UI Node with absolute position seems to be incorrectly scaled

[rongcuid]

Bevy version

0.15.3

[Optional] Relevant system information

• Mac M2

If your bug is rendering-related, copy the adapter info that appears when you run Bevy.

2025-04-18T21:29:44.996370Z  INFO bevy_diagnostic::system_information_diagnostics_plugin::internal: SystemInfo { os: "MacOS 15.3.1 ", kernel: "24.3.0", cpu: "Apple M2", core_count: "8", memory: "24.0 GiB" }
2025-04-18T21:29:45.084210Z  INFO bevy_render::renderer: AdapterInfo { name: "Apple M2", vendor: 0, device: 0, device_type: IntegratedGpu, driver: "", driver_info: "", backend: Metal }
2025-04-18T21:29:45.248183Z  INFO bevy_winit::system: Creating new window "App" (0v1#4294967296)

What you did

I spawn a crosshair image using the following code:

pub fn spawn_crosshair(mut commands: Commands, window_query: Query<&Window, With<PrimaryWindow>>) {
    if let Ok(window) = window_query.get_single() {
        let crosshair_size = 8.0;
        commands
            .spawn(Node {
                width: Val::Percent(100.0),
                height: Val::Percent(100.0),
                ..default()
            })
            .with_children(|p| {
                p.spawn((
                    ImageNode::solid_color(Color::srgb(0., 1., 0.)),
                    Node {
                        width: Val::Px(crosshair_size),
                        height: Val::Px(crosshair_size),
                        position_type: PositionType::Absolute,
                        left: Val::Px(window.width() / 2.0 - (crosshair_size / 2.0)),
                        top: Val::Px(window.height() / 2.0 - (crosshair_size / 2.0)),
                        ..default()
                    },
                ));
            });
    }
}

What went wrong

If it's not clear, break this out into:

• Crosshair (square) should appear at the center of the window
• Crosshair actually appear at lower-right corner
• If I divide the width and height by 4, crosshair appear at the center
• However, scaling factor is reported to be 1. Physical width/height are also same as logical.
• If I use percentage instead of absolute size, positioning is correct.