libXrender - documentation?
chl at clerew.man.ac.uk
Wed Jan 28 06:36:30 PST 2009
In <871vupgnte.fsf at opera.com> Eirik Byrkjeflot Anonsen <eirik at opera.com> writes:
>Clemens Eisserer <linuxhippy at gmail.com> writes:
>>> For sure the Opera/QT combination is not doing anything like that - all
>>> the calls that actually pass glyphs to/from the server use good ol' Xlib.
>>> Though there is evidence that xft does use Xrender elsewhere in its
>> I don't know about opera, but im am pretty (99,5%) sure QT uses Render
>> - now if Opera uses QT's graphic context for drawing it will
>> implicitly use it.
>The text handling in Qt 2 was abysmal (in particular the font
>switching), so we (opera) implemented our own. I don't think we've
>changed it much since then. I believe our implementation uses xft and
>"classic x fonts" directly.
Well, since my copy of Opera has QT bundled inside it, I cannot tell which
is actually making the xft calls.
But for sure, every time the cursor blinks in a mail-editing window,
Opera/QT (whichever) calls XftDrawString16 on every word in the whole
window, just on the offchance that words happens to overlap the cursor
area. And if libxft is doing its own antialiassing (see my reply to
Clemens regarding Solaris-10), the resultant cpu usage hogs 100% (and more
if it could) of the processor.
Which is plain silly (and I shall be moaning to you in opera.os.solaris
about it once I have established exactly why Sun have messed it up :-( ).
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131 Fax: +44 161 436 6133 Web: http://www.cs.man.ac.uk/~chl
Email: chl at 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
More information about the xorg