[vdr] Call for help: anti-aliasing in DrawEllipse()

Klaus Schmidinger Klaus.Schmidinger at tvdr.de
Sat Jun 9 12:17:16 CEST 2012


VDR's OSD uses anti-aliasing for smoothly rendering its fonts.
The same could be used to make rendering ellipses look nicer.
Is there anybody who might be able to figure out how

   cBitmap::DrawEllipse()
   cPixmapMemory::DrawEllipse()

and maybe also

   cBitmap::DrawSlope()
   cPixmapMemory::DrawSlope()

could be modified in order to do anti-aliasing and thus make
the drawings smoother?

I'm pretty sure at some point along the calculations in these
functions there is enough information available to determine
a value in the range 0..255 that could be used to generate
a shade of foreground/background color that can be used to
set intermediate pixels. Of course this would require these
functions to be given both fg and bg colors, but we'll cross
that bridge when we get there. For starters just assume that
both colors will be available.

I would appreciate any help on this topic.
If you have any suggestions, please post them here, to avoid
duplicate work.

Klaus



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