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stb_image_write.h
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stb_image_write.h
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/* stb_image_write - v1.13 - public domain - http://nothings.org/stb
writes out PNG/BMP/TGA/JPEG/HDR images to C stdio - Sean Barrett 2010-2015
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.
Will probably not work correctly with strict-aliasing optimizations.
ABOUT:
This header file is a library for writing images to C stdio or a callback.
The PNG output is not optimal; it is 20-50% larger than the file
written by a decent optimizing implementation; though providing a custom
zlib compress function (see STBIW_ZLIB_COMPRESS) can mitigate that.
This library is designed for source code compactness and simplicity,
not optimal image file size or run-time performance.
BUILDING:
You can #define STBIW_ASSERT(x) before the #include to avoid using assert.h.
You can #define STBIW_MALLOC(), STBIW_REALLOC(), and STBIW_FREE() to replace
malloc,realloc,free.
You can #define STBIW_MEMMOVE() to replace memmove()
You can #define STBIW_ZLIB_COMPRESS to use a custom zlib-style compress function
for PNG compression (instead of the builtin one), it must have the following signature:
unsigned char * my_compress(unsigned char *data, int data_len, int *out_len, int quality);
The returned data will be freed with STBIW_FREE() (free() by default),
so it must be heap allocated with STBIW_MALLOC() (malloc() by default),
UNICODE:
If compiling for Windows and you wish to use Unicode filenames, compile
with
#define STBIW_WINDOWS_UTF8
and pass utf8-encoded filenames. Call stbiw_convert_wchar_to_utf8 to convert
Windows wchar_t filenames to utf8.
USAGE:
There are five 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);
int stbi_write_jpg(char const *filename, int w, int h, int comp, const void *data, int quality);
int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
void stbi_flip_vertically_on_write(int flag); // flag is non-zero to flip data vertically
There are also five equivalent functions that use an arbitrary write function. You are
expected to open/close your file-equivalent before and after calling these:
int stbi_write_png_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data, int stride_in_bytes);
int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
int stbi_write_tga_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const float *data);
int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality);
where the callback is:
void stbi_write_func(void *context, void *data, int size);
You can configure it with these global variables:
int stbi_write_tga_with_rle; // defaults to true; set to 0 to disable RLE
int stbi_write_png_compression_level; // defaults to 8; set to higher for more compression
int stbi_write_force_png_filter; // defaults to -1; set to 0..5 to force a filter mode
You can define STBI_WRITE_NO_STDIO to disable the file variant of these
functions, so the library will not use stdio.h at all. However, this will
also disable HDR writing, because it requires stdio for formatted output.
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=Y, 2=YA, 3=RGB, 4=RGBA. (Y is
monochrome color.) 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.
PNG creates output files with the same number of components as the input.
The BMP format expands Y to RGB in the file format and 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 a native-format BMP through the BMP
writer, both because it is in BGR order and because it may have padding
at the end of the line.)
PNG allows you to set the deflate compression level by setting the global
variable 'stbi_write_png_compression_level' (it defaults to 8).
HDR expects linear float data. Since the format is always 32-bit rgb(e)
data, alpha (if provided) is discarded, and for monochrome data it is
replicated across all three channels.
TGA supports RLE or non-RLE compressed data. To use non-RLE-compressed
data, set the global variable 'stbi_write_tga_with_rle' to 0.
JPEG does ignore alpha channels in input data; quality is between 1 and 100.
Higher quality looks better but results in a bigger image.
JPEG baseline (no JPEG progressive).
CREDITS:
Sean Barrett - PNG/BMP/TGA
Baldur Karlsson - HDR
Jean-Sebastien Guay - TGA monochrome
Tim Kelsey - misc enhancements
Alan Hickman - TGA RLE
Emmanuel Julien - initial file IO callback implementation
Jon Olick - original jo_jpeg.cpp code
Daniel Gibson - integrate JPEG, allow external zlib
Aarni Koskela - allow choosing PNG filter
bugfixes:
github:Chribba
Guillaume Chereau
github:jry2
github:romigrou
Sergio Gonzalez
Jonas Karlsson
Filip Wasil
Thatcher Ulrich
github:poppolopoppo
Patrick Boettcher
github:xeekworx
Cap Petschulat
Simon Rodriguez
Ivan Tikhonov
github:ignotion
Adam Schackart
LICENSE
See end of file for license information.
