|
|
@@ -0,0 +1,514 @@
|
|
|
+/* stbiw-0.92 - public domain - http://nothings.org/stb/stb_image_write.h
|
|
|
+ writes out PNG/BMP/TGA images to C stdio - Sean Barrett 2010
|
|
|
+ no warranty implied; use at your own risk
|
|
|
+
|
|
|
+
|
|
|
+Before #including,
|
|
|
+
|
|
|
+ #define STB_IMAGE_WRITE_IMPLEMENTATION
|
|
|
+
|
|
|
+in the file that you want to have the implementation.
|
|
|
+
|
|
|
+
|
|
|
+ABOUT:
|
|
|
+
|
|
|
+ This header file is a library for writing images to C stdio. It could be
|
|
|
+ adapted to write to memory or a general streaming interface; let me know.
|
|
|
+
|
|
|
+ The PNG output is not optimal; it is 20-50% larger than the file
|
|
|
+ written by a decent optimizing implementation. This library is designed
|
|
|
+ for source code compactness and simplicitly, not optimal image file size
|
|
|
+ or run-time performance.
|
|
|
+
|
|
|
+USAGE:
|
|
|
+
|
|
|
+ There are three functions, one for each image file format:
|
|
|
+
|
|
|
+ int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
|
|
|
+ int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
|
|
|
+ int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
|
|
|
+
|
|
|
+ Each function returns 0 on failure and non-0 on success.
|
|
|
+
|
|
|
+ The functions create an image file defined by the parameters. The image
|
|
|
+ is a rectangle of pixels stored from left-to-right, top-to-bottom.
|
|
|
+ Each pixel contains 'comp' channels of data stored interleaved with 8-bits
|
|
|
+ per channel, in the following order: 1=L, 2=LA, 3=RGB, 4=RGBA. (L is
|
|
|
+ luminance, i.e. monochrome "color", i.e. grey value.) The rectangle is
|
|
|
+ 'w' pixels wide and 'h' pixels tall. The *data pointer points to the
|
|
|
+ first byte of the top-left-most pixel. For PNG, "stride_in_bytes" is
|
|
|
+ the distance in bytes from the first byte of a row of pixels to the
|
|
|
+ first byte of the next row of pixels. Other file formats assume the
|
|
|
+ first byte of the each row of pixels begins immediately after the last
|
|
|
+ byte of the previous row.
|
|
|
+
|
|
|
+ PNG creates output files with the same number of components as the input.
|
|
|
+ The BMP and TGA formats expand Y to RGB in the file format. BMP does not
|
|
|
+ output alpha.
|
|
|
+
|
|
|
+ PNG supports writing rectangles of data even when the bytes storing rows of
|
|
|
+ data are not consecutive in memory (e.g. sub-rectangles of a larger image),
|
|
|
+ by supplying the stride between the beginning of adjacent rows. The other
|
|
|
+ formats do not. (Thus you cannot write an in-memory BMP through the BMP
|
|
|
+ writer, both because it is in BGR order and because it may have padding
|
|
|
+ at the end of the line.)
