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#include <SDL.h>
#include <time.h>
#include <png.h>
#include <string>
#include <iostream>
using namespace std;
Uint32 getPixel(SDL_Surface *surface, int x, int y)
{
int bpp = surface->format->BytesPerPixel;
/* Here p is the address to the pixel we want to retrieve */
Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;
switch(bpp) {
case 1:
return *p;
case 2:
return *(Uint16 *)p;
case 3:
if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
return p[0] << 16 | p[1] << 8 | p[2];
else
return p[0] | p[1] << 8 | p[2] << 16;
case 4:
return *(Uint32 *)p;
default:
return 0; /* shouldn't happen, but avoids warnings */
}
}
bool saveAsPNG(SDL_Surface* toSave, string fileName)
{
FILE* file = fopen(fileName.c_str(), "wb");
png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
if(!png_ptr)
{
fclose(file);
return false;
}
png_infop png_info = png_create_info_struct(png_ptr);
if(!png_info)
{
png_destroy_write_struct(&png_ptr, &png_info);
fclose(file);
return false;
}
if(setjmp(png_ptr->jmpbuf))
{
png_destroy_write_struct(&png_ptr, &png_info);
fclose(file);
return false;
}
/* données de l'image */
png_init_io(png_ptr, file);
// type de compression
png_set_compression_level(png_ptr, Z_BEST_SPEED);
// infos de l'image
png_set_IHDR(png_ptr, png_info, static_cast<png_uint_32>(toSave->w),
static_cast<png_uint_32>(toSave->h), 8,
PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
// date de création
png_time modtime;
png_convert_from_time_t(&modtime, time(NULL));
png_set_tIME(png_ptr, png_info, &modtime);
// commentaires de l'image
png_text text[6];
text[0].key = "Title";
text[0].text = "";
text[0].compression = PNG_TEXT_COMPRESSION_NONE;
text[1].key = "Author";
text[1].text = "";
text[1].compression = PNG_TEXT_COMPRESSION_NONE;
text[2].key = "Description";
text[2].text = "";
text[2].compression = PNG_TEXT_COMPRESSION_NONE;
text[3].key = "Copyright";
text[3].text = "";
text[3].compression = PNG_TEXT_COMPRESSION_NONE;
text[4].key = "E-mail";
text[4].text = "";
text[4].compression = PNG_TEXT_COMPRESSION_NONE;
text[5].key = "Url";
text[5].text = "";
text[5].compression = PNG_TEXT_COMPRESSION_NONE;
png_set_text(png_ptr, png_info, text, 6);
/* écriture de l'image */
png_write_info(png_ptr, png_info);
png_byte* line;
line = new png_byte[toSave->w * 3];
for(int i = 0; i < 480; ++i)
{
for(int p = 0, j = 0; j < toSave->w; ++j)
{
// extraction du pixel de la SDL_Surface*
Uint32 pixel = getPixel(toSave, j, i);
// extraction de chaque composante et écriture du pixel dans la ligne du png
line[p++] = pixel>>16;
line[p++] = pixel>>8;
line[p++] = pixel;
}
// écriture de la ligne dans le fichier
png_write_row(png_ptr, line);
}
delete[] line;
png_write_end(png_ptr, png_info);
png_destroy_write_struct(&png_ptr, &png_info);
fclose(file);
return true;
} |
