+   png_fixed_point result;
+
+   if (png_muldiv(&result, microns, 500, 127) != 0)
+      return result;
+
+   png_warning(png_ptr, "fixed point overflow ignored");
+   return 0;
 }
 
 png_fixed_point PNGAPI
@@ -390,7 +396,7 @@ png_get_x_offset_inches_fixed(png_const_structrp png_ptr,
    return png_fixed_inches_from_microns(png_ptr,
        png_get_x_offset_microns(png_ptr, info_ptr));
 }
-#endif
+#endif /* FIXED_POINT */
 
 #ifdef PNG_FIXED_POINT_SUPPORTED
 png_fixed_point PNGAPI
@@ -518,44 +524,31 @@ png_get_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
 #  ifdef PNG_FLOATING_POINT_SUPPORTED
 png_uint_32 PNGAPI
 png_get_cHRM(png_const_structrp png_ptr, png_const_inforp info_ptr,
-    double *white_x, double *white_y, double *red_x, double *red_y,
-    double *green_x, double *green_y, double *blue_x, double *blue_y)
+    double *whitex, double *whitey, double *redx, double *redy,
+    double *greenx, double *greeny, double *bluex, double *bluey)
 {
    png_debug1(1, "in %s retrieval function", "cHRM");
 
-   /* Quiet API change: this code used to only return the end points if a cHRM
-    * chunk was present, but the end points can also come from iCCP or sRGB
-    * chunks, so in 1.6.0 the png_get_ APIs return the end points regardless and
-    * the png_set_ APIs merely check that set end points are mutually
-    * consistent.
-    */
+   /* PNGv3: this just returns the values store from the cHRM, if any. */
    if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+       (info_ptr->valid & PNG_INFO_cHRM) != 0)
    {
-      if (white_x != NULL)
-         *white_x = png_float(png_ptr,
-             info_ptr->colorspace.end_points_xy.whitex, "cHRM white X");
-      if (white_y != NULL)
-         *white_y = png_float(png_ptr,
-             info_ptr->colorspace.end_points_xy.whitey, "cHRM white Y");
-      if (red_x != NULL)
-         *red_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redx,
-             "cHRM red X");
-      if (red_y != NULL)
-         *red_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redy,
-             "cHRM red Y");
-      if (green_x != NULL)
-         *green_x = png_float(png_ptr,
-             info_ptr->colorspace.end_points_xy.greenx, "cHRM green X");
-      if (green_y != NULL)
-         *green_y = png_float(png_ptr,
-             info_ptr->colorspace.end_points_xy.greeny, "cHRM green Y");
-      if (blue_x != NULL)
-         *blue_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluex,
-             "cHRM blue X");
-      if (blue_y != NULL)
-         *blue_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluey,
-             "cHRM blue Y");
+      if (whitex != NULL)
+         *whitex = png_float(png_ptr, info_ptr->cHRM.whitex, "cHRM wx");
+      if (whitey != NULL)
+         *whitey = png_float(png_ptr, info_ptr->cHRM.whitey, "cHRM wy");
+      if (redx   != NULL)
+         *redx   = png_float(png_ptr, info_ptr->cHRM.redx,   "cHRM rx");
+      if (redy   != NULL)
+         *redy   = png_float(png_ptr, info_ptr->cHRM.redy,   "cHRM ry");
+      if (greenx != NULL)
+         *greenx = png_float(png_ptr, info_ptr->cHRM.greenx, "cHRM gx");
+      if (greeny != NULL)
+         *greeny = png_float(png_ptr, info_ptr->cHRM.greeny, "cHRM gy");
+      if (bluex  != NULL)
+         *bluex  = png_float(png_ptr, info_ptr->cHRM.bluex,  "cHRM bx");
+      if (bluey  != NULL)
+         *bluey  = png_float(png_ptr, info_ptr->cHRM.bluey,  "cHRM by");
       return PNG_INFO_cHRM;
    }
 
@@ -568,38 +561,31 @@ png_get_cHRM_XYZ(png_const_structrp png_ptr, png_const_inforp info_ptr,
     double *green_Y, double *green_Z, double *blue_X, double *blue_Y,
     double *blue_Z)
 {
+   png_XYZ XYZ;
    png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)");
 
    if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+       (info_ptr->valid & PNG_INFO_cHRM) != 0 &&
+       png_XYZ_from_xy(&XYZ, &info_ptr->cHRM) == 0)
    {
       if (red_X != NULL)
-         *red_X = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_X,
-             "cHRM red X");
+         *red_X = png_float(png_ptr, XYZ.red_X, "cHRM red X");
       if (red_Y != NULL)
-         *red_Y = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Y,
-             "cHRM red Y");
+         *red_Y = png_float(png_ptr, XYZ.red_Y, "cHRM red Y");
       if (red_Z != NULL)
-         *red_Z = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Z,
-             "cHRM red Z");
+         *red_Z = png_float(png_ptr, XYZ.red_Z, "cHRM red Z");
       if (green_X != NULL)
-         *green_X = png_float(png_ptr,
-             info_ptr->colorspace.end_points_XYZ.green_X, "cHRM green X");
+         *green_X = png_float(png_ptr, XYZ.green_X, "cHRM green X");
       if (green_Y != NULL)
-         *green_Y = png_float(png_ptr,
-             info_ptr->colorspace.end_points_XYZ.green_Y, "cHRM green Y");
+         *green_Y = png_float(png_ptr, XYZ.green_Y, "cHRM green Y");
       if (green_Z != NULL)
-         *green_Z = png_float(png_ptr,
-             info_ptr->colorspace.end_points_XYZ.green_Z, "cHRM green Z");
+         *green_Z = png_float(png_ptr, XYZ.green_Z, "cHRM green Z");
       if (blue_X != NULL)
-         *blue_X = png_float(png_ptr,
-             info_ptr->colorspace.end_points_XYZ.blue_X, "cHRM blue X");
+         *blue_X = png_float(png_ptr, XYZ.blue_X, "cHRM blue X");
       if (blue_Y != NULL)
-         *blue_Y = png_float(png_ptr,
-             info_ptr->colorspace.end_points_XYZ.blue_Y, "cHRM blue Y");
+         *blue_Y = png_float(png_ptr, XYZ.blue_Y, "cHRM blue Y");
       if (blue_Z != NULL)
-         *blue_Z = png_float(png_ptr,
-             info_ptr->colorspace.end_points_XYZ.blue_Z, "cHRM blue Z");
+         *blue_Z = png_float(png_ptr, XYZ.blue_Z, "cHRM blue Z");
       return PNG_INFO_cHRM;
    }
 
@@ -616,29 +602,22 @@ png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
     png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
     png_fixed_point *int_blue_Z)
 {
+   png_XYZ XYZ;
    png_debug1(1, "in %s retrieval function", "cHRM_XYZ");
 
    if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+       (info_ptr->valid & PNG_INFO_cHRM) != 0U &&
+       png_XYZ_from_xy(&XYZ, &info_ptr->cHRM) == 0)
    {
-      if (int_red_X != NULL)
-         *int_red_X = info_ptr->colorspace.end_points_XYZ.red_X;
-      if (int_red_Y != NULL)
-         *int_red_Y = info_ptr->colorspace.end_points_XYZ.red_Y;
-      if (int_red_Z != NULL)
-         *int_red_Z = info_ptr->colorspace.end_points_XYZ.red_Z;
-      if (int_green_X != NULL)
-         *int_green_X = info_ptr->colorspace.end_points_XYZ.green_X;
-      if (int_green_Y != NULL)
-         *int_green_Y = info_ptr->colorspace.end_points_XYZ.green_Y;
-      if (int_green_Z != NULL)
-         *int_green_Z = info_ptr->colorspace.end_points_XYZ.green_Z;
-      if (int_blue_X != NULL)
-         *int_blue_X = info_ptr->colorspace.end_points_XYZ.blue_X;
-      if (int_blue_Y != NULL)
-         *int_blue_Y = info_ptr->colorspace.end_points_XYZ.blue_Y;
-      if (int_blue_Z != NULL)
-         *int_blue_Z = info_ptr->colorspace.end_points_XYZ.blue_Z;
+      if (int_red_X != NULL) *int_red_X = XYZ.red_X;
+      if (int_red_Y != NULL) *int_red_Y = XYZ.red_Y;
+      if (int_red_Z != NULL) *int_red_Z = XYZ.red_Z;
+      if (int_green_X != NULL) *int_green_X = XYZ.green_X;
+      if (int_green_Y != NULL) *int_green_Y = XYZ.green_Y;
+      if (int_green_Z != NULL) *int_green_Z = XYZ.green_Z;
+      if (int_blue_X != NULL) *int_blue_X = XYZ.blue_X;
+      if (int_blue_Y != NULL) *int_blue_Y = XYZ.blue_Y;
+      if (int_blue_Z != NULL) *int_blue_Z = XYZ.blue_Z;
       return PNG_INFO_cHRM;
    }
 
@@ -647,31 +626,24 @@ png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
 
 png_uint_32 PNGAPI
 png_get_cHRM_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
-    png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x,
-    png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y,
-    png_fixed_point *blue_x, png_fixed_point *blue_y)
+    png_fixed_point *whitex, png_fixed_point *whitey, png_fixed_point *redx,
+    png_fixed_point *redy, png_fixed_point *greenx, png_fixed_point *greeny,
+    png_fixed_point *bluex, png_fixed_point *bluey)
 {
    png_debug1(1, "in %s retrieval function", "cHRM");
 
+   /* PNGv3: this just returns the values store from the cHRM, if any. */
    if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+       (info_ptr->valid & PNG_INFO_cHRM) != 0)
    {
-      if (white_x != NULL)
-         *white_x = info_ptr->colorspace.end_points_xy.whitex;
-      if (white_y != NULL)
-         *white_y = info_ptr->colorspace.end_points_xy.whitey;
-      if (red_x != NULL)
-         *red_x = info_ptr->colorspace.end_points_xy.redx;
-      if (red_y != NULL)
-         *red_y = info_ptr->colorspace.end_points_xy.redy;
-      if (green_x != NULL)
-         *green_x = info_ptr->colorspace.end_points_xy.greenx;
-      if (green_y != NULL)
-         *green_y = info_ptr->colorspace.end_points_xy.greeny;
-      if (blue_x != NULL)
-         *blue_x = info_ptr->colorspace.end_points_xy.bluex;
-      if (blue_y != NULL)
-         *blue_y = info_ptr->colorspace.end_points_xy.bluey;
+      if (whitex != NULL) *whitex = info_ptr->cHRM.whitex;
+      if (whitey != NULL) *whitey = info_ptr->cHRM.whitey;
+      if (redx   != NULL) *redx   = info_ptr->cHRM.redx;
+      if (redy   != NULL) *redy   = info_ptr->cHRM.redy;
+      if (greenx != NULL) *greenx = info_ptr->cHRM.greenx;
+      if (greeny != NULL) *greeny = info_ptr->cHRM.greeny;
+      if (bluex  != NULL) *bluex  = info_ptr->cHRM.bluex;
+      if (bluey  != NULL) *bluey  = info_ptr->cHRM.bluey;
       return PNG_INFO_cHRM;
    }
 
@@ -688,11 +660,11 @@ png_get_gAMA_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
    png_debug1(1, "in %s retrieval function", "gAMA");
 
+   /* PNGv3 compatibility: only report gAMA if it is really present. */
    if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
-       file_gamma != NULL)
+       (info_ptr->valid & PNG_INFO_gAMA) != 0)
    {
-      *file_gamma = info_ptr->colorspace.gamma;
+      if (file_gamma != NULL) *file_gamma = info_ptr->gamma;
       return PNG_INFO_gAMA;
    }
 
@@ -707,12 +679,13 @@ png_get_gAMA(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
    png_debug1(1, "in %s retrieval function", "gAMA(float)");
 
+   /* PNGv3 compatibility: only report gAMA if it is really present. */
    if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
-      file_gamma != NULL)
+       (info_ptr->valid & PNG_INFO_gAMA) != 0)
    {
-      *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma,
-          "png_get_gAMA");
+      if (file_gamma != NULL)
+         *file_gamma = png_float(png_ptr, info_ptr->gamma, "gAMA");
+
       return PNG_INFO_gAMA;
    }
 
@@ -729,9 +702,10 @@ png_get_sRGB(png_const_structrp png_ptr, png_const_inforp info_ptr,
    png_debug1(1, "in %s retrieval function", "sRGB");
 
    if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->valid & PNG_INFO_sRGB) != 0 && file_srgb_intent != NULL)
+      (info_ptr->valid & PNG_INFO_sRGB) != 0)
    {
-      *file_srgb_intent = info_ptr->colorspace.rendering_intent;
+      if (file_srgb_intent != NULL)
+         *file_srgb_intent = info_ptr->rendering_intent;
       return PNG_INFO_sRGB;
    }
 
@@ -787,7 +761,7 @@ png_get_sPLT(png_const_structrp png_ptr, png_inforp info_ptr,
 #ifdef PNG_cICP_SUPPORTED
 png_uint_32 PNGAPI
 png_get_cICP(png_const_structrp png_ptr,
-             png_inforp info_ptr, png_bytep colour_primaries,
+             png_const_inforp info_ptr, png_bytep colour_primaries,
              png_bytep transfer_function, png_bytep matrix_coefficients,
              png_bytep video_full_range_flag)
 {
@@ -805,10 +779,115 @@ png_get_cICP(png_const_structrp png_ptr,
         return (PNG_INFO_cICP);
     }
 
