Bug 575553

Summary:	[performance] cache CTabFolder backgroundImage bounds
Product:	[Eclipse Project] Platform	Reporter:	Jörg Kubitz <jkubitz-eclipse>
Component:	SWT	Assignee:	Jörg Kubitz <jkubitz-eclipse>
Status:	RESOLVED FIXED	QA Contact:	Niraj Modi <niraj.modi>
Severity:	enhancement
Priority:	P3	CC:	Lars.Vogel, niraj.modi, rolf.theunissen
Version:	4.21	Keywords:	performance
Target Milestone:	4.21 RC1
Hardware:	All
OS:	All
See Also:	https://git.eclipse.org/r/c/platform/eclipse.platform.swt/+/184288 https://git.eclipse.org/c/platform/eclipse.platform.swt.git/commit/?id=584fc122be5067521f2ce395e5e0b049eefb8f55 https://bugs.eclipse.org/bugs/show_bug.cgi?id=575873
Whiteboard:
Bug Depends on:	576287
Bug Blocks:	575658, 574015

Description Jörg Kubitz

2021-08-21 15:25:47 EDT

When i resize eclipse window the repaint feels rather slow.
As far as i see one reason is that the CTabFolder backgroundimages are disposed and recreated (involving drawing an image and the new costly disposetracking). Why would you do so? The background doesnt change.
There is already a check in setButtonBounds() if updateBkImages() needs to be called but it fails to detect that the background was only moved but did not realy change.

Well, lets cache the old size and only repaint if changed.

Comment 1 Eclipse Genie

2021-08-21 15:32:51 EDT

New Gerrit change created: https://git.eclipse.org/r/c/platform/eclipse.platform.swt/+/184288

Comment 2 Eclipse Genie

2021-08-24 04:04:50 EDT

Gerrit change https://git.eclipse.org/r/c/platform/eclipse.platform.swt/+/184288 was merged to [master].
Commit: http://git.eclipse.org/c/platform/eclipse.platform.swt.git/commit/?id=584fc122be5067521f2ce395e5e0b049eefb8f55

Comment 3 Niraj Modi

2021-08-24 04:06:38 EDT

(In reply to Eclipse Genie from comment #2)
> Gerrit change
> https://git.eclipse.org/r/c/platform/eclipse.platform.swt/+/184288 was
> merged to [master].
> Commit:
> http://git.eclipse.org/c/platform/eclipse.platform.swt.git/commit/
> ?id=584fc122be5067521f2ce395e5e0b049eefb8f55

Thanks Joerg for the fix, resolving now.

Comment 4 Jörg Kubitz

2021-08-24 04:16:01 EDT

Thanks for review, Niraj!

Comment 5 Lars Vogel

2021-08-24 05:43:41 EDT

Thanks, Jörg.

Comment 6 Rolf Theunissen

2021-12-31 10:16:29 EST

This change causes a regression, see Bug 576287.

Furthermore, it creates regressions for horizontal gradients, i.e. the background should be updated when the width changes. However, the background images for horizontal gradients are broken anyhow. You can use the snippet in Bug 576287 with horizontal gradient to test.