source: libpipi/trunk/pipi/codec/modular/jpeg.c @ 3081 Tweet

/*
 *  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)
{
    int quality = 75; /* FIXME */

    struct jpeg_compress_struct cinfo;
    struct jpeg_error_mgr jerr;
    unsigned char *data = NULL;
    unsigned char *line = NULL;

    pipi_pixels_t *pixels = pipi_getpixels(img, PIPI_PIXELS_RGBA_C);

    if (!pixels)
        return 0;

    data = pixels->pixels;


    line = malloc(img->w * 3 * sizeof(unsigned char));
    if (!line)
        return 0;

    FILE *fp = fopen(name, "wb");
    if (!fp) {
        free(line);
        return 0;
    }

    jerr.error_exit = error_msg;
    jerr.emit_message = emit_msg;
    jerr.output_message = output_msg;

    cinfo.err = jpeg_std_error(&(jerr));

    jpeg_create_compress(&cinfo);
    jpeg_stdio_dest(&cinfo, fp);
    cinfo.image_width = img->w;
    cinfo.image_height = img->h;
    cinfo.input_components = 3;
    cinfo.in_color_space = JCS_RGB;

    jpeg_set_defaults(&cinfo);
    jpeg_set_quality(&cinfo, quality, TRUE);
    jpeg_start_compress(&cinfo, TRUE);

    int j, i, y = 0;
    uint32_t *ptr = (uint32_t*)data;
    JSAMPROW           *jbuf;

    while (cinfo.next_scanline < cinfo.image_height)
    {
        for (j = 0, i = 0; i < img->w; i++)
        {
            line[j++] = ((*ptr) >> 16) & 0xff;
            line[j++] = ((*ptr) >> 8) & 0xff;
            line[j++] = ((*ptr)) & 0xff;
            ptr++;
        }
        /* write scanline */
        jbuf = (JSAMPROW *) (&line);
        jpeg_write_scanlines(&cinfo, jbuf, 1);
        y++;
    }

    jpeg_finish_compress(&cinfo);
    jpeg_destroy_compress(&cinfo);
    free(line);
    fclose(fp);

    return 1;
}

static int pipi_free_jpeg(pipi_image_t *img)
{
    if(img->p[PIPI_PIXELS_RGBA_C].pixels)
        free(img->p[PIPI_PIXELS_RGBA_C].pixels);
    return 0;
}