Add wallpaper color scheme

base/src/main/java/de/mm20/launcher2/licenses/OpenSourceLicenses.kt

@@ -201,4 +201,12 @@ val OpenSourceLicenses = arrayOf(
         licenseText = R.raw.license_apache_2,
         url = "https://github.com/promeG/TinyPinyin"
     ),
+    OpenSourceLibrary(
+        name = "material-color-utilities",
+        copyrightNote = "Copyright 2021 Google LLC",
+        description = "Algorithms and utilities that power the Material Design 3 (M3) color system, including choosing theme colors from images and creating tones of colors; all in a new color space.",
+        licenseName = R.string.apache_license_name,
+        licenseText = R.raw.license_apache_2,
+        url = "https://github.com/material-foundation/material-color-utilities"
+    ),
 )

build.gradle.kts

@@ -8,7 +8,6 @@ buildscript {
     dependencies {
         classpath("com.android.tools.build:gradle:7.1.3")
         classpath(libs.kotlin.gradle)
-        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:1.6.10")
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }

i18n/src/main/res/values/strings.xml

@@ -387,6 +387,7 @@
     <string name="preference_screen_colors">Color scheme</string>
     <string name="preference_colors_default">Default</string>
     <string name="preference_colors_bw">Black and White</string>
+    <string name="preference_colors_wallpaper">From wallpaper</string>
     <string name="preference_screen_about">About</string>
     <string name="preference_version">Version</string>
     <string name="preference_category_links">Links</string>

material-color-utilities/.gitignore

@@ -0,0 +1 @@
+/build

material-color-utilities/build.gradle.kts

@@ -0,0 +1,42 @@
+plugins {
+    id("com.android.library")
+    id("kotlin-android")
+}
+
+android {
+    compileSdk = sdk.versions.compileSdk.get().toInt()
+
+    defaultConfig {
+        minSdk = sdk.versions.minSdk.get().toInt()
+        targetSdk = sdk.versions.targetSdk.get().toInt()
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+        consumerProguardFiles("consumer-rules.pro")
+    }
+
+    buildTypes {
+        release {
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
+    }
+
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+dependencies {
+    implementation(libs.bundles.kotlin)
+    implementation(libs.androidx.core)
+
+    implementation(libs.koin.android)
+
+}

material-color-utilities/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

material-color-utilities/src/main/AndroidManifest.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="de.mm20.launcher2.materialcolorutilities">
+
+</manifest>

