source: trunk/src/testing/app/bitplay/libimg/jpegdisp.c @ 4

/******************************************************************************
 * SAGE - Scalable Adaptive Graphics Environment
 *
 * Copyright (C) 2004 Electronic Visualization Laboratory,
 * University of Illinois at Chicago
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following disclaimer
 *    in the documentation and/or other materials provided with the distribution.
 *  * Neither the name of the University of Illinois at Chicago nor
 *    the names of its contributors may be used to endorse or promote
 *    products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 *****************************************************************************/

/*
 * Given a JPEG file, return a DISPIMAGE
 * containing its raster data and with size <= (xsize, ysize).
 */

#include <stdio.h>
#include <stdlib.h>
#include "jpeglib.h"
#include "imginfo.h"

#ifndef alloca
# include <alloca.h>
#endif

IMG *
jpegmakedisp(char *filename)
{
    FILE *f;
    IMG *di = NULL;
    int xsize, ysize, zsize;
    int x, y;
    struct jpeg_error_mgr jerr[1];
    struct jpeg_decompress_struct jp[1];
    JSAMPARRAY yx;
    JSAMPROW trow;

    f = fopen(filename, "r");
    if(f == NULL) {
        fprintf(stderr, "%s: cannot open: ", filename);
        perror("");
        return NULL;
    }

    jp->err = jpeg_std_error( jerr );
    jpeg_create_decompress( jp );
    jpeg_stdio_src( jp, f );
    if(jpeg_read_header( jp, TRUE ) != JPEG_HEADER_OK)
        goto fail;

    jpeg_start_decompress( jp );


    di = (IMG *)malloc(sizeof(IMG));
    di->xsize = xsize = jp->output_width;
    di->ysize = ysize = jp->output_height;
    zsize = jp->output_components;
    di->data = (unsigned char *)malloc( xsize * ysize * 4 * sizeof(char) );
    di->type = IT_LONG;
    if(di->data == NULL) {
        fprintf(stderr, "Not enough memory for %dx%dx%d image %s!\n",
                xsize, ysize, zsize, filename);
        goto fail;
    }

    yx = (JSAMPARRAY) alloca( jp->rec_outbuf_height * sizeof(JSAMPROW) );
    trow = (JSAMPROW) alloca( zsize * xsize * jp->rec_outbuf_height * sizeof(JSAMPLE) );

    for(y = 0; y < jp->rec_outbuf_height; y++)
        yx[y] = &trow[ y * xsize * zsize ];

    while(jp->output_scanline < ysize) {
        int y, got, nleft;
        JSAMPLE *ip = trow;
        y = jp->output_scanline;
        nleft = ysize - y;
        if(nleft > jp->rec_outbuf_height) nleft = jp->rec_outbuf_height;
        got = jpeg_read_scanlines( jp, yx, nleft );
        if(got <= 0) {
            fprintf(stderr, "%s: trouble reading JPEG row %d of 0..%d (nleft %d)\n", filename, y, ysize-1, nleft);
            break;
        }
        while(--got >= 0) {
            unsigned int *op = (unsigned int *)&di->data[ (ysize-1 - y) * xsize * 4 ];
            x = xsize;
            switch(zsize) {
            case 1:
                do {
                    *op++ = (0xFF<<24) | (*ip++ * 0x010101);
                } while(--x > 0);
                break;
            case 3:
                do {
                    *op++ = (0xFF<<24) | (ip[2]<<16) | (ip[1]<<8) | (ip[0]);
                    ip += 3;
                } while(--x > 0);
                break;
            }
            y++;
        }
    }
    jpeg_finish_decompress( jp );
    jpeg_destroy( (j_common_ptr) jp );
    fclose(f);
    return di;

  fail:
    jpeg_destroy( (j_common_ptr) jp );
    if(di) {
        if(di->data) free(di->data);
        free(di);
    }
    if(f != NULL)
        fclose(f);
    return NULL;
}