On Sat, Dec 12, 2009 at 1:31 PM, Anthony Liguori <anth...@codemonkey.ws> wrote: > Soeren Sandmann wrote: >> >> Hi, >> >> Here is an overview of what the current QXL driver does and does not >> do. The parts of X rendering that are currently being used by cairo >> and Qt are: >> >> - Most of XRender - Image compositing >> - Glyphs >> > > Does anything use Xrender for drawing glyphs these days?
Yes all of cairo apps and gtk, pretty much anything doing anti-aliased fonts on a modern Linux desktop uses X render to draw glyps. I think QT can use Xrender also but not 100% sure what the default is. > > Certainly, with a compositing window manager, nothing is getting rendered by > X... Yes there is, with a GL compositing window manager nothing is rendered by X, with an Xrender compositing window manager (metacity or kwin xrender mode). Also allanti-aliased font operations, and a number of cairo operations are done using xrender, which means most of the modern desktop, I actually broke sw fallbacks to the frontbuffer on my driver last week and it took me nearly a half a day to realise it. X rendering in modern apps is like Soeren describes, render to offscreen pixmap, copy to onscreen. > Scrolling is accelerated in VNC. In the Cirrus adapter, both X and Windows > use a video-to-video bitblt, we use this to create a VNC CopyRect which > makes scrolling and Window movement smooth. Firefox scrolling? (though I'm not sure anyone deals with it sainly). > >> However, as things stand right now, there is not much point in adding >> this support, because X applications essentially always work like >> this: >> >> - render to offscreen pixmap >> - copy pixmap to screen >> >> There is not yet support for offscreen pixmaps in SPICE, so at the >> moment, solid fill and CopyArea are the two main things that actually >> make a difference. >> > > Okay, that's in line with what my expectations were. So what's the future > of Spice for X? Anything clever or is Windows the only target right now? > If spice grows offscreen surfaces along with some a few more rendering operations I expect we can make it go fairly fast for most X apps. Since at RH we have both spice and X teams I think we can probably produce some sort of collaborative plan in the short term on how to go forward. Dave.