material-color-utilities/src/main/java/hct/Cam16.java

@@ -0,0 +1,435 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package hct;
+
+import static java.lang.Math.max;
+
+import utils.ColorUtils;
+
+/**
+ * CAM16, a color appearance model. Colors are not just defined by their hex code, but rather, a hex
+ * code and viewing conditions.
+ *
+ * <p>CAM16 instances also have coordinates in the CAM16-UCS space, called J*, a*, b*, or jstar,
+ * astar, bstar in code. CAM16-UCS is included in the CAM16 specification, and should be used when
+ * measuring distances between colors.
+ *
+ * <p>In traditional color spaces, a color can be identified solely by the observer's measurement of
+ * the color. Color appearance models such as CAM16 also use information about the environment where
+ * the color was observed, known as the viewing conditions.
+ *
+ * <p>For example, white under the traditional assumption of a midday sun white point is accurately
+ * measured as a slightly chromatic blue by CAM16. (roughly, hue 203, chroma 3, lightness 100)
+ */
+public final class Cam16 {
+  // Transforms XYZ color space coordinates to 'cone'/'RGB' responses in CAM16.
+  static final float[][] XYZ_TO_CAM16RGB = {
+    {0.401288f, 0.650173f, -0.051461f},
+    {-0.250268f, 1.204414f, 0.045854f},
+    {-0.002079f, 0.048952f, 0.953127f}
+  };
+
+  // Transforms 'cone'/'RGB' responses in CAM16 to XYZ color space coordinates.
+  static final float[][] CAM16RGB_TO_XYZ = {
+    {1.8620678f, -1.0112547f, 0.14918678f},
+    {0.38752654f, 0.62144744f, -0.00897398f},
+    {-0.01584150f, -0.03412294f, 1.0499644f}
+  };
+
+  // CAM16 color dimensions, see getters for documentation.
+  private final float hue;
+  private final float chroma;
+  private final float j;
+  private final float q;
+  private final float m;
+  private final float s;
+
+  // Coordinates in UCS space. Used to determine color distance, like delta E equations in L*a*b*.
+  private final float jstar;
+  private final float astar;
+  private final float bstar;
+
+  /**
+   * CAM16 instances also have coordinates in the CAM16-UCS space, called J*, a*, b*, or jstar,
+   * astar, bstar in code. CAM16-UCS is included in the CAM16 specification, and is used to measure
+   * distances between colors.
+   */
+  float distance(Cam16 other) {
+    float dJ = getJStar() - other.getJStar();
+    float dA = getAStar() - other.getAStar();
+    float dB = getBStar() - other.getBStar();
+    double dEPrime = Math.sqrt(dJ * dJ + dA * dA + dB * dB);
+    double dE = 1.41 * Math.pow(dEPrime, 0.63);
+    return (float) dE;
+  }
+
+  /** Hue in CAM16 */
+  public float getHue() {
+    return hue;
+  }
+
+  /** Chroma in CAM16 */
+  public float getChroma() {
+    return chroma;
+  }
+
+  /** Lightness in CAM16 */
+  public float getJ() {
+    return j;
+  }
+
+  /**
+   * Brightness in CAM16.
+   *
+   * <p>Prefer lightness, brightness is an absolute quantity. For example, a sheet of white paper is
+   * much brighter viewed in sunlight than in indoor light, but it is the lightest object under any
+   * lighting.
+   */
+  public float getQ() {
+    return q;
+  }
+
+  /**
+   * Colorfulness in CAM16.
+   *
+   * <p>Prefer chroma, colorfulness is an absolute quantity. For example, a yellow toy car is much
+   * more colorful outside than inside, but it has the same chroma in both environments.
+   */
+  public float getM() {
+    return m;
+  }
+
+  /**
+   * Saturation in CAM16.
+   *
+   * <p>Colorfulness in proportion to brightness. Prefer chroma, saturation measures colorfulness
+   * relative to the color's own brightness, where chroma is colorfulness relative to white.
+   */
+  public float getS() {
+    return s;
+  }
+
+  /** Lightness coordinate in CAM16-UCS */
