+void Slider::start_drag(int p)
+{
+ dragging=true;
+ drag_start_pos=p;
+ drag_start_value=value;
+}
+
+void Slider::drag(int p)
+{
+ if(max>min)
+ set_value(drag_start_value+(p-drag_start_pos)*(max-min)/drag_area_size);
+}
+
+void Slider::end_drag()
+{
+ dragging=false;
+}
+