Gets the size of the destination drawing area. For a wx:canvas-dc% object, this is the (virtual client) size of the desintation window; for a wx:memory-dc% object, this is the size of the selected bitmap (or 0 if no bitmap is selected); for a wx:post-script-dc% or wx:printer-dc% device context, this gets the horizontal and vertical size of the drawing area.
The width box is filled with the width and height is filled with the height.