-    return (0);
+    return 0;
 }
 #endif
 
+#ifdef PNG_cLLI_SUPPORTED
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cLLI_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32p maxCLL,
+    png_uint_32p maxFALL)
+{
+   png_debug1(1, "in %s retrieval function", "cLLI");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_cLLI) != 0)
+   {
+      if (maxCLL != NULL) *maxCLL = info_ptr->maxCLL;
+      if (maxFALL != NULL) *maxFALL = info_ptr->maxFALL;
+      return PNG_INFO_cLLI;
+   }
+
+   return 0;
+}
+#  endif
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cLLI(png_const_structrp png_ptr, png_const_inforp info_ptr,
+      double *maxCLL, double *maxFALL)
+{
+   png_debug1(1, "in %s retrieval function", "cLLI(float)");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_cLLI) != 0)
+   {
+      if (maxCLL != NULL) *maxCLL = info_ptr->maxCLL * .0001;
+      if (maxFALL != NULL) *maxFALL = info_ptr->maxFALL * .0001;
+      return PNG_INFO_cLLI;
+   }
+
+   return 0;
+}
+#  endif
+#endif /* cLLI */
+
+#ifdef PNG_mDCV_SUPPORTED
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_mDCV_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *white_x, png_fixed_point *white_y,
+    png_fixed_point *red_x, png_fixed_point *red_y,
+    png_fixed_point *green_x, png_fixed_point *green_y,
+    png_fixed_point *blue_x, png_fixed_point *blue_y,
+    png_uint_32p mastering_maxDL, png_uint_32p mastering_minDL)
+{
+   png_debug1(1, "in %s retrieval function", "mDCV");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_mDCV) != 0)
+   {
+      if (white_x != NULL) *white_x = info_ptr->mastering_white_x * 2;
+      if (white_y != NULL) *white_y = info_ptr->mastering_white_y * 2;
+      if (red_x != NULL) *red_x = info_ptr->mastering_red_x * 2;
+      if (red_y != NULL) *red_y = info_ptr->mastering_red_y * 2;
+      if (green_x != NULL) *green_x = info_ptr->mastering_green_x * 2;
+      if (green_y != NULL) *green_y = info_ptr->mastering_green_y * 2;
+      if (blue_x != NULL) *blue_x = info_ptr->mastering_blue_x * 2;
+      if (blue_y != NULL) *blue_y = info_ptr->mastering_blue_y * 2;
+      if (mastering_maxDL != NULL) *mastering_maxDL = info_ptr->mastering_maxDL;
+      if (mastering_minDL != NULL) *mastering_minDL = info_ptr->mastering_minDL;
+      return PNG_INFO_mDCV;
+   }
+
+   return 0;
+}
+#  endif
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_mDCV(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    double *white_x, double *white_y, double *red_x, double *red_y,
+    double *green_x, double *green_y, double *blue_x, double *blue_y,
+    double *mastering_maxDL, double *mastering_minDL)
+{
+   png_debug1(1, "in %s retrieval function", "mDCV(float)");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_mDCV) != 0)
+   {
+      if (white_x != NULL) *white_x = info_ptr->mastering_white_x * .00002;
+      if (white_y != NULL) *white_y = info_ptr->mastering_white_y * .00002;
+      if (red_x != NULL) *red_x = info_ptr->mastering_red_x * .00002;
+      if (red_y != NULL) *red_y = info_ptr->mastering_red_y * .00002;
+      if (green_x != NULL) *green_x = info_ptr->mastering_green_x * .00002;
+      if (green_y != NULL) *green_y = info_ptr->mastering_green_y * .00002;
+      if (blue_x != NULL) *blue_x = info_ptr->mastering_blue_x * .00002;
+      if (blue_y != NULL) *blue_y = info_ptr->mastering_blue_y * .00002;
+      if (mastering_maxDL != NULL)
+         *mastering_maxDL = info_ptr->mastering_maxDL * .0001;
+      if (mastering_minDL != NULL)
+         *mastering_minDL = info_ptr->mastering_minDL * .0001;
+      return PNG_INFO_mDCV;
+   }
+
+   return 0;
+}
+#  endif /* FLOATING_POINT */
+#endif /* mDCV */
+
 #ifdef PNG_eXIf_SUPPORTED
 png_uint_32 PNGAPI
 png_get_eXIf(png_const_structrp png_ptr, png_inforp info_ptr,

thirdparty/libpng/pnginfo.h

@@ -86,20 +86,6 @@ struct png_info_def
     * and initialize the appropriate fields below.
     */
 
-#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
-   /* png_colorspace only contains 'flags' if neither GAMMA or COLORSPACE are
-    * defined.  When COLORSPACE is switched on all the colorspace-defining
-    * chunks should be enabled, when GAMMA is switched on all the gamma-defining
-    * chunks should be enabled.  If this is not done it becomes possible to read
-    * inconsistent PNG files and assign a probably incorrect interpretation to
-    * the information.  (In other words, by carefully choosing which chunks to
-    * recognize the system configuration can select an interpretation for PNG
-    * files containing ambiguous data and this will result in inconsistent
-    * behavior between different libpng builds!)
-    */
-   png_colorspace colorspace;
-#endif
-
 #ifdef PNG_cICP_SUPPORTED
    /* cICP chunk data */
    png_byte cicp_colour_primaries;
@@ -115,6 +101,24 @@ struct png_info_def
    png_uint_32 iccp_proflen;  /* ICC profile data length */
 #endif
 
+#ifdef PNG_cLLI_SUPPORTED
+   png_uint_32 maxCLL;  /* cd/m2 (nits) * 10,000 */
+   png_uint_32 maxFALL;
+#endif
+
+#ifdef PNG_mDCV_SUPPORTED
+   png_uint_16 mastering_red_x;  /* CIE (xy) x * 50,000 */
+   png_uint_16 mastering_red_y;
+   png_uint_16 mastering_green_x;
+   png_uint_16 mastering_green_y;
+   png_uint_16 mastering_blue_x;
+   png_uint_16 mastering_blue_y;
+   png_uint_16 mastering_white_x;
+   png_uint_16 mastering_white_y;
+   png_uint_32 mastering_maxDL; /* cd/m2 (nits) * 10,000 */
+   png_uint_32 mastering_minDL;
+#endif
+
 #ifdef PNG_TEXT_SUPPORTED
    /* The tEXt, and zTXt chunks contain human-readable textual data in
     * uncompressed, compressed, and optionally compressed forms, respectively.
@@ -193,11 +197,8 @@ defined(PNG_READ_BACKGROUND_SUPPORTED)
 #endif
 
 #ifdef PNG_eXIf_SUPPORTED
-   int num_exif;  /* Added at libpng-1.6.31 */
+   png_uint_32 num_exif;  /* Added at libpng-1.6.31 */
    png_bytep exif;
-# ifdef PNG_READ_eXIf_SUPPORTED
-   png_bytep eXIf_buf;  /* Added at libpng-1.6.32 */
-# endif
 #endif
 
 #ifdef PNG_hIST_SUPPORTED
@@ -270,5 +271,16 @@ defined(PNG_READ_BACKGROUND_SUPPORTED)
    png_bytepp row_pointers;        /* the image bits */
 #endif
 
+#ifdef PNG_cHRM_SUPPORTED
+   png_xy cHRM;
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+   png_fixed_point gamma;
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+   int rendering_intent;
+#endif
 };
 #endif /* PNGINFO_H */

thirdparty/libpng/pnglibconf.h

@@ -1,6 +1,6 @@
 /* pnglibconf.h - library build configuration */
 
-/* libpng version 1.6.45 */
+/* libpng version 1.6.47 */
 
 /* Copyright (c) 2018-2025 Cosmin Truta */
 /* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */
@@ -89,11 +89,13 @@
 #define PNG_READ_bKGD_SUPPORTED
 #define PNG_READ_cHRM_SUPPORTED
 #define PNG_READ_cICP_SUPPORTED
+#define PNG_READ_cLLI_SUPPORTED
 #define PNG_READ_eXIf_SUPPORTED
 #define PNG_READ_gAMA_SUPPORTED
 #define PNG_READ_hIST_SUPPORTED
 #define PNG_READ_iCCP_SUPPORTED
 #define PNG_READ_iTXt_SUPPORTED
+#define PNG_READ_mDCV_SUPPORTED
 #define PNG_READ_oFFs_SUPPORTED
 #define PNG_READ_pCAL_SUPPORTED
 #define PNG_READ_pHYs_SUPPORTED
@@ -160,11 +162,13 @@
 #define PNG_WRITE_bKGD_SUPPORTED
 #define PNG_WRITE_cHRM_SUPPORTED
 #define PNG_WRITE_cICP_SUPPORTED
+#define PNG_WRITE_cLLI_SUPPORTED
 #define PNG_WRITE_eXIf_SUPPORTED
 #define PNG_WRITE_gAMA_SUPPORTED
 #define PNG_WRITE_hIST_SUPPORTED
 #define PNG_WRITE_iCCP_SUPPORTED
 #define PNG_WRITE_iTXt_SUPPORTED
+#define PNG_WRITE_mDCV_SUPPORTED
 #define PNG_WRITE_oFFs_SUPPORTED
 #define PNG_WRITE_pCAL_SUPPORTED
 #define PNG_WRITE_pHYs_SUPPORTED
@@ -179,11 +183,13 @@
 #define PNG_bKGD_SUPPORTED
 #define PNG_cHRM_SUPPORTED
 #define PNG_cICP_SUPPORTED
+#define PNG_cLLI_SUPPORTED
 #define PNG_eXIf_SUPPORTED
 #define PNG_gAMA_SUPPORTED
 #define PNG_hIST_SUPPORTED
 #define PNG_iCCP_SUPPORTED
 #define PNG_iTXt_SUPPORTED
+#define PNG_mDCV_SUPPORTED
 #define PNG_oFFs_SUPPORTED
 #define PNG_pCAL_SUPPORTED
 #define PNG_pHYs_SUPPORTED

thirdparty/libpng/pngmem.c

@@ -72,30 +72,29 @@ png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size),
     * to implement a user memory handler.  This checks to be sure it isn't
     * called with big numbers.
     */
-#ifndef PNG_USER_MEM_SUPPORTED
-   PNG_UNUSED(png_ptr)
-#endif
+#  ifdef PNG_MAX_MALLOC_64K
+      /* This is support for legacy systems which had segmented addressing
+       * limiting the maximum allocation size to 65536.  It takes precedence
+       * over PNG_SIZE_MAX which is set to 65535 on true 16-bit systems.
+       *
+       * TODO: libpng-1.8: finally remove both cases.
+       */
+      if (size > 65536U) return NULL;
+#  endif
 
-   /* Some compilers complain that this is always true.  However, it
-    * can be false when integer overflow happens.
+   /* This is checked too because the system malloc call below takes a (size_t).
     */
-   if (size > 0 && size <= PNG_SIZE_MAX
-#     ifdef PNG_MAX_MALLOC_64K
-         && size <= 65536U
-#     endif
-      )
-   {
-#ifdef PNG_USER_MEM_SUPPORTED
+   if (size > PNG_SIZE_MAX) return NULL;
+
+#  ifdef PNG_USER_MEM_SUPPORTED
       if (png_ptr != NULL && png_ptr->malloc_fn != NULL)
          return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size);
+#  else
+      PNG_UNUSED(png_ptr)
+#  endif
 
-      else
-#endif
-         return malloc((size_t)size); /* checked for truncation above */
-   }
-
-   else
-      return NULL;
+   /* Use the system malloc */
+   return malloc((size_t)/*SAFE*/size); /* checked for truncation above */
 }
 
 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\

thirdparty/libpng/pngpread.c

@@ -193,17 +193,8 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
     */
    if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
    {
-      png_byte chunk_length[4];
-      png_byte chunk_tag[4];
-
       PNG_PUSH_SAVE_BUFFER_IF_LT(8)
-      png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
-      png_reset_crc(png_ptr);
-      png_crc_read(png_ptr, chunk_tag, 4);
-      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
-      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
-      png_check_chunk_length(png_ptr, png_ptr->push_length);
+      png_ptr->push_length = png_read_chunk_header(png_ptr);
       png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
    }
 
@@ -244,13 +235,13 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
          png_error(png_ptr, "Invalid IHDR length");
 
       PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
+      png_handle_chunk(png_ptr, info_ptr, png_ptr->push_length);
    }
 
    else if (chunk_name == png_IEND)
    {
       PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
+      png_handle_chunk(png_ptr, info_ptr, png_ptr->push_length);
 
       png_ptr->process_mode = PNG_READ_DONE_MODE;
       png_push_have_end(png_ptr, info_ptr);
@@ -267,12 +258,6 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
    }
 #endif
 
-   else if (chunk_name == png_PLTE)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
    else if (chunk_name == png_IDAT)
    {
       png_ptr->idat_size = png_ptr->push_length;
@@ -285,163 +270,10 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
       return;
    }
 