+  public float getJStar() {
+    return jstar;
+  }
+
+  /** a* coordinate in CAM16-UCS */
+  public float getAStar() {
+    return astar;
+  }
+
+  /** b* coordinate in CAM16-UCS */
+  public float getBStar() {
+    return bstar;
+  }
+
+  /**
+   * All of the CAM16 dimensions can be calculated from 3 of the dimensions, in the following
+   * combinations: - {j or q} and {c, m, or s} and hue - jstar, astar, bstar Prefer using a static
+   * method that constructs from 3 of those dimensions. This constructor is intended for those
+   * methods to use to return all possible dimensions.
+   *
+   * @param hue for example, red, orange, yellow, green, etc.
+   * @param chroma informally, colorfulness / color intensity. like saturation in HSL, except
+   *     perceptually accurate.
+   * @param j lightness
+   * @param q brightness; ratio of lightness to white point's lightness
+   * @param m colorfulness
+   * @param s saturation; ratio of chroma to white point's chroma
+   * @param jstar CAM16-UCS J coordinate
+   * @param astar CAM16-UCS a coordinate
+   * @param bstar CAM16-UCS b coordinate
+   */
+  private Cam16(
+      float hue,
+      float chroma,
+      float j,
+      float q,
+      float m,
+      float s,
+      float jstar,
+      float astar,
+      float bstar) {
+    this.hue = hue;
+    this.chroma = chroma;
+    this.j = j;
+    this.q = q;
+    this.m = m;
+    this.s = s;
+    this.jstar = jstar;
+    this.astar = astar;
+    this.bstar = bstar;
+  }
+
+  /**
+   * Create a CAM16 color from a color, assuming the color was viewed in default viewing conditions.
+   *
+   * @param argb ARGB representation of a color.
+   */
+  public static Cam16 fromInt(int argb) {
+    return fromIntInViewingConditions(argb, ViewingConditions.DEFAULT);
+  }
+
+  /**
+   * Create a CAM16 color from a color in defined viewing conditions.
+   *
+   * @param argb ARGB representation of a color.
+   * @param viewingConditions Information about the environment where the color was observed.
+   */
+  // The RGB => XYZ conversion matrix elements are derived scientific constants. While the values
+  // may differ at runtime due to floating point imprecision, keeping the values the same, and
+  // accurate, across implementations takes precedence.
+  @SuppressWarnings("FloatingPointLiteralPrecision")
+  static Cam16 fromIntInViewingConditions(int argb, ViewingConditions viewingConditions) {
+    // Transform ARGB int to XYZ
+    int red = (argb & 0x00ff0000) >> 16;
+    int green = (argb & 0x0000ff00) >> 8;
+    int blue = (argb & 0x000000ff);
+    float redL = (float) ColorUtils.linearized(red);
+    float greenL = (float) ColorUtils.linearized(green);
+    float blueL = (float) ColorUtils.linearized(blue);
+    float x = 0.41233895f * redL + 0.35762064f * greenL + 0.18051042f * blueL;
+    float y = 0.2126f * redL + 0.7152f * greenL + 0.0722f * blueL;
+    float z = 0.01932141f * redL + 0.11916382f * greenL + 0.95034478f * blueL;
+
+    // Transform XYZ to 'cone'/'rgb' responses
+    float[][] matrix = XYZ_TO_CAM16RGB;
+    float rT = (x * matrix[0][0]) + (y * matrix[0][1]) + (z * matrix[0][2]);
+    float gT = (x * matrix[1][0]) + (y * matrix[1][1]) + (z * matrix[1][2]);
+    float bT = (x * matrix[2][0]) + (y * matrix[2][1]) + (z * matrix[2][2]);
+
+    // Discount illuminant
+    float rD = viewingConditions.getRgbD()[0] * rT;
+    float gD = viewingConditions.getRgbD()[1] * gT;
+    float bD = viewingConditions.getRgbD()[2] * bT;
+
+    // Chromatic adaptation
+    float rAF = (float) Math.pow(viewingConditions.getFl() * Math.abs(rD) / 100.0, 0.42);
+    float gAF = (float) Math.pow(viewingConditions.getFl() * Math.abs(gD) / 100.0, 0.42);
+    float bAF = (float) Math.pow(viewingConditions.getFl() * Math.abs(bD) / 100.0, 0.42);
