#1547 BLOC Future : Decide frame buffer depth - 565 vs ARGB 8888

[Zarro Boogs per Child]

#1547: Decide frame buffer depth - 565 vs ARGB 8888
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  Reporter:  jg               |       Owner:  cjb           
      Type:  task             |      Status:  new           
  Priority:  blocker          |   Milestone:  Future Release
 Component:  x window system  |     Version:                
Resolution:                   |    Keywords:                
  Verified:  0                |    Blocking:                
 Blockedby:                   |  
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Comment(by AlbertCahalan):

 Replying to [comment:9 bernie]:

 > Do you have some specific software in mind?  I've been using my PC and
 laptop in 16bpp since forever, without any issue.  Why do I do that?
 Because it's *twice* as fast for some operations, and uses 50% less video
 and system RAM for graphics.
 >
 > What's are downsides?  I can barely notice color banding on LCD
 displays, only in grey scale with no dithering.  Conversions from 24bpp to
 16bpp may be slow and there is indeed some stupid software out there that
 does not convert pixmaps to screen format beforehand.

 Converting pixmaps to screen format beforehand does not really work for
 many programs. Paint programs are one example. If the paint program
 supports anti-aliasing or fuzzy brushes (alpha channel on paint brushes)
 then internal use of 5:6:5 will cause 3 conversions with each dot of
 paint. The use of 5:6:5 also means that merely loading and saving a 24-bit
 image will cause data loss.

 As far as bugs go... YES!!! Despite being originally designed for low bit
 depths, Tux Paint now has several bugs at low bit depth. Software
 developers just don't see the problems anymore with everybody running at
 32 bits per pixel. To avoid these problems, the TuxPaint-1.xo uses 32 bits
 per pixel internally now.

 To really see color banding, view an image with a gray or magenta radial
 gradiant. Slow movement may make things show up more. I've seen it look
 really bad in a flash animation: http://cat-in-the-kettle.funnypart.com/

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Ticket URL: <http://dev.laptop.org/ticket/1547#comment:10>
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