Raw layer draw method. This gives you 1 surface cropped by _position for drawing.
Note that you are not forced to draw to the surfaces at all.
UIElement are drawn by increasing z-order, or lexical order if lack thereof.
Those elements who have non-overlapping _position are drawn in parallel.
Hence you CAN'T draw outside _position and receive cropped surfaces.
IMPORTANT: you MUST NOT draw outside dirtyRects. This allows more fine-grained updates.
A UIElement that doesn't respect dirtyRects will have PAINFUL display problems.
Raw layer draw method. This gives you 1 surface cropped by _position for drawing. Note that you are not forced to draw to the surfaces at all.
UIElement are drawn by increasing z-order, or lexical order if lack thereof. Those elements who have non-overlapping _position are drawn in parallel. Hence you CAN'T draw outside _position and receive cropped surfaces.
IMPORTANT: you MUST NOT draw outside dirtyRects. This allows more fine-grained updates. A UIElement that doesn't respect dirtyRects will have PAINFUL display problems.