GIMP gets canvas rotation
Since last night unstable version of GIMP has canvas rotation. The new feature is mostly useful for digital painting and drawing, as well as for preparing textures in CG, where you need to work on parts of a picture while viewing them from a different angle.
Canvas rotation was originally prototyped by sigetch in the GIMP Painter fork which could be considered to be a playground for various new features in upstream GIMP. Here's a quick demo:
The canvas rotation mode can be activated with any currently selected tool. Just press Shift and start dragging the middle mouse button up or down. Use the additional Ctrl modifier to rotate with 15° step.
To reset the rotation either choose “View / Rotate / Reset to 0°” command in menu or use Ctrl + Shift + dragging.
Canvas rotation isn't 100% complete yet, expect further refining. The feature was implemented by Michael Natterer and is expected to be available in v2.10 (no release date estimations possible at the moment). You can also sponsor this little project.