-#ifdef PNG_READ_gAMA_SUPPORTED
-   else if (png_ptr->chunk_name == png_gAMA)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sBIT_SUPPORTED
-   else if (png_ptr->chunk_name == png_sBIT)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_cHRM_SUPPORTED
-   else if (png_ptr->chunk_name == png_cHRM)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_cICP_SUPPORTED
-   else if (png_ptr->chunk_name == png_cICP)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_cICP(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_eXIf_SUPPORTED
-   else if (png_ptr->chunk_name == png_eXIf)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_eXIf(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sRGB_SUPPORTED
-   else if (chunk_name == png_sRGB)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_iCCP_SUPPORTED
-   else if (png_ptr->chunk_name == png_iCCP)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sPLT_SUPPORTED
-   else if (chunk_name == png_sPLT)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tRNS_SUPPORTED
-   else if (chunk_name == png_tRNS)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_bKGD_SUPPORTED
-   else if (chunk_name == png_bKGD)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_hIST_SUPPORTED
-   else if (chunk_name == png_hIST)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_pHYs_SUPPORTED
-   else if (chunk_name == png_pHYs)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_oFFs_SUPPORTED
-   else if (chunk_name == png_oFFs)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
-   }
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-   else if (chunk_name == png_pCAL)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_sCAL_SUPPORTED
-   else if (chunk_name == png_sCAL)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tIME_SUPPORTED
-   else if (chunk_name == png_tIME)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_tEXt_SUPPORTED
-   else if (chunk_name == png_tEXt)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_zTXt_SUPPORTED
-   else if (chunk_name == png_zTXt)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-
-#endif
-#ifdef PNG_READ_iTXt_SUPPORTED
-   else if (chunk_name == png_iTXt)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
-   }
-#endif
-
    else
    {
       PNG_PUSH_SAVE_BUFFER_IF_FULL
-      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
-          PNG_HANDLE_CHUNK_AS_DEFAULT);
+      png_handle_chunk(png_ptr, info_ptr, png_ptr->push_length);
    }
 
    png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;

thirdparty/libpng/pngpriv.h

@@ -671,7 +671,7 @@
 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200U
 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400U
 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800U
-#define PNG_FLAG_ASSUME_sRGB              0x1000U /* Added to libpng-1.5.4 */
+/*      PNG_FLAG_ASSUME_sRGB unused       0x1000U  * Added to libpng-1.5.4 */
 #define PNG_FLAG_OPTIMIZE_ALPHA           0x2000U /* Added to libpng-1.5.4 */
 #define PNG_FLAG_DETECT_UNINITIALIZED     0x4000U /* Added to libpng-1.5.4 */
 /* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000U */
@@ -782,6 +782,8 @@
 #ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
 #define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
     ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
+#define png_fixed_ITU(png_ptr, fp, s) ((fp) <= 214748 && (fp) >= 0 ?\
+    ((png_uint_32)(10000 * (fp))) : (png_fixed_error(png_ptr, s),0))
 #endif
 /* else the corresponding function is defined below, inside the scope of the
  * cplusplus test.
@@ -800,11 +802,31 @@
  *
  * PNG_32b correctly produces a value shifted by up to 24 bits, even on
  * architectures where (int) is only 16 bits.
+ *
+ * 1.6.47: PNG_32b was made into a preprocessor evaluable macro by replacing the
+ * static_cast with a promoting binary operation using a guaranteed 32-bit
+ * (minimum) unsigned value.
  */
-#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_32b(b,s) (((0xFFFFFFFFU)&(b)) << (s))
 #define PNG_U32(b1,b2,b3,b4) \
    (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
 
+/* Chunk name validation.  When using these macros all the arguments should be
+ * constants, otherwise code bloat may well occur.  The macros are provided
+ * primarily for use in #if checks.
+ *
+ * PNG_32to8 produces a byte value with the right shift; used to extract the
+ * byte value from a chunk name.
+ */
+#define PNG_32to8(cn,s) (((cn) >> (s)) & 0xffU)
+#define PNG_CN_VALID_UPPER(b) ((b) >= 65 && (b) <= 90) /* upper-case ASCII */
+#define PNG_CN_VALID_ASCII(b) PNG_CN_VALID_UPPER((b) & ~32U)
+#define PNG_CHUNK_NAME_VALID(cn) (\
+   PNG_CN_VALID_ASCII(PNG_32to8(cn,24)) && /* critical, !ancillary */\
+   PNG_CN_VALID_ASCII(PNG_32to8(cn,16)) && /* public, !privately defined */\
+   PNG_CN_VALID_UPPER(PNG_32to8(cn, 8)) && /* VALID, !reserved */\
+   PNG_CN_VALID_ASCII(PNG_32to8(cn, 0))   /* data-dependent, !copy ok */)
+
 /* Constants for known chunk types.
  *
  * MAINTAINERS: If you need to add a chunk, define the name here.
@@ -832,10 +854,14 @@
 #define png_IEND PNG_U32( 73,  69,  78,  68)
 #define png_IHDR PNG_U32( 73,  72,  68,  82)
 #define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_acTL PNG_U32( 97,  99,  84,  76) /* PNGv3: APNG */
 #define png_bKGD PNG_U32( 98,  75,  71,  68)
 #define png_cHRM PNG_U32( 99,  72,  82,  77)
-#define png_cICP PNG_U32( 99,  73,  67,  80)
+#define png_cICP PNG_U32( 99,  73,  67,  80) /* PNGv3 */
+#define png_cLLI PNG_U32( 99,  76,  76,  73) /* PNGv3 */
 #define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
+#define png_fcTL PNG_U32(102,  99,  84,  76) /* PNGv3: APNG */
+#define png_fdAT PNG_U32(102, 100,  65,  84) /* PNGv3: APNG */
 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
 #define png_gAMA PNG_U32(103,  65,  77,  65)
 #define png_gIFg PNG_U32(103,  73,  70, 103)
@@ -844,6 +870,7 @@
 #define png_hIST PNG_U32(104,  73,  83,  84)
 #define png_iCCP PNG_U32(105,  67,  67,  80)
 #define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_mDCV PNG_U32(109,  68,  67,  86) /* PNGv3 */
 #define png_oFFs PNG_U32(111,  70,  70, 115)
 #define png_pCAL PNG_U32(112,  67,  65,  76)
 #define png_pHYs PNG_U32(112,  72,  89, 115)
@@ -884,11 +911,74 @@
 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
 
+/* Known chunks.  All supported chunks must be listed here.  The macro PNG_CHUNK
+ * contains the four character ASCII name by which the chunk is identified.  The
+ * macro is implemented as required to build tables or switch statements which
+ * require entries for every known chunk.  The macro also contains an index
+ * value which should be in order (this is checked in png.c).
+ *
+ * Notice that "known" does not require "SUPPORTED"; tables should be built in
+ * such a way that chunks unsupported in a build require no more than the table
+ * entry (which should be small.)  In particular function pointers for
+ * unsupported chunks should be NULL.
+ *
+ * At present these index values are not exported (not part of the public API)
+ * so can be changed at will.  For convenience the names are in lexical sort
+ * order but with the critical chunks at the start in the order of occurence in
+ * a PNG.
+ *
+ * PNG_INFO_ values do not exist for every one of these chunk handles; for
+ * example PNG_INFO_{IDAT,IEND,tEXt,iTXt,zTXt} and possibly other chunks in the
+ * future.
+ */
+#define PNG_KNOWN_CHUNKS\
+   PNG_CHUNK(IHDR,  0)\
+   PNG_CHUNK(PLTE,  1)\
+   PNG_CHUNK(IDAT,  2)\
+   PNG_CHUNK(IEND,  3)\
+   PNG_CHUNK(acTL,  4)\
+   PNG_CHUNK(bKGD,  5)\
+   PNG_CHUNK(cHRM,  6)\
+   PNG_CHUNK(cICP,  7)\
+   PNG_CHUNK(cLLI,  8)\
+   PNG_CHUNK(eXIf,  9)\
+   PNG_CHUNK(fcTL, 10)\
+   PNG_CHUNK(fdAT, 11)\
+   PNG_CHUNK(gAMA, 12)\
+   PNG_CHUNK(hIST, 13)\
+   PNG_CHUNK(iCCP, 14)\
+   PNG_CHUNK(iTXt, 15)\
+   PNG_CHUNK(mDCV, 16)\
+   PNG_CHUNK(oFFs, 17)\
+   PNG_CHUNK(pCAL, 18)\
+   PNG_CHUNK(pHYs, 19)\
+   PNG_CHUNK(sBIT, 20)\
+   PNG_CHUNK(sCAL, 21)\
+   PNG_CHUNK(sPLT, 22)\
+   PNG_CHUNK(sRGB, 23)\
+   PNG_CHUNK(tEXt, 24)\
+   PNG_CHUNK(tIME, 25)\
+   PNG_CHUNK(tRNS, 26)\
+   PNG_CHUNK(zTXt, 27)
+
 /* Gamma values (new at libpng-1.5.4): */
 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
 #define PNG_GAMMA_MAC_INVERSE 65909
 #define PNG_GAMMA_sRGB_INVERSE 45455
 
+/* gamma sanity check.  libpng cannot implement gamma transforms outside a
+ * certain limit because of its use of 16-bit fixed point intermediate values.
+ * Gamma values that are too large or too small will zap the 16-bit values all
+ * to 0 or 65535 resulting in an obvious 'bad' image.
+ *
+ * In libpng 1.6.0 the limits were changed from 0.07..3 to 0.01..100 to
+ * accommodate the optimal 16-bit gamma of 36 and its reciprocal.
+ *
+ * These are png_fixed_point integral values:
+ */
+#define PNG_LIB_GAMMA_MIN 1000
+#define PNG_LIB_GAMMA_MAX 10000000
+
 /* Almost everything below is C specific; the #defines above can be used in
  * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
  */
@@ -952,7 +1042,6 @@ extern "C" {
  *
  * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
  */
-
 /* Zlib support */
 #define PNG_UNEXPECTED_ZLIB_RETURN (-7)
 PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
@@ -971,6 +1060,7 @@ PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
    !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
    (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
    defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_mDCV_SUPPORTED) || \
    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
    (defined(PNG_sCAL_SUPPORTED) && \
    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
@@ -978,12 +1068,38 @@ PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
    double fp, png_const_charp text),PNG_EMPTY);
 #endif
 
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+   !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
+   (defined(PNG_cLLI_SUPPORTED) || defined(PNG_mDCV_SUPPORTED))
+PNG_INTERNAL_FUNCTION(png_uint_32,png_fixed_ITU,(png_const_structrp png_ptr,
+   double fp, png_const_charp text),PNG_EMPTY);
+#endif
+
 /* Check the user version string for compatibility, returns false if the version
  * numbers aren't compatible.
  */
 PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
    png_const_charp user_png_ver),PNG_EMPTY);
 
+#ifdef PNG_READ_SUPPORTED /* should only be used on read */
+/* Security: read limits on the largest allocations while reading a PNG.  This
+ * avoids very large allocations caused by PNG files with damaged or altered
+ * chunk 'length' fields.
+ */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED /* run-time limit */
+#  define png_chunk_max(png_ptr) ((png_ptr)->user_chunk_malloc_max)
+
+#elif PNG_USER_CHUNK_MALLOC_MAX > 0 /* compile-time limit */
+#  define png_chunk_max(png_ptr) ((void)png_ptr, PNG_USER_CHUNK_MALLOC_MAX)
+
+#elif (defined PNG_MAX_MALLOC_64K)  /* legacy system limit */
+#  define png_chunk_max(png_ptr) ((void)png_ptr, 65536U)
+
+#else                               /* modern system limit SIZE_MAX (C99) */
+#  define png_chunk_max(png_ptr) ((void)png_ptr, PNG_SIZE_MAX)
+#endif
+#endif /* READ */
+
 /* Internal base allocator - no messages, NULL on failure to allocate.  This
  * does, however, call the application provided allocator and that could call
  * png_error (although that would be a bug in the application implementation.)
@@ -1083,9 +1199,6 @@ PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
 PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
    png_uint_32 skip),PNG_EMPTY);
 
-/* Read the CRC from the file and compare it to the libpng calculated CRC */
-PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
-
 /* Calculate the CRC over a section of data.  Note that we are only
  * passing a maximum of 64K on systems that have this as a memory limit,
  * since this is the maximum buffer size we can specify.
@@ -1137,6 +1250,20 @@ PNG_INTERNAL_FUNCTION(void,png_write_cICP,(png_structrp png_ptr,
     png_byte matrix_coefficients, png_byte video_full_range_flag), PNG_EMPTY);
 #endif
 
+#ifdef PNG_WRITE_cLLI_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_cLLI_fixed,(png_structrp png_ptr,
+   png_uint_32 maxCLL, png_uint_32 maxFALL), PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_mDCV_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_mDCV_fixed,(png_structrp png_ptr,
+   png_uint_16 red_x, png_uint_16 red_y,
+   png_uint_16 green_x, png_uint_16 green_y,
+   png_uint_16 blue_x, png_uint_16 blue_y,
+   png_uint_16 white_x, png_uint_16 white_y,
+   png_uint_32 maxDL, png_uint_32 minDL), PNG_EMPTY);
+#endif
+
 #ifdef PNG_WRITE_sRGB_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
     int intent),PNG_EMPTY);
@@ -1149,10 +1276,10 @@ PNG_INTERNAL_FUNCTION(void,png_write_eXIf,(png_structrp png_ptr,
 
 #ifdef PNG_WRITE_iCCP_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
-   png_const_charp name, png_const_bytep profile), PNG_EMPTY);
-   /* The profile must have been previously validated for correctness, the
-    * length comes from the first four bytes.  Only the base, deflate,
-    * compression is supported.
+   png_const_charp name, png_const_bytep profile, png_uint_32 proflen),
+   PNG_EMPTY);
+   /* Writes a previously 'set' profile.  The profile argument is **not**
+    * compressed.
     */
 #endif
 
@@ -1461,124 +1588,36 @@ PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
 /* The following decodes the appropriate chunks, and does error correction,
  * then calls the appropriate callback for the chunk if it is valid.
  */
-
-/* Decode the IHDR chunk */
-PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-
-#ifdef PNG_READ_bKGD_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_cHRM_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_cICP_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_cICP,(png_structrp png_ptr,
-        png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_eXIf_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_eXIf,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_hIST_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_iCCP_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif /* READ_iCCP */
-
-#ifdef PNG_READ_iTXt_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_oFFs_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_pHYs_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_sBIT_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_sCAL_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_sPLT_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif /* READ_sPLT */
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_tEXt_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_tIME_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_tRNS_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_zTXt_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif
-
-PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_const_structrp png_ptr,
-    png_uint_32 chunk_name),PNG_EMPTY);
-
-PNG_INTERNAL_FUNCTION(void,png_check_chunk_length,(png_const_structrp png_ptr,
-    png_uint_32 chunk_length),PNG_EMPTY);
-
-PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
+typedef enum
+{
+   /* Result of a call to png_handle_chunk made to handle the current chunk
+    * png_struct::chunk_name on read.  Always informational, either the stream
+    * is read for the next chunk or the routine will call png_error.
+    *
+    * NOTE: order is important internally.  handled_saved and above are regarded
+    * as handling the chunk.
+    */
+   handled_error = 0,  /* bad crc or known and bad format or too long */
+   handled_discarded,  /* not saved in the unknown chunk list */
+   handled_saved,      /* saved in the unknown chunk list */
+   handled_ok          /* known, supported and handled without error */
+} png_handle_result_code;
+
+PNG_INTERNAL_FUNCTION(png_handle_result_code,png_handle_unknown,
+    (png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length, int keep),
+    PNG_EMPTY);
    /* This is the function that gets called for unknown chunks.  The 'keep'
     * argument is either non-zero for a known chunk that has been set to be
     * handled as unknown or zero for an unknown chunk.  By default the function
     * just skips the chunk or errors out if it is critical.
     */
 
