[cairo] [pixman] C optimization for x888->0565

Vladimir Vukicevic vladimir at pobox.com
Sat Sep 6 17:57:10 PDT 2008


The x8r8g8b8 -> r5g6b5 with operator source case was going through  
composite_general, complete with fbFetch_x8r8g8b8's and  
fbStore_r5g6b5's.  Youch.  This case happens pretty commonly when an  
app is using a 24-bpp surface as a backbuffer when it does the final  
blit to a 16bpp X server as part of expose handling.

This can maybe be done faster on arm with assembly (where it'll get  
the most use), but Jeff can do that better than me if it's necessary  
-- looking at gcc's code, it doesn't look awful.

     - Vlad

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