shithub: jbig2

ref: b6c58d62f2a0b4af079622afad099a06f045ab1a
dir: /jbig2_image_png.c/

/* Copyright (C) 2001-2012 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  7 Mt. Lassen Drive - Suite A-134, San Rafael,
   CA  94903, U.S.A., +1(415)492-9861, for further information.
*/

/*
    jbig2dec
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "os_types.h"

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

#ifndef OLD_LIB_PNG
# if PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR < 2
#  define OLD_LIB_PNG 1
# else
#  define OLD_LIB_PNG 0
# endif
#endif

#if OLD_LIB_PNG
#include <pngstruct.h>
#endif

#define CVT_PTR(ptr) (ptr)

#include "jbig2.h"
#include "jbig2_priv.h"
#include "jbig2_image.h"

/* take an image structure and write it out in png format */

static void
jbig2_png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
    png_size_t check;

#if OLD_LIB_PNG
    png_FILE_p f = (png_FILE_p) png_ptr->io_ptr;
#else
    png_FILE_p f = (png_FILE_p) png_get_io_ptr(png_ptr);
#endif

    check = fwrite(data, 1, length, f);
    if (check != length) {
        png_error(png_ptr, "Write Error");
    }
}

static void
jbig2_png_flush(png_structp png_ptr)
{
#if OLD_LIB_PNG
    png_FILE_p f = (png_FILE_p) png_ptr->io_ptr;
#else
    png_FILE_p f = (png_FILE_p) png_get_io_ptr(png_ptr);
#endif

    if (f != NULL)
        fflush(f);
}

int
jbig2_image_write_png_file(Jbig2Image *image, char *filename)
{
    FILE *out;
    int error;

    if ((out = fopen(filename, "wb")) == NULL) {
        fprintf(stderr, "unable to open '%s' for writing\n", filename);
        return 1;
    }

    error = jbig2_image_write_png(image, out);

    fclose(out);
    return (error);
}

/* write out an image struct in png format to an open file pointer */

int
jbig2_image_write_png(Jbig2Image *image, FILE *out)
{
    int i;
    png_structp png;
    png_infop info;
    png_bytep rowpointer;

    png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
    if (png == NULL) {
        fprintf(stderr, "unable to create png structure\n");
        return 2;
    }

    info = png_create_info_struct(png);
    if (info == NULL) {
        fprintf(stderr, "unable to create png info structure\n");
        png_destroy_write_struct(&png, (png_infopp) NULL);
        return 3;
    }

    /* set/check error handling */
    if (setjmp(png_jmpbuf(png))) {
        /* we've returned here after an internal error */
        fprintf(stderr, "internal error in libpng saving file\n");
        png_destroy_write_struct(&png, &info);
        return 4;
    }

    /* png_init_io() doesn't work linking dynamically to libpng on win32
       one has to either link statically or use callbacks because of runtime
       variations */
    /* png_init_io(png, out); */
    png_set_write_fn(png, (png_voidp) out, jbig2_png_write_data, jbig2_png_flush);

    /* now we fill out the info structure with our format data */
    png_set_IHDR(png, info, image->width, image->height, 1, PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
    png_write_info(png, info);

    /* png natively treates 0 as black. This will convert for us */
    png_set_invert_mono(png);

    /* write out each row in turn */
    rowpointer = (png_bytep) image->data;
    for (i = 0; i < image->height; i++) {
        png_write_row(png, rowpointer);
        rowpointer += image->stride;
    }

    /* finish and clean up */
    png_write_end(png, info);
    png_destroy_write_struct(&png, &info);

    return 0;
}