[android] improve ToolbarExtensions.UpdateIconColor performance (#17241)

I've been working to get back some of our lost startup performance on
Android in .NET MAUI. We are really close, a few changes will get .NET 8
on par or faster than .NET 7.

Profiling startup of a `dotnet new maui` app on a Pixel 5,
`dotnet-trace` reported time spent in:

    16.62ms microsoft.maui.controls!Microsoft.Maui.Controls.Platform.ToolbarExtensions.UpdateIconColor(

If you drill in further in this method, you can see the time spent in:

    10.19ms xamarin.androidx.appcompat!AndroidX.AppCompat.Widget.Toolbar.get_OverflowIcon()
     6.42ms microsoft.maui!Microsoft.Maui.Platform.DrawableExtensions.SetColorFilter()

The project template doesn't even display a `Toolbar` icon, but it looks
like there are some straightforward performance wins here.

In 9b091fd, accessing `OverflowIcon` was introduced to fix the color of
the overflow icon. This code had the pattern:

    if (navIconColor != null && nativeToolbar.OverflowIcon != null)
    {
        nativeToolbar.OverflowIcon.SetColorFilter(navIconColor, FilterMode.SrcAtop);
    }

This accesses `OverflowIcon` twice, where we can use pattern matching
instead to avoid this.

Additionally, `SetColorFilter` appears to be called in a couple places
throughout .NET MAUI, we can move most of its logic to Java to avoid
interop.

So for example:

    switch (mode)
    {
        case FilterMode.SrcIn:
            return BlendMode.SrcIn;
        case FilterMode.Multiply:
            return BlendMode.Multiply;
        case FilterMode.SrcAtop:
            return BlendMode.SrcAtop;
    }

`Enum` values are just classes in Java, so this calling a Java method
from C# that returns an object. We then have to do various bookkeeping
around handling this Java object instance in C#.

Then the other call, also does Java interop for `BlendModeColorFilter`'s
constructor and the `SetColorFilter()`:

    drawable.SetColorFilter(new BlendModeColorFilter(color, filterMode29));

By moving this logic to Java, we can instead call:

    PlatformInterop.SetColorFilter(drawable, color, (int)mode);

We also do the API Q/29 platform checks on the Java side.

With these changes in place, the three methods above are improved:

    6.19ms microsoft.maui.controls!Microsoft.Maui.Controls.Platform.ToolbarExtensions.UpdateIconColor()
    3.87ms xamarin.androidx.appcompat!AndroidX.AppCompat.Widget.Toolbar.get_OverflowIcon()
    1.15ms microsoft.maui!Microsoft.Maui.Platform.DrawableExtensions.SetColorFilter()

I would estimate these changes improve startup by about ~10ms on a Pixel
5, seeing the savings on the topmost method, `UpdateIconColor()`.

src/Controls/src/Core/Platform/Android/Extensions/ToolbarExtensions.cs

@@ -147,17 +147,21 @@ public static void UpdateBarBackground(this AToolbar nativeToolbar, Toolbar tool
 		public static void UpdateIconColor(this AToolbar nativeToolbar, Toolbar toolbar)
 		{
 			var navIconColor = toolbar.IconColor;
-			if (navIconColor != null && nativeToolbar.NavigationIcon != null)
+			if (navIconColor is null)
+				return;
+
+			var platformColor = navIconColor.ToPlatform();
+			if (nativeToolbar.NavigationIcon is Drawable navigationIcon)
 			{
-				if (nativeToolbar.NavigationIcon is DrawerArrowDrawable dad)
+				if (navigationIcon is DrawerArrowDrawable dad)
 					dad.Color = AGraphics.Color.White;
 
-				nativeToolbar.NavigationIcon.SetColorFilter(navIconColor, FilterMode.SrcAtop);
+				navigationIcon.SetColorFilter(platformColor, FilterMode.SrcAtop);
 			}
 
-			if (navIconColor != null && nativeToolbar.OverflowIcon != null)
+			if (nativeToolbar.OverflowIcon is Drawable overflowIcon)
 			{
-				nativeToolbar.OverflowIcon.SetColorFilter(navIconColor, FilterMode.SrcAtop);
+				overflowIcon.SetColorFilter(platformColor, FilterMode.SrcAtop);
 			}
 		}
 

src/Core/AndroidNative/maui/src/main/java/com/microsoft/maui/PlatformInterop.java

@@ -2,11 +2,14 @@
 
 import android.content.Context;
 import android.content.res.ColorStateList;
+import android.graphics.BlendMode;
+import android.graphics.BlendModeColorFilter;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Path;
 import android.graphics.PathEffect;
+import android.graphics.PorterDuff;
 import android.graphics.Typeface;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.PaintDrawable;
@@ -26,6 +29,7 @@
 
