Bug 153472

Summary:	Moving applet is slow on zoomed workspace
Product:	[Plasma] plasma4	Reporter:	Luca Gambetta <l.gambetta>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs>
Status:	RESOLVED FIXED
Severity:	minor
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
Latest Commit:		Version Fixed In:
Attachments:	Image of the zones

Description Luca Gambetta 2007-12-05 10:58:30 UTC

Version:            (using KDE Devel)
Installed from:    Compiled sources
Compiler:          gcc 4.2.2 
OS:                Linux

Put a plasma applet on the workspace, the "Zoom Out" the workspace and start moving the applet: you can see that if you move the applet where is the desktop wallpaper the movements are slow, when you drag it on the "white zone" the movement are very fast.

Comment 1 Luca Gambetta 2007-12-05 11:25:52 UTC

Created attachment 22350 [details]
Image of the zones

Comment 2 Beat Wolf 2007-12-06 11:12:16 UTC

i can confirm this. Plasma would be great! if it would move on a wallpaper in the same speed as it does on the white background

Comment 3 Aaron J. Seigo 2007-12-06 15:49:34 UTC

this is due to the scaling that happens when zoomed out. the background repaints and is then rescaled. i'm guessing that in Qt 4.3 is rescales the entire item in memory rather than just the effective exposed rect; i'll have to test 4.4 to see if this is the same, but i won't be fixing this before 4.1 i don't think. this is just a performance quibble, while there are too many significant issues to address in the meantime.

Comment 4 Aaron J. Seigo 2008-01-11 05:17:36 UTC

so even in qt 4.3 it's only painting the absolute necessary, but all the math to scale in real time is killing us. will have to look and see what we can do in the Qt layers below us and see how things improve from there..

Comment 5 Thomas Georgiou 2008-07-05 07:35:29 UTC

Qt 4.4 and KDE 4.1 significantly improves performance in this area