On Sun, May 19, 2013 at 4:59 AM, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: > On Fri, May 17, 2013 at 07:40:23PM +0200, Jean-Francois Moine wrote: >> Maybe I did not explain correctly: the colored cursor maybe RGB888 + >> transparency (64x64) or full ARGB (64x32 or 32x64). I coded the first >> case. And, yes, I better like a hardware cursor: it asks for less >> computation, and I get it immediately at graphic starting time! > > Having looked at this now, using the RGB+transparency is less than ideal > because we're having to reduce an alpha channel down to a simple on/off > transparency. X cursors really are alphablended components! > > So, the options here are: > (a) use "software" rendered cursor > + correct and expected cursor size > + correct rendering > + possible to use the GPU (I believe mine does) > - maybe time consuming as it has to be removed/replaced on the screen > (b) use RGB+transparency for 64x64 hardware cursor > + correct and expected cursor size > + does not have to be removed/replaced when screen contents change > - incorrect rendering due to reducing the alpha channel to a simple > on/off transparency mask > - has to be reloaded when the pointer is close to the edges of the > screen which is CPU intensive > - cursor image data passed into DRM is required to be ARGB (I've > discussed this with David Airlie last night.) This means we have > to do translation to RGB+T in the kernel which is *not* nice. > (c) use ARGB 32x64 or 64x32 hardware cursor > + does not have to be removed/replaced when screen contents change > + correct rendering of cursor > - unexpected cursor size; user clients do not expect to be restricted > to 32 rows or 32 lines of cursor > - can only select maximum cursor size on initialization of hardware > cursor; can't dynamically switch between 32x64 and 64x32 sizes > - has to be reloaded when the pointer is close to the edges of the > screen which is CPU intensive You can tell the xserver what size cursor you support when you call xf86_cursors_init() in the ddx. Just expose a 32x64 or 64x32 ARGB cursor. Most apps don't use a 64x64 cursor anyway. I've used hardware with non-64x64 cursors and haven't run into any problems yet. Alex _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
