jbig2_image_png.c

/*
    jbig2dec

    Copyright (C) 2002 Artifex Software, Inc.

    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.

    For further licensing information refer to http://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.
*/

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

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

#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;

    check = fwrite(data, 1, length, (png_FILE_p)png_ptr->io_ptr);
    if (check != length) {
      png_error(png_ptr, "Write Error");
    }
}

static void
jbig2_png_flush(png_structp png_ptr)
{
    png_FILE_p io_ptr;
    io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
    if (io_ptr != NULL)
        fflush(io_ptr);
}

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;
}