Set a minimum zoom of 1% on the tileset editor

[Ev01]

Fixes #57292 where zooming out too much stops you from being able to zoom back in.

[KoBeWi]

Works alright (not sure about the EDSCALE part though).

[Ev01]

Works alright (not sure about the EDSCALE part though).

Yeah, I put the EDSCALE part there because it's what EditorZoomWidget::_update_zoom_label() does to get the percentage. I'm not exactly sure what EDSCALE is and the bug could still happen if EDSCALE is 1000 or higher.

[KoBeWi]

EDSCALE is the scale of the editor (you can set it in Editor Settings). 1000 is insane value, so it won't be a problem.

[Ev01]

CanvasItemEditor does it like this:

// At top of file
#define MIN_ZOOM 1. / 128
#define MAX_ZOOM 128

// At top of zoom function
p_zoom = CLAMP(p_zoom, MIN_ZOOM, MAX_ZOOM);

Maybe this would be a better/more consistent way to do it?

[Ev01]

Setting a max zoom would also prevent reaching insane 40-digit zoom levels.

[Calinou]

I'd probably the clamp the zoom to a factor of 100 (that is, 10000%).

[Ev01]

After testing with different editor scales I discovered dividing by EDSCALE was unnecessary. I set the minimum zoom to 1% and the maximum to 10000%.

[akien-mga]

Thanks!

We discussed this in a PR review meeting and found that this is fine as an ad hoc solution, but it would be good to rework things in EditorZoomWidget directly so that it can prevent reaching 0 and being unable to zoom in. Then existing editor plugins that use EditorZoomWidget could have their ad hoc clamping removed as this should be part of the EditorZoomWidget behavior.