|
|
|
+*/
|
|
|
+
|
|
|
+#ifndef INCLUDE_STB_IMAGE_WRITE_H
|
|
|
+#define INCLUDE_STB_IMAGE_WRITE_H
|
|
|
+
|
|
|
+#ifdef __cplusplus
|
|
|
+extern "C" {
|
|
|
+#endif
|
|
|
+
|
|
|
+extern int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
|
|
|
+extern int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
|
|
|
+extern int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
|
|
|
+
|
|
|
+#ifdef __cplusplus
|
|
|
+}
|
|
|
+#endif
|
|
|
+
|
|
|
+#endif//INCLUDE_STB_IMAGE_WRITE_H
|
|
|
+
|
|
|
+#ifdef STB_IMAGE_WRITE_IMPLEMENTATION
|
|
|
+
|
|
|
+#include <stdarg.h>
|
|
|
+#include <stdlib.h>
|
|
|
+#include <stdio.h>
|
|
|
+#include <string.h>
|
|
|
+#include <assert.h>
|
|
|
+
|
|
|
+typedef unsigned int stbiw_uint32;
|
|
|
+typedef int stb_image_write_test[sizeof(stbiw_uint32)==4 ? 1 : -1];
|
|
|
+
|
|
|
+static void writefv(FILE *f, const char *fmt, va_list v)
|
|
|
+{
|
|
|
+ while (*fmt) {
|
|
|
+ switch (*fmt++) {
|
|
|
+ case ' ': break;
|
|
|
+ case '1': { unsigned char x = (unsigned char) va_arg(v, int); fputc(x,f); break; }
|
|
|
+ case '2': { int x = va_arg(v,int); unsigned char b[2];
|
|
|
+ b[0] = (unsigned char) x; b[1] = (unsigned char) (x>>8);
|
|
|
+ fwrite(b,2,1,f); break; }
|
|
|
+ case '4': { stbiw_uint32 x = va_arg(v,int); unsigned char b[4];
|
|
|
+ b[0]=(unsigned char)x; b[1]=(unsigned char)(x>>8);
|
|
|
+ b[2]=(unsigned char)(x>>16); b[3]=(unsigned char)(x>>24);
|
|
|
+ fwrite(b,4,1,f); break; }
|
|
|
+ default:
|
|
|
+ assert(0);
|
|
|
+ return;
|
|
|
+ }
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+static void write3(FILE *f, unsigned char a, unsigned char b, unsigned char c)
|
|
|
+{
|
|
|
+ unsigned char arr[3];
|
|
|
+ arr[0] = a, arr[1] = b, arr[2] = c;
|
|
|
+ fwrite(arr, 3, 1, f);
|
|
|
+}
|
|
|
+
|
|
|
+static void write_pixels(FILE *f, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad)
|
|
|
+{
|
|
|
+ unsigned char bg[3] = { 255, 0, 255}, px[3];
|
|
|
+ stbiw_uint32 zero = 0;
|
|
|
+ int i,j,k, j_end;
|
|
|
+
|
|
|
+ if (y <= 0)
|
|
|
+ return;
|
|
|
+
|
|
|
+ if (vdir < 0)
|
|
|
+ j_end = -1, j = y-1;
|
|
|
+ else
|
|
|
+ j_end = y, j = 0;
|
|
|
+
|
|
|
+ for (; j != j_end; j += vdir) {
|
|
|
+ for (i=0; i < x; ++i) {
|
|
|
+ unsigned char *d = (unsigned char *) data + (j*x+i)*comp;
|
|
|
+ if (write_alpha < 0)
|
|
|
+ fwrite(&d[comp-1], 1, 1, f);
|
|
|
+ switch (comp) {
|
|
|
+ case 1:
|
|
|
+ case 2: write3(f, d[0],d[0],d[0]);
|
|
|
+ break;
|
|
|
+ case 4:
|
|
|
+ if (!write_alpha) {
|
|
|
+ // composite against pink background
|
|
|
+ for (k=0; k < 3; ++k)
|
|
|
+ px[k] = bg[k] + ((d[k] - bg[k]) * d[3])/255;
|
|
|
+ write3(f, px[1-rgb_dir],px[1],px[1+rgb_dir]);
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ /* FALLTHROUGH */
|
|
|
+ case 3:
|
|
|
+ write3(f, d[1-rgb_dir],d[1],d[1+rgb_dir]);
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ if (write_alpha > 0)
|
|
|
+ fwrite(&d[comp-1], 1, 1, f);
|
|
|
+ }
|
|
|
+ fwrite(&zero,scanline_pad,1,f);
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+static int outfile(char const *filename, int rgb_dir, int vdir, int x, int y, int comp, void *data, int alpha, int pad, const char *fmt, ...)
