The DrawingArea widget is used for creating custom user interface
elements. It's essentially a blank widget; you can draw on
the Drawable returned by drawingAreaGetWindow.
After creating a drawing area, the application may want to connect to:
- Mouse and button press signals to respond to input from the user. (Use
widgetAddEvents to enable events you wish to receive.)
- The "realize" signal to take any necessary actions when the widget is
instantiated on a particular display. (Create GDK resources in response to
- The "configure_event" signal to take any necessary actions when the
widget changes size.
- The "expose_event" signal to handle redrawing the contents of the
Expose events are normally delivered when a drawing area first comes
onscreen, or when it's covered by another window and then uncovered
(exposed). You can also force an expose event by adding to the "damage
region" of the drawing area's window; widgetQueueDrawArea and
windowInvalidateRect are equally good ways to do this. You'll then get an
expose event for the invalid region.
The available routines for drawing are documented on the GDK Drawing
Primitives page. See also pixbufRenderToDrawable for drawing a Pixbuf.
To receive mouse events on a drawing area, you will need to enable them
with widgetAddEvents. To receive keyboard events, you will need to set the
CanFocus flag on the drawing area, and should probably draw some
user-visible indication that the drawing area is focused.