[Xorg-driver-geode] Glyph rendering

[Michel Dänzer]

On Mon, 2010-07-12 at 18:07 +0300, Jonathan Morton wrote: 
> On Mon, 2010-07-12 at 18:06 +0800, Huang, FrankR wrote:
> > Our driver is in low performance in glyph rendering.
> > Based on the debug and discussion with Michel, There are three operation:
> 
> > 1)Op:PictOpAdd, Src:PICT_a8r8g8b8 Mask:0 Dest:PICT_a8
> > 2)Op:PictOpAdd, Src:PICT_a8 Mask:0 Dest:PICT_a8r8g8b8
> > 3)Op:PictOpOver, Src:PICT_a8r8g8b8 Mask:PICT_a8r8g8b8 Dst:PICT_r5g6b5
> 
> Is Component Alpha turned on for this?  If not, extract the Alpha
> component from the mask and otherwise treat as for A8 mask.
> 
> It's not entirely clear to me why the above operations would be commonly
> encountered.

Not sure either about 1) - would be interesting to see at least a gdb
backtrace if this really happens in practice.

2) + 3) (without component alpha) are tried as a fallback path in case
the driver can't seem to handle the same operations with a8 instead of
a8r8g8b8 for the glyph mask picture.

3) (with component alpha) is used for sub-pixel anti-aliased text.


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer