Improve Popup content_scale_factor

[scgm0]

Change the content_scale_factor used by some Popups from being retrieved from the parent Window to being retrieved from the parent Viewport.

Fix #69749
Fix #69171
Fix #98672

master:

this pr:

test:

popup_test_2025-03-20_23-17-23.zip

[Calinou]

Tested locally, it works as expected both with subwindow embedding enabled and disabled.

However, when subwindow embedding is disabled, the stretched popup will be blurry when using the viewport stretch mode (instead of being pixelated as I'd expect). I recall seeing another issue (and PR) specifically tackling this.

Subwindow embedding enabled

disabled	canvas_items	viewport

Subwindow embedding disabled

disabled	canvas_items	viewport

Also, this PR doesn't fix #98672:

[scgm0]

Changing the texture filter mode of the popup window would make it display pixelated as expected, but I think that's beyond the scope of this pr.
It's already very late here (currently 3 AM in China), so I'll check tomorrow to see if I can fix #98672.

[scgm0]

@Calinou
I've been having some insomnia, so I took the opportunity to fix #98672:

There's one modification I'm unsure about, which is that the tooltip now follows the scaling of the tooltip_owner. If this isn't suitable, I can revert this change:
Before:

After:

[bruvzg]

Seems to be working as expected with both embedded and native windows.

[Calinou]

There's one modification I'm unsure about, which is that the tooltip now follows the scaling of the tooltip_owner. If this isn't suitable, I can revert this change:

This makes sense to do, but I can see use cases where this is an issue. In general, we discourage using Control scaling outside of animation purposes (as it breaks within containers), but if you do use it for animation, it might look weird if it affects the tooltip at the same time as the button.

[scgm0]

This makes sense to do, but I can see use cases where this is an issue. In general, we discourage using Control scaling outside of animation purposes (as it breaks within containers), but if you do use it for animation, it might look weird if it affects the tooltip at the same time as the button.

So, should I cancel it?

[Calinou]

So, should I cancel it?

Yes, I suggest removing that change from the PR then submitting it in a separate PR instead.

[scgm0]

So, should I cancel it?

Yes, I suggest removing that change from the PR then submitting it in a separate PR instead.

Done.