GNOME Bugzilla – Bug 736220
Tools lag when using tablet
Last modified: 2015-05-23 11:36:07 UTC
I'm using Windows 8.1 64 bit and a Wacom Bamboo Fun tablet. When I select a tool with the tablet, the tool selected lags behind the cursor. The small black arrows on the rulers also lag. I noticed when recording the bug that the lag is gone when I make Gimp's window smaller (the lag is proportional to the window size it seems). I'm using single window mode, but it's the same with the multi window mode as well.
Created attachment 285604 [details] screenshot of video of me using tablet here's a dropbox link (I'll probably remove the link after this is resolved or after a year or so) https://dl.dropboxusercontent.com/u/16325832/temp/tabletlagbug.mp4
If you have the possibility, use a libcairo-2.dll from gimp-2.8.10. Maybe you have to use the libpixman-1-0.dll from gimp-2.8.10, too. This seems to be a matter of libcairo since version 1.12.0.
I replaced both files from 2.8.10 to 2.8.14 under "GIMP 2\bin" and "GIMP 2\32\bin" and it no longer lags, thanks!
Are you using the updated 2.8.14 installer http://download.gimp.org/pub/gimp/v2.8/windows/gimp-2.8.14-setup-1.exe which has an updated libcairo? Does that fix the issue too?
I used the updated 2.8.14 installer to update Gimp, and it looks like the updated libcairo (libcario-2.dll) introduces the lag. When I replaced libcairo-2.dll and libpixman-1-0.dll from a previous install of 2.8.10 that was what fixed the issue.
It is a libcairo issue since version 1.12.0. In 02/13, i filed a bug (https://bugs.freedesktop.org/show_bug.cgi?id=60496) and is maybe related to (https://bugs.freedesktop.org/show_bug.cgi?id=71833)
So, according to the latter of these bugs, this might be related to the graphics adapter, or its drivers, respectively.
Bug 736411 has traced this to the way the ruler code makes use of libcairo (the actual bug, if it is one, might still be in libcairo though, and that code could just have found the trigger).
I had been asked if I could have a look at this bug. For info, I've been trying to reproduce the issue in my Win 7 virtual machine without success. Maybe I need to make bigger windows (my laptop screen is not huge enough perhaps), or this does not happen in a virtual machine. So unfortunately it seems I can't really help on this matter with my current set-up.
*** Bug 737431 has been marked as a duplicate of this bug. ***
On my video card, hardware acceleration stops at 1600x1200, and if an application tries to use it beyond that, it's much much slower than software rendering. Maybe this is related? HTH
I'm tempted to resolve this as a duplicate of bug 736411 - that one actually mentions a fix for one possible reason for the lag... and links to a nightly build with that fix. Setting to NEEDINFO, maybe this will make someone try that build.
Let's resolve it as a duplicate. *** This bug has been marked as a duplicate of bug 736411 ***