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 .... --p _______________________________________________ gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
