feat: add separate field for monitor scale factor; fix incorrect dpi field

packages/wm/src/common/platform/native_monitor.rs

@@ -31,7 +31,8 @@ struct MonitorInfo {
   hardware_id: Option<String>,
   rect: Rect,
   working_rect: Rect,
-  dpi: f32,
+  dpi: u32,
+  scale_factor: f32,
 }
 
 impl NativeMonitor {
@@ -62,10 +63,14 @@ impl NativeMonitor {
     self.monitor_info().map(|info| &info.working_rect)
   }
 
-  pub fn dpi(&self) -> anyhow::Result<f32> {
+  pub fn dpi(&self) -> anyhow::Result<u32> {
     self.monitor_info().map(|info| info.dpi)
   }
 
+  pub fn scale_factor(&self) -> anyhow::Result<f32> {
+    self.monitor_info().map(|info| info.scale_factor)
+  }
+
   fn monitor_info(&self) -> anyhow::Result<&MonitorInfo> {
     self.info.get_or_try_init(|| {
       let mut monitor_info = MONITORINFOEXW::default();
@@ -124,6 +129,7 @@ impl NativeMonitor {
 
       let device_name = String::from_utf16_lossy(&monitor_info.szDevice);
       let dpi = monitor_dpi(self.handle)?;
+      let scale_factor = dpi as f32 / 96.0;
 
       let rc_monitor = monitor_info.monitorInfo.rcMonitor;
       let rect = Rect::from_ltrb(
@@ -148,6 +154,7 @@ impl NativeMonitor {
         rect,
         working_rect,
         dpi,
+        scale_factor,
       })
     })
   }
@@ -209,7 +216,7 @@ pub fn nearest_monitor(window_handle: isize) -> NativeMonitor {
   NativeMonitor::new(handle.0)
 }
 
-fn monitor_dpi(handle: isize) -> anyhow::Result<f32> {
+fn monitor_dpi(handle: isize) -> anyhow::Result<u32> {
   let mut dpi_x = u32::default();
   let mut dpi_y = u32::default();
 
@@ -222,5 +229,6 @@ fn monitor_dpi(handle: isize) -> anyhow::Result<f32> {
     )
   }?;
 
-  Ok(dpi_y as f32 / 96.0)
+  // Arbitrarily choose the Y DPI.
+  Ok(dpi_y)
 }

packages/wm/src/containers/traits/tiling_size_getters.rs

@@ -29,7 +29,7 @@ pub trait TilingSizeGetters: CommonGetters {
     let gaps_config = self.gaps_config();
 
     let scale_factor = match gaps_config.scale_with_dpi {
-      true => monitor.native().dpi()?,
+      true => monitor.native().scale_factor()?,
       false => 1.,
     };
 

packages/wm/src/monitors/monitor.rs

@@ -45,7 +45,8 @@ pub struct MonitorDto {
   height: i32,
   x: i32,
   y: i32,
-  dpi: f32,
+  dpi: u32,
+  scale_factor: f32,
   handle: isize,
   device_name: String,
   device_path: Option<String>,
@@ -96,12 +97,13 @@ impl Monitor {
     other: &Container,
   ) -> anyhow::Result<bool> {
     let dpi = self.native().dpi()?;
+
     let other_dpi = other
       .monitor()
       .and_then(|monitor| monitor.native().dpi().ok())
       .context("Failed to get DPI of other monitor.")?;
 
-    Ok((dpi - other_dpi).abs() < f32::EPSILON)
+    Ok(dpi != other_dpi)
   }
 
   pub fn to_dto(&self) -> anyhow::Result<ContainerDto> {
@@ -123,6 +125,7 @@ impl Monitor {
       x: rect.x(),
       y: rect.y(),
       dpi: self.native().dpi()?,
+      scale_factor: self.native().scale_factor()?,
       handle: self.native().handle,
       device_name: self.native().device_name()?.clone(),
       device_path: self.native().device_path()?.cloned(),

packages/wm/src/workspaces/workspace.rs

@@ -136,7 +136,7 @@ impl PositionGetters for Workspace {
 
     let gaps_config = &self.0.borrow().gaps_config;
     let scale_factor = match &gaps_config.scale_with_dpi {
-      true => monitor.native().dpi()?,
+      true => monitor.native().scale_factor()?,
       false => 1.,
     };