cairo-renderer: Update coding style and add comment explaining how to use the inter process communication to update the GUI with rendering status updates

gds-render-gui.c

@@ -187,8 +187,7 @@ static gboolean cell_store_filter_visible_func(GtkTreeModel *model, GtkTreeIter
 
 	gtk_tree_model_get(model, iter, CELL_SEL_CELL, &cell, CELL_SEL_LIBRARY, &lib, -1);
 
-    /* Show always, if this is a pure lib entry */
-    if (lib && !cell) {
+	if (lib) {
 		result = TRUE;
 		goto exit_filter;
 	}

output-renderers/cairo-renderer.c

@@ -275,11 +275,19 @@ static int cairo_renderer_render_cell_to_vector_file(GdsOutputRenderer *renderer
 		goto ret_parent;
 	}
 
-	/* Close stdin and (stdout and stderr may live on) */
-	close(0);
-	//close(1);
-	close(comm_pipe[0]);
+	/* We are now in a separate process just for rendering the output image.
+     * You may print a log message to the activity bar of the gui by writing a line
+     * teminated with '\n' to comm_pipe[1]. This will be handled by the parent process.
+     * Directly calling the update function 
+     *     gds_output_renderer_update_async_progress()
+     * does not have any effect because this is a separate process.
+     */
   
+	/*
+     * Close stdin and (stdout and stderr may live on)
+     */
+	close(0);
+	close(comm_pipe[0]);
 
 	layers = (struct cairo_layer *)calloc(MAX_LAYERS, sizeof(struct cairo_layer));
 

output-renderers/latex-renderer.c

@@ -370,7 +370,7 @@ static int latex_renderer_render_output(GdsOutputRenderer *renderer,
 						l_renderer->pdf_layers, l_renderer->tex_standalone, renderer);
 		fclose(tex_file);
 	} else {
-        g_warning(_("Could not open LaTeX output file"));
+		g_error(_("Could not open LaTeX output file"));
 	}
 
 	if (settings)