merge main

<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request
This pull request introduces a small UI improvement to the
`ShellPage.xaml` file. The change sets a breakpoint for the compact
state of the title bar, which will help the interface adapt better to
different window sizes.

* UI responsiveness: Added `CompactStateBreakpoint="900"` to the
`AppTitleBar` control in `ShellPage.xaml` to improve layout adaptation
for smaller window widths.

**Before:**


https://github.com/user-attachments/assets/5ec424f4-b441-4eff-967f-a97cc92e180a


**After:**


https://github.com/user-attachments/assets/a1487c39-dce7-4055-90e9-aa6ed95e4beb



<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist

- [ ] Closes: #xxx
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [x] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

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## Validation Steps Performed

---------

Signed-off-by: Shawn Yuan <shuaiyuan@microsoft.com>

src/modules/MouseUtils/FindMyMouse/FindMyMouse.cpp

@@ -30,6 +30,8 @@ namespace muxc = winrt::Microsoft::UI::Composition;
 namespace muxx = winrt::Microsoft::UI::Xaml;
 namespace muxxc = winrt::Microsoft::UI::Xaml::Controls;
 namespace muxxh = winrt::Microsoft::UI::Xaml::Hosting;
+namespace mgc = winrt::Microsoft::Graphics::Canvas;
+namespace mgce = winrt::Microsoft::Graphics::Canvas::Effects;
 
 #pragma region Super_Sonar_Base_Code
 
@@ -813,33 +815,42 @@ private:
         m_spotlight.Shapes().Append(m_circleShape);
         layer.Children().InsertAtTop(m_spotlight);
 
-        // Dim color (source)
-        m_dimColorBrush = m_compositor.CreateColorBrush(m_backgroundColor);
-        // Radial gradient mask (center transparent, outer opaque)
+        // Radial gradient mask (center opaque to carve hole, outer transparent for soft fade)
         m_spotlightMaskGradient = m_compositor.CreateRadialGradientBrush();
         m_spotlightMaskGradient.MappingMode(muxc::CompositionMappingMode::Absolute);
-        m_maskStopCenter = m_compositor.CreateColorGradientStop();
-        m_maskStopCenter.Offset(0.0f);
-        m_maskStopCenter.Color(winrt::Windows::UI::ColorHelper::FromArgb(0, 0, 0, 0));
-        m_maskStopInner = m_compositor.CreateColorGradientStop();
-        m_maskStopInner.Offset(0.995f);
-        m_maskStopInner.Color(winrt::Windows::UI::ColorHelper::FromArgb(0, 0, 0, 0));
-        m_maskStopOuter = m_compositor.CreateColorGradientStop();
-        m_maskStopOuter.Offset(1.0f);
-        m_maskStopOuter.Color(winrt::Windows::UI::ColorHelper::FromArgb(255, 255, 255, 255));
-        m_spotlightMaskGradient.ColorStops().Append(m_maskStopCenter);
-        m_spotlightMaskGradient.ColorStops().Append(m_maskStopInner);
-        m_spotlightMaskGradient.ColorStops().Append(m_maskStopOuter);
+        auto maskStopCenter = m_compositor.CreateColorGradientStop();
+        maskStopCenter.Offset(0.0f);
+        maskStopCenter.Color(winrt::Windows::UI::ColorHelper::FromArgb(255, 255, 255, 255));
+        auto maskStopInner = m_compositor.CreateColorGradientStop();
+        maskStopInner.Offset(0.995f);
+        maskStopInner.Color(winrt::Windows::UI::ColorHelper::FromArgb(255, 255, 255, 255));
+        auto maskStopOuter = m_compositor.CreateColorGradientStop();
+        maskStopOuter.Offset(1.0f);
+        maskStopOuter.Color(winrt::Windows::UI::ColorHelper::FromArgb(0, 0, 0, 0));
+        m_spotlightMaskGradient.ColorStops().Append(maskStopCenter);
+        m_spotlightMaskGradient.ColorStops().Append(maskStopInner);
+        m_spotlightMaskGradient.ColorStops().Append(maskStopOuter);
         m_spotlightMaskGradient.EllipseCenter({ rDip * zoom, rDip * zoom });
         m_spotlightMaskGradient.EllipseRadius({ rDip * zoom, rDip * zoom });
 