|
|
|
+{
|
|
|
+ FILE *f;
|
|
|
+ if (y < 0 || x < 0) return 0;
|
|
|
+ f = fopen(filename, "wb");
|
|
|
+ if (f) {
|
|
|
+ va_list v;
|
|
|
+ va_start(v, fmt);
|
|
|
+ writefv(f, fmt, v);
|
|
|
+ va_end(v);
|
|
|
+ write_pixels(f,rgb_dir,vdir,x,y,comp,data,alpha,pad);
|
|
|
+ fclose(f);
|
|
|
+ }
|
|
|
+ return f != NULL;
|
|
|
+}
|
|
|
+
|
|
|
+int stbi_write_bmp(char const *filename, int x, int y, int comp, const void *data)
|
|
|
+{
|
|
|
+ int pad = (-x*3) & 3;
|
|
|
+ return outfile(filename,-1,-1,x,y,comp,(void *) data,0,pad,
|
|
|
+ "11 4 22 4" "4 44 22 444444",
|
|
|
+ 'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40, // file header
|
|
|
+ 40, x,y, 1,24, 0,0,0,0,0,0); // bitmap header
|
|
|
+}
|
|
|
+
|
|
|
+int stbi_write_tga(char const *filename, int x, int y, int comp, const void *data)
|
|
|
+{
|
|
|
+ int has_alpha = !(comp & 1);
|
|
|
+ return outfile(filename, -1,-1, x, y, comp, (void *) data, has_alpha, 0,
|
|
|
+ "111 221 2222 11", 0,0,2, 0,0,0, 0,0,x,y, 24+8*has_alpha, 8*has_alpha);
|
|
|
+}
|
|
|
+
|
|
|
+// stretchy buffer; stbi__sbpush() == vector<>::push_back() -- stbi__sbcount() == vector<>::size()
|
|
|
+#define stbi__sbraw(a) ((int *) (a) - 2)
|
|
|
+#define stbi__sbm(a) stbi__sbraw(a)[0]
|
|
|
+#define stbi__sbn(a) stbi__sbraw(a)[1]
|
|
|
+
|
|
|
+#define stbi__sbneedgrow(a,n) ((a)==0 || stbi__sbn(a)+n >= stbi__sbm(a))
|
|
|
+#define stbi__sbmaybegrow(a,n) (stbi__sbneedgrow(a,(n)) ? stbi__sbgrow(a,n) : 0)
|
|
|
+#define stbi__sbgrow(a,n) stbi__sbgrowf((void **) &(a), (n), sizeof(*(a)))
|
|
|
+
|
|
|
+#define stbi__sbpush(a, v) (stbi__sbmaybegrow(a,1), (a)[stbi__sbn(a)++] = (v))
|
|
|
+#define stbi__sbcount(a) ((a) ? stbi__sbn(a) : 0)
|
|
|
+#define stbi__sbfree(a) ((a) ? free(stbi__sbraw(a)),0 : 0)
|
|
|
+
|
|
|
+static void *stbi__sbgrowf(void **arr, int increment, int itemsize)
|
|
|
+{
|
|
|
+ int m = *arr ? 2*stbi__sbm(*arr)+increment : increment+1;
|
|
|
+ void *p = realloc(*arr ? stbi__sbraw(*arr) : 0, itemsize * m + sizeof(int)*2);
|
|
|
+ assert(p);
|
|
|
+ if (p) {
|
|
|
+ if (!*arr) ((int *) p)[1] = 0;
|
|
|
+ *arr = (void *) ((int *) p + 2);
|
|
|
+ stbi__sbm(*arr) = m;
|
|
|
+ }
|
|
|
+ return *arr;
|
|
|
+}
|
|
|
+
|
|
|
+static unsigned char *stbi__zlib_flushf(unsigned char *data, unsigned int *bitbuffer, int *bitcount)
|
|
|
+{
|
|
|
+ while (*bitcount >= 8) {
|
|
|
+ stbi__sbpush(data, (unsigned char) *bitbuffer);
|
|
|
+ *bitbuffer >>= 8;
|
|
|
+ *bitcount -= 8;
|
|
|
+ }
|
|
|
+ return data;
|
|
|
+}
|
|
|
+
|
|
|
+static int stbi__zlib_bitrev(int code, int codebits)
|
|
|
+{
|
|
|
+ int res=0;
|
|
|
+ while (codebits--) {
|
|
|
+ res = (res << 1) | (code & 1);
|
|
|
+ code >>= 1;
|
|
|
+ }
|
|
|
+ return res;
|
|
|
+}
|
|
|
+
|
|
|
