Re: [Render] OpenType support in Pango

[Keith Packard <keithp keithp com>]

> Currently, I just use a request per glyph, both for the X backend
> and for the Xft/Xrender backend. I could optimize this at render
> time by taking into account knowledge of the natural advance
> widths of the glyphs. A request that took multiple positioned
> glyphs would also be an optimization.

It's not so much the performance effect, but the effect of rendering 
overlapping or adjacent glyphs.  Render allows glyphs to be added together
before being composited to the screen, but you need to transmit all of the 
overlapping glyphs in one request.

The Render protocol (and server) already supports this encoding, but 
there's no client side library support.  I suggest a simple API:

	typedef struct _XftThingy {
		INT16		x;
		INT16		y;
		XftChar32	c;
	} XftThingy;
	
	XftDrawThingies (XftDraw *draw, XftColor *color, XftFont *font,
			 XftThingy *things, int n);

(a suitable name for this object would be most welcome)

I can emulate this (slowly) with the core protocol...

keithp keithp com	 XFree86 Core Team		SuSE, Inc.