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@@ -21,7 +21,7 @@
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avoid problematic images and only need the trivial interface
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JPEG baseline & progressive (12 bpc/arithmetic not supported, same as stock IJG lib)
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- PNG 1/2/4/8-bit-per-channel (16 bpc not supported)
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+ PNG 1/2/4/8/16-bit-per-channel
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TGA (not sure what subset, if a subset)
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BMP non-1bpp, non-RLE
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@@ -42,110 +42,13 @@
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Full documentation under "DOCUMENTATION" below.
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- Revision 2.00 release notes:
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-
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- - Progressive JPEG is now supported.
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-
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- - PPM and PGM binary formats are now supported, thanks to Ken Miller.
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-
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- - x86 platforms now make use of SSE2 SIMD instructions for
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- JPEG decoding, and ARM platforms can use NEON SIMD if requested.
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- This work was done by Fabian "ryg" Giesen. SSE2 is used by
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- default, but NEON must be enabled explicitly; see docs.
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-
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- With other JPEG optimizations included in this version, we see
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- 2x speedup on a JPEG on an x86 machine, and a 1.5x speedup
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- on a JPEG on an ARM machine, relative to previous versions of this
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- library. The same results will not obtain for all JPGs and for all
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- x86/ARM machines. (Note that progressive JPEGs are significantly
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- slower to decode than regular JPEGs.) This doesn't mean that this
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- is the fastest JPEG decoder in the land; rather, it brings it
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- closer to parity with standard libraries. If you want the fastest
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- decode, look elsewhere. (See "Philosophy" section of docs below.)
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-
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- See final bullet items below for more info on SIMD.
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-
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- - Added STBI_MALLOC, STBI_REALLOC, and STBI_FREE macros for replacing
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- the memory allocator. Unlike other STBI libraries, these macros don't
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- support a context parameter, so if you need to pass a context in to
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- the allocator, you'll have to store it in a global or a thread-local
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- variable.
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-
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- - Split existing STBI_NO_HDR flag into two flags, STBI_NO_HDR and
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- STBI_NO_LINEAR.
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- STBI_NO_HDR: suppress implementation of .hdr reader format
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- STBI_NO_LINEAR: suppress high-dynamic-range light-linear float API
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-
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- - You can suppress implementation of any of the decoders to reduce
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- your code footprint by #defining one or more of the following
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- symbols before creating the implementation.
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-
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- STBI_NO_JPEG
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- STBI_NO_PNG
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- STBI_NO_BMP
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- STBI_NO_PSD
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- STBI_NO_TGA
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- STBI_NO_GIF
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- STBI_NO_HDR
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- STBI_NO_PIC
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- STBI_NO_PNM (.ppm and .pgm)
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-
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- - You can request *only* certain decoders and suppress all other ones
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- (this will be more forward-compatible, as addition of new decoders
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- doesn't require you to disable them explicitly):
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-
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- STBI_ONLY_JPEG
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- STBI_ONLY_PNG
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- STBI_ONLY_BMP
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- STBI_ONLY_PSD
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- STBI_ONLY_TGA
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- STBI_ONLY_GIF
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- STBI_ONLY_HDR
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- STBI_ONLY_PIC
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- STBI_ONLY_PNM (.ppm and .pgm)
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-
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- Note that you can define multiples of these, and you will get all
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- of them ("only x" and "only y" is interpreted to mean "only x&y").
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-
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- - If you use STBI_NO_PNG (or _ONLY_ without PNG), and you still
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- want the zlib decoder to be available, #define STBI_SUPPORT_ZLIB
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-
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- - Compilation of all SIMD code can be suppressed with
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- #define STBI_NO_SIMD
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- It should not be necessary to disable SIMD unless you have issues
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- compiling (e.g. using an x86 compiler which doesn't support SSE
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- intrinsics or that doesn't support the method used to detect
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- SSE2 support at run-time), and even those can be reported as
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- bugs so I can refine the built-in compile-time checking to be
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- smarter.
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-
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- - The old STBI_SIMD system which allowed installing a user-defined
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- IDCT etc. has been removed. If you need this, don't upgrade. My
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- assumption is that almost nobody was doing this, and those who
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- were will find the built-in SIMD more satisfactory anyway.
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-
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- - RGB values computed for JPEG images are slightly different from
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- previous versions of stb_image. (This is due to using less
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- integer precision in SIMD.) The C code has been adjusted so
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- that the same RGB values will be computed regardless of whether
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- SIMD support is available, so your app should always produce
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- consistent results. But these results are slightly different from
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- previous versions. (Specifically, about 3% of available YCbCr values
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- will compute different RGB results from pre-1.49 versions by +-1;
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- most of the deviating values are one smaller in the G channel.)