*/
#ifndef INCLUDE_STB_IMAGE_WRITE_H
#define INCLUDE_STB_IMAGE_WRITE_H
#include <stdlib.h>
// if STB_IMAGE_WRITE_STATIC causes problems, try defining STBIWDEF to 'inline' or 'static inline'
#ifndef STBIWDEF
#ifdef STB_IMAGE_WRITE_STATIC
#define STBIWDEF static
#else
#ifdef __cplusplus
#define STBIWDEF extern "C"
#else
#define STBIWDEF extern
#endif
#endif
#endif
#ifndef STB_IMAGE_WRITE_STATIC // C++ forbids static forward declarations
extern int stbi_write_tga_with_rle;
extern int stbi_write_png_compression_level;
extern int stbi_write_force_png_filter;
#endif
#ifndef STBI_WRITE_NO_STDIO
STBIWDEF int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
STBIWDEF int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
STBIWDEF int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
STBIWDEF int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void *data, int quality);
#ifdef STBI_WINDOWS_UTF8
STBIWDEF int stbiw_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input);
#endif
#endif
typedef void stbi_write_func(void *context, void *data, int size);
STBIWDEF int stbi_write_png_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data, int stride_in_bytes);
STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const float *data);
STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality);
STBIWDEF void stbi_flip_vertically_on_write(int flip_boolean);
#endif//INCLUDE_STB_IMAGE_WRITE_H
#ifdef STB_IMAGE_WRITE_IMPLEMENTATION
#ifdef _WIN32
#ifndef _CRT_SECURE_NO_WARNINGS
#define _CRT_SECURE_NO_WARNINGS
#endif
#ifndef _CRT_NONSTDC_NO_DEPRECATE
#define _CRT_NONSTDC_NO_DEPRECATE
#endif
#endif
#ifndef STBI_WRITE_NO_STDIO
#include <stdio.h>
#endif // STBI_WRITE_NO_STDIO
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#if defined(STBIW_MALLOC) && defined(STBIW_FREE) && (defined(STBIW_REALLOC) || defined(STBIW_REALLOC_SIZED))
// ok
#elif !defined(STBIW_MALLOC) && !defined(STBIW_FREE) && !defined(STBIW_REALLOC) && !defined(STBIW_REALLOC_SIZED)
// ok
#else
#error "Must define all or none of STBIW_MALLOC, STBIW_FREE, and STBIW_REALLOC (or STBIW_REALLOC_SIZED)."
#endif
#ifndef STBIW_MALLOC
#define STBIW_MALLOC(sz) malloc(sz)
#define STBIW_REALLOC(p,newsz) realloc(p,newsz)
#define STBIW_FREE(p) free(p)
#endif
#ifndef STBIW_REALLOC_SIZED
#define STBIW_REALLOC_SIZED(p,oldsz,newsz) STBIW_REALLOC(p,newsz)
#endif
#ifndef STBIW_MEMMOVE
#define STBIW_MEMMOVE(a,b,sz) memmove(a,b,sz)
#endif
#ifndef STBIW_ASSERT
#include <assert.h>
#define STBIW_ASSERT(x) assert(x)
#endif
#define STBIW_UCHAR(x) (unsigned char) ((x) & 0xff)
#ifdef STB_IMAGE_WRITE_STATIC
static int stbi__flip_vertically_on_write=0;
static int stbi_write_png_compression_level = 8;
static int stbi_write_tga_with_rle = 1;
static int stbi_write_force_png_filter = -1;
#else
int stbi_write_png_compression_level = 8;
int stbi__flip_vertically_on_write=0;
int stbi_write_tga_with_rle = 1;
int stbi_write_force_png_filter = -1;
#endif
STBIWDEF void stbi_flip_vertically_on_write(int flag)
{
stbi__flip_vertically_on_write = flag;
}
typedef struct
{
stbi_write_func *func;
void *context;
} stbi__write_context;
// initialize a callback-based context
static void stbi__start_write_callbacks(stbi__write_context *s, stbi_write_func *c, void *context)
{
s->func = c;
s->context = context;
}
#ifndef STBI_WRITE_NO_STDIO
static void stbi__stdio_write(void *context, void *data, int size)
{
fwrite(data,1,size,(FILE*) context);
}
#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
#ifdef __cplusplus
#define STBIW_EXTERN extern "C"
#else
#define STBIW_EXTERN extern
#endif
STBIW_EXTERN __declspec(dllimport) int __stdcall MultiByteToWideChar(unsigned int cp, unsigned long flags, const char *str, int cbmb, wchar_t *widestr, int cchwide);
