Xrender cursor performance / double buffering?

Bert Freudenberg bert at freudenbergs.de
Tue Apr 17 10:25:48 EDT 2007


On Apr 17, 2007, at 16:08 , Dan Williams wrote:

> On Tue, 2007-04-17 at 10:05 -0400, Dan Williams wrote:
>> On Tue, 2007-04-17 at 12:21 +0200, Bert Freudenberg wrote:
>>> Hi folks,
>>>
>>> for drag'n'dropping an image between an activity and the sugar frame
>>> I thought it would be nice to just set it as cursor. This way, it
>>> gets rendered on top of both the activity and the frame.
>>
>> Cursors can be hardware accelerated up to a point.  See section  
>> 6.5.1.3
>> of the AMD Geode GX2 data book.
>
> I hit Ctl+Enter too soon...
>
> http://www.amd.com/us-en/ConnectivitySolutions/ProductInformation/ 
> 0,,50_2330_9863_9864%5E9867,00.html
>
> "The GUI supports a 64x64x2-bit hardware cursor overlay."
>
> Beyond 64x64, you're not going to get hardware acceleration at all,  
> and
> it will be X11 drawing the cursor.  That's gonna be just as slow as
> anything else you draw from an app.
>
>>> Ideas appreciated - or will the LX make this work magically? This is
>>> a B2.
>
> The LX data book says that the LX has the same hardware cursor size as
> the GX, 64x64.  So I don't think it will help here.

XO is not using the HW cursor anyway because, as you point out, that  
only supports 2 bit cursors (1 bit black/white, 1 bit alpha).

What I was asking is can I make the software cursor faster - for  
example by using a different format than PictStandardARGB32.  
Actually, as long as there is no animation behind the large cursor,  
performance doesn't feel so bad.

Or, even better, if Xrender would use double-buffering when showing  
the cursor, this would be much less distracting.

- Bert -




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