More generic use of event.

[familia.git] / src / ui / drawing_area.c

diff --git a/src/ui/drawing_area.c b/src/ui/drawing_area.c
index 8eefe5fc8015349391173c79f18e67c201f21c85..16448474091ed73e66c535cb5477e5ef3a713bbd 100644 (file)
--- a/src/ui/drawing_area.c
+++ b/src/ui/drawing_area.c
@@ -2,8 +2,10 @@
 #include <gtk/gtkgl.h>
 #include <GL/gl.h>
 #include <GL/glu.h>
+#include <assert.h>
 
 #include "../debug.h"
+#include "../familia.h"
 #include "drawing_area.h"
 #include "../math/3d.h"
 #include "../graphics/constants.h"
@@ -148,3 +150,47 @@ void drawing_area_unrealize (GtkWidget *widget, gpointer data)
 {
        /* Code */
 }
+
+/**
+ * The "scroll-event" signal handler. Responsible for correctly scrolling
+ * drawing area using mouse or touchpad.
+ */
+void drawing_area_event_scroll (GtkWidget *widget,
+                               GdkEvent *event, FamiliaData *data)
+{
+       GtkAdjustment *adjustment = NULL;
+       gdouble value = 0;
+       gdouble step = 0;
+
+       assert(event->type == GDK_SCROLL);
+
+       switch(event->scroll.direction) {
+               case GDK_SCROLL_UP:
+                       adjustment = data->vadjustment;
+                       step = 1;
+                       break;
+               case GDK_SCROLL_DOWN:
+                       adjustment = data->vadjustment;
+                       step = -1;
+                       break;
+               case GDK_SCROLL_LEFT:
+                       adjustment = data->hadjustment;
+                       step = -1;
+                       break;
+               case GDK_SCROLL_RIGHT:
+                       adjustment = data->hadjustment;
+                       step = 1;
+                       break;
+               default:
+                       break;
+       }
+
+       if (adjustment != NULL) {
+               value = gtk_adjustment_get_value (adjustment);
+               step  = step * gtk_adjustment_get_step_increment(adjustment);
+               value += step;
+
+               gtk_adjustment_set_value (adjustment, value);
+               gtk_adjustment_value_changed (adjustment);
+       }
+}