+PNG_INTERNAL_FUNCTION(png_handle_result_code,png_handle_chunk,
+    (png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+   /* This handles the current chunk png_ptr->chunk_name with unread
+    * data[length] and returns one of the above result codes.
+    */
+
 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
     defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
 PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
@@ -1618,8 +1657,6 @@ PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
     png_bytep buffer, size_t buffer_length),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
     PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
-   png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
    png_inforp info_ptr),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
@@ -1632,109 +1669,28 @@ PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
     png_inforp info_ptr),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
     PNG_EMPTY);
-#  ifdef PNG_READ_tEXt_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
-    png_inforp info_ptr),PNG_EMPTY);
-#  endif
-#  ifdef PNG_READ_zTXt_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
-    png_inforp info_ptr),PNG_EMPTY);
-#  endif
-#  ifdef PNG_READ_iTXt_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
-    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
-    png_inforp info_ptr),PNG_EMPTY);
-#  endif
-
 #endif /* PROGRESSIVE_READ */
 
-/* Added at libpng version 1.6.0 */
-#ifdef PNG_GAMMA_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
-    png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
-   /* Set the colorspace gamma with a value provided by the application or by
-    * the gAMA chunk on read.  The value will override anything set by an ICC
-    * profile.
-    */
-
-PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
-    png_inforp info_ptr), PNG_EMPTY);
-   /* Synchronize the info 'valid' flags with the colorspace */
-
-PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
-    png_inforp info_ptr), PNG_EMPTY);
-   /* Copy the png_struct colorspace to the info_struct and call the above to
-    * synchronize the flags.  Checks for NULL info_ptr and does nothing.
-    */
-#endif
-
-/* Added at libpng version 1.4.0 */
-#ifdef PNG_COLORSPACE_SUPPORTED
-/* These internal functions are for maintaining the colorspace structure within
- * a png_info or png_struct (or, indeed, both).
- */
-PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
-   (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
-    int preferred), PNG_EMPTY);
-
-PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
-   (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
-    int preferred), PNG_EMPTY);
-
-#ifdef PNG_sRGB_SUPPORTED
-PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
-   png_colorspacerp colorspace, int intent), PNG_EMPTY);
-   /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
-    * flags to write them, if it returns false there was a problem and an error
-    * message has already been output (but the colorspace may still need to be
-    * synced to record the invalid flag).
-    */
-#endif /* sRGB */
-
 #ifdef PNG_iCCP_SUPPORTED
-PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
-   png_colorspacerp colorspace, png_const_charp name,
-   png_uint_32 profile_length, png_const_bytep profile, int color_type),
-   PNG_EMPTY);
-   /* The 'name' is used for information only */
-
 /* Routines for checking parts of an ICC profile. */
 #ifdef PNG_READ_iCCP_SUPPORTED
 PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
-   png_colorspacerp colorspace, png_const_charp name,
-   png_uint_32 profile_length), PNG_EMPTY);
+   png_const_charp name, png_uint_32 profile_length), PNG_EMPTY);
 #endif /* READ_iCCP */
 PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
-   png_colorspacerp colorspace, png_const_charp name,
-   png_uint_32 profile_length,
+   png_const_charp name, png_uint_32 profile_length,
    png_const_bytep profile /* first 132 bytes only */, int color_type),
    PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
-   png_colorspacerp colorspace, png_const_charp name,
-   png_uint_32 profile_length,
+   png_const_charp name, png_uint_32 profile_length,
    png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
-#ifdef PNG_sRGB_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
-   png_const_structrp png_ptr, png_colorspacerp colorspace,
-   png_const_bytep profile, uLong adler), PNG_EMPTY);
-   /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
-    * be zero to indicate that it is not available.  It is used, if provided,
-    * as a fast check on the profile when checking to see if it is sRGB.
-    */
-#endif
 #endif /* iCCP */
 
 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
-   (png_structrp png_ptr), PNG_EMPTY);
-   /* Set the rgb_to_gray coefficients from the colorspace Y values */
+PNG_INTERNAL_FUNCTION(void,png_set_rgb_coefficients, (png_structrp png_ptr),
+   PNG_EMPTY);
+   /* Set the rgb_to_gray coefficients from the cHRM Y values (if unset) */
 #endif /* READ_RGB_TO_GRAY */
-#endif /* COLORSPACE */
 
 /* Added at libpng version 1.4.0 */
 PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
@@ -1996,8 +1952,10 @@ PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
    size_t size),PNG_EMPTY);
 #endif /* pCAL || sCAL */
 
-#if defined(PNG_GAMMA_SUPPORTED) ||\
-    defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
+#if defined(PNG_READ_GAMMA_SUPPORTED) ||\
+    defined(PNG_COLORSPACE_SUPPORTED) ||\
+    defined(PNG_INCH_CONVERSIONS_SUPPORTED) ||\
+    defined(PNG_READ_pHYs_SUPPORTED)
 /* Added at libpng version 1.5.0 */
 /* This is a utility to provide a*times/div (rounded) and indicate
  * if there is an overflow.  The result is a boolean - false (0)
@@ -2006,22 +1964,14 @@ PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
  */
 PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
    png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
-#endif
 
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
-/* Same deal, but issue a warning on overflow and return 0. */
-PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
-   (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
-   png_int_32 divided_by),PNG_EMPTY);
-#endif
-
-#ifdef PNG_GAMMA_SUPPORTED
 /* Calculate a reciprocal - used for gamma values.  This returns
  * 0 if the argument is 0 in order to maintain an undefined value;
  * there are no warnings.
  */
 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
    PNG_EMPTY);
+#endif
 
 #ifdef PNG_READ_GAMMA_SUPPORTED
 /* The same but gives a reciprocal of the product of two fixed point
@@ -2030,14 +1980,22 @@ PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
  */
 PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
    png_fixed_point b),PNG_EMPTY);
-#endif
 
 /* Return true if the gamma value is significantly different from 1.0 */
 PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
    PNG_EMPTY);
-#endif
 
-#ifdef PNG_READ_GAMMA_SUPPORTED
+/* PNGv3: 'resolve' the file gamma according to the new PNGv3 rules for colour
+ * space information.
+ *
+ * NOTE: this uses precisely those chunks that libpng supports.  For example it
+ * doesn't use iCCP and it can only use cICP for known and manageable
+ * transforms.  For this reason a gamma specified by png_set_gamma always takes
+ * precedence.
+ */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_resolve_file_gamma,
+   (png_const_structrp png_ptr),PNG_EMPTY);
+
 /* Internal fixed point gamma correction.  These APIs are called as
  * required to convert single values - they don't need to be fast,
  * they are not used when processing image pixel values.
@@ -2055,6 +2013,22 @@ PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
    PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
    int bit_depth),PNG_EMPTY);
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* Set the RGB coefficients if not already set by png_set_rgb_to_gray */
+PNG_INTERNAL_FUNCTION(void,png_set_rgb_coefficients,(png_structrp png_ptr),
+   PNG_EMPTY);
+#endif
+
+#if defined(PNG_cHRM_SUPPORTED) || defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+PNG_INTERNAL_FUNCTION(int,png_XYZ_from_xy,(png_XYZ *XYZ, const png_xy *xy),
+   PNG_EMPTY);
+#endif /* cHRM || READ_RGB_TO_GRAY */
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_xy_from_XYZ,(png_xy *xy, const png_XYZ *XYZ),
+   PNG_EMPTY);
 #endif
 
 /* SIMPLIFIED READ/WRITE SUPPORT */

thirdparty/libpng/pngread.c

@@ -131,14 +131,11 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
          png_ptr->mode |= PNG_AFTER_IDAT;
       }
 
-      /* This should be a binary subdivision search or a hash for
-       * matching the chunk name rather than a linear search.
-       */
       if (chunk_name == png_IHDR)
-         png_handle_IHDR(png_ptr, info_ptr, length);
+         png_handle_chunk(png_ptr, info_ptr, length);
 
       else if (chunk_name == png_IEND)
-         png_handle_IEND(png_ptr, info_ptr, length);
+         png_handle_chunk(png_ptr, info_ptr, length);
 
 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
       else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
@@ -155,8 +152,6 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
          }
       }
 #endif
-      else if (chunk_name == png_PLTE)
-         png_handle_PLTE(png_ptr, info_ptr, length);
 
       else if (chunk_name == png_IDAT)
       {
@@ -164,104 +159,8 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
          break;
       }
 
-#ifdef PNG_READ_bKGD_SUPPORTED
-      else if (chunk_name == png_bKGD)
-         png_handle_bKGD(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_cHRM_SUPPORTED
-      else if (chunk_name == png_cHRM)
-         png_handle_cHRM(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_cICP_SUPPORTED
-      else if (chunk_name == png_cICP)
-         png_handle_cICP(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_eXIf_SUPPORTED
-      else if (chunk_name == png_eXIf)
-         png_handle_eXIf(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-      else if (chunk_name == png_gAMA)
-         png_handle_gAMA(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_hIST_SUPPORTED
-      else if (chunk_name == png_hIST)
-         png_handle_hIST(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_oFFs_SUPPORTED
-      else if (chunk_name == png_oFFs)
-         png_handle_oFFs(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-      else if (chunk_name == png_pCAL)
-         png_handle_pCAL(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sCAL_SUPPORTED
-      else if (chunk_name == png_sCAL)
-         png_handle_sCAL(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_pHYs_SUPPORTED
-      else if (chunk_name == png_pHYs)
-         png_handle_pHYs(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sBIT_SUPPORTED
-      else if (chunk_name == png_sBIT)
-         png_handle_sBIT(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-      else if (chunk_name == png_sRGB)
-         png_handle_sRGB(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_iCCP_SUPPORTED
-      else if (chunk_name == png_iCCP)
-         png_handle_iCCP(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sPLT_SUPPORTED
-      else if (chunk_name == png_sPLT)
-         png_handle_sPLT(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tEXt_SUPPORTED
-      else if (chunk_name == png_tEXt)
-         png_handle_tEXt(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tIME_SUPPORTED
-      else if (chunk_name == png_tIME)
-         png_handle_tIME(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tRNS_SUPPORTED
-      else if (chunk_name == png_tRNS)
-         png_handle_tRNS(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_zTXt_SUPPORTED
-      else if (chunk_name == png_zTXt)
-         png_handle_zTXt(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_iTXt_SUPPORTED
-      else if (chunk_name == png_iTXt)
-         png_handle_iTXt(png_ptr, info_ptr, length);
-#endif
-
       else
-         png_handle_unknown(png_ptr, info_ptr, length,
-             PNG_HANDLE_CHUNK_AS_DEFAULT);
+         png_handle_chunk(png_ptr, info_ptr, length);
    }
 }
 #endif /* SEQUENTIAL_READ */
@@ -806,10 +705,10 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
          png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
 
       if (chunk_name == png_IEND)
-         png_handle_IEND(png_ptr, info_ptr, length);
+         png_handle_chunk(png_ptr, info_ptr, length);
 
       else if (chunk_name == png_IHDR)
-         png_handle_IHDR(png_ptr, info_ptr, length);
+         png_handle_chunk(png_ptr, info_ptr, length);
 
       else if (info_ptr == NULL)
          png_crc_finish(png_ptr, length);
@@ -843,107 +742,9 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
 
          png_crc_finish(png_ptr, length);
       }
-      else if (chunk_name == png_PLTE)
-         png_handle_PLTE(png_ptr, info_ptr, length);
-
-#ifdef PNG_READ_bKGD_SUPPORTED
-      else if (chunk_name == png_bKGD)
-         png_handle_bKGD(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_cHRM_SUPPORTED
-      else if (chunk_name == png_cHRM)
-         png_handle_cHRM(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_cICP_SUPPORTED
-      else if (chunk_name == png_cICP)
-         png_handle_cICP(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_eXIf_SUPPORTED
-      else if (chunk_name == png_eXIf)
-         png_handle_eXIf(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_gAMA_SUPPORTED
-      else if (chunk_name == png_gAMA)
-         png_handle_gAMA(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_hIST_SUPPORTED
-      else if (chunk_name == png_hIST)
-         png_handle_hIST(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_oFFs_SUPPORTED
-      else if (chunk_name == png_oFFs)
-         png_handle_oFFs(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
-      else if (chunk_name == png_pCAL)
-         png_handle_pCAL(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sCAL_SUPPORTED
-      else if (chunk_name == png_sCAL)
-         png_handle_sCAL(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_pHYs_SUPPORTED
-      else if (chunk_name == png_pHYs)
-         png_handle_pHYs(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sBIT_SUPPORTED
-      else if (chunk_name == png_sBIT)
-         png_handle_sBIT(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sRGB_SUPPORTED
-      else if (chunk_name == png_sRGB)
-         png_handle_sRGB(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_iCCP_SUPPORTED
-      else if (chunk_name == png_iCCP)
-         png_handle_iCCP(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_sPLT_SUPPORTED
-      else if (chunk_name == png_sPLT)
-         png_handle_sPLT(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tEXt_SUPPORTED
-      else if (chunk_name == png_tEXt)
-         png_handle_tEXt(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tIME_SUPPORTED
-      else if (chunk_name == png_tIME)
-         png_handle_tIME(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_tRNS_SUPPORTED
-      else if (chunk_name == png_tRNS)
-         png_handle_tRNS(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_zTXt_SUPPORTED
-      else if (chunk_name == png_zTXt)
-         png_handle_zTXt(png_ptr, info_ptr, length);
-#endif
-
-#ifdef PNG_READ_iTXt_SUPPORTED
-      else if (chunk_name == png_iTXt)
-         png_handle_iTXt(png_ptr, info_ptr, length);
-#endif
 
       else
-         png_handle_unknown(png_ptr, info_ptr, length,
-             PNG_HANDLE_CHUNK_AS_DEFAULT);
+         png_handle_chunk(png_ptr, info_ptr, length);
    } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
 }
 #endif /* SEQUENTIAL_READ */
@@ -1394,6 +1195,31 @@ png_image_format(png_structrp png_ptr)
    return format;
 }
 
