Can you link the relevant WebRender logic?

Hello @Loirooriol

Please find it attached here

https://github.com/servo/webrender/blob/main/webrender/src/util.rs

pub trait MaxRect {
    fn max_rect() -> Self;
}

impl MaxRect for DeviceIntRect {
    fn max_rect() -> Self {
        DeviceIntRect::from_origin_and_size(
            DeviceIntPoint::new(i32::MIN / 2, i32::MIN / 2),
            DeviceIntSize::new(i32::MAX, i32::MAX),
        )
    }
}

impl<U> MaxRect for Rect<f32, U> {
    fn max_rect() -> Self {
        // Having an unlimited bounding box is fine up until we try
        // to cast it to `i32`, where we get `-2147483648` for any
        // values larger than or equal to 2^31.
        //
        // Note: clamping to i32::MIN and i32::MAX is not a solution,
        // with explanation left as an exercise for the reader.
        const MAX_COORD: f32 = 1.0e9;

        Rect::new(
            Point2D::new(-MAX_COORD, -MAX_COORD),
            Size2D::new(2.0 * MAX_COORD, 2.0 * MAX_COORD),
        )
    }
}

impl<U> MaxRect for Box2D<f32, U> {
    fn max_rect() -> Self {
        // Having an unlimited bounding box is fine up until we try
        // to cast it to `i32`, where we get `-2147483648` for any
        // values larger than or equal to 2^31.
        //
        // Note: clamping to i32::MIN and i32::MAX is not a solution,
        // with explanation left as an exercise for the reader.
        const MAX_COORD: f32 = 1.0e9;

        Box2D::new(
            Point2D::new(-MAX_COORD, -MAX_COORD),
            Point2D::new(MAX_COORD, MAX_COORD),
        )
    }
}

@Loirooriol Please let me know if I'm missing something

I can't reproduce the problem in the issue.

   // Having an unlimited bounding box is fine up until we try
   // to cast it to `i32`

Is it cast to i32?

Instead of hardcoding const MAX_COORD: f32 = 1.0e9 in Servo too, I would use Box2D::max_rect()

@Messi002, can you confirm whether the issue is reproductible in your side?

Also following Oriol's suggestion, please use max_rect defined by WebRender if it is possible.

For the PR description, we could use prefix fixes: to mention the issue, so that CI could automatically close the issue when it is merged.

The problem is that WebRender then does max - min

Can you point where this happens for Windows, but not for Linux? The difference in behavior seems a bit weird.

@stevennovaryo
Yes, I can reproduce it. It happens when the device pixel ratio is above 1 (as @Loirooriol found). On my Linux machine with --device-pixel-ratio 1 it looks fine, but with --device-pixel-ratio 2 the child disappears. I've updated the code to use LayoutRect::max_rect() as suggested. I'll also update the PR description.

@Loirooriol
I was able to reproduce it on Linux using --device-pixel-ratio 2, so it's not a Windows-only issue

@Loirooriol @mrobinson

Waiting for updates from you

🛠 These changes could not be applied onto the latest upstream WPT. Servo's copy of the Web Platform Tests may be out of sync.

https://servo.zulipchat.com/#narrow/channel/263398-general/topic/Run.20test.20with.20custom.20device.20pixel.20ratio/with/581900453

Please use Fixes: #43599 in the description, as Steven said.

Ok!
Thank you for the highglight @Loirooriol

🛠 These changes could not be applied onto the latest upstream WPT. Servo's copy of the Web Platform Tests may be out of sync.