STBIW_EXTERN __declspec(dllimport) int __stdcall WideCharToMultiByte(unsigned int cp, unsigned long flags, const wchar_t *widestr, int cchwide, char *str, int cbmb, const char *defchar, int *used_default);
STBIWDEF int stbiw_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input)
{
return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, (int) bufferlen, NULL, NULL);
}
#endif
static FILE *stbiw__fopen(char const *filename, char const *mode)
{
FILE *f;
#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
wchar_t wMode[64];
wchar_t wFilename[1024];
if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)))
return 0;
if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)))
return 0;
#if _MSC_VER >= 1400
if (0 != _wfopen_s(&f, wFilename, wMode))
f = 0;
#else
f = _wfopen(wFilename, wMode);
#endif
#elif defined(_MSC_VER) && _MSC_VER >= 1400
if (0 != fopen_s(&f, filename, mode))
f=0;
#else
f = fopen(filename, mode);
#endif
return f;
}
static int stbi__start_write_file(stbi__write_context *s, const char *filename)
{
FILE *f = stbiw__fopen(filename, "wb");
stbi__start_write_callbacks(s, stbi__stdio_write, (void *) f);
return f != NULL;
}
static void stbi__end_write_file(stbi__write_context *s)
{
fclose((FILE *)s->context);
}
#endif // !STBI_WRITE_NO_STDIO
typedef unsigned int stbiw_uint32;
typedef int stb_image_write_test[sizeof(stbiw_uint32)==4 ? 1 : -1];
static void stbiw__writefv(stbi__write_context *s, const char *fmt, va_list v)
{
while (*fmt) {
switch (*fmt++) {
case ' ': break;
case '1': { unsigned char x = STBIW_UCHAR(va_arg(v, int));
s->func(s->context,&x,1);
break; }
case '2': { int x = va_arg(v,int);
unsigned char b[2];
b[0] = STBIW_UCHAR(x);
b[1] = STBIW_UCHAR(x>>8);
s->func(s->context,b,2);
break; }
case '4': { stbiw_uint32 x = va_arg(v,int);
unsigned char b[4];
b[0]=STBIW_UCHAR(x);
b[1]=STBIW_UCHAR(x>>8);
b[2]=STBIW_UCHAR(x>>16);
b[3]=STBIW_UCHAR(x>>24);
s->func(s->context,b,4);
break; }
default:
STBIW_ASSERT(0);
return;
}
}
}
static void stbiw__writef(stbi__write_context *s, const char *fmt, ...)
{
va_list v;
va_start(v, fmt);
stbiw__writefv(s, fmt, v);
va_end(v);
}
static void stbiw__putc(stbi__write_context *s, unsigned char c)
{
s->func(s->context, &c, 1);
}
static void stbiw__write3(stbi__write_context *s, unsigned char a, unsigned char b, unsigned char c)
{
unsigned char arr[3];
arr[0] = a; arr[1] = b; arr[2] = c;
s->func(s->context, arr, 3);
}
static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, int write_alpha, int expand_mono, unsigned char *d)
{
unsigned char bg[3] = { 255, 0, 255}, px[3];
int k;
if (write_alpha < 0)
s->func(s->context, &d[comp - 1], 1);
switch (comp) {
case 2: // 2 pixels = mono + alpha, alpha is written separately, so same as 1-channel case
case 1:
if (expand_mono)
stbiw__write3(s, d[0], d[0], d[0]); // monochrome bmp
else
s->func(s->context, d, 1); // monochrome TGA
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;
stbiw__write3(s, px[1 - rgb_dir], px[1], px[1 + rgb_dir]);
break;
}
/* FALLTHROUGH */
case 3:
stbiw__write3(s, d[1 - rgb_dir], d[1], d[1 + rgb_dir]);
break;
}
if (write_alpha > 0)
s->func(s->context, &d[comp - 1], 1);
}
static void stbiw__write_pixels(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad, int expand_mono)
{
stbiw_uint32 zero = 0;
int i,j, j_end;
if (y <= 0)
return;
if (stbi__flip_vertically_on_write)
vdir *= -1;
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;
stbiw__write_pixel(s, rgb_dir, comp, write_alpha, expand_mono, d);
}
s->func(s->context, &zero, scanline_pad);
}
}
static int stbiw__outfile(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, int expand_mono, void *data, int alpha, int pad, const char *fmt, ...)
