Change y-axis direction without restart
Details
Y-axis direction currently requires a restart to change.
It should be possible to update this without a restart.
This would allow us to set the property per document instead of globally (and have it behave well).
This affects whether the origin is in the top left or the bottom left.
- The ruler should flip immediately (and canvas).
- All toolbar/dialog information should reflect new y-axis direction.
- Actions like move in the Transform dialog should be updated accordingly
- 3D boxes should appear the same before and after the flip
- Ditto with guides, grids, etc.
- Undo history shouldn't be affected (it shouldn't, but just make sure). If set per document, I'd expect this to be an entry in the history.
One possible approach
y-axis direction does update without a restart if we check the preferences more than once per document.
In e7b3085a, the following steps are sufficient to do that.
- Change the direction in preferences
- Adjust page size (via document properties) (flips the canvas)
- Zoom (in or out) (corrects rulers, displays canvas correctly)
Currently, the preferences are only checked once since we couldn't figure out how to do this all at once without side effects.
See discussion !793 (comment 195317262) for more details.