libpipi/pipi/codec/modular/jpeg.c

/*
 *  libpipi       Pathetic image processing interface library
 *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
 *                2008 Jean-Yves Lamoureux <jylam@lnxscene.org>
 *                All Rights Reserved
 *
 *  $Id$
 *
 *  This library is free software. It comes without any warranty, to
 *  the extent permitted by applicable law. You can redistribute it
 *  and/or modify it under the terms of the Do What The Fuck You Want
 *  To Public License, Version 2, as published by Sam Hocevar. See
 *  http://sam.zoy.org/wtfpl/COPYING for more details.
 */

/*
 * jpeg.c: libjpeg I/O functions
 */

#include "../modular.h"

static int pipi_free_jpeg(pipi_image_t *img);


static void format_msg(j_common_ptr cinfo, char *buf)
{
}
static void emit_msg(j_common_ptr cinfo, int level)
{
}
static void error_msg(j_common_ptr cinfo)
{
    cinfo->client_data = (void*)0x1;
}
static void output_msg(j_common_ptr cinfo)
{
}

pipi_image_t *pipi_load_jpeg(const char *name)
{
    struct jpeg_decompress_struct cinfo;
    struct jpeg_error_mgr jerr;
    unsigned char *image = NULL, *scanline = NULL;
    pipi_image_t *img = NULL;
    unsigned int i, j, k = 0;

    FILE *fp = fopen(name, "rb");
    if(!fp) goto end;


    cinfo.err = jpeg_std_error(&jerr);
    jerr.error_exit = error_msg;
    jerr.emit_message = emit_msg;
    jerr.output_message = output_msg;
    jerr.format_message = format_msg;

    jpeg_create_decompress(&cinfo);
    cinfo.client_data = 0x0;
    jpeg_stdio_src(&cinfo, fp);
    if((int)cinfo.client_data == 0x1) {
        goto end;
    }
    jpeg_read_header(&cinfo, TRUE);
    if((int)cinfo.client_data == 0x1) {
        goto end;
    }
    jpeg_start_decompress(&cinfo);
    if((int)cinfo.client_data == 0x1) {
        goto end;
    }

    image = malloc(cinfo.output_width * cinfo.output_height * 4);
    if(!image) goto end;

    scanline = malloc(cinfo.output_width * 3);

    /* Read scanlines, converting them to RGBA */
    for(i=0; i < cinfo.output_height; i++)
    {
        jpeg_read_scanlines(&cinfo, &scanline, 1);
        if((int)cinfo.client_data == 0x1) {
            free(img);
            img = NULL;
            goto end;
        }
        for(j=0 ; j<cinfo.output_width*3; j+=3)
        {
            image[k+2] = scanline[j];
            image[k+1] = scanline[j+1];
            image[k]   = scanline[j+2];
            image[k+3] = 255;
            k+=4;
        }
    }

    img = pipi_new(cinfo.output_width, cinfo.output_height);

    img->p[PIPI_PIXELS_RGBA_C].pixels = image;
    img->p[PIPI_PIXELS_RGBA_C].w = cinfo.output_width;
    img->p[PIPI_PIXELS_RGBA_C].h = cinfo.output_height;
    img->p[PIPI_PIXELS_RGBA_C].pitch = cinfo.output_width*4;
    img->p[PIPI_PIXELS_RGBA_C].bpp = 24;
    img->p[PIPI_PIXELS_RGBA_C].bytes = 4 * img->w * img->h;
    img->last_modified = PIPI_PIXELS_RGBA_C;

    img->codec_priv = (void *)&cinfo;
    img->codec_format = PIPI_PIXELS_RGBA_C;
    img->codec_free = pipi_free_jpeg;

    img->wrap = 0;
    img->u8 = 1;

end:
    if(fp) fclose(fp);
    if(scanline) free(scanline);
    jpeg_destroy_decompress(&cinfo);
    return img;
}

int pipi_save_jpeg(pipi_image_t *img, const char *name)
{
    return 0;
}

static int pipi_free_jpeg(pipi_image_t *img)
{
    return 0;
}