{
if (y < 0 || x < 0) {
return 0;
} else {
va_list v;
va_start(v, fmt);
stbiw__writefv(s, fmt, v);
va_end(v);
stbiw__write_pixels(s,rgb_dir,vdir,x,y,comp,data,alpha,pad, expand_mono);
return 1;
}
}
static int stbi_write_bmp_core(stbi__write_context *s, int x, int y, int comp, const void *data)
{
int pad = (-x*3) & 3;
return stbiw__outfile(s,-1,-1,x,y,comp,1,(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
}
STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
{
stbi__write_context s;
stbi__start_write_callbacks(&s, func, context);
return stbi_write_bmp_core(&s, x, y, comp, data);
}
#ifndef STBI_WRITE_NO_STDIO
STBIWDEF int stbi_write_bmp(char const *filename, int x, int y, int comp, const void *data)
{
stbi__write_context s;
if (stbi__start_write_file(&s,filename)) {
int r = stbi_write_bmp_core(&s, x, y, comp, data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
#endif //!STBI_WRITE_NO_STDIO
static int stbi_write_tga_core(stbi__write_context *s, int x, int y, int comp, void *data)
{
int has_alpha = (comp == 2 || comp == 4);
int colorbytes = has_alpha ? comp-1 : comp;
int format = colorbytes < 2 ? 3 : 2; // 3 color channels (RGB/RGBA) = 2, 1 color channel (Y/YA) = 3
if (y < 0 || x < 0)
return 0;
if (!stbi_write_tga_with_rle) {
return stbiw__outfile(s, -1, -1, x, y, comp, 0, (void *) data, has_alpha, 0,
"111 221 2222 11", 0, 0, format, 0, 0, 0, 0, 0, x, y, (colorbytes + has_alpha) * 8, has_alpha * 8);
} else {
int i,j,k;
int jend, jdir;
stbiw__writef(s, "111 221 2222 11", 0,0,format+8, 0,0,0, 0,0,x,y, (colorbytes + has_alpha) * 8, has_alpha * 8);
if (stbi__flip_vertically_on_write) {
j = 0;
jend = y;
jdir = 1;
} else {
j = y-1;
jend = -1;
jdir = -1;
}
for (; j != jend; j += jdir) {
unsigned char *row = (unsigned char *) data + j * x * comp;
int len;
for (i = 0; i < x; i += len) {
unsigned char *begin = row + i * comp;
int diff = 1;
len = 1;
if (i < x - 1) {
++len;
diff = memcmp(begin, row + (i + 1) * comp, comp);
if (diff) {
const unsigned char *prev = begin;
for (k = i + 2; k < x && len < 128; ++k) {
if (memcmp(prev, row + k * comp, comp)) {
prev += comp;
++len;
} else {
--len;
break;
}
}
} else {
for (k = i + 2; k < x && len < 128; ++k) {
if (!memcmp(begin, row + k * comp, comp)) {
++len;
} else {
break;
}
}
}
}
if (diff) {
unsigned char header = STBIW_UCHAR(len - 1);
s->func(s->context, &header, 1);
for (k = 0; k < len; ++k) {
stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin + k * comp);
}
} else {
unsigned char header = STBIW_UCHAR(len - 129);
s->func(s->context, &header, 1);
stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin);
}
}
}
}
return 1;
}
STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
{
stbi__write_context s;
stbi__start_write_callbacks(&s, func, context);
return stbi_write_tga_core(&s, x, y, comp, (void *) data);
}
#ifndef STBI_WRITE_NO_STDIO
STBIWDEF int stbi_write_tga(char const *filename, int x, int y, int comp, const void *data)
{
stbi__write_context s;
if (stbi__start_write_file(&s,filename)) {
int r = stbi_write_tga_core(&s, x, y, comp, (void *) data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
#endif
// *************************************************************************************************
// Radiance RGBE HDR writer
// by Baldur Karlsson
#define stbiw__max(a, b) ((a) > (b) ? (a) : (b))
