On Thu, 11 Dec 2008 14:23:51 -0000, Clemens Eisserer <linuxhi...@gmail.com> wrote:
>> From the plain X Server POV, antialiasing is always going to be hard, >> because to do it you need to know the background color or pixmap, and >> the >> Xserver does not keep track of how you had earlier set it, so it is up >> to >> individual toolkits to keep track, and not all of them do. > Well, using XRender nobody needs to keep track of anything, its just > composition with a mask (which is generated by the CPU in the case of > trapezoids). No, I think you miss my point (or else I miss yours). AIUI, the purpose of Xrender is to enable as much as possible of the image information to be stored on the server, rather than in the client application which may be far away over some network. So it allows you to to construct your image out of various bits and pieces which may be more or less transparent. In the simplest cases (yes, I know you can do more complicated things) you are simply trying to paint some glyphs on top of a "background". But when you have combined those together, all the server is allowed to store is the result of the compositing - i.e. it has no knowledge of what was the original background and was was the added glyph. And that is no problem at all, until you want to throw away the glyph that was there before and write a new glyph in its place. And then you need to know what the original background behind the old glyph was, but the server does not have that information, and so it has to be kept in the application, which is precisely what Xrender was trying to avoid :-( . Now even the original X-11 system allowed you to specify a background (as a plain color, or as a pixmap - possibly tiled). But it never retained that information, and it was the lack of that retention that I was complaining about. -- Charles H. Lindsey ---------At Home, doing my own thing------------------------ Tel: +44 161 436 6131 Web: http://www.cs.man.ac.uk/~chl Email: ...@clerew.man.ac.uk snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K. PGP: 2C15F1A9 Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5 _______________________________________________ xorg mailing list xorg@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/xorg
