PNGLoader.cpp

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// Copyright (C) 2005 Dave Griffiths
//
// 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
// (at your option) 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, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

#include <png.h>
#include "PNGLoader.h"
#include "Trace.h"

using namespace Fluxus;

unsigned char *PNGLoader::Load(const string &Filename, int &w, int &h, PixelFormat &pf)
{
    unsigned char *ImageData = NULL;
    FILE *fp=fopen(Filename.c_str(),"rb");
    if (!fp) Trace::Stream<<"Couldn't open image ["<<Filename<<"]"<<endl;
    else
    {
        png_structp png_ptr;
        png_infop info_ptr;
        
        png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
        info_ptr = png_create_info_struct(png_ptr);
        png_init_io(png_ptr, fp);
        png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);      
        fclose(fp);
        
        ImageData = new unsigned char[png_ptr->rowbytes*png_ptr->height];
        int p=0;
        for (unsigned int row = 0; row < png_ptr->height; row++)
        {
            for (unsigned int i=0; i<png_ptr->rowbytes; i++)
            {
                ImageData[p]=(unsigned char)info_ptr->row_pointers[row][i];
                p++;
            }
        }
        
        w=png_ptr->width;
        h=png_ptr->height;
        
        switch (png_ptr->color_type)
        {
            case PNG_COLOR_TYPE_RGB : pf=RGB; break;
            case PNG_COLOR_TYPE_RGB_ALPHA : pf=RGBA; break;
            default : Trace::Stream<<"PNG pixel format not supported : "<<png_ptr->color_type<<endl;
        }

        png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL); 
    }
    
    return ImageData;
}

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