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-
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- - If you must produce consistent results with previous versions of
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- stb_image, #define STBI_JPEG_OLD and you will get the same results
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- you used to; however, you will not get the SIMD speedups for
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- the YCbCr-to-RGB conversion step (although you should still see
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- significant JPEG speedup from the other changes).
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-
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- Please note that STBI_JPEG_OLD is a temporary feature; it will be
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- removed in future versions of the library. It is only intended for
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- near-term back-compatibility use.
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-
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-
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- Latest revision history:
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+LICENSE
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+
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+ See end of file for license information.
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+
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+RECENT REVISION HISTORY:
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+
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+ 2.14 (2017-03-03) remove deprecated STBI_JPEG_OLD
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2.13 (2016-12-04) experimental 16-bit API, only for PNG so far; fixes
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2.12 (2016-04-02) fix typo in 2.11 PSD fix that caused crashes
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2.11 (2016-04-02) 16-bit PNGS; enable SSE2 in non-gcc x64
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@@ -194,11 +97,6 @@
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Philipp Wiesemann Josh Tobin github:rlyeh github:grim210@github
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Blazej Dariusz Roszkowski github:sammyhw
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-
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-LICENSE
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-
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- See end of file for licensing information.
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-
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*/
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#ifndef STBI_INCLUDE_STB_IMAGE_H
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@@ -272,13 +170,13 @@ LICENSE
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// and for best performance I may provide less-easy-to-use APIs that give higher
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// performance, in addition to the easy to use ones. Nevertheless, it's important
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// to keep in mind that from the standpoint of you, a client of this library,
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-// all you care about is #1 and #3, and stb libraries do not emphasize #3 above all.
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+// all you care about is #1 and #3, and stb libraries DO NOT emphasize #3 above all.
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//
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// Some secondary priorities arise directly from the first two, some of which
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// make more explicit reasons why performance can't be emphasized.
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//
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// - Portable ("ease of use")
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-// - Small footprint ("easy to maintain")
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+// - Small source code footprint ("easy to maintain")
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// - No dependencies ("ease of use")
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//
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// ===========================================================================
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@@ -310,13 +208,6 @@ LICENSE
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// (at least this is true for iOS and Android). Therefore, the NEON support is
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// toggled by a build flag: define STBI_NEON to get NEON loops.
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//
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-// The output of the JPEG decoder is slightly different from versions where
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-// SIMD support was introduced (that is, for versions before 1.49). The
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-// difference is only +-1 in the 8-bit RGB channels, and only on a small
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-// fraction of pixels. You can force the pre-1.49 behavior by defining
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-// STBI_JPEG_OLD, but this will disable some of the SIMD decoding path
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-// and hence cost some performance.
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-//
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// If for some reason you do not want to use any of SIMD code, or if
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// you have issues compiling it, you can disable it entirely by
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// defining STBI_NO_SIMD.
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@@ -372,6 +263,41 @@ LICENSE
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// says there's premultiplied data (currently only happens in iPhone images,
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// and only if iPhone convert-to-rgb processing is on).
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//
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+// ===========================================================================
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+//
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+// ADDITIONAL CONFIGURATION
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+//
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+// - You can suppress implementation of any of the decoders to reduce
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+// your code footprint by #defining one or more of the following
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+// symbols before creating the implementation.
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+//
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+// STBI_NO_JPEG
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+// STBI_NO_PNG
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+// STBI_NO_BMP
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+// STBI_NO_PSD
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+// STBI_NO_TGA
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+// STBI_NO_GIF
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+// STBI_NO_HDR
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+// STBI_NO_PIC
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+// STBI_NO_PNM (.ppm and .pgm)
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+//
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+// - You can request *only* certain decoders and suppress all other ones
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+// (this will be more forward-compatible, as addition of new decoders
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+// doesn't require you to disable them explicitly):
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+//
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+// STBI_ONLY_JPEG
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+// STBI_ONLY_PNG
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+// STBI_ONLY_BMP
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+// STBI_ONLY_PSD
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+// STBI_ONLY_TGA
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+// STBI_ONLY_GIF
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+// STBI_ONLY_HDR
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+// STBI_ONLY_PIC