+static unsigned int stbi__zlib_countm(unsigned char *a, unsigned char *b, int limit)
|
|
|
+{
|
|
|
+ int i;
|
|
|
+ for (i=0; i < limit && i < 258; ++i)
|
|
|
+ if (a[i] != b[i]) break;
|
|
|
+ return i;
|
|
|
+}
|
|
|
+
|
|
|
+static unsigned int stbi__zhash(unsigned char *data)
|
|
|
+{
|
|
|
+ stbiw_uint32 hash = data[0] + (data[1] << 8) + (data[2] << 16);
|
|
|
+ hash ^= hash << 3;
|
|
|
+ hash += hash >> 5;
|
|
|
+ hash ^= hash << 4;
|
|
|
+ hash += hash >> 17;
|
|
|
+ hash ^= hash << 25;
|
|
|
+ hash += hash >> 6;
|
|
|
+ return hash;
|
|
|
+}
|
|
|
+
|
|
|
+#define stbi__zlib_flush() (out = stbi__zlib_flushf(out, &bitbuf, &bitcount))
|
|
|
+#define stbi__zlib_add(code,codebits) \
|
|
|
+ (bitbuf |= (code) << bitcount, bitcount += (codebits), stbi__zlib_flush())
|
|
|
+#define stbi__zlib_huffa(b,c) stbi__zlib_add(stbi__zlib_bitrev(b,c),c)
|
|
|
+// default huffman tables
|
|
|
+#define stbi__zlib_huff1(n) stbi__zlib_huffa(0x30 + (n), 8)
|
|
|
+#define stbi__zlib_huff2(n) stbi__zlib_huffa(0x190 + (n)-144, 9)
|
|
|
+#define stbi__zlib_huff3(n) stbi__zlib_huffa(0 + (n)-256,7)
|
|
|
+#define stbi__zlib_huff4(n) stbi__zlib_huffa(0xc0 + (n)-280,8)
|
|
|
+#define stbi__zlib_huff(n) ((n) <= 143 ? stbi__zlib_huff1(n) : (n) <= 255 ? stbi__zlib_huff2(n) : (n) <= 279 ? stbi__zlib_huff3(n) : stbi__zlib_huff4(n))
|
|
|
+#define stbi__zlib_huffb(n) ((n) <= 143 ? stbi__zlib_huff1(n) : stbi__zlib_huff2(n))
|
|
|
+
|
|
|
+#define stbi__ZHASH 16384
|
|
|
+
|
|
|
+unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, int *out_len, int quality)
|
|
|
+{
|
|
|
+ static unsigned short lengthc[] = { 3,4,5,6,7,8,9,10,11,13,15,17,19,23,27,31,35,43,51,59,67,83,99,115,131,163,195,227,258, 259 };
|
|
|
+ static unsigned char lengtheb[]= { 0,0,0,0,0,0,0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0 };
|
|
|
+ static unsigned short distc[] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577, 32768 };
|
|
|
+ static unsigned char disteb[] = { 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13 };
|
|
|
+ unsigned int bitbuf=0;
|
|
|
+ int i,j, bitcount=0;
|
|
|
+ unsigned char *out = NULL;
|
|
|
+ unsigned char **hash_table[stbi__ZHASH]; // 64KB on the stack!
|
|
|
+ if (quality < 5) quality = 5;
|
|
|
+
|
|
|
+ stbi__sbpush(out, 0x78); // DEFLATE 32K window
|
|
|
+ stbi__sbpush(out, 0x5e); // FLEVEL = 1
|
|
|
+ stbi__zlib_add(1,1); // BFINAL = 1
|
|
|
+ stbi__zlib_add(1,2); // BTYPE = 1 -- fixed huffman
|
|
|
+
|
|
|
+ for (i=0; i < stbi__ZHASH; ++i)
|
|
|
+ hash_table[i] = NULL;
|
|
|
+
|
|
|
+ i=0;
|
|
|
+ while (i < data_len-3) {
|
|
|
+ // hash next 3 bytes of data to be compressed
|
|
|
+ int h = stbi__zhash(data+i)&(stbi__ZHASH-1), best=3;
|
|
|
+ unsigned char *bestloc = 0;
|
|
|
+ unsigned char **hlist = hash_table[h];
