PngLib Namespace Reference

Functions
bool	writePNG (SDL_Surface *const surface, const std::string &filename)

Function Documentation

writePNG()

bool PngLib::writePNG	(	SDL_Surface *const	surface,
		const std::string &	filename
	)

< Surface is in video memory

< Use asynchronous blits if possible

< Surface is RLE encoded

< Surface is in video memory

< Use asynchronous blits if possible

< Surface is RLE encoded

Definition at line 37 of file pnglib.cpp.

{
 if (surface == nullptr)
 return false;
 
 
 if (SDL_MUSTLOCK(surface))
 SDL_LockSurface(surface);
 
 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
 nullptr, nullptr, nullptr);
 if (png_ptr == nullptr)
 {
 reportAlways("Had trouble creating png_structp")
 return false;
 }
 
 png_infop info_ptr = png_create_info_struct(png_ptr);
 if (info_ptr == nullptr)
 {
 png_destroy_write_struct(&png_ptr, static_cast<png_infopp>(nullptr));
 reportAlways("Could not create png_info")
 return false;
 }
 
 if (setjmp(png_jmpbuf(png_ptr)))
 {
 png_destroy_write_struct(&png_ptr, &info_ptr);
 reportAlways("problem writing to %s", filename.c_str())
 return false;
 }
 
 FILE *const fp = fopen(filename.c_str(), "wb");
 if (fp == nullptr)
 {
 reportAlways("could not open file %s for writing",
 filename.c_str())
 return false;
 }
 
 png_init_io(png_ptr, fp);
 
 const int colortype = (surface->format->BitsPerPixel == 24) ?
 PNG_COLOR_TYPE_RGB : PNG_COLOR_TYPE_RGB_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_write_info(png_ptr, info_ptr);
 
 png_set_packing(png_ptr);
 
 png_bytep *const row_pointers
 = new png_bytep[CAST_SIZE(surface->h)];
 
 for (int i = 0; i < surface->h; i++)
 {
 row_pointers[i] = static_cast<png_bytep>(static_cast<uint8_t *>(
 surface->pixels) + CAST_SIZE(i * surface->pitch));
 }
 
 png_write_image(png_ptr, row_pointers);
 png_write_end(png_ptr, info_ptr);
 
 fclose(fp);
 
 delete [] row_pointers;
 
 png_destroy_write_struct(&png_ptr,
 &info_ptr);
 
 if (SDL_MUSTLOCK(surface))
 SDL_UnlockSurface(surface);
 
 return true;
}

References CAST_SIZE, and reportAlways.

Referenced by main(), and Game::saveScreenshot().