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
+import androidx.annotation.RequiresApi;
 import androidx.appcompat.widget.SearchView;
 import androidx.appcompat.widget.TintTypedArray;
 import androidx.coordinatorlayout.widget.CoordinatorLayout;
@@ -224,6 +228,42 @@ public static ViewPager2 createShellViewPager(Context context, CoordinatorLayout
         return pager;
     }
 
+    /**
+     * Call setColorFilter on a Drawable, passing in (int)Microsoft.Maui.FilterMode
+     * Calls the appropriate methods for Android API 29/Q+
+     * @param drawable android.graphics.Drawable
+     * @param color android.graphics.Color
+     * @param mode (int)Microsoft.Maui.FilterMode
+     */
+    public static void setColorFilter(@NonNull Drawable drawable, int color, int mode) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+            drawable.setColorFilter(new BlendModeColorFilter(color, getBlendMode(mode)));
+        } else {
+            drawable.setColorFilter(color, getPorterMode(mode));
+        }
+    }
+
+    @RequiresApi(api = Build.VERSION_CODES.Q)
+    static BlendMode getBlendMode(int mode) {
+        // NOTE: keep in sync with src/Core/src/Primitives/FilterMode.cs
+        switch (mode) {
+            case 0: return BlendMode.SRC_IN;
+            case 1: return BlendMode.MULTIPLY;
+            case 2: return BlendMode.SRC_ATOP;
+            default: throw new RuntimeException("Invalid Mode");
+        }
+    }
+
+    static PorterDuff.Mode getPorterMode(int mode) {
+        // NOTE: keep in sync with src/Core/src/Primitives/FilterMode.cs
+        switch (mode) {
+            case 0: return PorterDuff.Mode.SRC_IN;
+            case 1: return PorterDuff.Mode.MULTIPLY;
+            case 2: return PorterDuff.Mode.SRC_ATOP;
+            default: throw new RuntimeException("Invalid Mode");
+        }
+    }
+
     private static void prepare(RequestBuilder<Drawable> builder, Target<Drawable> target, Boolean cachingEnabled, ImageLoaderCallback callback) {
         // A special value to work around https://github.com/dotnet/maui/issues/6783 where targets
         // are actually re-used if all the variables are the same.

src/Core/src/Platform/Android/DrawableExtensions.cs

@@ -25,22 +25,6 @@ public static class DrawableExtensions
 			throw new Exception("Invalid Mode");
 		}
 
-		[Obsolete]
-		static PorterDuff.Mode? GetFilterModePre29(FilterMode mode)
-		{
-			switch (mode)
-			{
-				case FilterMode.SrcIn:
-					return PorterDuff.Mode.SrcIn;
-				case FilterMode.Multiply:
-					return PorterDuff.Mode.Multiply;
-				case FilterMode.SrcAtop:
-					return PorterDuff.Mode.SrcAtop;
-			}
-
-			throw new Exception("Invalid Mode");
-		}
-
 		public static AColorFilter? GetColorFilter(this ADrawable drawable)
 		{
 			if (drawable == null)
@@ -71,27 +55,8 @@ public static void SetColorFilter(this ADrawable drawable, Graphics.Color color,
 
 		public static void SetColorFilter(this ADrawable drawable, AColor color, FilterMode mode)
 		{
-			if (drawable == null)
-				return;
-
-			if (OperatingSystem.IsAndroidVersionAtLeast(29))
-			{
-				BlendMode? filterMode29 = GetFilterMode(mode);
-
-				if (filterMode29 != null)
-					drawable.SetColorFilter(new BlendModeColorFilter(color, filterMode29));
-			}
-			else
-			{
-#pragma warning disable CS0612 // Type or member is obsolete
-				PorterDuff.Mode? filterModePre29 = GetFilterModePre29(mode);
-#pragma warning restore CS0612 // Type or member is obsolete
-
-				if (filterModePre29 != null)
-#pragma warning disable CS0618 // Type or member is obsolete
-					drawable.SetColorFilter(color, filterModePre29);
-#pragma warning restore CS0618 // Type or member is obsolete
-			}
+			if (drawable is not null)
+				PlatformInterop.SetColorFilter(drawable, color, (int)mode);
 		}
 	}
 }

src/Core/src/Primitives/FilterMode.cs

@@ -1,9 +1,10 @@
 namespace Microsoft.Maui
 {
+	// Keep in sync with src/Core/AndroidNative/maui/src/main/java/com/microsoft/maui/PlatformInterop.java
 	public enum FilterMode
 	{
-		SrcIn,
-		Multiply,
-		SrcAtop
+		SrcIn = 0,
+		Multiply = 1,
+		SrcAtop = 2,
 	}
 }