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#660 High CPU usage for scrolling
System: Ubuntu Linux, x86, Gnome, XFCE-Desktop
When scrolling with the "down-arrow" key, Scintilla's CPU usage explodes (100% and its jerking...). My CPU is definitely fast enough for it (1 Ghz, 1.5 GB RAM). The bug is really in Scintilla because both SciTe and Geany behave in this way.
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Text measurement and display is much slower on GTK+ than on other platforms such as Window so a faster processor would help. I do not intend to work on this.
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Well, "gedit" is much faster in this respect, so I guess it is not GTK2's fault. (I use the same font for the tests (DejaVu Sans Mono Book (size: 10).)
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Many users have chosen SciTE/Scintilla because for them it is much faster than gedit/gtksourceview.
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Look, I don't want to get on your nerves, but getting a faster CPU for a text editor is not reasonable. I'll try to fix it myself. Could you give me starting point? Which files should I look at?
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I have actually spent a lot of time on the performance of Scintilla and if I knew some simple way to improve performance further than I would implement it. The simplest way to improve performance is to drop Pango and return to X fonts but recent versions of GTK+ have bugs with X fonts. http://scintilla.sourceforge.net/SciTEFAQ.html#SpeedUpGTK
Best starting point would be to run a profiler on your machine to discover where slow downs are occurring for you. If you are happy using gedit then you would be better off using it rather than expending what is likely to be considerable effort on optimisation.
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Some more information: Scrolling with the mouse wheel is fine as is scrolling with the scroll bar. If I press the down-button of the scroll bar, it scrolls line by line and performance is fine too. However, scrolling line by line by pressing the "down-arrow" key on my keyboard is horribly slow. So I guess this bug is not hard to fix as scrolling in the generall case is fast enough.
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i can confirm the bad font rendering performance. for me it only happens when using anti-aliased fonts.
e.g. moving the cursor over a curly brace and holding down the jump-to-matching-brace-shortcut, s.t. the cursor jumps back and forth
between the two braces is fast if the braces don't have a dotted line connecting them (first level of indentation?).
if they do have the line, the jumping gets as slow as one jump per second or even worse.
neither gedit nor kate have comparable problems.
if i find the time, i'll see if i can identify the expensive code with gprof.
I'm closing this since it is so old and systems are considerably faster now.