+    float rA = Math.signum(rD) * 400.0f * rAF / (rAF + 27.13f);
+    float gA = Math.signum(gD) * 400.0f * gAF / (gAF + 27.13f);
+    float bA = Math.signum(bD) * 400.0f * bAF / (bAF + 27.13f);
+
+    // redness-greenness
+    float a = (float) (11.0 * rA + -12.0 * gA + bA) / 11.0f;
+    // yellowness-blueness
+    float b = (float) (rA + gA - 2.0 * bA) / 9.0f;
+
+    // auxiliary components
+    float u = (20.0f * rA + 20.0f * gA + 21.0f * bA) / 20.0f;
+    float p2 = (40.0f * rA + 20.0f * gA + bA) / 20.0f;
+
+    // hue
+    float atan2 = (float) Math.atan2(b, a);
+    float atanDegrees = atan2 * 180.0f / (float) Math.PI;
+    float hue =
+        atanDegrees < 0
+            ? atanDegrees + 360.0f
+            : atanDegrees >= 360 ? atanDegrees - 360.0f : atanDegrees;
+    float hueRadians = hue * (float) Math.PI / 180.0f;
+
+    // achromatic response to color
+    float ac = p2 * viewingConditions.getNbb();
+
+    // CAM16 lightness and brightness
+    float j =
+        100.0f
+            * (float)
+                Math.pow(
+                    ac / viewingConditions.getAw(),
+                    viewingConditions.getC() * viewingConditions.getZ());
+    float q =
+        4.0f
+            / viewingConditions.getC()
+            * (float) Math.sqrt(j / 100.0f)
+            * (viewingConditions.getAw() + 4.0f)
+            * viewingConditions.getFlRoot();
+
+    // CAM16 chroma, colorfulness, and saturation.
+    float huePrime = (hue < 20.14) ? hue + 360 : hue;
+    float eHue = 0.25f * (float) (Math.cos(Math.toRadians(huePrime) + 2.0) + 3.8);
+    float p1 = 50000.0f / 13.0f * eHue * viewingConditions.getNc() * viewingConditions.getNcb();
+    float t = p1 * (float) Math.hypot(a, b) / (u + 0.305f);
+    float alpha =
+        (float) Math.pow(1.64 - Math.pow(0.29, viewingConditions.getN()), 0.73)
+            * (float) Math.pow(t, 0.9);
+    // CAM16 chroma, colorfulness, saturation
+    float c = alpha * (float) Math.sqrt(j / 100.0);
+    float m = c * viewingConditions.getFlRoot();
+    float s =
+        50.0f
+            * (float)
+                Math.sqrt((alpha * viewingConditions.getC()) / (viewingConditions.getAw() + 4.0f));
+
+    // CAM16-UCS components
+    float jstar = (1.0f + 100.0f * 0.007f) * j / (1.0f + 0.007f * j);
+    float mstar = 1.0f / 0.0228f * (float) Math.log1p(0.0228f * m);
+    float astar = mstar * (float) Math.cos(hueRadians);
+    float bstar = mstar * (float) Math.sin(hueRadians);
+
+    return new Cam16(hue, c, j, q, m, s, jstar, astar, bstar);
+  }
+
+  /**
+   * @param j CAM16 lightness
+   * @param c CAM16 chroma
+   * @param h CAM16 hue
+   */
+  static Cam16 fromJch(float j, float c, float h) {
+    return fromJchInViewingConditions(j, c, h, ViewingConditions.DEFAULT);
+  }
+
+  /**
+   * @param j CAM16 lightness
+   * @param c CAM16 chroma
+   * @param h CAM16 hue
+   * @param viewingConditions Information about the environment where the color was observed.
+   */
+  private static Cam16 fromJchInViewingConditions(
+      float j, float c, float h, ViewingConditions viewingConditions) {
+    float q =
+        4.0f
+            / viewingConditions.getC()
+            * (float) Math.sqrt(j / 100.0)
+            * (viewingConditions.getAw() + 4.0f)
+            * viewingConditions.getFlRoot();
+    float m = c * viewingConditions.getFlRoot();
+    float alpha = c / (float) Math.sqrt(j / 100.0);
+    float s =
+        50.0f
+            * (float)
+                Math.sqrt((alpha * viewingConditions.getC()) / (viewingConditions.getAw() + 4.0f));
+
+    float hueRadians = h * (float) Math.PI / 180.0f;
+    float jstar = (1.0f + 100.0f * 0.007f) * j / (1.0f + 0.007f * j);
+    float mstar = 1.0f / 0.0228f * (float) Math.log1p(0.0228 * m);