|
|
|
+ int n = stbi__sbcount(hlist);
|
|
|
+ for (j=0; j < n; ++j) {
|
|
|
+ if (hlist[j]-data > i-32768) { // if entry lies within window
|
|
|
+ int d = stbi__zlib_countm(hlist[j], data+i, data_len-i);
|
|
|
+ if (d >= best) best=d,bestloc=hlist[j];
|
|
|
+ }
|
|
|
+ }
|
|
|
+ // when hash table entry is too long, delete half the entries
|
|
|
+ if (hash_table[h] && stbi__sbn(hash_table[h]) == 2*quality) {
|
|
|
+ memcpy(hash_table[h], hash_table[h]+quality, sizeof(hash_table[h][0])*quality);
|
|
|
+ stbi__sbn(hash_table[h]) = quality;
|
|
|
+ }
|
|
|
+ stbi__sbpush(hash_table[h],data+i);
|
|
|
+
|
|
|
+ if (bestloc) {
|
|
|
+ // "lazy matching" - check match at *next* byte, and if it's better, do cur byte as literal
|
|
|
+ h = stbi__zhash(data+i+1)&(stbi__ZHASH-1);
|
|
|
+ hlist = hash_table[h];
|
|
|
+ n = stbi__sbcount(hlist);
|
|
|
+ for (j=0; j < n; ++j) {
|
|
|
+ if (hlist[j]-data > i-32767) {
|
|
|
+ int e = stbi__zlib_countm(hlist[j], data+i+1, data_len-i-1);
|
|
|
+ if (e > best) { // if next match is better, bail on current match
|
|
|
+ bestloc = NULL;
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ if (bestloc) {
|
|
|
+ int d = data+i - bestloc; // distance back
|
|
|
+ assert(d <= 32767 && best <= 258);
|
|
|
+ for (j=0; best > lengthc[j+1]-1; ++j);
|
|
|
+ stbi__zlib_huff(j+257);
|
|
|
+ if (lengtheb[j]) stbi__zlib_add(best - lengthc[j], lengtheb[j]);
|
|
|
+ for (j=0; d > distc[j+1]-1; ++j);
|
|
|
+ stbi__zlib_add(stbi__zlib_bitrev(j,5),5);
|
|
|
+ if (disteb[j]) stbi__zlib_add(d - distc[j], disteb[j]);
|
|
|
+ i += best;
|
|
|
+ } else {
|
|
|
+ stbi__zlib_huffb(data[i]);
|
|
|
+ ++i;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ // write out final bytes
|
|
|
+ for (;i < data_len; ++i)
|
|
|
+ stbi__zlib_huffb(data[i]);
|
|
|
+ stbi__zlib_huff(256); // end of block
|
|
|
+ // pad with 0 bits to byte boundary
|
|
|
+ while (bitcount)
|
|
|
+ stbi__zlib_add(0,1);
|
|
|
+
|
|
|
+ for (i=0; i < stbi__ZHASH; ++i)
|
|
|
+ (void) stbi__sbfree(hash_table[i]);
|
|
|
+
|
|
|
+ {
|
|
|
+ // compute adler32 on input
|
|
|
+ unsigned int i=0, s1=1, s2=0, blocklen = data_len % 5552;
|
|
|
+ int j=0;
|
|
|
+ while (j < data_len) {
|
|
|
+ for (i=0; i < blocklen; ++i) s1 += data[j+i], s2 += s1;
|
|
|
+ s1 %= 65521, s2 %= 65521;
|
|
|
+ j += blocklen;
|
|
|
+ blocklen = 5552;
|
|
|
+ }
|
|
|
+ stbi__sbpush(out, (unsigned char) (s2 >> 8));
|
|
|
+ stbi__sbpush(out, (unsigned char) s2);
|
|
|
+ stbi__sbpush(out, (unsigned char) (s1 >> 8));
|
|
|
+ stbi__sbpush(out, (unsigned char) s1);
|
|
|
+ }
|
|
|
+ *out_len = stbi__sbn(out);
|
|
|
+ // make returned pointer freeable
|
|
|
+ memmove(stbi__sbraw(out), out, *out_len);
|
|
|
+ return (unsigned char *) stbi__sbraw(out);
|
|
