patch for antialiased text with Xrender/Xft

[I'd sent this the first time a little bit ago to xemacs-patches, before realizing that -beta might be a better location for it. So here it is.] Here's a patch against 21.1.12 that gives xemacs the ability to take advantage of the XRender extension and use antialiased fonts for display. A new configure flag, --enable-xrender, turns this on. Fonts are specified using "XFT:font name:size". There are still a few issues, but by and large it works. It also doesn't handle non-proportional fonts gracefully (it does the maximum-width thing). The patch is at http://www.intrepid.com/~vladimir/xemacs21_aa.patch.gz . Screenshot at http://www.intrepid.com/~vladimir/xemacs_aa.png Xrender setup bits are at http://www.xfree86.org/~keithp/render/, it's included in xfree86 CVS or the 4.0.1z release. (I /think/ the latest debian woody should do fine, but you may have to end up rebuilding X so that you can define FREETYPE2.. it's not defined in the debian X dist for yet :-P) Try "xemacs -fn 'XFT:Lucida Console:24'" and drool ;-) Things left to do: - bug in clipping. lines which should be half-drawn will draw over the modeline. this involves getting the right bits to XftDrawSetClip. - get rid of XFT:blah. this is a hack, as the fonts come from a different namespace. However, the right way to do this would be to parse the fontspec string with a family of -xft-...; this would enable lisp code which modifies these strings (i.e. to make bold/italic variants) work corrently. - a color bug that I need to hunt down. Let me know what you think! (Please keep me in the Cc line of any responses, I'm not subscribed to xemacs-beta.) - Vlad