Add a draw callback to draw a theme based up/down arrow

gnucash/gnome-utils/dialog-utils.c

@@ -293,6 +293,38 @@ gnc_widget_set_style_context (GtkWidget *widget, const char *gnc_class)
     gtk_style_context_add_class (context, gnc_class);
 }
 
+/********************************************************************\
+ * Draw an arrow on a Widget so it can be altered with css          *
+ *                                                                  *
+ * Args:     widget - widget to add arrow to in the draw callback   *
+ *               cr - cairo context for the draw callback           *
+ *        direction - 0 for up, 1 for down                          *
+ * Returns:  TRUE, stop other handlers being invoked for the event  *
+\********************************************************************/
+gboolean
+gnc_draw_arrow_cb (GtkWidget *widget, cairo_t *cr, gpointer direction)
+{
+    GtkStyleContext *context = gtk_widget_get_style_context (widget);
+    gint width = gtk_widget_get_allocated_width (widget);
+    gint height = gtk_widget_get_allocated_height (widget);
+    gint size;
+
+    gtk_render_background (context, cr, 0, 0, width, height);
+    gtk_style_context_add_class (context, GTK_STYLE_CLASS_ARROW);
+
+    size = MIN(width / 2, height / 2);
+
+    if (GPOINTER_TO_INT(direction) == 0)
+        gtk_render_arrow (context, cr, 0,
+                         (width - size)/2, (height - size)/2, size);
+    else
+        gtk_render_arrow (context, cr, G_PI,
+                         (width - size)/2, (height - size)/2, size);
+
+    return TRUE;
+}
+
+
 gboolean
 gnc_handle_date_accelerator (GdkEventKey *event,
                              struct tm *tm,

gnucash/gnome-utils/dialog-utils.h

@@ -88,6 +88,16 @@ GtkTreeViewGridLines gnc_tree_view_get_grid_lines_pref (void);
 \********************************************************************/
 void gnc_widget_set_style_context (GtkWidget *widget, const char *gnc_class);
 
+/********************************************************************\
+ * Draw an arrow on a Widget so it can be altered with css          *
+ *                                                                  *
+ * Args:     widget - widget to add arrow to in the draw callback   *
+ *               cr - cairo context for the draw callback           *
+ *        direction - 0 for up, 1 for down                          *
+ * Returns:  TRUE, stop other handlers being invoked for the event  *
+\********************************************************************/
+gboolean gnc_draw_arrow_cb (GtkWidget *widget, cairo_t *cr, gpointer direction);
+
 gboolean gnc_handle_date_accelerator (GdkEventKey *event,
                                       struct tm *tm,
                                       const char *date_str);