|
+}
|
|
|
+
|
|
|
+unsigned int stbi__crc32(unsigned char *buffer, int len)
|
|
|
+{
|
|
|
+ static unsigned int crc_table[256];
|
|
|
+ unsigned int crc = ~0u;
|
|
|
+ int i,j;
|
|
|
+ if (crc_table[1] == 0)
|
|
|
+ for(i=0; i < 256; i++)
|
|
|
+ for (crc_table[i]=i, j=0; j < 8; ++j)
|
|
|
+ crc_table[i] = (crc_table[i] >> 1) ^ (crc_table[i] & 1 ? 0xedb88320 : 0);
|
|
|
+ for (i=0; i < len; ++i)
|
|
|
+ crc = (crc >> 8) ^ crc_table[buffer[i] ^ (crc & 0xff)];
|
|
|
+ return ~crc;
|
|
|
+}
|
|
|
+
|
|
|
+#define stbi__wpng4(o,a,b,c,d) ((o)[0]=(unsigned char)(a),(o)[1]=(unsigned char)(b),(o)[2]=(unsigned char)(c),(o)[3]=(unsigned char)(d),(o)+=4)
|
|
|
+#define stbi__wp32(data,v) stbi__wpng4(data, (v)>>24,(v)>>16,(v)>>8,(v));
|
|
|
+#define stbi__wptag(data,s) stbi__wpng4(data, s[0],s[1],s[2],s[3])
|
|
|
+
|
|
|
+static void stbi__wpcrc(unsigned char **data, int len)
|
|
|
+{
|
|
|
+ unsigned int crc = stbi__crc32(*data - len - 4, len+4);
|
|
|
+ stbi__wp32(*data, crc);
|
|
|
+}
|
|
|
+
|
|
|
+static unsigned char stbi__paeth(int a, int b, int c)
|
|
|
+{
|
|
|
+ int p = a + b - c, pa = abs(p-a), pb = abs(p-b), pc = abs(p-c);
|
|
|
+ if (pa <= pb && pa <= pc) return (unsigned char) a;
|
|
|
+ if (pb <= pc) return (unsigned char) b;
|
|
|
+ return (unsigned char) c;
|
|
|
+}
|
|
|
+
|
|
|
+unsigned char *stbi_write_png_to_mem(unsigned char *pixels, int stride_bytes, int x, int y, int n, int *out_len)
|
|
|
+{
|
|
|
+ int ctype[5] = { -1, 0, 4, 2, 6 };
|
|
|
+ unsigned char sig[8] = { 137,80,78,71,13,10,26,10 };
|
|
|
+ unsigned char *out,*o, *filt, *zlib;
|
|
|
+ signed char *line_buffer;
|
|
|
+ int i,j,k,p,zlen;
|
|
|
+
|
|
|
+ if (stride_bytes == 0)
|
|
|
+ stride_bytes = x * n;
|
|
|
+
|
|
|
+ filt = (unsigned char *) malloc((x*n+1) * y); if (!filt) return 0;
|
|
|
+ line_buffer = (signed char *) malloc(x * n); if (!line_buffer) { free(filt); return 0; }
|
|
|
+ for (j=0; j < y; ++j) {
|
|
|
+ static int mapping[] = { 0,1,2,3,4 };
|
|
|
+ static int firstmap[] = { 0,1,0,5,6 };
|
|
|
+ int *mymap = j ? mapping : firstmap;
|
|
|
+ int best = 0, bestval = 0x7fffffff;
|
|
|
+ for (p=0; p < 2; ++p) {
|
|
|
+ for (k= p?best:0; k < 5; ++k) {
|
|
|
+ int type = mymap[k],est=0;
|
|
|
+ unsigned char *z = pixels + stride_bytes*j;
|
|
|
+ for (i=0; i < n; ++i)
|
|
|
+ switch (type) {
|
|
|
+ case 0: line_buffer[i] = z[i]; break;
|
|
|
+ case 1: line_buffer[i] = z[i]; break;
|
|
|
+ case 2: line_buffer[i] = z[i] - z[i-stride_bytes]; break;
|
|
|
+ case 3: line_buffer[i] = z[i] - (z[i-stride_bytes]>>1); break;
|
|
|
+ case 4: line_buffer[i] = (signed char) (z[i] - stbi__paeth(0,z[i-stride_bytes],0)); break;
|
|
|
+ case 5: line_buffer[i] = z[i]; break;
|
|
|
+ case 6: line_buffer[i] = z[i]; break;
|
|
|
+ }
|
