[Cairo] Text APIs round 2

[Keith Packard]

Around 16 o'clock on Aug 15, Owen Taylor wrote:

>    I also note that XftGlyphFontSpec uses separate calls per 
>    font change;

I think you might be misreading that code.  It had some serious problems 
doing the right thing with a mixture of bitmap and AA-fonts, so I know 
it's at least doing something...

>  - An entire set of text rendering operations is grouped
>    with BT/ET.

Ah.  I like that a lot more.  We can have bt/et as 'optional' functions 
and let people choose if they care; text done within bt/et gets merged 
together while text done outside is separate.

	cairo_text_begin (cairo_state_t *ct);
	cairo_text_end (cairo_state_t *ct);

As they're optional, the only apps paying the price will be the ones that 
really care.

-keith