-        m_maskBrush = m_compositor.CreateMaskBrush();
-        m_maskBrush.Source(m_dimColorBrush);
-        m_maskBrush.Mask(m_spotlightMaskGradient);
+        // Win2D effect brush removes the spotlight area using DestinationOut composite
+        mgce::CompositeEffect compositeEffect{};
+        compositeEffect.Mode(mgc::CanvasComposite::DestinationOut);
+        mgce::ColorSourceEffect backgroundFill{};
+        backgroundFill.Name(L"DimFill");
+        backgroundFill.Color(m_backgroundColor);
+        muxc::CompositionEffectSourceParameter maskSource{ L"Mask" };
+        compositeEffect.Sources().Append(backgroundFill);
+        compositeEffect.Sources().Append(maskSource);
+
+        auto effectFactory = m_compositor.CreateEffectFactory(compositeEffect, { L"DimFill.Color" });
+        m_backdropEffectBrush = effectFactory.CreateBrush();
+        m_backdropEffectBrush.SetSourceParameter(L"Mask", m_spotlightMaskGradient);
+        m_backdropEffectBrush.Properties().InsertColor(L"DimFill.Color", m_backgroundColor);
 
         m_backdrop = m_compositor.CreateSpriteVisual();
         m_backdrop.RelativeSizeAdjustment({ 1.0f, 1.0f });
-        m_backdrop.Brush(m_maskBrush);
+        m_backdrop.Brush(m_backdropEffectBrush);
         layer.Children().InsertAtTop(m_backdrop);
 
         // 5) Implicit opacity animation on the root
@@ -950,9 +961,9 @@ public:
                     UpdateMouseSnooping(); // For the shake mouse activation method
 
                     // Apply new settings to runtime composition objects.
-                    if (m_dimColorBrush)
+                    if (m_backdropEffectBrush)
                     {
-                        m_dimColorBrush.Color(m_backgroundColor);
+                        m_backdropEffectBrush.Properties().InsertColor(L"DimFill.Color", m_backgroundColor);
                     }
                     if (m_circleShape)
                     {
@@ -1007,12 +1018,8 @@ private:
     muxc::ShapeVisual m_spotlight{ nullptr };
     muxc::CompositionSpriteShape m_circleShape{ nullptr };
     // Radial gradient mask components
-    muxc::CompositionMaskBrush m_maskBrush{ nullptr };
-    muxc::CompositionColorBrush m_dimColorBrush{ nullptr };
     muxc::CompositionRadialGradientBrush m_spotlightMaskGradient{ nullptr };
-    muxc::CompositionColorGradientStop m_maskStopCenter{ nullptr };
-    muxc::CompositionColorGradientStop m_maskStopInner{ nullptr };
-    muxc::CompositionColorGradientStop m_maskStopOuter{ nullptr };
+    muxc::CompositionEffectBrush m_backdropEffectBrush{ nullptr };
     winrt::Windows::UI::Color m_backgroundColor = FIND_MY_MOUSE_DEFAULT_BACKGROUND_COLOR;
     winrt::Windows::UI::Color m_spotlightColor = FIND_MY_MOUSE_DEFAULT_SPOTLIGHT_COLOR;
     muxc::ScalarKeyFrameAnimation m_animation{ nullptr };

src/modules/MouseUtils/FindMyMouse/pch.h

@@ -13,8 +13,13 @@
 #include <winrt/Windows.System.h>
 #include <winrt/Windows.Foundation.h>
 #include <winrt/Microsoft.UI.Composition.h>
+#include <winrt/Microsoft.UI.Composition.Effects.h>
 #include <winrt/Microsoft.UI.h>
 #include <winrt/Windows.UI.h>
+#include <winrt/Windows.Graphics.Effects.h>
+// Win2D C++/WinRT projections
+#include <winrt/Microsoft.Graphics.Canvas.h>
+#include <winrt/Microsoft.Graphics.Canvas.Effects.h>
 #endif
 
 #include <winrt/Windows.Foundation.Collections.h>
@@ -23,4 +28,4 @@
 
 #ifdef GetCurrentTime
 #undef GetCurrentTime
-#endif
+#endif