static void stbiw__linear_to_rgbe(unsigned char *rgbe, float *linear)
{
int exponent;
float maxcomp = stbiw__max(linear[0], stbiw__max(linear[1], linear[2]));
if (maxcomp < 1e-32f) {
rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
} else {
float normalize = (float) frexp(maxcomp, &exponent) * 256.0f/maxcomp;
rgbe[0] = (unsigned char)(linear[0] * normalize);
rgbe[1] = (unsigned char)(linear[1] * normalize);
rgbe[2] = (unsigned char)(linear[2] * normalize);
rgbe[3] = (unsigned char)(exponent + 128);
}
}
static void stbiw__write_run_data(stbi__write_context *s, int length, unsigned char databyte)
{
unsigned char lengthbyte = STBIW_UCHAR(length+128);
STBIW_ASSERT(length+128 <= 255);
s->func(s->context, &lengthbyte, 1);
s->func(s->context, &databyte, 1);
}
static void stbiw__write_dump_data(stbi__write_context *s, int length, unsigned char *data)
{
unsigned char lengthbyte = STBIW_UCHAR(length);
STBIW_ASSERT(length <= 128); // inconsistent with spec but consistent with official code
s->func(s->context, &lengthbyte, 1);
s->func(s->context, data, length);
}
static void stbiw__write_hdr_scanline(stbi__write_context *s, int width, int ncomp, unsigned char *scratch, float *scanline)
{
unsigned char scanlineheader[4] = { 2, 2, 0, 0 };
unsigned char rgbe[4];
float linear[3];
int x;
scanlineheader[2] = (width&0xff00)>>8;
scanlineheader[3] = (width&0x00ff);
/* skip RLE for images too small or large */
if (width < 8 || width >= 32768) {
for (x=0; x < width; x++) {
switch (ncomp) {
case 4: /* fallthrough */
case 3: linear[2] = scanline[x*ncomp + 2];
linear[1] = scanline[x*ncomp + 1];
linear[0] = scanline[x*ncomp + 0];
break;
default:
linear[0] = linear[1] = linear[2] = scanline[x*ncomp + 0];
break;
}
stbiw__linear_to_rgbe(rgbe, linear);
s->func(s->context, rgbe, 4);
}
} else {
int c,r;
/* encode into scratch buffer */
for (x=0; x < width; x++) {
switch(ncomp) {
case 4: /* fallthrough */
case 3: linear[2] = scanline[x*ncomp + 2];
linear[1] = scanline[x*ncomp + 1];
linear[0] = scanline[x*ncomp + 0];
break;
default:
linear[0] = linear[1] = linear[2] = scanline[x*ncomp + 0];
break;
}
stbiw__linear_to_rgbe(rgbe, linear);
scratch[x + width*0] = rgbe[0];
scratch[x + width*1] = rgbe[1];
scratch[x + width*2] = rgbe[2];
scratch[x + width*3] = rgbe[3];
}
s->func(s->context, scanlineheader, 4);
/* RLE each component separately */
for (c=0; c < 4; c++) {
unsigned char *comp = &scratch[width*c];
x = 0;
while (x < width) {
// find first run
r = x;
while (r+2 < width) {
if (comp[r] == comp[r+1] && comp[r] == comp[r+2])
break;
++r;
}
if (r+2 >= width)
r = width;
// dump up to first run
while (x < r) {
int len = r-x;
if (len > 128) len = 128;
stbiw__write_dump_data(s, len, &comp[x]);
x += len;
}
// if there's a run, output it
if (r+2 < width) { // same test as what we break out of in search loop, so only true if we break'd
// find next byte after run
while (r < width && comp[r] == comp[x])
++r;
// output run up to r
while (x < r) {
int len = r-x;
if (len > 127) len = 127;
stbiw__write_run_data(s, len, comp[x]);
x += len;
}
}
}
}
}
}
static int stbi_write_hdr_core(stbi__write_context *s, int x, int y, int comp, float *data)
{
if (y <= 0 || x <= 0 || data == NULL)
return 0;
else {
// Each component is stored separately. Allocate scratch space for full output scanline.
