GNOME Bugzilla – Bug 332838
dancing effect while typing just one character
Last modified: 2006-03-03 01:22:22 UTC
That bug has been opened on https://launchpad.net/distros/ubuntu/+source/vte/+bug/33144 "When typing happily into GNOME Terminal, bold fonts seem to be rendered inconsistently even for the same character cell over time leading to a "dancing" effect which is bloody irritating. http://librarian.launchpad.net/1598375/dance.gif This is an animated GIF showing the dancing effect while typing just one character, note the change to the rendering of the already-typed characters. http://librarian.launchpad.net/1598376/dance.png The same graphics as the Animated GIF, but arranged vertically in case someone doesn't like gifs. ...... For me it happens in whole columns at once. So if I have a high window, the entire column of bold text (usually the ENTIRE part that's left of and below the cursor) does the mambo when I move the cursor. I can see this easily using vim in a perl file (the Perl syntax file in vim uses bold a lot, it seems)"
Mandriva has also a bug about that: http://qa.mandriva.com/show_bug.cgi?id=13910 Could be a pango or freetype bug too. This happens with GNOME 2.13.92 on Ubuntu, the Mandriva bug is open for a year so it's not new
It's not Pango, not FreeType. Plain vte bug. Here are the details: vtexft doesn't know about bold faces. When it wants to draw something in bold, it redraws it again shifted one pixel to the right. Of course that means it may be overlapping the next box, which it is in the example. Now following the example here, if the chars 'mp' are redrawn together, you see them overlapping, but when later the 'p' is redrawn only, it clears its box and draws a p, which means the part of m overlappint p's box is cleared... Not sure how to fix this. Widening the boxes by one pixel is not that appealing.
why is the "p" redraw when you enter the "h"?
Heh, *just in case*. Because ph may be a wide character. So instead of checking whether it needs t redraw p, it simply does that all the time. It's one of the things I'm working on currently in vte: to remove excess redraws. But that doesn't really solve the entire problem. It will still show up in other situations.
Marking as a duplicate of a more general bug. *** This bug has been marked as a duplicate of 333157 ***