begin-drawing

Allows optimization of drawing code. Enclose drawing primitives between begin-drawing and end-drawing calls.

Drawing to a panel's wx:dc% object outside of a system-generated on-paint event requires this pair of calls to enclose drawing code. This is because a Windows dialog box does not have a retained device context associated with it, and selections such as pen and brush settings would be lost if the device context were obtained and released for each drawing operation.

• (send a-wx:canvas begin-drawing) -> void