|
|
+ for (i=n; i < x*n; ++i) {
|
|
|
+ switch (type) {
|
|
|
+ case 0: line_buffer[i] = z[i]; break;
|
|
|
+ case 1: line_buffer[i] = z[i] - z[i-n]; break;
|
|
|
+ case 2: line_buffer[i] = z[i] - z[i-stride_bytes]; break;
|
|
|
+ case 3: line_buffer[i] = z[i] - ((z[i-n] + z[i-stride_bytes])>>1); break;
|
|
|
+ case 4: line_buffer[i] = z[i] - stbi__paeth(z[i-n], z[i-stride_bytes], z[i-stride_bytes-n]); break;
|
|
|
+ case 5: line_buffer[i] = z[i] - (z[i-n]>>1); break;
|
|
|
+ case 6: line_buffer[i] = z[i] - stbi__paeth(z[i-n], 0,0); break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (p) break;
|
|
|
+ for (i=0; i < x*n; ++i)
|
|
|
+ est += abs((signed char) line_buffer[i]);
|
|
|
+ if (est < bestval) { bestval = est; best = k; }
|
|
|
+ }
|
|
|
+ }
|
|
|
+ // when we get here, best contains the filter type, and line_buffer contains the data
|
|
|
+ filt[j*(x*n+1)] = (unsigned char) best;
|
|
|
+ memcpy(filt+j*(x*n+1)+1, line_buffer, x*n);
|
|
|
+ }
|
|
|
+ free(line_buffer);
|
|
|
+ zlib = stbi_zlib_compress(filt, y*( x*n+1), &zlen, 8); // increase 8 to get smaller but use more memory
|
|
|
+ free(filt);
|
|
|
+ if (!zlib) return 0;
|
|
|
+
|
|
|
+ // each tag requires 12 bytes of overhead
|
|
|
+ out = (unsigned char *) malloc(8 + 12+13 + 12+zlen + 12);
|
|
|
+ if (!out) return 0;
|
|
|
+ *out_len = 8 + 12+13 + 12+zlen + 12;
|
|
|
+
|
|
|
+ o=out;
|
|
|
+ memcpy(o,sig,8); o+= 8;
|
|
|
+ stbi__wp32(o, 13); // header length
|
|
|
+ stbi__wptag(o, "IHDR");
|
|
|
+ stbi__wp32(o, x);
|
|
|
+ stbi__wp32(o, y);
|
|
|
+ *o++ = 8;
|
|
|
+ *o++ = (unsigned char) ctype[n];
|
|
|
+ *o++ = 0;
|
|
|
+ *o++ = 0;
|
|
|
+ *o++ = 0;
|
|
|
+ stbi__wpcrc(&o,13);
|
|
|
+
|
|
|
+ stbi__wp32(o, zlen);
|
|
|
+ stbi__wptag(o, "IDAT");
|
|
|
+ memcpy(o, zlib, zlen); o += zlen; free(zlib);
|
|
|
+ stbi__wpcrc(&o, zlen);
|
|
|
+
|
|
|
+ stbi__wp32(o,0);
|
|
|
+ stbi__wptag(o, "IEND");
|
|
|
+ stbi__wpcrc(&o,0);
|
|
|
+
|
|
|
+ assert(o == out + *out_len);
|
|
|
+
|
|
|
+ return out;
|
|
|
+}
|
|
|
+
|
|
|
+int stbi_write_png(char const *filename, int x, int y, int comp, const void *data, int stride_bytes)
|
|
|
+{
|
|
|
+ FILE *f;
|
|
|
+ int len;
|
|
|
+ unsigned char *png = stbi_write_png_to_mem((unsigned char *) data, stride_bytes, x, y, comp, &len);
|
|
|
+ if (!png) return 0;
|
|
|
+ f = fopen(filename, "wb");
|
|
|
+ if (!f) { free(png); return 0; }
|
|
|
+ fwrite(png, 1, len, f);
|
|
|
+ fclose(f);
|
|
|
+ free(png);
|
|
|
+ return 1;
|
|
|
+}
|
|
|
+#endif // STB_IMAGE_WRITE_IMPLEMENTATION
|
|
|
+
|
|
|
+/* Revision history
|
|
|
+
|
|
|
+ 0.92 (2010-08-01)
|
|
|
+ casts to unsigned char to fix warnings
|
|
|
+ 0.91 (2010-07-17)
|
|
|
+ first public release
|
|
|
+ 0.90 first internal release
|
|
|
+*/
|
raysan5