pnglib.cpp

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/*
 * The ManaPlus Client
 * Copyright (C) 2004-2009 The Mana World Development Team
 * Copyright (C) 2009-2010 The Mana Developers
 * Copyright (C) 2011-2019 The ManaPlus Developers
 * Copyright (C) 2019-2021 Andrei Karas
 *
 * This file is part of The ManaPlus Client.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "utils/pnglib.h"
 
#include "utils/cast.h"
#include "utils/checkutils.h"
 
#include <png.h>
PRAGMA48(GCC diagnostic push)
PRAGMA48(GCC diagnostic ignored "-Wshadow")
#include <SDL_video.h>
PRAGMA48(GCC diagnostic pop)
 
#include "debug.h"
 
bool PngLib::writePNG(SDL_Surface *const surface,
 const std::string &filename)
{
 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;
}