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+// STBI_ONLY_PNM (.ppm and .pgm)
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+//
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+// - If you use STBI_NO_PNG (or _ONLY_ without PNG), and you still
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+// want the zlib decoder to be available, #define STBI_SUPPORT_ZLIB
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+//
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#ifndef STBI_NO_STDIO
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@@ -3345,38 +3271,9 @@ static stbi_uc *stbi__resample_row_generic(stbi_uc *out, stbi_uc *in_near, stbi_
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return out;
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}
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-#ifdef STBI_JPEG_OLD
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-// this is the same YCbCr-to-RGB calculation that stb_image has used
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-// historically before the algorithm changes in 1.49
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-#define float2fixed(x) ((int) ((x) * 65536 + 0.5))
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-static void stbi__YCbCr_to_RGB_row(stbi_uc *out, const stbi_uc *y, const stbi_uc *pcb, const stbi_uc *pcr, int count, int step)
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-{
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- int i;
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- for (i=0; i < count; ++i) {
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- int y_fixed = (y[i] << 16) + 32768; // rounding
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- int r,g,b;
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- int cr = pcr[i] - 128;
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- int cb = pcb[i] - 128;
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- r = y_fixed + cr*float2fixed(1.40200f);
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- g = y_fixed - cr*float2fixed(0.71414f) - cb*float2fixed(0.34414f);
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- b = y_fixed + cb*float2fixed(1.77200f);
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- r >>= 16;
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- g >>= 16;
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- b >>= 16;
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- if ((unsigned) r > 255) { if (r < 0) r = 0; else r = 255; }
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- if ((unsigned) g > 255) { if (g < 0) g = 0; else g = 255; }
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- if ((unsigned) b > 255) { if (b < 0) b = 0; else b = 255; }
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- out[0] = (stbi_uc)r;
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- out[1] = (stbi_uc)g;
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- out[2] = (stbi_uc)b;
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- out[3] = 255;
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- out += step;
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- }
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-}
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-#else
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// this is a reduced-precision calculation of YCbCr-to-RGB introduced
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// to make sure the code produces the same results in both SIMD and scalar
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-#define float2fixed(x) (((int) ((x) * 4096.0f + 0.5f)) << 8)
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+#define stbi__float2fixed(x) (((int) ((x) * 4096.0f + 0.5f)) << 8)
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static void stbi__YCbCr_to_RGB_row(stbi_uc *out, const stbi_uc *y, const stbi_uc *pcb, const stbi_uc *pcr, int count, int step)
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{
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int i;
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@@ -3385,9 +3282,9 @@ static void stbi__YCbCr_to_RGB_row(stbi_uc *out, const stbi_uc *y, const stbi_uc
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int r,g,b;
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int cr = pcr[i] - 128;
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int cb = pcb[i] - 128;
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- r = y_fixed + cr* float2fixed(1.40200f);
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- g = y_fixed + (cr*-float2fixed(0.71414f)) + ((cb*-float2fixed(0.34414f)) & 0xffff0000);
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- b = y_fixed + cb* float2fixed(1.77200f);
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+ r = y_fixed + cr* stbi__float2fixed(1.40200f);
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+ g = y_fixed + (cr*-stbi__float2fixed(0.71414f)) + ((cb*-stbi__float2fixed(0.34414f)) & 0xffff0000);
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+ b = y_fixed + cb* stbi__float2fixed(1.77200f);
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r >>= 20;
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g >>= 20;
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b >>= 20;
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@@ -3401,7 +3298,6 @@ static void stbi__YCbCr_to_RGB_row(stbi_uc *out, const stbi_uc *y, const stbi_uc
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out += step;
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}
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}
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-#endif
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#if defined(STBI_SSE2) || defined(STBI_NEON)
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static void stbi__YCbCr_to_RGB_simd(stbi_uc *out, stbi_uc const *y, stbi_uc const *pcb, stbi_uc const *pcr, int count, int step)
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@@ -3520,9 +3416,9 @@ static void stbi__YCbCr_to_RGB_simd(stbi_uc *out, stbi_uc const *y, stbi_uc cons
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int r,g,b;
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int cr = pcr[i] - 128;
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int cb = pcb[i] - 128;
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- r = y_fixed + cr* float2fixed(1.40200f);
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- g = y_fixed + cr*-float2fixed(0.71414f) + ((cb*-float2fixed(0.34414f)) & 0xffff0000);
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- b = y_fixed + cb* float2fixed(1.77200f);
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+ r = y_fixed + cr* stbi__float2fixed(1.40200f);
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+ g = y_fixed + cr*-stbi__float2fixed(0.71414f) + ((cb*-stbi__float2fixed(0.34414f)) & 0xffff0000);
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+ b = y_fixed + cb* stbi__float2fixed(1.77200f);
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r >>= 20;
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g >>= 20;
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b >>= 20;
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@@ -3548,18 +3444,14 @@ static void stbi__setup_jpeg(stbi__jpeg *j)
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#ifdef STBI_SSE2
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if (stbi__sse2_available()) {
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j->idct_block_kernel = stbi__idct_simd;
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- #ifndef STBI_JPEG_OLD
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j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_simd;
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- #endif
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j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd;
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}
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#endif
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#ifdef STBI_NEON
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j->idct_block_kernel = stbi__idct_simd;
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- #ifndef STBI_JPEG_OLD
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j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_simd;
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- #endif
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j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd;
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#endif
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}
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Sean Barrett