Add support for ColorScheme.scrim

Author: Nick Rout

material3Lib/src/androidTest/java/com/google/android/material/composethemeadapter3/test/Mdc3ThemeTest.kt

@@ -83,12 +83,15 @@ class Mdc3ThemeTest {
             Assert.assertEquals(colorResource(R.color.orchid), colorScheme.inverseOnSurface)
 
             Assert.assertEquals(colorResource(R.color.violet), colorScheme.outline)
+            // TODO: MDC-Android doesn't include outlineVariant yet, add when available
 
             Assert.assertEquals(colorResource(R.color.beige), colorScheme.error)
             Assert.assertEquals(colorResource(R.color.white_smoke), colorScheme.onError)
             Assert.assertEquals(colorResource(R.color.olive), colorScheme.errorContainer)
             Assert.assertEquals(colorResource(R.color.olive_drab), colorScheme.onErrorContainer)
 
+            Assert.assertEquals(colorResource(R.color.crimson), colorScheme.scrim)
+
             // Mdc3Theme updates the LocalContentColor to match the calculated onBackground
             Assert.assertEquals(colorResource(R.color.navy), LocalContentColor.current)
         }

material3Lib/src/androidTest/res/values/test_colors.xml

@@ -33,6 +33,7 @@
     <color name="medium_spring_green">#00FA9A</color>
     <color name="navy">#000080</color>
     <color name="dark_blue">#00008B</color>
+    <color name="crimson">#DC143C</color>
     <color name="indian_red">#CD5C5C</color>
     <color name="light_coral">#F08080</color>
     <color name="salmon">#FA8072</color>

material3Lib/src/androidTest/res/values/themes.xml

@@ -42,10 +42,12 @@
         <item name="colorSurfaceInverse">@color/light_salmon</item>
         <item name="colorOnSurfaceInverse">@color/orchid</item>
         <item name="colorOutline">@color/violet</item>
+        <!-- TODO: MDC-Android doesn't include outlineVariant yet, add when available -->
         <item name="colorError">@color/beige</item>
         <item name="colorOnError">@color/white_smoke</item>
         <item name="colorErrorContainer">@color/olive</item>
         <item name="colorOnErrorContainer">@color/olive_drab</item>
+        <item name="scrimBackground">@color/crimson</item>
 
         <!-- Text Appearances -->
         <item name="textAppearanceDisplayLarge">@style/TextAppearance.Mdc3ThemeTest.DisplayLarge</item>

material3Lib/src/main/java/com/google/android/material/composethemeadapter3/Mdc3Theme.kt

@@ -189,6 +189,7 @@ fun createMdc3Theme(
             val onError = ta.getComposeColor(R.styleable.ComposeThemeAdapterTheme_colorOnError)
             val errorContainer = ta.getComposeColor(R.styleable.ComposeThemeAdapterTheme_colorErrorContainer)
             val onErrorContainer = ta.getComposeColor(R.styleable.ComposeThemeAdapterTheme_colorOnErrorContainer)
+            val scrimBackground = ta.getComposeColor(R.styleable.ComposeThemeAdapterTheme_scrimBackground)
 
             val isLightTheme = ta.getBoolean(R.styleable.ComposeThemeAdapterTheme_isLightTheme, true)
 
@@ -217,10 +218,12 @@ fun createMdc3Theme(
                     inverseSurface = surfaceInverse,
                     inverseOnSurface = onSurfaceInverse,
                     outline = outline,
+                    // TODO: MDC-Android doesn't include outlineVariant yet, add when available
                     error = error,
                     onError = onError,
                     errorContainer = errorContainer,
-                    onErrorContainer = onErrorContainer
+                    onErrorContainer = onErrorContainer,
+                    scrim = scrimBackground
                 )
             } else {
                 darkColorScheme(
@@ -247,10 +250,12 @@ fun createMdc3Theme(
                     inverseSurface = surfaceInverse,
                     inverseOnSurface = onSurfaceInverse,
                     outline = outline,
+                    // TODO: MDC-Android doesn't include outlineVariant yet, add when available
                     error = error,
                     onError = onError,
                     errorContainer = errorContainer,
-                    onErrorContainer = onErrorContainer
+                    onErrorContainer = onErrorContainer,
+                    scrim = scrimBackground
                 )
             }
         } else null

material3Lib/src/main/res/values/theme_attrs.xml

@@ -47,6 +47,7 @@
         <attr name="colorOnError" />
         <attr name="colorErrorContainer" />
         <attr name="colorOnErrorContainer" />
+        <attr name="scrimBackground" />
 
         <attr name="fontFamily" />
         <attr name="android:fontFamily" />