Bug 366531 - git master: Transform (qtblend) effect doesn't allow for CCW rotation; rotation origin is top-left instead of center
Summary: git master: Transform (qtblend) effect doesn't allow for CCW rotation; rotati...
Status: RESOLVED FIXED
Alias: None
Product: kdenlive
Classification: Applications
Component: Effects & Transitions (show other bugs)
Version: unspecified
Platform: Compiled Sources Linux
: NOR normal
Target Milestone: ---
Assignee: Vincent PINON
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2016-08-08 16:34 UTC by Wegwerf
Modified: 2021-03-03 16:20 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
fritzibaby: Brainstorm+


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Description Wegwerf 2016-08-08 16:34:56 UTC
While playing around with the new Transform effect I noticed these two shortcomings:

1. As the angle of rotation is limited to 0...+360° it is only possible to rotate CW. For static compositing this is fine, but when using keyframes it might be necessary to rotate CCW instead. So please add support for rotation from -360°...+360° as, for instance, Affine does.

2. The origin of rotation is the upper left corner. However, I would expect this to be the center of the image, where also the cross marker for moving the frame is located. Please support rotation along the center axis.

Reproducible: Always
Comment 1 Wegwerf 2016-08-09 15:07:45 UTC
3. Can the alpha operation parameter be used at all for a filter/effect?
Comment 2 farid 2017-03-05 14:56:45 UTC
Agree with all suggestions.
Comment 3 alberto 2017-09-12 12:44:08 UTC
Yes, please!

Go to the easy fast fix, moving the origin of the rotation to the center of the image instead of 0,0

This is oneliner fix :)

(Maybe more if you have to migrate old .kdenlive after the change..)

Or the complex one, allow to put set the origin of the rotation
Comment 4 alberto 2017-09-16 23:16:30 UTC
The workaround for this one is to use affine

After trying everything, affine is the only one that keeps everything good about transform (rotation, keyframes, scaling) and its able to rotate using the center of the image
Comment 5 Wegwerf 2017-09-17 18:47:48 UTC
The affine transition is not necessarilya substitute for composite&transform, or the transform effect: affine uses "atop" compositing, which often yields undesired results when working with multiple layers of transparency. Instead, often "over" compositing is desired.

For details on how affine/atop and transform/over differ, please see our toolbox article "compositing with transparency", https://kdenlive.org/project/compositing-with-transparency/.
Comment 6 farid 2021-03-03 16:20:46 UTC
Hello, both CCW rotation and rotate from center options are available since latest release. Closing, but if you encounter any issues don't hesitate to reopen.