wmaker/util/directjpeg.c

/* directjpeg.c- loads a jpeg file directly into a XImage
 *
 *  WindowMaker window manager
 *
 *  Copyright (c) 1999-2003 Alfredo K. Kojima
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "../config.h"

#ifdef USE_JPEG

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

#include <jpeglib.h>

#include "../wrlib/wraster.h"

#include <setjmp.h>

struct my_error_mgr {
	struct jpeg_error_mgr pub;	/* "public" fields */

	jmp_buf setjmp_buffer;	/* for return to caller */
};

typedef struct my_error_mgr *my_error_ptr;

/*
 * Here's the routine that will replace the standard error_exit method:
 */

static void my_error_exit(j_common_ptr cinfo)
{
	/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
	my_error_ptr myerr = (my_error_ptr) cinfo->err;

	/* Always display the message. */
	/* We could postpone this until after returning, if we chose. */
	(*cinfo->err->output_message) (cinfo);

	/* Return control to the setjmp point */
	longjmp(myerr->setjmp_buffer, 1);
}

static Bool canLoad(RContext * rc)
{
	if (rc->depth != 16 || rc->vclass != TrueColor
	    || rc->red_offset != 11 || rc->green_offset != 5 || rc->blue_offset != 0)
		return False;

	return True;
}

static void readData(RContext * rc, struct jpeg_decompress_struct *cinfo, JSAMPROW * buffer, RXImage * ximg)
{
	int i, j;
	unsigned long pixel;
	int y = 0;

	/* for 16bpp only */
	while (cinfo->output_scanline < cinfo->output_height) {

		jpeg_read_scanlines(cinfo, buffer, (JDIMENSION) 1);

		if (cinfo->out_color_space == JCS_RGB) {
			for (i = 0, j = 0; i < cinfo->image_width; i++) {

				printf("%i %i %i\n",
				       (((unsigned long)buffer[0][j]) & 0xf8) << 8,
				       (((unsigned long)buffer[0][j + 1]) & 0xf4) << 3,
				       (((unsigned long)buffer[0][j + 2])) >> 3);

				pixel = (((unsigned long)buffer[0][j++]) & 0xf8) << 8
				    | (((unsigned long)buffer[0][j++]) & 0xf4) << 3
				    | (((unsigned long)buffer[0][j++])) >> 3;

				XPutPixel(ximg->image, i, y, pixel);
			}
		} else {
			for (i = 0, j = 0; i < cinfo->image_width; i++, j++) {

				pixel = (unsigned long)buffer[0][j] << 8
				    | (unsigned long)buffer[0][j] << 3 | (unsigned long)buffer[0][j] >> 3;

				XPutPixel(ximg->image, i, y, pixel);
			}
		}
		y++;
	}
}

Pixmap LoadJPEG(RContext * rc, char *file_name, int *width, int *height)
{
	struct jpeg_decompress_struct cinfo;
	JSAMPROW buffer[1];
	FILE *file;
	struct my_error_mgr jerr;
	RXImage *ximg = NULL;
	unsigned char buf[8];
	Pixmap p = None;

	if (!canLoad(rc))
		return None;

	file = fopen(file_name, "rb");
	if (!file) {
		return None;
	}
	if (fread(buf, 2, 1, file) != 1) {
		fclose(file);
		return None;
	}
	if (buf[0] != 0xff || buf[1] != 0xd8) {
		fclose(file);
		return None;
	}
	rewind(file);

	cinfo.err = jpeg_std_error(&jerr.pub);
	jerr.pub.error_exit = my_error_exit;
	/* Establish the setjmp return context for my_error_exit to use. */
	if (setjmp(jerr.setjmp_buffer)) {
		/* If we get here, the JPEG code has signaled an error.
		 * We need to clean up the JPEG object, close the input file, and return.
		 */
		jpeg_destroy_decompress(&cinfo);
		fclose(file);

		if (ximg) {
			RDestroyXImage(rc, ximg);
		}

		return None;
	}

	jpeg_create_decompress(&cinfo);

	jpeg_stdio_src(&cinfo, file);

	jpeg_read_header(&cinfo, TRUE);

	buffer[0] = (JSAMPROW) malloc(cinfo.image_width * cinfo.num_components);
	if (!buffer[0]) {
		RErrorCode = RERR_NOMEMORY;
		goto bye;
	}

	if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
		cinfo.out_color_space = JCS_GRAYSCALE;
	} else
		cinfo.out_color_space = JCS_RGB;
	cinfo.quantize_colors = FALSE;
	cinfo.do_fancy_upsampling = FALSE;
	cinfo.do_block_smoothing = FALSE;
	jpeg_calc_output_dimensions(&cinfo);

	ximg = RCreateXImage(rc, rc->depth, cinfo.image_width, cinfo.image_height);
	if (!ximg) {
		goto bye;
	}
	jpeg_start_decompress(&cinfo);

	readData(rc, &cinfo, buffer, ximg);

	jpeg_finish_decompress(&cinfo);

	p = XCreatePixmap(rc->dpy, rc->drawable, cinfo.image_width, cinfo.image_height, rc->depth);

	RPutXImage(rc, p, rc->copy_gc, ximg, 0, 0, 0, 0, cinfo.image_width, cinfo.image_height);

	*width = cinfo.image_width;
	*height = cinfo.image_height;

 bye:
	jpeg_destroy_decompress(&cinfo);

	fclose(file);

	if (buffer[0])
		free(buffer[0]);

	if (ximg)
		RDestroyXImage(rc, ximg);

	return p;
}

#endif				/* USE_JPEG */