+static int
+chromaticities_match_sRGB(const png_xy *xy)
+{
+#  define sRGB_TOLERANCE 1000
+   static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */
+   {
+      /* color      x       y */
+      /* red   */ 64000, 33000,
+      /* green */ 30000, 60000,
+      /* blue  */ 15000,  6000,
+      /* white */ 31270, 32900
+   };
+
+   if (PNG_OUT_OF_RANGE(xy->whitex, sRGB_xy.whitex,sRGB_TOLERANCE) ||
+       PNG_OUT_OF_RANGE(xy->whitey, sRGB_xy.whitey,sRGB_TOLERANCE) ||
+       PNG_OUT_OF_RANGE(xy->redx,   sRGB_xy.redx,  sRGB_TOLERANCE) ||
+       PNG_OUT_OF_RANGE(xy->redy,   sRGB_xy.redy,  sRGB_TOLERANCE) ||
+       PNG_OUT_OF_RANGE(xy->greenx, sRGB_xy.greenx,sRGB_TOLERANCE) ||
+       PNG_OUT_OF_RANGE(xy->greeny, sRGB_xy.greeny,sRGB_TOLERANCE) ||
+       PNG_OUT_OF_RANGE(xy->bluex,  sRGB_xy.bluex, sRGB_TOLERANCE) ||
+       PNG_OUT_OF_RANGE(xy->bluey,  sRGB_xy.bluey, sRGB_TOLERANCE))
+      return 0;
+   return 1;
+}
+
 /* Is the given gamma significantly different from sRGB?  The test is the same
  * one used in pngrtran.c when deciding whether to do gamma correction.  The
  * arithmetic optimizes the division by using the fact that the inverse of the
@@ -1402,22 +1228,44 @@ png_image_format(png_structrp png_ptr)
 static int
 png_gamma_not_sRGB(png_fixed_point g)
 {
-   if (g < PNG_FP_1)
-   {
-      /* An uninitialized gamma is assumed to be sRGB for the simplified API. */
-      if (g == 0)
-         return 0;
-
-      return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
-   }
+   /* 1.6.47: use the same sanity checks as used in pngrtran.c */
+   if (g < PNG_LIB_GAMMA_MIN || g > PNG_LIB_GAMMA_MAX)
+      return 0; /* Includes the uninitialized value 0 */
 
-   return 1;
+   return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
 }
 
 /* Do the main body of a 'png_image_begin_read' function; read the PNG file
  * header and fill in all the information.  This is executed in a safe context,
  * unlike the init routine above.
  */
+static int
+png_image_is_not_sRGB(png_const_structrp png_ptr)
+{
+   /* Does the colorspace **not** match sRGB?  The flag is only set if the
+    * answer can be determined reliably.
+    *
+    * png_struct::chromaticities always exists since the simplified API
+    * requires rgb-to-gray.  The mDCV, cICP and cHRM chunks may all set it to
+    * a non-sRGB value, so it needs to be checked but **only** if one of
+    * those chunks occured in the file.
+    */
+   /* Highest priority: check to be safe. */
+   if (png_has_chunk(png_ptr, cICP) || png_has_chunk(png_ptr, mDCV))
+      return !chromaticities_match_sRGB(&png_ptr->chromaticities);
+
+   /* If the image is marked as sRGB then it is... */
+   if (png_has_chunk(png_ptr, sRGB))
+      return 0;
+
+   /* Last stop: cHRM, must check: */
+   if (png_has_chunk(png_ptr, cHRM))
+      return !chromaticities_match_sRGB(&png_ptr->chromaticities);
+
+   /* Else default to sRGB */
+   return 0;
+}
+
 static int
 png_image_read_header(png_voidp argument)
 {
@@ -1439,17 +1287,13 @@ png_image_read_header(png_voidp argument)
 
       image->format = format;
 
-#ifdef PNG_COLORSPACE_SUPPORTED
-      /* Does the colorspace match sRGB?  If there is no color endpoint
-       * (colorant) information assume yes, otherwise require the
-       * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set.  If the
-       * colorspace has been determined to be invalid ignore it.
+      /* Greyscale images don't (typically) have colour space information and
+       * using it is pretty much impossible, so use sRGB for grayscale (it
+       * doesn't matter r==g==b so the transform is irrelevant.)
        */
-      if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags
-         & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB|
-            PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS))
+      if ((format & PNG_FORMAT_FLAG_COLOR) != 0 &&
+          png_image_is_not_sRGB(png_ptr))
          image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB;
-#endif
    }
 
    /* We need the maximum number of entries regardless of the format the
@@ -1637,21 +1481,18 @@ png_image_skip_unused_chunks(png_structrp png_ptr)
     * potential vulnerability to security problems in the unused chunks.
     *
     * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored
-    * too.  This allows the simplified API to be compiled without iCCP support,
-    * however if the support is there the chunk is still checked to detect
-    * errors (which are unfortunately quite common.)
+    * too.  This allows the simplified API to be compiled without iCCP support.
     */
    {
          static const png_byte chunks_to_process[] = {
             98,  75,  71,  68, '\0',  /* bKGD */
             99,  72,  82,  77, '\0',  /* cHRM */
+            99,  73,  67,  80, '\0',  /* cICP */
            103,  65,  77,  65, '\0',  /* gAMA */
-#        ifdef PNG_READ_iCCP_SUPPORTED
-           105,  67,  67,  80, '\0',  /* iCCP */
-#        endif
+           109,  68,  67,  86, '\0',  /* mDCV */
            115,  66,  73,  84, '\0',  /* sBIT */
            115,  82,  71,  66, '\0',  /* sRGB */
-           };
+         };
 
        /* Ignore unknown chunks and all other chunks except for the
         * IHDR, PLTE, tRNS, IDAT, and IEND chunks.
@@ -1680,7 +1521,15 @@ png_image_skip_unused_chunks(png_structrp png_ptr)
 static void
 set_file_encoding(png_image_read_control *display)
 {
-   png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
+   png_structrp png_ptr = display->image->opaque->png_ptr;
+   png_fixed_point g = png_resolve_file_gamma(png_ptr);
+
+   /* PNGv3: the result may be 0 however the 'default_gamma' should have been
+    * set before this is called so zero is an error:
+    */
+   if (g == 0)
+      png_error(png_ptr, "internal: default gamma not set");
+
    if (png_gamma_significant(g) != 0)
    {
       if (png_gamma_not_sRGB(g) != 0)
@@ -2168,24 +2017,18 @@ png_image_read_colormap(png_voidp argument)
    /* Default the input file gamma if required - this is necessary because
     * libpng assumes that if no gamma information is present the data is in the
     * output format, but the simplified API deduces the gamma from the input
-    * format.
+    * format.  The 'default' gamma value is also set by png_set_alpha_mode, but
+    * this is happening before any such call, so:
+    *
+    * TODO: should be an internal API and all this code should be copied into a
+    * single common gamma+colorspace file.
     */
-   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0)
-   {
-      /* Do this directly, not using the png_colorspace functions, to ensure
-       * that it happens even if the colorspace is invalid (though probably if
-       * it is the setting will be ignored)  Note that the same thing can be
-       * achieved at the application interface with png_set_gAMA.
-       */
-      if (png_ptr->bit_depth == 16 &&
-         (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
-         png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR;
-
-      else
-         png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE;
+   if (png_ptr->bit_depth == 16 &&
+      (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+      png_ptr->default_gamma = PNG_GAMMA_LINEAR;
 
-      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
-   }
+   else
+      png_ptr->default_gamma = PNG_GAMMA_sRGB_INVERSE;
 
    /* Decide what to do based on the PNG color type of the input data.  The
     * utility function png_create_colormap_entry deals with most aspects of the
@@ -2563,6 +2406,8 @@ png_image_read_colormap(png_voidp argument)
 
             else
             {
+               const png_fixed_point gamma = png_resolve_file_gamma(png_ptr);
+
                /* Either the input or the output has no alpha channel, so there
                 * will be no non-opaque pixels in the color-map; it will just be
                 * grayscale.
@@ -2577,10 +2422,13 @@ png_image_read_colormap(png_voidp argument)
                 * this case and doing it in the palette; this will result in
                 * duplicate palette entries, but that's better than the
                 * alternative of double gamma correction.
+                *
+                * NOTE: PNGv3: check the resolved result of all the potentially
+                * different colour space chunks.
                 */
                if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
                   png_ptr->num_trans > 0) &&
-                  png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
+                  png_gamma_not_sRGB(gamma) != 0)
                {
                   cmap_entries = (unsigned int)make_gray_file_colormap(display);
                   data_encoding = P_FILE;
@@ -2612,8 +2460,8 @@ png_image_read_colormap(png_voidp argument)
                      if (output_encoding == P_sRGB)
                         gray = png_sRGB_table[gray]; /* now P_LINEAR */
 
-                     gray = PNG_DIV257(png_gamma_16bit_correct(gray,
-                         png_ptr->colorspace.gamma)); /* now P_FILE */
+                     gray = PNG_DIV257(png_gamma_16bit_correct(gray, gamma));
+                        /* now P_FILE */
 
                      /* And make sure the corresponding palette entry contains
                       * exactly the required sRGB value.
@@ -3744,6 +3592,12 @@ png_image_read_direct(png_voidp argument)
       /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise.
        */
       {
+         /* This is safe but should no longer be necessary as
+          * png_ptr->default_gamma should have been set after the
+          * info-before-IDAT was read in png_image_read_header.
+          *
+          * TODO: 1.8: remove this and see what happens.
+          */
          png_fixed_point input_gamma_default;
 
          if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
@@ -3799,8 +3653,9 @@ png_image_read_direct(png_voidp argument)
           * yet; it's set below.  png_struct::gamma, however, is set to the
           * final value.
           */
-         if (png_muldiv(&gtest, output_gamma, png_ptr->colorspace.gamma,
-             PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
+         if (png_muldiv(&gtest, output_gamma,
+                  png_resolve_file_gamma(png_ptr), PNG_FP_1) != 0 &&
+             png_gamma_significant(gtest) == 0)
             do_local_background = 0;
 
          else if (mode == PNG_ALPHA_STANDARD)

thirdparty/libpng/pngrtran.c

@@ -218,9 +218,59 @@ png_set_strip_alpha(png_structrp png_ptr)
 #endif
 
 #if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
+/* PNGv3 conformance: this private API exists to resolve the now mandatory error
+ * resolution when multiple conflicting sources of gamma or colour space
+ * information are available.
+ *
+ * Terminology (assuming power law, "gamma", encodings):
+ *    "screen" gamma: a power law imposed by the output device when digital
+ *    samples are converted to visible light output.  The EOTF - volage to
+ *    luminance on output.
+ *
+ *    "file" gamma: a power law used to encode luminance levels from the input
+ *    data (the scene or the mastering display system) into digital voltages.
+ *    The OETF - luminance to voltage on input.
+ *
+ *    gamma "correction": a power law matching the **inverse** of the overall
+ *    transfer function from input luminance levels to output levels.  The
+ *    **inverse** of the OOTF; the correction "corrects" for the OOTF by aiming
+ *    to make the overall OOTF (including the correction) linear.
+ *
+ * It is important to understand this terminology because the defined terms are
+ * scattered throughout the libpng code and it is very easy to end up with the
+ * inverse of the power law required.
+ *
+ * Variable and struct::member names:
+ *    file_gamma        OETF  how the PNG data was encoded
+ *
+ *    screen_gamma      EOTF  how the screen will decode digital levels
+ *
+ *    -- not used --    OOTF  the net effect OETF x EOTF
+ *    gamma_correction        the inverse of OOTF to make the result linear
+ *
+ * All versions of libpng require a call to "png_set_gamma" to establish the
+ * "screen" gamma, the power law representing the EOTF.  png_set_gamma may also
+ * set or default the "file" gamma; the OETF.  gamma_correction is calculated
+ * internally.
+ *
+ * The earliest libpng versions required file_gamma to be supplied to set_gamma.
+ * Later versions started allowing png_set_gamma and, later, png_set_alpha_mode,
+ * to cause defaulting from the file data.
+ *
+ * PNGv3 mandated a particular form for this defaulting, one that is compatible
+ * with what libpng did except that if libpng detected inconsistencies it marked
+ * all the chunks as "invalid".  PNGv3 effectively invalidates this prior code.
+ *
+ * Behaviour implemented below:
+ *    translate_gamma_flags(gamma, is_screen)
+ *       The libpng-1.6 API for the gamma parameters to libpng APIs
+ *       (png_set_gamma and png_set_alpha_mode at present).  This allows the
+ *       'gamma' value to be passed as a png_fixed_point number or as one of a
+ *       set of integral values for specific "well known" examples of transfer
+ *       functions.  This is compatible with PNGv3.
+ */
 static png_fixed_point
-translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma,
-    int is_screen)
+translate_gamma_flags(png_fixed_point output_gamma, int is_screen)
 {
    /* Check for flag values.  The main reason for having the old Mac value as a
     * flag is that it is pretty near impossible to work out what the correct
@@ -230,14 +280,6 @@ translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma,
    if (output_gamma == PNG_DEFAULT_sRGB ||
       output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
    {
-      /* If there is no sRGB support this just sets the gamma to the standard
-       * sRGB value.  (This is a side effect of using this function!)
-       */
-#     ifdef PNG_READ_sRGB_SUPPORTED
-         png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
-#     else
-         PNG_UNUSED(png_ptr)
-#     endif
       if (is_screen != 0)
          output_gamma = PNG_GAMMA_sRGB;
       else
@@ -279,6 +321,33 @@ convert_gamma_value(png_structrp png_ptr, double output_gamma)
    return (png_fixed_point)output_gamma;
 }
 #  endif
+
+static int
+unsupported_gamma(png_structrp png_ptr, png_fixed_point gamma, int warn)
+{
+   /* Validate a gamma value to ensure it is in a reasonable range.  The value
+    * is expected to be 1 or greater, but this range test allows for some
+    * viewing correction values.  The intent is to weed out the API users
+    * who might use the inverse of the gamma value accidentally!
+    *
+    * 1.6.47: apply the test in png_set_gamma as well but only warn and return
+    * false if it fires.
+    *
+    * TODO: 1.8: make this an app_error in png_set_gamma as well.
+    */
+   if (gamma < PNG_LIB_GAMMA_MIN || gamma > PNG_LIB_GAMMA_MAX)
+   {
+#     define msg "gamma out of supported range"
+      if (warn)
+         png_app_warning(png_ptr, msg);
+      else
+         png_app_error(png_ptr, msg);
+      return 1;
+#     undef msg
+   }
+
+   return 0;
+}
 #endif /* READ_ALPHA_MODE || READ_GAMMA */
 
