> -----Original Message----- > From: gtk-list-bounces@xxxxxxxxx > [mailto:gtk-list-bounces@xxxxxxxxx] On Behalf Of Paul Davis > Sent: 14 October 2005 04:30 > To: gtk-list@xxxxxxxxx > Subject: so,is this claim about pango still true? or does > nobody actually care? > > We are about 60% of the way through porting Ardour, probably > the premier digital audio workstation for Linux (winner of > Linux Journal's Best Project prize for 2005, and other > awards) from GTK1 to GTK2. Today, someone sent me this email: > > ------ > sorry to bug you directly, but I caught a post of yours on > slashdot regarding ardour being ported to GTK=2.x I did that > to some of my apps and hit several things that may cause you > problems. Teh main thing is it's about 3-12x slower, and > text rendering is the primary problem. (the main fault isn't > necessarily in > GTK+ (though it IS slower and more bloated in the 2.x trees) it's with > Pango. > IF you have any fields that need to render text and change it > often, you'll find that it consumes and exhorbitant amount of > CPU. I've traced this issue in my own code. (not nearly > complex as anything like ardour) and pango was the culprit, > bugs were filed and fell on deaf ears (owen taylor) and > nothing has been done over the past 3 years. I've since > decided that QT-4 was a better route. (requires a LOT of work > for me, but in the end the gui will be far more flexible and > faster, and much easier for me to run on multiple platforms > including win32) > > Just thought you'd want to know that there are some > significant performance concerns on GTK+-2.x. As a reference > the perf issue I was having was most evident when updating a > textual label (reporting some ADC value) at a rapid rate (10x > per second or so). Updating 5-10 labels at h the above rate > (this was reporting data for an outside slow-speed data > acquisition system) resulted in cpu usage of over 40-60% on a > 1200 mhz processor. All other major functions were disabled > in the program to make 100% sure that the text rendering was > causing the problems. gprof'ing the executable pointed to > calls in pango (a large number of them eating a little for > each function, but that added up to horrible performance). > GTK+-1.x doesn't have this issue as it used core > X11 > fonts and that is screaming fast. QT doesn't use pango it > uses somethign else but it didn't seem to show any > appreciable cpu usage for a similar application.. > ----------------- > > is this still true? does anybody care? is there a way to > avoid pango entirely and still get AA fonts inside GTK2? will > this ever be fixed before everyone is using h/w acceleration > to print button labels? > > the issue raised here will *kill* ardour dead, and would > force us to also have to abandon GTK for Qt (a move I would > really, really not want to make). some clarification would help .... I don't know if the above is all true, but some of it is. I've been given various advice by people here on speeding up GTK+ applications that may be useful to you. I haven't tested them properly yet: - * Text measurement in XaW is free, it is not in GTK+. Do not re-layout text assuming it is. * Disable double buffering if you don't need it with: gtk_widget_set_double_buffered() (may help, may cause flickering) * If you have to, use gdk_draw_string to bypass Pango, or bypass it by calling X. GTK+ certainly won't work very well on an original Pentium. GTK+ developers see the library as being primarily for fast machines. _______________________________________________ gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