unsigned char *scratch = (unsigned char *) STBIW_MALLOC(x*4);
int i, len;
char buffer[128];
char header[] = "#?RADIANCE\n# Written by stb_image_write.h\nFORMAT=32-bit_rle_rgbe\n";
s->func(s->context, header, sizeof(header)-1);
#ifdef __STDC_WANT_SECURE_LIB__
len = sprintf_s(buffer, sizeof(buffer), "EXPOSURE= 1.0000000000000\n\n-Y %d +X %d\n", y, x);
#else
len = sprintf(buffer, "EXPOSURE= 1.0000000000000\n\n-Y %d +X %d\n", y, x);
#endif
s->func(s->context, buffer, len);
for(i=0; i < y; i++)
stbiw__write_hdr_scanline(s, x, comp, scratch, data + comp*x*(stbi__flip_vertically_on_write ? y-1-i : i));
STBIW_FREE(scratch);
return 1;
}
}
STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const float *data)
{
stbi__write_context s;
stbi__start_write_callbacks(&s, func, context);
return stbi_write_hdr_core(&s, x, y, comp, (float *) data);
}
#ifndef STBI_WRITE_NO_STDIO
STBIWDEF int stbi_write_hdr(char const *filename, int x, int y, int comp, const float *data)
{
stbi__write_context s;
if (stbi__start_write_file(&s,filename)) {
int r = stbi_write_hdr_core(&s, x, y, comp, (float *) data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
#endif // STBI_WRITE_NO_STDIO
//////////////////////////////////////////////////////////////////////////////
//
// PNG writer
//
#ifndef STBIW_ZLIB_COMPRESS
// stretchy buffer; stbiw__sbpush() == vector<>::push_back() -- stbiw__sbcount() == vector<>::size()
#define stbiw__sbraw(a) ((int *) (a) - 2)
#define stbiw__sbm(a) stbiw__sbraw(a)[0]
#define stbiw__sbn(a) stbiw__sbraw(a)[1]
#define stbiw__sbneedgrow(a,n) ((a)==0 || stbiw__sbn(a)+n >= stbiw__sbm(a))
#define stbiw__sbmaybegrow(a,n) (stbiw__sbneedgrow(a,(n)) ? stbiw__sbgrow(a,n) : 0)
#define stbiw__sbgrow(a,n) stbiw__sbgrowf((void **) &(a), (n), sizeof(*(a)))
#define stbiw__sbpush(a, v) (stbiw__sbmaybegrow(a,1), (a)[stbiw__sbn(a)++] = (v))
#define stbiw__sbcount(a) ((a) ? stbiw__sbn(a) : 0)
#define stbiw__sbfree(a) ((a) ? STBIW_FREE(stbiw__sbraw(a)),0 : 0)
static void *stbiw__sbgrowf(void **arr, int increment, int itemsize)
{
int m = *arr ? 2*stbiw__sbm(*arr)+increment : increment+1;
void *p = STBIW_REALLOC_SIZED(*arr ? stbiw__sbraw(*arr) : 0, *arr ? (stbiw__sbm(*arr)*itemsize + sizeof(int)*2) : 0, itemsize * m + sizeof(int)*2);
STBIW_ASSERT(p);
if (p) {
if (!*arr) ((int *) p)[1] = 0;
*arr = (void *) ((int *) p + 2);
stbiw__sbm(*arr) = m;
}
return *arr;
}
static unsigned char *stbiw__zlib_flushf(unsigned char *data, unsigned int *bitbuffer, int *bitcount)
{
while (*bitcount >= 8) {
stbiw__sbpush(data, STBIW_UCHAR(*bitbuffer));
*bitbuffer >>= 8;
*bitcount -= 8;
}
return data;
}
static int stbiw__zlib_bitrev(int code, int codebits)
{
int res=0;
while (codebits--) {
res = (res << 1) | (code & 1);
code >>= 1;
}
return res;
}
static unsigned int stbiw__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 stbiw__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 stbiw__zlib_flush() (out = stbiw__zlib_flushf(out, &bitbuf, &bitcount))
#define stbiw__zlib_add(code,codebits) \
(bitbuf |= (code) << bitcount, bitcount += (codebits), stbiw__zlib_flush())
#define stbiw__zlib_huffa(b,c) stbiw__zlib_add(stbiw__zlib_bitrev(b,c),c)
// default huffman tables
#define stbiw__zlib_huff1(n) stbiw__zlib_huffa(0x30 + (n), 8)
#define stbiw__zlib_huff2(n) stbiw__zlib_huffa(0x190 + (n)-144, 9)
#define stbiw__zlib_huff3(n) stbiw__zlib_huffa(0 + (n)-256,7)
