imagewriter.cpp

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/*
 *  The Mana Client
 *  Copyright (C) 2004-2009  The Mana World Development Team
 *  Copyright (C) 2009-2012  The Mana Developers
 *
 *  This file is part of The Mana 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 "resources/imagewriter.h"
 
#include "log.h"
 
#include <png.h>
#include <SDL.h>
#include <string>
 
bool ImageWriter::writePNG(SDL_Surface *surface, const std::string &filename)
{
    // TODO Maybe someone can make this look nice?
 
    png_structp png_ptr;
    png_infop info_ptr;
    png_bytep *row_pointers;
    int colortype;
 
    if (SDL_MUSTLOCK(surface))
        SDL_LockSurface(surface);
 
    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
    if (!png_ptr)
    {
        Log::info("Had trouble creating png_structp");
        return false;
    }
 
    info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr)
    {
        png_destroy_write_struct(&png_ptr, (png_infopp)nullptr);
        Log::info("Could not create png_info");
        return false;
    }
 
    if (setjmp(png_jmpbuf(png_ptr)))
    {
        png_destroy_write_struct(&png_ptr, (png_infopp)nullptr);
        Log::info("problem writing to %s", filename.c_str());
        return false;
    }
 
    FILE *fp = fopen(filename.c_str(), "wb");
    if (!fp)
    {
        Log::info("could not open file %s for writing", filename.c_str());
        return false;
    }
 
    png_init_io(png_ptr, fp);
 
    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);
 
    row_pointers = new png_bytep[surface->h];
    if (!row_pointers)
    {
        Log::info("Had trouble converting surface to row pointers");
        fclose(fp);
        return false;
    }
 
    for (int i = 0; i < surface->h; i++)
    {
        row_pointers[i] = (png_bytep)(Uint8 *)surface->pixels + 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, (png_infopp)nullptr);
 
    if (SDL_MUSTLOCK(surface))
        SDL_UnlockSurface(surface);
 
    return true;
}