 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
@@ -286,31 +355,29 @@ void PNGFAPI
 png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
     png_fixed_point output_gamma)
 {
-   int compose = 0;
    png_fixed_point file_gamma;
+   int compose = 0;
 
    png_debug(1, "in png_set_alpha_mode_fixed");
 
    if (png_rtran_ok(png_ptr, 0) == 0)
       return;
 
-   output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
-
-   /* Validate the value to ensure it is in a reasonable range.  The value
-    * is expected to be 1 or greater, but this range test allows for some
-    * viewing correction values.  The intent is to weed out the API users
-    * who might use the inverse of the gamma value accidentally!
-    *
-    * In libpng 1.6.0, we changed from 0.07..3 to 0.01..100, to accommodate
-    * the optimal 16-bit gamma of 36 and its reciprocal.
-    */
-   if (output_gamma < 1000 || output_gamma > 10000000)
-      png_error(png_ptr, "output gamma out of expected range");
+   output_gamma = translate_gamma_flags(output_gamma, 1/*screen*/);
+   if (unsupported_gamma(png_ptr, output_gamma, 0/*error*/))
+      return;
 
    /* The default file gamma is the inverse of the output gamma; the output
-    * gamma may be changed below so get the file value first:
+    * gamma may be changed below so get the file value first.  The default_gamma
+    * is set here and from the simplified API (which uses a different algorithm)
+    * so don't overwrite a set value:
     */
-   file_gamma = png_reciprocal(output_gamma);
+   file_gamma = png_ptr->default_gamma;
+   if (file_gamma == 0)
+   {
+      file_gamma = png_reciprocal(output_gamma);
+      png_ptr->default_gamma = file_gamma;
+   }
 
    /* There are really 8 possibilities here, composed of any combination
     * of:
@@ -361,17 +428,7 @@ png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
          png_error(png_ptr, "invalid alpha mode");
    }
 
-   /* Only set the default gamma if the file gamma has not been set (this has
-    * the side effect that the gamma in a second call to png_set_alpha_mode will
-    * be ignored.)
-    */
-   if (png_ptr->colorspace.gamma == 0)
-   {
-      png_ptr->colorspace.gamma = file_gamma;
-      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
-   }
-
-   /* But always set the output gamma: */
+   /* Set the screen gamma values: */
    png_ptr->screen_gamma = output_gamma;
 
    /* Finally, if pre-multiplying, set the background fields to achieve the
@@ -381,7 +438,7 @@ png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
    {
       /* And obtain alpha pre-multiplication by composing on black: */
       memset(&png_ptr->background, 0, (sizeof png_ptr->background));
-      png_ptr->background_gamma = png_ptr->colorspace.gamma; /* just in case */
+      png_ptr->background_gamma = file_gamma; /* just in case */
       png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
       png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
 
@@ -819,8 +876,8 @@ png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
       return;
 
    /* New in libpng-1.5.4 - reserve particular negative values as flags. */
-   scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
-   file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
+   scrn_gamma = translate_gamma_flags(scrn_gamma, 1/*screen*/);
+   file_gamma = translate_gamma_flags(file_gamma, 0/*file*/);
 
    /* Checking the gamma values for being >0 was added in 1.5.4 along with the
     * premultiplied alpha support; this actually hides an undocumented feature
@@ -834,17 +891,19 @@ png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
     * libpng-1.6.0.
     */
    if (file_gamma <= 0)
-      png_error(png_ptr, "invalid file gamma in png_set_gamma");
-
+      png_app_error(png_ptr, "invalid file gamma in png_set_gamma");
    if (scrn_gamma <= 0)
-      png_error(png_ptr, "invalid screen gamma in png_set_gamma");
+      png_app_error(png_ptr, "invalid screen gamma in png_set_gamma");
 
-   /* Set the gamma values unconditionally - this overrides the value in the PNG
-    * file if a gAMA chunk was present.  png_set_alpha_mode provides a
-    * different, easier, way to default the file gamma.
+   if (unsupported_gamma(png_ptr, file_gamma, 1/*warn*/) ||
+       unsupported_gamma(png_ptr, scrn_gamma, 1/*warn*/))
+      return;
+
+   /* 1.6.47: png_struct::file_gamma and png_struct::screen_gamma are now only
+    * written by this API.  This removes dependencies on the order of API calls
+    * and allows the complex gamma checks to be delayed until needed.
     */
-   png_ptr->colorspace.gamma = file_gamma;
-   png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+   png_ptr->file_gamma = file_gamma;
    png_ptr->screen_gamma = scrn_gamma;
 }
 
@@ -1022,26 +1081,9 @@ png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
          png_ptr->rgb_to_gray_coefficients_set = 1;
       }
 
-      else
-      {
-         if (red >= 0 && green >= 0)
-            png_app_warning(png_ptr,
-                "ignoring out of range rgb_to_gray coefficients");
-
-         /* Use the defaults, from the cHRM chunk if set, else the historical
-          * values which are close to the sRGB/HDTV/ITU-Rec 709 values.  See
-          * png_do_rgb_to_gray for more discussion of the values.  In this case
-          * the coefficients are not marked as 'set' and are not overwritten if
-          * something has already provided a default.
-          */
-         if (png_ptr->rgb_to_gray_red_coeff == 0 &&
-             png_ptr->rgb_to_gray_green_coeff == 0)
-         {
-            png_ptr->rgb_to_gray_red_coeff   = 6968;
-            png_ptr->rgb_to_gray_green_coeff = 23434;
-            /* png_ptr->rgb_to_gray_blue_coeff  = 2366; */
-         }
-      }
+      else if (red >= 0 && green >= 0)
+         png_app_warning(png_ptr,
+               "ignoring out of range rgb_to_gray coefficients");
    }
 }
 
@@ -1282,6 +1324,80 @@ png_init_rgb_transformations(png_structrp png_ptr)
 #endif /* READ_EXPAND && READ_BACKGROUND */
 }
 
+#ifdef PNG_READ_GAMMA_SUPPORTED
+png_fixed_point /* PRIVATE */
+png_resolve_file_gamma(png_const_structrp png_ptr)
+{
+   png_fixed_point file_gamma;
+
+   /* The file gamma is determined by these precedence rules, in this order
+    * (i.e. use the first value found):
+    *
+    *    png_set_gamma; png_struct::file_gammma if not zero, then:
+    *    png_struct::chunk_gamma if not 0 (determined the PNGv3 rules), then:
+    *    png_set_gamma; 1/png_struct::screen_gamma if not zero
+    *
+    *    0 (i.e. do no gamma handling)
+    */
+   file_gamma = png_ptr->file_gamma;
+   if (file_gamma != 0)
+      return file_gamma;
+
+   file_gamma = png_ptr->chunk_gamma;
+   if (file_gamma != 0)
+      return file_gamma;
+
+   file_gamma = png_ptr->default_gamma;
+   if (file_gamma != 0)
+      return file_gamma;
+
+   /* If png_reciprocal oveflows it returns 0 which indicates to the caller that
+    * there is no usable file gamma.  (The checks added to png_set_gamma and
+    * png_set_alpha_mode should prevent a screen_gamma which would overflow.)
+    */
+   if (png_ptr->screen_gamma != 0)
+      file_gamma = png_reciprocal(png_ptr->screen_gamma);
+
+   return file_gamma;
+}
+
+static int
+png_init_gamma_values(png_structrp png_ptr)
+{
+   /* The following temporary indicates if overall gamma correction is
+    * required.
+    */
+   int gamma_correction = 0;
+   png_fixed_point file_gamma, screen_gamma;
+
+   /* Resolve the file_gamma.  See above: if png_ptr::screen_gamma is set
+    * file_gamma will always be set here:
+    */
+   file_gamma = png_resolve_file_gamma(png_ptr);
+   screen_gamma = png_ptr->screen_gamma;
+
+   if (file_gamma > 0) /* file has been set */
+   {
+      if (screen_gamma > 0) /* screen set too */
+         gamma_correction = png_gamma_threshold(file_gamma, screen_gamma);
+
+      else
+         /* Assume the output matches the input; a long time default behavior
+          * of libpng, although the standard has nothing to say about this.
+          */
+         screen_gamma = png_reciprocal(file_gamma);
+   }
+
+   else /* both unset, prevent corrections: */
+      file_gamma = screen_gamma = PNG_FP_1;
+
+   png_ptr->file_gamma = file_gamma;
+   png_ptr->screen_gamma = screen_gamma;
+   return gamma_correction;
+
+}
+#endif /* READ_GAMMA */
+
 void /* PRIVATE */
 png_init_read_transformations(png_structrp png_ptr)
 {
@@ -1301,59 +1417,22 @@ png_init_read_transformations(png_structrp png_ptr)
     * the test needs to be performed later - here.  In addition prior to 1.5.4
     * the tests were repeated for the PALETTE color type here - this is no
     * longer necessary (and doesn't seem to have been necessary before.)
+    *
+    * PNGv3: the new mandatory precedence/priority rules for colour space chunks
+    * are handled here (by calling the above function).
+    *
+    * Turn the gamma transformation on or off as appropriate.  Notice that
+    * PNG_GAMMA just refers to the file->screen correction.  Alpha composition
+    * may independently cause gamma correction because it needs linear data
+    * (e.g. if the file has a gAMA chunk but the screen gamma hasn't been
+    * specified.)  In any case this flag may get turned off in the code
+    * immediately below if the transform can be handled outside the row loop.
     */
-   {
-      /* The following temporary indicates if overall gamma correction is
-       * required.
-       */
-      int gamma_correction = 0;
+   if (png_init_gamma_values(png_ptr) != 0)
+      png_ptr->transformations |= PNG_GAMMA;
 
-      if (png_ptr->colorspace.gamma != 0) /* has been set */
-      {
-         if (png_ptr->screen_gamma != 0) /* screen set too */
-            gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma,
-                png_ptr->screen_gamma);
-
-         else
-            /* Assume the output matches the input; a long time default behavior
-             * of libpng, although the standard has nothing to say about this.
-             */
-            png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma);
-      }
-
-      else if (png_ptr->screen_gamma != 0)
-         /* The converse - assume the file matches the screen, note that this
-          * perhaps undesirable default can (from 1.5.4) be changed by calling
-          * png_set_alpha_mode (even if the alpha handling mode isn't required
-          * or isn't changed from the default.)
-          */
-         png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma);
-
-      else /* neither are set */
-         /* Just in case the following prevents any processing - file and screen
-          * are both assumed to be linear and there is no way to introduce a
-          * third gamma value other than png_set_background with 'UNIQUE', and,
-          * prior to 1.5.4
-          */
-         png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1;
-
-      /* We have a gamma value now. */
-      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
-
-      /* Now turn the gamma transformation on or off as appropriate.  Notice
-       * that PNG_GAMMA just refers to the file->screen correction.  Alpha
-       * composition may independently cause gamma correction because it needs
-       * linear data (e.g. if the file has a gAMA chunk but the screen gamma
-       * hasn't been specified.)  In any case this flag may get turned off in
-       * the code immediately below if the transform can be handled outside the
-       * row loop.
-       */
-      if (gamma_correction != 0)
-         png_ptr->transformations |= PNG_GAMMA;
-
-      else
-         png_ptr->transformations &= ~PNG_GAMMA;
-   }
+   else
+      png_ptr->transformations &= ~PNG_GAMMA;
 #endif
 
    /* Certain transformations have the effect of preventing other
@@ -1425,7 +1504,7 @@ png_init_read_transformations(png_structrp png_ptr)
     * appropriately.
     */
    if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
-      png_colorspace_set_rgb_coefficients(png_ptr);
+      png_set_rgb_coefficients(png_ptr);
 #endif
 
 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
@@ -1568,10 +1647,10 @@ png_init_read_transformations(png_structrp png_ptr)
     */
    if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
        ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
-        (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+        (png_gamma_significant(png_ptr->file_gamma) != 0 ||
          png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
         ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
-         (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+         (png_gamma_significant(png_ptr->file_gamma) != 0 ||
           png_gamma_significant(png_ptr->screen_gamma) != 0
 #  ifdef PNG_READ_BACKGROUND_SUPPORTED
          || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
@@ -1627,8 +1706,8 @@ png_init_read_transformations(png_structrp png_ptr)
                      break;
 
                   case PNG_BACKGROUND_GAMMA_FILE:
-                     g = png_reciprocal(png_ptr->colorspace.gamma);
-                     gs = png_reciprocal2(png_ptr->colorspace.gamma,
+                     g = png_reciprocal(png_ptr->file_gamma);
+                     gs = png_reciprocal2(png_ptr->file_gamma,
                          png_ptr->screen_gamma);
                      break;
 
