Performance of XRenderCompositeTrapezoids in the aliased case

Clemens Eisserer linuxhippy at
Mon Feb 2 10:52:44 PST 2009


1.) As far as I have seen the only way to get aliased rasterization
with XRenderCompositeTrapezoids is to pass PictStandardA1 as mask
However a lot of hardware can't use A1 as mask, leading to a fallback.

On my 945GM I get for a 100x100 circle consisting of ~180 traps:
20ms, A8
120ms A1
270ms no mask format

Wouldn't it make sence to use an A8 mask instead and tell pixman to
render aliased?

2.) What do you think about a data structure where EXA drivers could
tell EXA which features they support.
This way EXA could e.g. choose to use A8 instead of A1 only when it
really needed?
This could help in various cases to decide which route to go.

Thanks, Clemens

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