Panning canvas does not work if partially zoomed

[grofaty]

I installedPinta 1.8-dev on Ubuntu 20.04
https://github.com/PintaProject/Pinta/actions/runs/459305831

I see canvas panning was added to the Pinta gtk3-v2 branch, by:
https://github.com/PintaProject/Pinta/commit/df360087a68df644b1e93137022db4180541620a
excellent. Thanks.

But I think I have found a way this pan does not work as in Gimp. In Gimp it always works, but in Pinta it seems there are some corner cases when it doesn't work.

1. New image 200 x 2000.
2. With Paintbrush draw some line from top to bottom (this step is not required, but it makes it easier to see if canvas panning is working).
3. Zoom in image, but only to the point that top and bottom edge part of image is not visible anymore. Make sure left and right edge part of the image are still displayed (so some partial zoom only).
4. Now try triggering the canvas panning. Mouse middle click + hold + move mouse up and down.
Problem appears. Canvas panning does not work. I expect canvas to be moved in the mouse pulling direction.

Additional test 1:
5. Zoom in so that left and right edge of canvas is also not visible. (The simplest way zoom to 3600%).
6. Repeat step 4 and canvas panning is working fine.

Additional test 2:
7. New image 2000 x 200.
8. Repeat step 2.
9. Zoom in image, but only to the point that left and right edge part of image is not visible anymore. Make sure top and bottom edge part of the image are still displayed (so some partial zoom only).
10. Mouse middle click + hold + move mouse left and right and canvas panning is working fine.

[grofaty (grofaty)]

It looks like there is a problem with original pan already.

11. Repeat step 1, 2, and 3.
12. Click on Pan icon from Tools.
13. Left mouse click + hold + move up or down. Problem appears. Pan does not work.

[grofaty (grofaty)]

I have tested steps 11, 12 and 13 in Pinta 1.7 snap package on Ubuntu 20.04 and problem is already in previous version, so no regression here.

[Cameron White (cameronwhite91)]

Fixed by https://github.com/PintaProject/Pinta/commit/fa6da8448ccfd6ff51bdc3c699348086fae69d1f

[grofaty (grofaty)]

I can confirm problem is fixed now in Pinta 1.8-dev on Ubuntu 20.04:
https://github.com/PintaProject/Pinta/actions/runs/459690362