[image-view] Add scroll support to zoom-in and zoom-out

[asiloisad]

It's natural to zoom-in and zoom-out images by Ctrl-Scroll. It was required to change how zoom-to-fit works.

[confused-Techie]

Really excited about this feature idea, and something I've absent-mindedly tried to do way to many times forgetting it doesn't exist.

But I do see some test failures here, that I don't necessarily believe are the fault of your code at all, but are ones we don't expect to see, so we will probably want to take a closer look at those sometime soon.

@DeeDeeG a ping for whenever your available if you'd like to help look into this.

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EDIT:

Sorry, I missed this was aimed at updated-latest-electron, which most certainly may be the reason we are seeing the failures.

If you intended to target the dev electron branch, feel free to ignore my above comment. But if you otherwise think this is something that can work now, which seems to me like it could, maybe you can retarget to the master branch and we can merge it for the rolling releases now, and ideally our CI will be much happier