Rotation/reflection

[edemaine]

Surprisingly, this doesn't seem to be an issue already, but it's frequently requested at this point.

• Rotation by ±90°
• Horizontal/vertical reflection
• Arbitrary rotation

The first two make sense as part of a selection overlay menu (#184).

[jaltekruse]

I like the UI for rotation that is used in the fabric.js canvas library. It leaves an extra handle hanging out that can be dragged for arbitrary rotation. It also allows for rotating elements in groups and can resolve multiple separate rotations applied to different sub-groupings over time (where the point of rotation changes with different selections), as show in this screen-capture. You can possibly check out their codebase for some inspiration while implementing this feature. If you'd like some help I could probably spend some time working on this.

fabric_js_rotating_objects-2022-06-16_14.49.27.mp4