|
|
@ -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 |
|
|
|
*/ |