/* tiff.c - load TIFF image from file
 *
 * Raster graphics library
 *
 * Copyright (c) 1997-2003 Alfredo K. Kojima
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <config.h>


#ifdef USE_TIFF

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <tiff.h>
#include <tiffio.h>


#include "wraster.h"


RImage*
RLoadTIFF(RContext *context, char *file, int index)
{
    RImage *image = NULL;
    TIFF *tif;
    int i;
    unsigned char *r, *g, *b, *a;
    uint16 alpha, amode;
    uint32 width, height;
    uint32 *data, *ptr;
    uint16 extrasamples;
    uint16 *sampleinfo;
    int ch;


    tif = TIFFOpen(file, "r");
    if (!tif)
        return NULL;

    /* seek index */
    i = index;
    while (i>0) {
        if (!TIFFReadDirectory(tif)) {
            RErrorCode = RERR_BADINDEX;
            TIFFClose(tif);
            return NULL;
        }
        i--;
    }

    /* get info */
    TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &width);
    TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &height);

    TIFFGetFieldDefaulted(tif, TIFFTAG_EXTRASAMPLES,
                          &extrasamples, &sampleinfo);

    alpha = (extrasamples == 1 &&
             ((sampleinfo[0] == EXTRASAMPLE_ASSOCALPHA) || (sampleinfo[0] == EXTRASAMPLE_UNASSALPHA)));
    amode = (extrasamples == 1 && sampleinfo[0] == EXTRASAMPLE_ASSOCALPHA);

    if (width<1 || height<1) {
        RErrorCode = RERR_BADIMAGEFILE;
        TIFFClose(tif);
        return NULL;
    }

    /* read data */
    ptr = data = (uint32*)_TIFFmalloc(width * height * sizeof(uint32));

    if (!data) {
        RErrorCode = RERR_NOMEMORY;
    } else {
        if (!TIFFReadRGBAImage(tif, width, height, data, 0)) {
            RErrorCode = RERR_BADIMAGEFILE;
        } else {

            /* convert data */
            image = RCreateImage(width, height, alpha);

            if (alpha)
                ch = 4;
            else
                ch = 3;

            if (image) {
                int x, y;

                r = image->data;
                g = image->data+1;
                b = image->data+2;
                a = image->data+3;

                /* data seems to be stored upside down */
                data += width * (height-1);
                for (y=0; y<height; y++) {
                    for (x=0; x<width; x++) {

                        *(r) = (*data) & 0xff;
                        *(g) = (*data >> 8) & 0xff;
                        *(b) = (*data >> 16) & 0xff;

                        if (alpha) {
                            *(a) = (*data >> 24) & 0xff;

                            if (amode && (*a > 0)) {
                                *r = (*r * 255) / *(a);
                                *g = (*g * 255) / *(a);
                                *b = (*b * 255) / *(a);
                            }

                            a+=4;
                        }

                        r+=ch; g+=ch; b+=ch;
                        data++;
                    }
                    data -= 2*width;
                }
            }
        }
        _TIFFfree(ptr);
    }

    TIFFClose(tif);

    return image;
}

#endif /* USE_TIFF */