@@ -1736,8 +1815,8 @@ png_init_read_transformations(png_structrp png_ptr)
                   break;
 
                case PNG_BACKGROUND_GAMMA_FILE:
-                  g = png_reciprocal(png_ptr->colorspace.gamma);
-                  gs = png_reciprocal2(png_ptr->colorspace.gamma,
+                  g = png_reciprocal(png_ptr->file_gamma);
+                  gs = png_reciprocal2(png_ptr->file_gamma,
                       png_ptr->screen_gamma);
                   break;
 
@@ -1987,11 +2066,11 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
     * been called before this from png_read_update_info->png_read_start_row
     * sometimes does the gamma transform and cancels the flag.
     *
-    * TODO: this looks wrong; the info_ptr should end up with a gamma equal to
-    * the screen_gamma value.  The following probably results in weirdness if
-    * the info_ptr is used by the app after the rows have been read.
+    * TODO: this is confusing.  It only changes the result of png_get_gAMA and,
+    * yes, it does return the value that the transformed data effectively has
+    * but does any app really understand this?
     */
-   info_ptr->colorspace.gamma = png_ptr->colorspace.gamma;
+   info_ptr->gamma = png_ptr->file_gamma;
 #endif
 
    if (info_ptr->bit_depth == 16)

thirdparty/libpng/pngset.c

@@ -41,27 +41,21 @@ png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
     png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
     png_fixed_point blue_x, png_fixed_point blue_y)
 {
-   png_xy xy;
-
    png_debug1(1, "in %s storage function", "cHRM fixed");
 
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   xy.redx = red_x;
-   xy.redy = red_y;
-   xy.greenx = green_x;
-   xy.greeny = green_y;
-   xy.bluex = blue_x;
-   xy.bluey = blue_y;
-   xy.whitex = white_x;
-   xy.whitey = white_y;
-
-   if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
-       2/* override with app values*/) != 0)
-      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+   info_ptr->cHRM.redx = red_x;
+   info_ptr->cHRM.redy = red_y;
+   info_ptr->cHRM.greenx = green_x;
+   info_ptr->cHRM.greeny = green_y;
+   info_ptr->cHRM.bluex = blue_x;
+   info_ptr->cHRM.bluey = blue_y;
+   info_ptr->cHRM.whitex = white_x;
+   info_ptr->cHRM.whitey = white_y;
 
-   png_colorspace_sync_info(png_ptr, info_ptr);
+   info_ptr->valid |= PNG_INFO_cHRM;
 }
 
 void PNGFAPI
@@ -73,6 +67,7 @@ png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
     png_fixed_point int_blue_Z)
 {
    png_XYZ XYZ;
+   png_xy xy;
 
    png_debug1(1, "in %s storage function", "cHRM XYZ fixed");
 
@@ -89,11 +84,14 @@ png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
    XYZ.blue_Y = int_blue_Y;
    XYZ.blue_Z = int_blue_Z;
 
-   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
-       &XYZ, 2) != 0)
-      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+   if (png_xy_from_XYZ(&xy, &XYZ) == 0)
+   {
+      info_ptr->cHRM = xy;
+      info_ptr->valid |= PNG_INFO_cHRM;
+   }
 
-   png_colorspace_sync_info(png_ptr, info_ptr);
+   else
+      png_app_error(png_ptr, "invalid cHRM XYZ");
 }
 
 #  ifdef PNG_FLOATING_POINT_SUPPORTED
@@ -159,6 +157,166 @@ png_set_cICP(png_const_structrp png_ptr, png_inforp info_ptr,
 }
 #endif /* cICP */
 
+#ifdef PNG_cLLI_SUPPORTED
+void PNGFAPI
+png_set_cLLI_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+    /* The values below are in cd/m2 (nits) and are scaled by 10,000; not
+     * 100,000 as in the case of png_fixed_point.
+     */
+    png_uint_32 maxCLL, png_uint_32 maxFALL)
+{
+   png_debug1(1, "in %s storage function", "cLLI");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* Check the light level range: */
+   if (maxCLL > 0x7FFFFFFFU || maxFALL > 0x7FFFFFFFU)
+   {
+      /* The limit is 200kcd/m2; somewhat bright but not inconceivable because
+       * human vision is said to run up to 100Mcd/m2.  The sun is about 2Gcd/m2.
+       *
+       * The reference sRGB monitor is 80cd/m2 and the limit of PQ encoding is
+       * 2kcd/m2.
+       */
+      png_chunk_report(png_ptr, "cLLI light level exceeds PNG limit",
+            PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   info_ptr->maxCLL = maxCLL;
+   info_ptr->maxFALL = maxFALL;
+   info_ptr->valid |= PNG_INFO_cLLI;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_cLLI(png_const_structrp png_ptr, png_inforp info_ptr,
+   double maxCLL, double maxFALL)
+{
+   png_set_cLLI_fixed(png_ptr, info_ptr,
+       png_fixed_ITU(png_ptr, maxCLL, "png_set_cLLI(maxCLL)"),
+       png_fixed_ITU(png_ptr, maxFALL, "png_set_cLLI(maxFALL)"));
+}
+#  endif /* FLOATING_POINT */
+#endif /* cLLI */
+
+#ifdef PNG_mDCV_SUPPORTED
+static png_uint_16
+png_ITU_fixed_16(int *error, png_fixed_point v)
+{
+   /* Return a safe uint16_t value scaled according to the ITU H273 rules for
+    * 16-bit display chromaticities.  Functions like the corresponding
+    * png_fixed() internal function with regard to errors: it's an error on
+    * write, a chunk_benign_error on read: See the definition of
+    * png_chunk_report in pngpriv.h.
+    */
+   v /= 2; /* rounds to 0 in C: avoids insignificant arithmetic errors */
+   if (v > 65535 || v < 0)
+   {
+      *error = 1;
+      return 0;
+   }
+
+   return (png_uint_16)/*SAFE*/v;
+}
+
+void PNGAPI
+png_set_mDCV_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_fixed_point white_x, png_fixed_point white_y,
+    png_fixed_point red_x, png_fixed_point red_y,
+    png_fixed_point green_x, png_fixed_point green_y,
+    png_fixed_point blue_x, png_fixed_point blue_y,
+    png_uint_32 maxDL,
+    png_uint_32 minDL)
+{
+   png_uint_16 rx, ry, gx, gy, bx, by, wx, wy;
+   int error;
+
+   png_debug1(1, "in %s storage function", "mDCV");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* Check the input values to ensure they are in the expected range: */
+   error = 0;
+   rx = png_ITU_fixed_16(&error, red_x);
+   ry = png_ITU_fixed_16(&error, red_y);
+   gx = png_ITU_fixed_16(&error, green_x);
+   gy = png_ITU_fixed_16(&error, green_y);
+   bx = png_ITU_fixed_16(&error, blue_x);
+   by = png_ITU_fixed_16(&error, blue_y);
+   wx = png_ITU_fixed_16(&error, white_x);
+   wy = png_ITU_fixed_16(&error, white_y);
+
+   if (error)
+   {
+      png_chunk_report(png_ptr,
+         "mDCV chromaticities outside representable range",
+         PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   /* Check the light level range: */
+   if (maxDL > 0x7FFFFFFFU || minDL > 0x7FFFFFFFU)
+   {
+      /* The limit is 200kcd/m2; somewhat bright but not inconceivable because
+       * human vision is said to run up to 100Mcd/m2.  The sun is about 2Gcd/m2.
+       *
+       * The reference sRGB monitor is 80cd/m2 and the limit of PQ encoding is
+       * 2kcd/m2.
+       */
+      png_chunk_report(png_ptr, "mDCV display light level exceeds PNG limit",
+            PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   /* All values are safe, the settings are accepted.
+    *
+    * IMPLEMENTATION NOTE: in practice the values can be checked and assigned
+    * but the result is confusing if a writing app calls png_set_mDCV more than
+    * once, the second time with an invalid value.  This approach is more
+    * obviously correct at the cost of typing and a very slight machine
+    * overhead.
+    */
+   info_ptr->mastering_red_x = rx;
+   info_ptr->mastering_red_y = ry;
+   info_ptr->mastering_green_x = gx;
+   info_ptr->mastering_green_y = gy;
+   info_ptr->mastering_blue_x = bx;
+   info_ptr->mastering_blue_y = by;
+   info_ptr->mastering_white_x = wx;
+   info_ptr->mastering_white_y = wy;
+   info_ptr->mastering_maxDL = maxDL;
+   info_ptr->mastering_minDL = minDL;
+   info_ptr->valid |= PNG_INFO_mDCV;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_mDCV(png_const_structrp png_ptr, png_inforp info_ptr,
+    double white_x, double white_y, double red_x, double red_y, double green_x,
+    double green_y, double blue_x, double blue_y,
+    double maxDL, double minDL)
+{
+   png_set_mDCV_fixed(png_ptr, info_ptr,
+      /* The ITU approach is to scale by 50,000, not 100,000 so just divide
+       * the input values by 2 and use png_fixed:
+       */
+      png_fixed(png_ptr, white_x / 2, "png_set_mDCV(white(x))"),
+      png_fixed(png_ptr, white_y / 2, "png_set_mDCV(white(y))"),
+      png_fixed(png_ptr, red_x / 2, "png_set_mDCV(red(x))"),
+      png_fixed(png_ptr, red_y / 2, "png_set_mDCV(red(y))"),
+      png_fixed(png_ptr, green_x / 2, "png_set_mDCV(green(x))"),
+      png_fixed(png_ptr, green_y / 2, "png_set_mDCV(green(y))"),
+      png_fixed(png_ptr, blue_x / 2, "png_set_mDCV(blue(x))"),
+      png_fixed(png_ptr, blue_y / 2, "png_set_mDCV(blue(y))"),
+      png_fixed_ITU(png_ptr, maxDL, "png_set_mDCV(maxDL)"),
+      png_fixed_ITU(png_ptr, minDL, "png_set_mDCV(minDL)"));
+}
+#  endif /* FLOATING_POINT */
+#endif /* mDCV */
+
 #ifdef PNG_eXIf_SUPPORTED
 void PNGAPI
 png_set_eXIf(png_const_structrp png_ptr, png_inforp info_ptr,
@@ -210,8 +368,8 @@ png_set_gAMA_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   png_colorspace_set_gamma(png_ptr, &info_ptr->colorspace, file_gamma);
-   png_colorspace_sync_info(png_ptr, info_ptr);
+   info_ptr->gamma = file_gamma;
+   info_ptr->valid |= PNG_INFO_gAMA;
 }
 
 #  ifdef PNG_FLOATING_POINT_SUPPORTED
@@ -670,8 +828,8 @@ png_set_sRGB(png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent)
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   (void)png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent);
-   png_colorspace_sync_info(png_ptr, info_ptr);
+   info_ptr->rendering_intent = srgb_intent;
+   info_ptr->valid |= PNG_INFO_sRGB;
 }
 
 void PNGAPI
@@ -683,15 +841,20 @@ png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
-       srgb_intent) != 0)
-   {
-      /* This causes the gAMA and cHRM to be written too */
-      info_ptr->colorspace.flags |=
-         PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
-   }
+   png_set_sRGB(png_ptr, info_ptr, srgb_intent);
+
+#  ifdef PNG_gAMA_SUPPORTED
+      png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
+#  endif /* gAMA */
 
-   png_colorspace_sync_info(png_ptr, info_ptr);
+#  ifdef PNG_cHRM_SUPPORTED
+      png_set_cHRM_fixed(png_ptr, info_ptr,
+         /* color      x       y */
+         /* white */ 31270, 32900,
+         /* red   */ 64000, 33000,
+         /* green */ 30000, 60000,
+         /* blue  */ 15000,  6000);
+#  endif /* cHRM */
 }
 #endif /* sRGB */
 
@@ -714,27 +877,6 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
    if (compression_type != PNG_COMPRESSION_TYPE_BASE)
       png_app_error(png_ptr, "Invalid iCCP compression method");
 
-   /* Set the colorspace first because this validates the profile; do not
-    * override previously set app cHRM or gAMA here (because likely as not the
-    * application knows better than libpng what the correct values are.)  Pass
-    * the info_ptr color_type field to png_colorspace_set_ICC because in the
-    * write case it has not yet been stored in png_ptr.
-    */
-   {
-      int result = png_colorspace_set_ICC(png_ptr, &info_ptr->colorspace, name,
-          proflen, profile, info_ptr->color_type);
-
-      png_colorspace_sync_info(png_ptr, info_ptr);
-
-      /* Don't do any of the copying if the profile was bad, or inconsistent. */
-      if (result == 0)
-         return;
-
-      /* But do write the gAMA and cHRM chunks from the profile. */
-      info_ptr->colorspace.flags |=
-         PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
-   }
-
    length = strlen(name)+1;
    new_iccp_name = png_voidcast(png_charp, png_malloc_warn(png_ptr, length));
 
@@ -1421,11 +1563,13 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
          98,  75,  71,  68, '\0',  /* bKGD */
          99,  72,  82,  77, '\0',  /* cHRM */
          99,  73,  67,  80, '\0',  /* cICP */
+         99,  76,  76,  73, '\0',  /* cLLI */
         101,  88,  73, 102, '\0',  /* eXIf */
         103,  65,  77,  65, '\0',  /* gAMA */
         104,  73,  83,  84, '\0',  /* hIST */
         105,  67,  67,  80, '\0',  /* iCCP */
         105,  84,  88, 116, '\0',  /* iTXt */
+        109,  68,  67,  86, '\0',  /* mDCV */
         111,  70,  70, 115, '\0',  /* oFFs */
         112,  67,  65,  76, '\0',  /* pCAL */
         112,  72,  89, 115, '\0',  /* pHYs */
@@ -1687,8 +1831,24 @@ png_set_chunk_malloc_max(png_structrp png_ptr,
 {
    png_debug(1, "in png_set_chunk_malloc_max");
 
