cairo/test/pdiff/RGBAImage.cpp

/*
  RGBAImage.cpp
  Copyright (C) 2006 Yangli Hector Yee

  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 "RGBAImage.h"
#include "png.h"

#if HAVE_LIBTIFF
#include "tiff.h"
#include "tiffio.h"

/* Reads Tiff Images */
RGBAImage* RGBAImage::ReadTiff(char *filename)
{
    RGBAImage *fimg = 0;

    TIFF* tif = TIFFOpen(filename, "r");
    char emsg[1024];
    emsg[0] = 0;
    if (tif) {
	TIFFRGBAImage img;

	if (TIFFRGBAImageBegin(&img, tif, 0, emsg)) {
	    size_t npixels;
	    uint32* raster;

	    npixels = img.width * img.height;
	    raster = (uint32*) _TIFFmalloc(npixels * sizeof (uint32));
	    if (raster != NULL) {
		if (TIFFRGBAImageGet(&img, raster, img.width, img.height)) {
		    /* result is in ABGR */
		    fimg = new RGBAImage(img.width, img.height);
		    for (int y = img.height - 1; y >= 0; y--) {
			for (int x = 0; x < (int) img.width; x++) {
			    fimg->Set(x,img.height - (y+1), raster[x + y * img.width]);
			}
		    }
		}
		_TIFFfree(raster);
	    }
	}
	TIFFRGBAImageEnd(&img);
    }
    return fimg;
}
#endif /* HAVE_LIBTIFF */

/* This portion was written by Scott Corley */
RGBAImage* RGBAImage::ReadPNG(char *filename)
{
    RGBAImage *fimg = 0;
    FILE *fp=fopen(filename, "rb");
    if (!fp)
    {
	return NULL;
    }
    png_byte header[8];

    fread(header, 1, 8, fp);
    bool is_png = !png_sig_cmp(header, 0, 8);
    if (!is_png)
    {
	return NULL;
    }

    png_structp png_ptr = png_create_read_struct
	(PNG_LIBPNG_VER_STRING, (png_voidp)NULL,
	 NULL, NULL);
    if (!png_ptr)
        return (NULL);

    png_infop info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr)
    {
        png_destroy_read_struct(&png_ptr,
				(png_infopp)NULL, (png_infopp)NULL);
        return (NULL);
    }

    png_infop end_info = png_create_info_struct(png_ptr);
    if (!end_info)
    {
        png_destroy_read_struct(&png_ptr, &info_ptr,
				(png_infopp)NULL);
        return (NULL);
    }

    png_init_io(png_ptr, fp);
    png_set_sig_bytes(png_ptr, 8);

    png_read_png(png_ptr, info_ptr, 0, NULL);

    png_bytep *row_pointers;
    row_pointers = png_get_rows(png_ptr, info_ptr);

    fimg = new RGBAImage(png_ptr->width, png_ptr->height);
    for (int y = 0; y < (int) png_ptr->height; y++) {
	for (int x = 0; x < (int) png_ptr->width; x++) {
	    uint32_t value = 0;
	    if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
		value = ((uint32_t)row_pointers[y][x*4]) | (((uint32_t)row_pointers[y][x*4+1])<<8) | (((uint32_t)row_pointers[y][x*4+2])<<16) |(((uint32_t)row_pointers[y][x*4+3])<<24);
	    else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
		value = ((uint32_t)row_pointers[y][x*3] /*B*/) | (((uint32_t)row_pointers[y][x*3+1] /*G*/)<<8) | (((uint32_t)row_pointers[y][x*3+2]/*R*/)<<16) | (0xFFUL << 24);
	    fimg->Set(x,y, value);
	}
    }

    png_read_destroy(png_ptr, info_ptr, end_info);
    return fimg;
}

bool RGBAImage::WritePPM()
{
    if (Width <= 0) return false;
    if (Height <=0 ) return false;
    FILE *out = fopen(Name.c_str(), "wb");
    if (!out) return false;
    fprintf(out, "P6\n%d %d 255\n", Width, Height);
    for (int y = 0; y < Height; y++) {
	for (int x = 0; x < Width; x++) {
	    int i = x + y * Width;
	    unsigned char r = Get_Red(i);
	    unsigned char g = Get_Green(i);
	    unsigned char b = Get_Blue(i);
	    fwrite(&r, 1, 1, out);
	    fwrite(&g, 1, 1, out);
	    fwrite(&b, 1, 1, out);
	}
    }
    fclose(out);
    return true;
}