fix: Update material color implementation to 13th June 2025

material-color-utilities/src/main/java/dynamiccolor/ColorSpec2025.java

@@ -1210,10 +1210,21 @@ public DynamicColor primaryFixed() {
             .setPalette((s) -> s.primaryPalette)
             .setTone(
                 (s) -> {
-                  DynamicScheme tempS = DynamicScheme.from(s, /* isDark= */ false);
+                  DynamicScheme tempS =
+                      DynamicScheme.from(s, /* isDark= */ false, /* contrastLevel= */ 0.0);
                   return primaryContainer().getTone(tempS);
                 })
             .setIsBackground(true)
+            .setBackground(
+                (s) -> {
+                  if (s.platform == PHONE) {
+                    return s.isDark ? surfaceBright() : surfaceDim();
+                  } else {
+                    return null;
+                  }
+                })
+            .setContrastCurve(
+                (s) -> s.platform == PHONE && s.contrastLevel > 0 ? getContrastCurve(1.5) : null)
             .build();
     return super.primaryFixed().toBuilder()
         .extendSpecVersion(SpecVersion.SPEC_2025, color2025)
@@ -1280,10 +1291,21 @@ public DynamicColor secondaryFixed() {
             .setPalette((s) -> s.secondaryPalette)
             .setTone(
                 (s) -> {
-                  DynamicScheme tempS = DynamicScheme.from(s, /* isDark= */ false);
+                  DynamicScheme tempS =
+                      DynamicScheme.from(s, /* isDark= */ false, /* contrastLevel= */ 0.0);
                   return secondaryContainer().getTone(tempS);
                 })
             .setIsBackground(true)
+            .setBackground(
+                (s) -> {
+                  if (s.platform == PHONE) {
+                    return s.isDark ? surfaceBright() : surfaceDim();
+                  } else {
+                    return null;
+                  }
+                })
+            .setContrastCurve(
+                (s) -> s.platform == PHONE && s.contrastLevel > 0 ? getContrastCurve(1.5) : null)
             .build();
     return super.secondaryFixed().toBuilder()
         .extendSpecVersion(SpecVersion.SPEC_2025, color2025)
@@ -1350,10 +1372,21 @@ public DynamicColor tertiaryFixed() {
             .setPalette((s) -> s.tertiaryPalette)
             .setTone(
                 (s) -> {
-                  DynamicScheme tempS = DynamicScheme.from(s, /* isDark= */ false);
+                  DynamicScheme tempS =
+                      DynamicScheme.from(s, /* isDark= */ false, /* contrastLevel= */ 0.0);
                   return tertiaryContainer().getTone(tempS);
                 })
             .setIsBackground(true)
+            .setBackground(
+                (s) -> {
+                  if (s.platform == PHONE) {
+                    return s.isDark ? surfaceBright() : surfaceDim();
+                  } else {
+                    return null;
+                  }
+                })
+            .setContrastCurve(
+                (s) -> s.platform == PHONE && s.contrastLevel > 0 ? getContrastCurve(1.5) : null)
             .build();
     return super.tertiaryFixed().toBuilder()
         .extendSpecVersion(SpecVersion.SPEC_2025, color2025)

material-color-utilities/src/main/java/dynamiccolor/DynamicScheme.java

@@ -152,11 +152,15 @@ public DynamicScheme(
   }
 
   public static DynamicScheme from(DynamicScheme other, boolean isDark) {
+    return from(other, isDark, other.contrastLevel);
+  }
+
+  public static DynamicScheme from(DynamicScheme other, boolean isDark, double contrastLevel) {
     return new DynamicScheme(
         other.sourceColorHct,
         other.variant,
         isDark,
-        other.contrastLevel,
+        contrastLevel,
         other.platform,
         other.specVersion,
         other.primaryPalette,

material-color-utilities/src/main/java/palettes/TonalPalette.java

@@ -79,7 +79,11 @@ private TonalPalette(double hue, double chroma, Hct keyColor) {
   public int tone(int tone) {
     Integer color = cache.get(tone);
     if (color == null) {
-      color = Hct.from(this.hue, this.chroma, tone).toInt();
+      if (tone == 99 && Hct.isYellow(this.hue)) {
+        color = averageArgb(this.tone(98), this.tone(100));
+      } else {
+        color = Hct.from(this.hue, this.chroma, tone).toInt();
+      }
       cache.put(tone, color);
     }
     return color;
@@ -105,6 +109,19 @@ public Hct getKeyColor() {
     return this.keyColor;
   }
 
+  private int averageArgb(int argb1, int argb2) {
+    int red1 = (argb1 >>> 16) & 0xff;
+    int green1 = (argb1 >>> 8) & 0xff;
+    int blue1 = argb1 & 0xff;
+    int red2 = (argb2 >>> 16) & 0xff;
+    int green2 = (argb2 >>> 8) & 0xff;
+    int blue2 = argb2 & 0xff;
+    int red = Math.round((red1 + red2) / 2f);
+    int green = Math.round((green1 + green2) / 2f);
+    int blue = Math.round((blue1 + blue2) / 2f);
+    return (255 << 24 | (red & 255) << 16 | (green & 255) << 8 | (blue & 255)) >>> 0;
+  }
+
   /** Key color is a color that represents the hue and chroma of a tonal palette. */
   private static final class KeyColor {
     private final double hue;