LAYERSUPER

Declaration

Source position: layers.pas line 45

Description

A super bitmap layer is similar to a smart refresh layer. It too has a back-up area for rendering graphics for currently obscured parts of the display. Whenever an obscured area is made visible, the corresponding part of the backup area is copied to the display automatically.

However, it differs from smart refresh in that:

• The back-up BitMap is user-supplied, rather than being allocated dynamically by the system.
• The back-up BitMap may be as large or larger than the the current size of the layer. It may also be larger than the maximum size of the layer.

To see a larger portion of a super bitmap on-display, use SizeLayer(). To see a different portion of the super bitmap in the layer, use ScrollLayer().

When the graphics routines perform drawing commands, part of the drawing appears in the common BitMap (the on-display portion). Any drawing outside the displayed portion itself is rendered into the super bitmap. When the layer is scrolled or sized, the layer contents are copied into the super bitmap, the scroll or size positioning is modified, and the appropriate portions are then copied back into the layer. (Refer to the graphics library functions SyncSBitMap() and CopySBitMap().