+   /* pngstruct::user_chunk_malloc_max is initialized to a non-zero value in
+    * png.c.  This API supports '0' for unlimited, make sure the correct
+    * (unlimited) value is set here to avoid a need to check for 0 everywhere
+    * the parameter is used.
+    */
    if (png_ptr != NULL)
-      png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
+   {
+      if (user_chunk_malloc_max == 0U) /* unlimited */
+      {
+#        ifdef PNG_MAX_MALLOC_64K
+            png_ptr->user_chunk_malloc_max = 65536U;
+#        else
+            png_ptr->user_chunk_malloc_max = PNG_SIZE_MAX;
+#        endif
+      }
+      else
+         png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
+   }
 }
 #endif /* ?SET_USER_LIMITS */
 

thirdparty/libpng/pngstruct.h

@@ -69,13 +69,7 @@ typedef struct png_compression_buffer
 
 /* Colorspace support; structures used in png_struct, png_info and in internal
  * functions to hold and communicate information about the color space.
- *
- * PNG_COLORSPACE_SUPPORTED is only required if the application will perform
- * colorspace corrections, otherwise all the colorspace information can be
- * skipped and the size of libpng can be reduced (significantly) by compiling
- * out the colorspace support.
  */
-#ifdef PNG_COLORSPACE_SUPPORTED
 /* The chromaticities of the red, green and blue colorants and the chromaticity
  * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).
  */
@@ -96,48 +90,36 @@ typedef struct png_XYZ
    png_fixed_point green_X, green_Y, green_Z;
    png_fixed_point blue_X, blue_Y, blue_Z;
 } png_XYZ;
-#endif /* COLORSPACE */
 
-#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
-/* A colorspace is all the above plus, potentially, profile information;
- * however at present libpng does not use the profile internally so it is only
- * stored in the png_info struct (if iCCP is supported.)  The rendering intent
- * is retained here and is checked.
- *
- * The file gamma encoding information is also stored here and gamma correction
- * is done by libpng, whereas color correction must currently be done by the
- * application.
+/* Chunk index values as an enum, PNG_INDEX_unknown is also a count of the
+ * number of chunks.
  */
-typedef struct png_colorspace
+#define PNG_CHUNK(cHNK, i) PNG_INDEX_ ## cHNK = (i),
+typedef enum
 {
-#ifdef PNG_GAMMA_SUPPORTED
-   png_fixed_point gamma;        /* File gamma */
-#endif
+   PNG_KNOWN_CHUNKS
+   PNG_INDEX_unknown
+} png_index;
+#undef PNG_CHUNK
 
-#ifdef PNG_COLORSPACE_SUPPORTED
-   png_xy      end_points_xy;    /* End points as chromaticities */
-   png_XYZ     end_points_XYZ;   /* End points as CIE XYZ colorant values */
-   png_uint_16 rendering_intent; /* Rendering intent of a profile */
-#endif
-
-   /* Flags are always defined to simplify the code. */
-   png_uint_16 flags;            /* As defined below */
-} png_colorspace, * PNG_RESTRICT png_colorspacerp;
+/* Chunk flag values.  These are (png_uint_32 values) with exactly one bit set
+ * and can be combined into a flag set with bitwise 'or'.
+ *
+ * TODO: C23: convert these macros to C23 inlines (which are static).
+ */
+#define png_chunk_flag_from_index(i) (0x80000000U >> (31 - (i)))
+   /* The flag coresponding to the given png_index enum value.  This is defined
+    * for png_unknown as well (until it reaches the value 32) but this should
+    * not be relied on.
+    */
 
-typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
+#define png_file_has_chunk(png_ptr, i)\
+   (((png_ptr)->chunks & png_chunk_flag_from_index(i)) != 0)
+   /* The chunk has been recorded in png_struct */
 
-/* General flags for the 'flags' field */
-#define PNG_COLORSPACE_HAVE_GAMMA           0x0001
-#define PNG_COLORSPACE_HAVE_ENDPOINTS       0x0002
-#define PNG_COLORSPACE_HAVE_INTENT          0x0004
-#define PNG_COLORSPACE_FROM_gAMA            0x0008
-#define PNG_COLORSPACE_FROM_cHRM            0x0010
-#define PNG_COLORSPACE_FROM_sRGB            0x0020
-#define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
-#define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */
-#define PNG_COLORSPACE_INVALID              0x8000
-#define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))
-#endif /* COLORSPACE || GAMMA */
+#define png_file_add_chunk(pnt_ptr, i)\
+   ((void)((png_ptr)->chunks |= png_chunk_flag_from_index(i)))
+   /* Record the chunk in the png_struct */
 
 struct png_struct_def
 {
@@ -209,6 +191,11 @@ struct png_struct_def
    int zlib_set_strategy;
 #endif
 
+   png_uint_32 chunks; /* PNG_CF_ for every chunk read or (NYI) written */
+#  define png_has_chunk(png_ptr, cHNK)\
+      png_file_has_chunk(png_ptr, PNG_INDEX_ ## cHNK)
+      /* Convenience accessor - use this to check for a known chunk by name */
+
    png_uint_32 width;         /* width of image in pixels */
    png_uint_32 height;        /* height of image in pixels */
    png_uint_32 num_rows;      /* number of rows in current pass */
@@ -285,9 +272,16 @@ struct png_struct_def
    png_uint_32 flush_rows;    /* number of rows written since last flush */
 #endif
 
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   png_xy          chromaticities; /* From mDVC, cICP, [iCCP], sRGB or cHRM */
+#endif
+
 #ifdef PNG_READ_GAMMA_SUPPORTED
    int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
-   png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
+   png_fixed_point screen_gamma; /* screen gamma value (display exponent) */
+   png_fixed_point file_gamma;   /* file gamma value (encoding exponent) */
+   png_fixed_point chunk_gamma;  /* from cICP, iCCP, sRGB or gAMA */
+   png_fixed_point default_gamma;/* from png_set_alpha_mode */
 
    png_bytep gamma_table;     /* gamma table for 8-bit depth files */
    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
@@ -299,7 +293,7 @@ struct png_struct_def
    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
 #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
-#endif
+#endif /* READ_GAMMA */
 
 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
    png_color_8 sig_bit;       /* significant bits in each available channel */
@@ -349,8 +343,8 @@ struct png_struct_def
 /* To do: remove this from libpng-1.7 */
 #ifdef PNG_TIME_RFC1123_SUPPORTED
    char time_buffer[29]; /* String to hold RFC 1123 time text */
-#endif
-#endif
+#endif /* TIME_RFC1123 */
+#endif /* LIBPNG_VER < 10700 */
 
 /* New members added in libpng-1.0.6 */
 
@@ -360,8 +354,8 @@ struct png_struct_def
    png_voidp user_chunk_ptr;
 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
-#endif
-#endif
+#endif /* READ_USER_CHUNKS */
+#endif /* USER_CHUNKS */
 
 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
    int          unknown_default; /* As PNG_HANDLE_* */
@@ -468,11 +462,5 @@ struct png_struct_def
 /* New member added in libpng-1.5.7 */
    void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
       png_bytep row, png_const_bytep prev_row);
-
-#ifdef PNG_READ_SUPPORTED
-#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
-   png_colorspace   colorspace;
-#endif
-#endif
 };
 #endif /* PNGSTRUCT_H */

thirdparty/libpng/pngwrite.c

@@ -157,8 +157,30 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
     * space priority.  As above it therefore behooves libpng to write the colour
     * space chunks in the priority order so that a streaming app need not buffer
     * them.
+    *
+    * PNG v3: Chunks mDCV and cLLI provide ancillary information for the
+    * interpretation of the colourspace chunkgs but do not require support for
+    * those chunks so are outside the "COLORSPACE" check but before the write of
+    * the colourspace chunks themselves.
     */
-#ifdef PNG_COLORSPACE_SUPPORTED
+#ifdef PNG_WRITE_cLLI_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_cLLI) != 0)
+   {
+      png_write_cLLI_fixed(png_ptr, info_ptr->maxCLL, info_ptr->maxFALL);
+   }
+#endif
+#ifdef PNG_WRITE_mDCV_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_mDCV) != 0)
+   {
+      png_write_mDCV_fixed(png_ptr,
+         info_ptr->mastering_red_x, info_ptr->mastering_red_y,
+         info_ptr->mastering_green_x, info_ptr->mastering_green_y,
+         info_ptr->mastering_blue_x, info_ptr->mastering_blue_y,
+         info_ptr->mastering_white_x, info_ptr->mastering_white_y,
+         info_ptr->mastering_maxDL, info_ptr->mastering_minDL);
+   }
+#endif
+
 #  ifdef PNG_WRITE_cICP_SUPPORTED /* Priority 4 */
    if ((info_ptr->valid & PNG_INFO_cICP) != 0)
       {
@@ -170,50 +192,28 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
       }
 #  endif
 
-      /* PNG v3 change: it is now permitted to write both sRGB and ICC profiles,
-       * however because the libpng code auto-generates an sRGB for the
-       * corresponding ICC profiles and because PNG v2 disallowed this we need
-       * to only write one.
-       *
-       * Remove the PNG v2 warning about writing an sRGB ICC profile as well
-       * because it's invalid with PNG v3.
-       */
 #  ifdef PNG_WRITE_iCCP_SUPPORTED /* Priority 3 */
-         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-             (info_ptr->valid & PNG_INFO_iCCP) != 0)
+         if ((info_ptr->valid & PNG_INFO_iCCP) != 0)
          {
             png_write_iCCP(png_ptr, info_ptr->iccp_name,
-                info_ptr->iccp_profile);
+                info_ptr->iccp_profile, info_ptr->iccp_proflen);
          }
-#     ifdef PNG_WRITE_sRGB_SUPPORTED
-         else
-#     endif
 #  endif
 
 #  ifdef PNG_WRITE_sRGB_SUPPORTED /* Priority 2 */
-         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-             (info_ptr->valid & PNG_INFO_sRGB) != 0)
-            png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
+         if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
+            png_write_sRGB(png_ptr, info_ptr->rendering_intent);
 #  endif /* WRITE_sRGB */
-#endif /* COLORSPACE */
 
-#ifdef PNG_GAMMA_SUPPORTED
 #  ifdef PNG_WRITE_gAMA_SUPPORTED /* Priority 1 */
-      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-          (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
-          (info_ptr->valid & PNG_INFO_gAMA) != 0)
-         png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
+      if ((info_ptr->valid & PNG_INFO_gAMA) != 0)
+         png_write_gAMA_fixed(png_ptr, info_ptr->gamma);
 #  endif
-#endif
 
-#ifdef PNG_COLORSPACE_SUPPORTED
 #  ifdef PNG_WRITE_cHRM_SUPPORTED /* Also priority 1 */
-         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-             (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
-             (info_ptr->valid & PNG_INFO_cHRM) != 0)
-            png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
+         if ((info_ptr->valid & PNG_INFO_cHRM) != 0)
+            png_write_cHRM_fixed(png_ptr, &info_ptr->cHRM);
 #  endif
-#endif
 
       png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
    }

thirdparty/libpng/pngwutil.c

@@ -1132,10 +1132,9 @@ png_write_sRGB(png_structrp png_ptr, int srgb_intent)
 /* Write an iCCP chunk */
 void /* PRIVATE */
 png_write_iCCP(png_structrp png_ptr, png_const_charp name,
-    png_const_bytep profile)
+    png_const_bytep profile, png_uint_32 profile_len)
 {
    png_uint_32 name_len;
-   png_uint_32 profile_len;
    png_byte new_name[81]; /* 1 byte for the compression byte */
    compression_state comp;
    png_uint_32 temp;
@@ -1148,11 +1147,12 @@ png_write_iCCP(png_structrp png_ptr, png_const_charp name,
    if (profile == NULL)
       png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
 
-   profile_len = png_get_uint_32(profile);
-
    if (profile_len < 132)
       png_error(png_ptr, "ICC profile too short");
 
+   if (png_get_uint_32(profile) != profile_len)
+      png_error(png_ptr, "Incorrect data in iCCP");
+
    temp = (png_uint_32) (*(profile+8));
    if (temp > 3 && (profile_len & 0x03))
       png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
@@ -1511,6 +1511,50 @@ png_write_cICP(png_structrp png_ptr,
 }
 #endif
 
+#ifdef PNG_WRITE_cLLI_SUPPORTED
+void /* PRIVATE */
+png_write_cLLI_fixed(png_structrp png_ptr, png_uint_32 maxCLL,
+   png_uint_32 maxFALL)
+{
+   png_byte buf[8];
+
+   png_debug(1, "in png_write_cLLI_fixed");
+
+   png_save_uint_32(buf, maxCLL);
+   png_save_uint_32(buf + 4, maxFALL);
+
+   png_write_complete_chunk(png_ptr, png_cLLI, buf, 8);
+}
+#endif
+
+#ifdef PNG_WRITE_mDCV_SUPPORTED
+void /* PRIVATE */
+png_write_mDCV_fixed(png_structrp png_ptr,
+   png_uint_16 red_x, png_uint_16 red_y,
+   png_uint_16 green_x, png_uint_16 green_y,
+   png_uint_16 blue_x, png_uint_16 blue_y,
+   png_uint_16 white_x, png_uint_16 white_y,
+   png_uint_32 maxDL, png_uint_32 minDL)
+{
+   png_byte buf[24];
+
+   png_debug(1, "in png_write_mDCV_fixed");
+
+   png_save_uint_16(buf +  0, red_x);
+   png_save_uint_16(buf +  2, red_y);
+   png_save_uint_16(buf +  4, green_x);
+   png_save_uint_16(buf +  6, green_y);
+   png_save_uint_16(buf +  8, blue_x);
+   png_save_uint_16(buf + 10, blue_y);
+   png_save_uint_16(buf + 12, white_x);
+   png_save_uint_16(buf + 14, white_y);
+   png_save_uint_32(buf + 16, maxDL);
+   png_save_uint_32(buf + 20, minDL);
+
+   png_write_complete_chunk(png_ptr, png_mDCV, buf, 24);
+}
+#endif
+
 #ifdef PNG_WRITE_eXIf_SUPPORTED
 /* Write the Exif data */
 void /* PRIVATE */