fix: window size on multiple monitors with different scaling

[ash-impl]

closes #661

[ash-impl]

Screenshots for the fixes below. Note that these screenshots go across monitors with scaling 125% for left monitor and 100% for my right monitor which is the boundary crossed in these screenshots. For reference-The power icon is the rightmost icon on my YASB status bar on both monitors.

Problem 1 as stated in #661
Before Fix

After Fix

Problem 2 as stated in #661
Before Fix

After Fix

[lars-berger]

thank you for the fix 💜

do the windows in question have a very large shadow borders which then crosses over to the other monitor? i'm still not fully wrapping my head around how the problem occurs in the first place. do these wonky scaled windows take up more % than they should when you have many windows open (even after the PR fix)?

[ash-impl]

Hi @lars-berger, thank you for your response. I think the issue was more that we were passing 'None' to methods like 'apply_delta' that accepted optional scale factors for different monitors which resulted in incorrect calculations affecting window size accuracy.

[lars-berger]

@ash-impl did some testing on a fresh W11 machine and from what i can tell, we shouldn't be scaling the border gaps. we get the border size by diffing GetWindowRect (includes shadow borders) and DwmGetWindowAttribute(..., DWMWA_EXTENDED_FRAME_BOUNDS, ...) (doesn't include shadow borders), and apparently both give already scaled rects.

1) with PR changes (borders are a bit wonky), 2) without changes

unfortunately i'm also unable to reproduce the underlying issue (maybe it's only on W10?). monitor 1 is 150% and monitor 2 is 100%, and then i'm moving an admin window (Event Viewer) between the two monitors like in #661.

my guess is that the root cause is border_delta or shadow_border_delta is returning some crazy large value. could you try logging them? do they return a different value when doing a cross-monitor move vs. a move within the same monitor?

// window_getters.rs

  fn total_border_delta(
    &self,
    scale_factor: Option<f32>,
  ) -> anyhow::Result<RectDelta> {
    let border_delta = self.border_delta();
    let shadow_border_delta = self.native().shadow_border_delta()?;
    tracing::info!("{:?}", border_delta);
    tracing::info!("{:?}", shadow_border_delta);
    // ...
  }

could you also see if it makes a difference to refresh border delta prior to redrawing?

// platform_sync.rs

    window.native().refresh_border_position()?; // add this
    
    let rect = window
      .to_rect()?
      .apply_delta(&window.total_border_delta()?, None); // leave the rect calculation as-is

[ash-impl]

Hi @lars-berger thank you for your response.
You're right about not wanting to scale border gaps.

I have since switched to using a single monitor only thanks to your great work on this application and then workplace upgraded to W11 (where I'm not sure this issue persists because of single monitor use).
I saw the issue only with Windows applications like Event Viewer, task manager etc. Other applications were working just fine. I have also since then gained a better understanding of this code-base for personal learning. And I can't seem to pin point why those applications in particular were the ones giving grief. My initial changes seemed to have worked for me in solving those issues with these code changes back when I was working on this.

I can test with your recommendations of logging, and work on this more in a couple weeks if it's still an issue (On W10 or W11).