Add support for mouse wheel scrolling in EScrollFrame.

2000-06-11  Anders Carlsson  <andersca@gnu.org>

	* e-scroll-frame.c (e_scroll_frame_button_press): Add support
	for mouse wheel scrolling in EScrollFrame.

svn path=/trunk/; revision=3526

1 files changed, 31 insertions, 2 deletions

diff --git a/widgets/misc/e-scroll-frame.c b/widgets/misc/e-scroll-frame.c
index f36e5a1fbe..f4317d51d7 100644
--- a/widgets/misc/e-scroll-frame.c
+++ b/widgets/misc/e-scroll-frame.c
@@ -128,7 +128,7 @@ static void e_scroll_frame_draw (GtkWidget *widget, GdkRectangle *area);
 static void e_scroll_frame_size_request (GtkWidget *widget, GtkRequisition *requisition);
 static void e_scroll_frame_size_allocate (GtkWidget *widget, GtkAllocation *allocation);
 static gint e_scroll_frame_expose (GtkWidget *widget, GdkEventExpose *event);
-
+static gint e_scroll_frame_button_press (GtkWidget *widget, GdkEventButton *event);
 static void e_scroll_frame_add (GtkContainer *container, GtkWidget *widget);
 static void e_scroll_frame_remove (GtkContainer *container, GtkWidget *widget);
 static void e_scroll_frame_forall (GtkContainer *container, gboolean include_internals,
@@ -223,7 +223,8 @@ e_scroll_frame_class_init (EScrollFrameClass *class)
 	widget_class->size_request = e_scroll_frame_size_request;
 	widget_class->size_allocate = e_scroll_frame_size_allocate;
 	widget_class->expose_event = e_scroll_frame_expose;
-
+	widget_class->button_press_event = e_scroll_frame_button_press;
+	
 	container_class->add = e_scroll_frame_add;
 	container_class->remove = e_scroll_frame_remove;
 	container_class->forall = e_scroll_frame_forall;
@@ -778,6 +779,34 @@ e_scroll_frame_size_allocate (GtkWidget *widget, GtkAllocation *allocation)
 		gtk_widget_hide (priv->vsb);
 }
 
+/* Button press handler for the scroll framw diget */
+static gint
+e_scroll_frame_button_press (GtkWidget *widget, GdkEventButton *event)
+{
+	g_return_val_if_fail (widget != NULL, FALSE);
+	g_return_val_if_fail (E_IS_SCROLL_FRAME (widget), FALSE);
+	g_return_val_if_fail (event != NULL, FALSE);
+
+	/* This is to handle mouse wheel scrolling */
+	if (event->button == 4 || event->button == 5) {
+		GtkAdjustment *adj;
+		gfloat new_value;
+		
+		gtk_object_get (GTK_OBJECT (widget),
+				"vadjustment", &adj,
+				NULL);
+		new_value = adj->value + ((event->button == 4) ? 
+					  -adj->page_increment / 2: 
+					  adj->page_increment / 2);
+		new_value = CLAMP (new_value, adj->lower, adj->upper - adj->page_size);
+		gtk_adjustment_set_value (adj, new_value);
+
+		return TRUE;
+	}
+
+	return FALSE;
+}
+
 /* Expose handler for the scroll frame widget */
 static gint
 e_scroll_frame_expose (GtkWidget *widget, GdkEventExpose *event)