Bug 168916

Summary:	Please put anti-aliasing in the perspective adjustment tool
Product:	[Applications] digikam	Reporter:	Gandalf Lechner <gandalflechner>
Component:	Plugin-Editor-Perspective	Assignee:	Digikam Developers <digikam-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	david.nolden.kde
Priority:	NOR
Version:	0.10.0
Target Milestone:	---
Platform:	unspecified
OS:	Linux
Latest Commit:		Version Fixed In:	0.10.0
Sentry Crash Report:

Description Gandalf Lechner 2008-08-11 15:57:17 UTC

Version:           unknown (using 4.1.00 (KDE 4.1.0), Kubuntu packages)
Compiler:          gcc
OS:                Linux (x86_64) release 2.6.24-17-generic

As in the rotate tool, it would be very helpful.

Perspective adjustments are often made on pictures of buildings with many straight lines, and on these, the zig zag lines produced by adjusting without anti-aliasing are well visible.

Comment 1 Andi Clemens 2008-09-02 18:45:36 UTC

Yes, you are right.
I just needed to use the perspective tool and it is annoying and even a bit misleading when trying to correct a photo.

Comment 2 caulier.gilles 2008-09-02 19:20:33 UTC

Andi,

Look here :

http://lxr.kde.org/source/extragear/graphics/digikam/imageplugins/perspective/perspectivewidget.cpp#587

...Antialiasing code already exist but if i remember nothing it doesn't work.

Gilles

Comment 3 Andi Clemens 2008-09-02 21:23:02 UTC

I tried to fix it, but without luck. I used shear and free rotation as a "template", but after that I got a funny looking blue image when changing perspective. But only in the preview mode, after applying it looked good and anti-aliasing was applied, too.
So in general it seems to work, but only the preview looks weird.

But I found another problem:

1. Take a portrait oriented image
2. move the upper right corner to the middle of the image (and below)
3. This works fine
4. Now take a landscape oriented image
5. Try to drag the upper right point to the middle of the image, but it will stop at some point and you can't drag it any further

Can you confirm this?

Comment 4 Andi Clemens 2008-09-02 21:35:45 UTC

AAAH I hate this new option in bugzilla... every time I'm added as CC when I comment somewhere. This is annoying... :-(

Comment 5 Gandalf Lechner 2008-09-02 22:31:05 UTC

I can confirm that in landscape mode, there is some area around the center of the picture in which you cannot drag the two upper vertices. I think it rarely matters because such vertex positions amount to quite extreme deformations, but maybe this behaviour indicates some strangeness in the code.

The two lower vertices can be dragged to the center.

Comment 6 Andi Clemens 2008-09-03 08:34:33 UTC

Sure it doesn't matter that much, but something is definitely wrong here I guess, although I just can't figure out what it is.
Another strange thing is that if you apply the filter, the result has anti-aliasing applied to it, although we commented it out right now in the source code. I need to take a closer look today.

Comment 7 David Nolden 2009-02-14 16:39:14 UTC

Fixed