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/*
* SDL_SavePNG -- libpng-based SDL_Surface writer.
*
* This code is free software, available under zlib/libpng license.
* http://www.libpng.org/pub/png/src/libpng-LICENSE.txt
*/
#ifdef CAP_SDL2
#if CAP_SDL2
#define USE_SDL2
#endif
#endif
#ifdef USE_SDL2
#include <SDL2/SDL.h>
#else
#include <SDL/SDL.h>
#endif
#include <png.h>
#define SUCCESS 0
#define ERROR -1
#define USE_ROW_POINTERS
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
#define rmask 0xFF000000
#define gmask 0x00FF0000
#define bmask 0x0000FF00
#define amask 0x000000FF
#else
#define rmask 0x000000FF
#define gmask 0x0000FF00
#define bmask 0x00FF0000
#define amask 0xFF000000
#endif
/* libpng callbacks */
static void png_error_SDL(png_structp ctx, png_const_charp str)
{
SDL_SetError("libpng: %s\n", str);
}
static void png_write_SDL(png_structp png_ptr, png_bytep data, png_size_t length)
{
SDL_RWops *rw = (SDL_RWops*)png_get_io_ptr(png_ptr);
SDL_RWwrite(rw, data, sizeof(png_byte), length);
}
#ifdef __cplusplus
extern "C"
#endif
SDL_Surface *SDL_PNGFormatAlpha(SDL_Surface *src)
{
SDL_Surface *surf;
SDL_Rect rect = { 0, 0, 0, 0 };
/* NO-OP for images < 32bpp and 32bpp images that already have Alpha channel */
if (src->format->BitsPerPixel <= 24 || src->format->Amask) {
src->refcount++;
return src;
}
/* Convert 32bpp alpha-less image to 24bpp alpha-less image */
rect.w = src->w;
rect.h = src->h;
surf = SDL_CreateRGBSurface(src->flags, src->w, src->h, 24,
src->format->Rmask, src->format->Gmask, src->format->Bmask, 0);
SDL_LowerBlit(src, &rect, surf, &rect);
return surf;
}
#ifdef __cplusplus
extern "C"
#endif
int SDL_SavePNG_RW(SDL_Surface *surface, SDL_RWops *dst, int freedst)
{
png_structp png_ptr;
png_infop info_ptr;
png_colorp pal_ptr;
SDL_Palette *pal;
int i, colortype;
#ifdef USE_ROW_POINTERS
png_bytep *row_pointers;
#endif
/* Initialize and do basic error checking */
if (!dst)
{
SDL_SetError("Argument 2 to SDL_SavePNG_RW can't be NULL, expecting SDL_RWops*\n");
return (ERROR);
}
if (!surface)
{
SDL_SetError("Argument 1 to SDL_SavePNG_RW can't be NULL, expecting SDL_Surface*\n");
if (freedst) SDL_RWclose(dst);
return (ERROR);
}
png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, png_error_SDL, NULL); /* err_ptr, err_fn, warn_fn */
if (!png_ptr)
{
SDL_SetError("Unable to png_create_write_struct on %s\n", PNG_LIBPNG_VER_STRING);
if (freedst) SDL_RWclose(dst);
return (ERROR);
}
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
{
SDL_SetError("Unable to png_create_info_struct\n");
png_destroy_write_struct(&png_ptr, NULL);
if (freedst) SDL_RWclose(dst);
return (ERROR);
}
if (setjmp(png_jmpbuf(png_ptr))) /* All other errors, see also "png_error_SDL" */
{
png_destroy_write_struct(&png_ptr, &info_ptr);
if (freedst) SDL_RWclose(dst);
return (ERROR);
}
/* Setup our RWops writer */
png_set_write_fn(png_ptr, dst, png_write_SDL, NULL); /* w_ptr, write_fn, flush_fn */
/* Prepare chunks */
colortype = PNG_COLOR_MASK_COLOR;
if (surface->format->BytesPerPixel > 0
&& surface->format->BytesPerPixel <= 8
&& (pal = surface->format->palette))
{
colortype |= PNG_COLOR_MASK_PALETTE;
pal_ptr = (png_colorp)malloc(pal->ncolors * sizeof(png_color));
for (i = 0; i < pal->ncolors; i++) {
pal_ptr[i].red = pal->colors[i].r;
pal_ptr[i].green = pal->colors[i].g;
pal_ptr[i].blue = pal->colors[i].b;
}
png_set_PLTE(png_ptr, info_ptr, pal_ptr, pal->ncolors);
free(pal_ptr);
}
else if (surface->format->BytesPerPixel > 3 || surface->format->Amask)
colortype |= PNG_COLOR_MASK_ALPHA;
png_set_IHDR(png_ptr, info_ptr, surface->w, surface->h, 8, colortype,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
// png_set_packing(png_ptr);
/* Allow BGR surfaces */
if (surface->format->Rmask == bmask
&& surface->format->Gmask == gmask
&& surface->format->Bmask == rmask)
png_set_bgr(png_ptr);
/* Write everything */
png_write_info(png_ptr, info_ptr);
#ifdef USE_ROW_POINTERS
row_pointers = (png_bytep*) malloc(sizeof(png_bytep)*surface->h);
for (i = 0; i < surface->h; i++)
row_pointers[i] = (png_bytep)(Uint8*)surface->pixels + i * surface->pitch;
png_write_image(png_ptr, row_pointers);
free(row_pointers);
#else
for (i = 0; i < surface->h; i++)
png_write_row(png_ptr, (png_bytep)(Uint8*)surface->pixels + i * surface->pitch);
#endif
png_write_end(png_ptr, info_ptr);
/* Done */
png_destroy_write_struct(&png_ptr, &info_ptr);
if (freedst) SDL_RWclose(dst);
return (SUCCESS);
}
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