UI node gets compressed in `ui` example scrollable area boundary

[doup]

Bevy version

v0.11.0-dev (ce33354)

Relevant system information

AdapterInfo { name: "Apple M2 Max", vendor: 0, device: 0, device_type: IntegratedGpu, driver: "", driver_info: "", backend: Metal }

What you did

• In the ui example, scroll until a node shows at the boundary

What went wrong

See how Item 18 gets vertically compressed when it's on the boundary:

For comparison, this is how it should look like (this image is when the node it's not at the boundary):

I've debugged in XCode and I'm seeing this:

I've compared the Y position & UVs for the letter m from Item 17 and Item 18:

• The height of Item 17 m letter is 9.5 (pos 2-1), and vertical UV range is 0.37 (uv 2-1)
• The height of Item 18 m letter is 3.5 (36.8% of 9.5)
• The UV (v) for 4 is 0.25 (67.6%), instead it should be 0.136 (36.8%)

[rparrett]

A previous instance of this bug was dependent on scale factor, and that seems to be the case here too.

Adding

.add_plugins(DefaultPlugins.set(WindowPlugin {
    primary_window: Some(Window {
        resolution: WindowResolution::default().with_scale_factor_override(1.),
        ..default()
    }),
    ..default()
}))

removes the squish.

[doup]

That "fixes" the issue… but it also scales everything to half the size. 😅

I'm looking /bevy_ui/src/render/mod.rs and I have the hunch that the issue might be here:
https://github.com/bevyengine/bevy/blob/main/crates/bevy_ui/src/render/mod.rs#L492

The clipping should be affecting atlas_extent, no?

(Good excuse to read the UI rendering code.)

[mockersf]

I think fixing this for text broke it for images, then fixing it for image broke it back for text...

Be sure to test both when trying a new fix 👍

[doup]

I think overflow clipping is just broken, it only supports AABB positions clipping (not UVs). If a node is rotated/scaled inside an Overflow::Hidden node it gets funky. To be fair, there is a comment mentioning that this is not supported.

Without Overflow::Hidden:

With Overflow::Hidden:

[doup]

OK, I think I'm going to prepare an overflow clipping debug example.

[ickshonpe]

I think this was probably introduced when scale_factor was removed from ExtractedUiNode.