Unit 'layers' Package
[Overview][Constants][Types][Procedures and functions][Variables][Index] [#os4units]

BeginUpdate

Prepare to repair damaged layer.

Declaration

Source position: layers.pas line 163

function BeginUpdate(

  L: PLayer

):LongInt;

Arguments

L

  

pointer to a layer

Function result

True if damage list converted to ClipRect list successfully. False if list conversion aborted. (probably out of memory)

Description

Convert damage list to ClipRect list and swap in for programmer to redraw through. This routine simulates the ROM library environment. The idea is to only render in the "damaged" areas, saving time over redrawing all of the layer. The layer is locked against changes made by the layer library.

Errors

If BeginUpdate returns False, programmer must abort the attempt to refresh this layer and instead call EndUpdate(Layer, False) to restore original ClipRect and damage list.

See also

EndUpdate

  

remove damage list and restore state of layer to normal.


Documentation generated on: 2021-07-30