BackedUp: backed-up windows

Found in: epoc32ex\Graphics\WS\BackedUp\

This example demonstrates how to implement a backed up window.

It implements freehand drawing in a similar way to the PtBuffer example, using the pointer move buffer. However, in this example, the window which may be drawn to is an RBackedUpWindow rather than an RWindow. This means that any drawing is redrawn automatically if it becomes covered up and then uncovered: the backed-up window receives no redraw events. The example includes a small window which can be dragged around the screen to illustrate this.

Drag the mouse with left mouse button down for freehand drawing. You do not need to press the Shift key.

Draw using the pointer. You do not need to press the Shift key.

• RBackedUpWindow: Backed-up window

• CWsScreenDevice: Screen device