On Wed, Nov 30, 2011 at 1:33 PM, Hans-Peter Diettrich <drdiettri...@aol.com> wrote: > What's the purpose of your clipper?
I use/will use the same clipper (lcl/lazregions.pas) for a multitude of purposes: 1> To prevent subcontrols from painting outside their area in LCL-CustomDrawn 2> To implement Canvas Region Clipping in lazcanvas (which is the Canvas from LCL-CustomDrawn). This feature is utilized for example by fpvectorial to be able to render PostScript correctly 3> To implement TWinControl.SetShape in LCL-CustomDrawn 4> To verify to which control a mouse/touch event bellongs to in LCL-CustomDrawn. > IMO the window manager uses an update region internally, from which one or > more paint requests are generated, for rectangular ClipRects. It looks like that you are confusing Invalidate Rect with canvas clip regions. They are not the same thing. > I'm not sure how far non-rectangular clipping regions are supported by all > widgetsets, and wouldn't rely on such a capability. I use canvas clip regions in fpvectorial so I know that at least LCL-Win32, LCL-Qt and LCL-Gtk2 support rectangular, poligonal, rounded rect and elliptical regions. From poligonal regions you can also support arbitrary paths by using a transformation implemented in fpvectorial. So summing up you can have pretty much any kind of region that you imagine. I think that only rarely used corner cases like internal holes in regions and poligons with lines which cross one another are not currently implemented. LCL-Carbon is a bit behind from what I remember, but I don't quite remember what exactly is missing or if I already fixed it. -- Felipe Monteiro de Carvalho _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-devel
