WRaster: add function to save image in memory

This patch adds the RSaveRawImage() function to the WRaster lib
to be able to save image structure in memory.
The WRaster lib version is bumped.

wrlib/save_jpeg.c

@@ -2,7 +2,7 @@
  *
  * Raster graphics library
  *
- * Copyright (c) 2023 Window Maker Team
+ * Copyright (c) 2023-2025 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
@@ -33,39 +33,92 @@
 #include "imgformat.h"
 #include "wr_i18n.h"
 
+/* Structure for JPEG memory destination */
+struct jpeg_mem_data {
+	unsigned char **out_buf;
+	size_t *out_size;
+	unsigned char *buffer;
+	size_t buffer_size;
+};
+
+/* JPEG memory destination methods */
+static void jpeg_init_mem_destination(j_compress_ptr cinfo)
+{
+	struct jpeg_mem_data *dest = (struct jpeg_mem_data *)cinfo->client_data;
+	dest->buffer_size = 32768; /* Initial buffer size */
+	dest->buffer = malloc(dest->buffer_size);
+	if (!dest->buffer) {
+		/* Memory allocation failed - will be caught by caller */
+		dest->buffer_size = 0;
+		return;
+	}
+	cinfo->dest->next_output_byte = dest->buffer;
+	cinfo->dest->free_in_buffer = dest->buffer_size;
+}
+
+static boolean jpeg_empty_mem_output_buffer(j_compress_ptr cinfo)
+{
+	struct jpeg_mem_data *dest = (struct jpeg_mem_data *)cinfo->client_data;
+	size_t old_size = dest->buffer_size;
+	dest->buffer_size *= 2;
+	dest->buffer = realloc(dest->buffer, dest->buffer_size);
+	if (!dest->buffer) {
+		/* Memory allocation failed - signal error */
+		dest->buffer_size = 0;
+		return FALSE;
+	}
+	cinfo->dest->next_output_byte = dest->buffer + old_size;
+	cinfo->dest->free_in_buffer = dest->buffer_size - old_size;
+	return TRUE;
+}
+
+static void jpeg_term_mem_destination(j_compress_ptr cinfo)
+{
+	struct jpeg_mem_data *dest = (struct jpeg_mem_data *)cinfo->client_data;
+	*dest->out_size = dest->buffer_size - cinfo->dest->free_in_buffer;
+	*dest->out_buf = dest->buffer;
+	/* Don't free dest->buffer here - caller will free it */
+}
+
 /*
- *  Save RImage to JPEG image
+ *  Save RImage to JPEG data in memory
  */
 
-Bool RSaveJPEG(RImage *img, const char *filename, char *title)
+Bool RSaveRawJPEG(RImage *img, char *title, unsigned char **out_buf, size_t *out_size)
 {
-	FILE *file;
-	int x, y, img_depth;
+	int x, y;
 	char *buffer;
 	RColor pixel;
 	struct jpeg_compress_struct cinfo;
 	struct jpeg_error_mgr jerr;
+	struct jpeg_destination_mgr jpeg_dest;
+	struct jpeg_mem_data mem_data;
 	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;
+	*out_buf = NULL;
+	*out_size = 0;
 
 	/* collect separate RGB values to a buffer */
 	buffer = malloc(sizeof(char) * 3 * img->width * img->height);
+	if (!buffer) {
+		RErrorCode = RERR_NOMEMORY;
+		return False;
+	}
+
 	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);
+			/* Handle transparent pixels by converting them to white
+			 * since JPEG doesn't support transparency */
+			if (pixel.alpha == 0) {
+				buffer[y*img->width*3+x*3+0] = (char)255; /* white red */
+				buffer[y*img->width*3+x*3+1] = (char)255; /* white green */
+				buffer[y*img->width*3+x*3+2] = (char)255; /* white blue */
+			} else {
+				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);
+			}
 		}
 	}
 
@@ -74,7 +127,17 @@ Bool RSaveJPEG(RImage *img, const char *filename, char *title)
 
 	/* Initialize cinfo structure */
 	jpeg_create_compress(&cinfo);
-	jpeg_stdio_dest(&cinfo, file);
+
+	/* Set up custom memory destination */
+	mem_data.out_buf = out_buf;
+	mem_data.out_size = out_size;
+	jpeg_dest.init_destination = jpeg_init_mem_destination;
+	jpeg_dest.empty_output_buffer = jpeg_empty_mem_output_buffer;
+	jpeg_dest.term_destination = jpeg_term_mem_destination;
+	cinfo.dest = &jpeg_dest;
+	cinfo.dest->next_output_byte = NULL;
+	cinfo.dest->free_in_buffer = 0;
+	cinfo.client_data = &mem_data;
 
 	cinfo.image_width = img->width;
 	cinfo.image_height = img->height;
@@ -90,15 +153,51 @@ Bool RSaveJPEG(RImage *img, const char *filename, char *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];
+		row_pointer = (JSAMPROW) &buffer[cinfo.next_scanline * 3 * img->width];
 		jpeg_write_scanlines(&cinfo, &row_pointer, 1);
 	}
 
 	jpeg_finish_compress(&cinfo);
+	jpeg_destroy_compress(&cinfo);
 	
 	/* Clean */
 	free(buffer);
-	fclose(file);
+
+	return True;
+}
+
+/*
+ *  Save RImage to JPEG file
+ */
+
+Bool RSaveJPEG(RImage *img, const char *filename, char *title)
+{
+	FILE *file;
+	unsigned char *jpeg_data;
+	size_t jpeg_size;
+	size_t written;
+
+	/* Generate JPEG data in memory */
+	if (!RSaveRawJPEG(img, title, &jpeg_data, &jpeg_size)) {
+		return False;
+	}
+
+	/* Write to file */
+	file = fopen(filename, "wb");
+	if (!file) {
+		free(jpeg_data);
+		RErrorCode = RERR_OPEN;
+		return False;
+	}
+
+	written = fwrite(jpeg_data, 1, jpeg_size, file);
+	fclose(file);
+	free(jpeg_data);
+
+	if (written != jpeg_size) {
+		RErrorCode = RERR_WRITE;
+		return False;
+	}
 
 	return True;
 }