[Lazarus] Getting update rect/region in Windows

Hans-Peter Diettrich DrDiettrich1 at aol.com
Tue May 24 17:47:07 CEST 2011


Max Vlasov schrieb:

> tetris-inspired game and is gnu gpl. I would like to made it compatible 
> with other platforms, but I'm not sure whether I should change 
> region-based logic to something else in this case. I will be glad to 
> hear any advice on this.

I don't know about concrete window managers, except for Windows, but IMO 
there is little room for very different algorithms. A window (screen) 
manager has to track modifications to a window (requiring repaint), and 
has to take into account possibly overlapping windows, and widgets 
inside the client area. In the simplest implementation all update and 
clip regions are implemented as lists of rectangles. The only choice is 
the implementation of clipping, which can be done by painting all update 
rectangles in explicit (sequential) painting requests, or otherwise 
leave clipping to the graphics library. In either case the paint 
handlers have to deal with a single rectangular area (ClipRect), IMO.

DoDi





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