#define stbiw__zlib_huff4(n) stbiw__zlib_huffa(0xc0 + (n)-280,8)
#define stbiw__zlib_huff(n) ((n) <= 143 ? stbiw__zlib_huff1(n) : (n) <= 255 ? stbiw__zlib_huff2(n) : (n) <= 279 ? stbiw__zlib_huff3(n) : stbiw__zlib_huff4(n))
#define stbiw__zlib_huffb(n) ((n) <= 143 ? stbiw__zlib_huff1(n) : stbiw__zlib_huff2(n))
#define stbiw__ZHASH 16384
#endif // STBIW_ZLIB_COMPRESS
STBIWDEF unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, int *out_len, int quality)
{
#ifdef STBIW_ZLIB_COMPRESS
// user provided a zlib compress implementation, use that
return STBIW_ZLIB_COMPRESS(data, data_len, out_len, quality);
#else // use builtin
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 = (unsigned char***) STBIW_MALLOC(stbiw__ZHASH * sizeof(unsigned char**));
if (hash_table == NULL)
return NULL;
if (quality < 5) quality = 5;
stbiw__sbpush(out, 0x78); // DEFLATE 32K window
stbiw__sbpush(out, 0x5e); // FLEVEL = 1
stbiw__zlib_add(1,1); // BFINAL = 1
stbiw__zlib_add(1,2); // BTYPE = 1 -- fixed huffman
for (i=0; i < stbiw__ZHASH; ++i)
hash_table[i] = NULL;
i=0;
while (i < data_len-3) {
// hash next 3 bytes of data to be compressed
int h = stbiw__zhash(data+i)&(stbiw__ZHASH-1), best=3;
unsigned char *bestloc = 0;
unsigned char **hlist = hash_table[h];
int n = stbiw__sbcount(hlist);
for (j=0; j < n; ++j) {
if (hlist[j]-data > i-32768) { // if entry lies within window
int d = stbiw__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] && stbiw__sbn(hash_table[h]) == 2*quality) {
STBIW_MEMMOVE(hash_table[h], hash_table[h]+quality, sizeof(hash_table[h][0])*quality);
stbiw__sbn(hash_table[h]) = quality;
}
stbiw__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 = stbiw__zhash(data+i+1)&(stbiw__ZHASH-1);
hlist = hash_table[h];
n = stbiw__sbcount(hlist);
for (j=0; j < n; ++j) {
if (hlist[j]-data > i-32767) {
int e = stbiw__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 = (int) (data+i - bestloc); // distance back
STBIW_ASSERT(d <= 32767 && best <= 258);
for (j=0; best > lengthc[j+1]-1; ++j);
stbiw__zlib_huff(j+257);
if (lengtheb[j]) stbiw__zlib_add(best - lengthc[j], lengtheb[j]);
for (j=0; d > distc[j+1]-1; ++j);
stbiw__zlib_add(stbiw__zlib_bitrev(j,5),5);
if (disteb[j]) stbiw__zlib_add(d - distc[j], disteb[j]);
i += best;
} else {
stbiw__zlib_huffb(data[i]);
++i;
}
}
// write out final bytes
for (;i < data_len; ++i)
stbiw__zlib_huffb(data[i]);
stbiw__zlib_huff(256); // end of block
// pad with 0 bits to byte boundary
while (bitcount)
stbiw__zlib_add(0,1);
for (i=0; i < stbiw__ZHASH; ++i)
(void) stbiw__sbfree(hash_table[i]);
STBIW_FREE(hash_table);
{
// compute adler32 on input
unsigned int s1=1, s2=0;
int blocklen = (int) (data_len % 5552);
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;
}
stbiw__sbpush(out, STBIW_UCHAR(s2 >> 8));
stbiw__sbpush(out, STBIW_UCHAR(s2));
stbiw__sbpush(out, STBIW_UCHAR(s1 >> 8));
stbiw__sbpush(out, STBIW_UCHAR(s1));
}
*out_len = stbiw__sbn(out);
// make returned pointer freeable
STBIW_MEMMOVE(stbiw__sbraw(out), out, *out_len);
return (unsigned char *) stbiw__sbraw(out);
#endif // STBIW_ZLIB_COMPRESS
}
static unsigned int stbiw__crc32(unsigned char *buffer, int len)
{
#ifdef STBIW_CRC32
return STBIW_CRC32(buffer, len);
#else
static unsigned int crc_table[256] =
{
0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
0x0eDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,