/* save_jpeg.c - save JPEG image
 *
 * Raster graphics library
 *
 * Copyright (c) 2023 Window Maker Team
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
 *  MA 02110-1301, USA.
 */

#include <config.h>

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <jpeglib.h>

#include <WINGs/WUtil.h>

#include "wraster.h"
#include "imgformat.h"
#include "wr_i18n.h"

/*
 *  Save RImage to JPEG image
 */

Bool RSaveJPEG(RImage *img, const char *filename, char *title)
{
	FILE *file;
	int x, y, img_depth;
	char *buffer;
	RColor pixel;
	struct jpeg_compress_struct cinfo;
	struct jpeg_error_mgr jerr;
	JSAMPROW row_pointer;

	file = fopen(filename, "wb");
	if (!file) {
		RErrorCode = RERR_OPEN;
		return False;
	}

	if (img->format == RRGBAFormat)
		img_depth = 4;
	else
		img_depth = 3;

	/* collect separate RGB values to a buffer */
	buffer = wmalloc(sizeof(char) * 3 * img->width * img->height);
	for (y = 0; y < img->height; y++) {
		for (x = 0; x < img->width; x++) {
			RGetPixel(img, x, y, &pixel);
			buffer[y*img->width*3+x*3+0] = (char)(pixel.red);
			buffer[y*img->width*3+x*3+1] = (char)(pixel.green);
			buffer[y*img->width*3+x*3+2] = (char)(pixel.blue);
		}
	}

	/* Setup Exception handling */
	cinfo.err = jpeg_std_error(&jerr);

	/* Initialize cinfo structure */
	jpeg_create_compress(&cinfo);
	jpeg_stdio_dest(&cinfo, file);

	cinfo.image_width = img->width;
	cinfo.image_height = img->height;
	cinfo.input_components = 3;
	cinfo.in_color_space = JCS_RGB;

	jpeg_set_defaults(&cinfo);
	jpeg_set_quality(&cinfo, 85, TRUE);
	jpeg_start_compress(&cinfo, TRUE);

	/* Set title if any */
	if (title)
		jpeg_write_marker(&cinfo, JPEG_COM, (const JOCTET*)title, strlen(title));

	while (cinfo.next_scanline < cinfo.image_height) {
        	row_pointer = (JSAMPROW) &buffer[cinfo.next_scanline * img_depth * img->width];
		jpeg_write_scanlines(&cinfo, &row_pointer, 1);
	}

	jpeg_finish_compress(&cinfo);
	
	/* Clean */
	wfree(buffer);
	fclose(file);

	return True;
}