+    float astar = mstar * (float) Math.cos(hueRadians);
+    float bstar = mstar * (float) Math.sin(hueRadians);
+    return new Cam16(h, c, j, q, m, s, jstar, astar, bstar);
+  }
+
+  /**
+   * Create a CAM16 color from CAM16-UCS coordinates.
+   *
+   * @param jstar CAM16-UCS lightness.
+   * @param astar CAM16-UCS a dimension. Like a* in L*a*b*, it is a Cartesian coordinate on the Y
+   *     axis.
+   * @param bstar CAM16-UCS b dimension. Like a* in L*a*b*, it is a Cartesian coordinate on the X
+   *     axis.
+   */
+  public static Cam16 fromUcs(float jstar, float astar, float bstar) {
+
+    return fromUcsInViewingConditions(jstar, astar, bstar, ViewingConditions.DEFAULT);
+  }
+
+  /**
+   * Create a CAM16 color from CAM16-UCS coordinates in defined viewing conditions.
+   *
+   * @param jstar CAM16-UCS lightness.
+   * @param astar CAM16-UCS a dimension. Like a* in L*a*b*, it is a Cartesian coordinate on the Y
+   *     axis.
+   * @param bstar CAM16-UCS b dimension. Like a* in L*a*b*, it is a Cartesian coordinate on the X
+   *     axis.
+   * @param viewingConditions Information about the environment where the color was observed.
+   */
+  public static Cam16 fromUcsInViewingConditions(
+      float jstar, float astar, float bstar, ViewingConditions viewingConditions) {
+
+    double m = Math.hypot(astar, bstar);
+    double m2 = Math.expm1(m * 0.0228f) / 0.0228f;
+    double c = m2 / viewingConditions.getFlRoot();
+    double h = Math.atan2(bstar, astar) * (180.0f / Math.PI);
+    if (h < 0.0) {
+      h += 360.0f;
+    }
+    float j = jstar / (1f - (jstar - 100f) * 0.007f);
+    return fromJchInViewingConditions(j, (float) c, (float) h, viewingConditions);
+  }
+
+  /**
+   * ARGB representation of the color. Assumes the color was viewed in default viewing conditions,
+   * which are near-identical to the default viewing conditions for sRGB.
+   */
+  public int getInt() {
+    return viewed(ViewingConditions.DEFAULT);
+  }
+
+  /**
+   * ARGB representation of the color, in defined viewing conditions.
+   *
+   * @param viewingConditions Information about the environment where the color will be viewed.
+   * @return ARGB representation of color
+   */
+  int viewed(ViewingConditions viewingConditions) {
+    float alpha =
+        (getChroma() == 0.0 || getJ() == 0.0)
+            ? 0.0f
+            : getChroma() / (float) Math.sqrt(getJ() / 100.0);
+
+    float t =
+        (float)
+            Math.pow(
+                alpha / Math.pow(1.64 - Math.pow(0.29, viewingConditions.getN()), 0.73), 1.0 / 0.9);
+    float hRad = getHue() * (float) Math.PI / 180.0f;
+
+    float eHue = 0.25f * (float) (Math.cos(hRad + 2.0) + 3.8);
+    float ac =
+        viewingConditions.getAw()
+            * (float)
+                Math.pow(getJ() / 100.0, 1.0 / viewingConditions.getC() / viewingConditions.getZ());
+    float p1 = eHue * (50000.0f / 13.0f) * viewingConditions.getNc() * viewingConditions.getNcb();
+    float p2 = (ac / viewingConditions.getNbb());
+
+    float hSin = (float) Math.sin(hRad);
+    float hCos = (float) Math.cos(hRad);
+
+    float gamma = 23.0f * (p2 + 0.305f) * t / (23.0f * p1 + 11.0f * t * hCos + 108.0f * t * hSin);
+    float a = gamma * hCos;
+    float b = gamma * hSin;
+    float rA = (460.0f * p2 + 451.0f * a + 288.0f * b) / 1403.0f;
+    float gA = (460.0f * p2 - 891.0f * a - 261.0f * b) / 1403.0f;
+    float bA = (460.0f * p2 - 220.0f * a - 6300.0f * b) / 1403.0f;
+
+    float rCBase = (float) max(0, (27.13 * Math.abs(rA)) / (400.0 - Math.abs(rA)));
+    float rC =
+        Math.signum(rA)
+            * (100.0f / viewingConditions.getFl())
+            * (float) Math.pow(rCBase, 1.0 / 0.42);
+    float gCBase = (float) max(0, (27.13 * Math.abs(gA)) / (400.0 - Math.abs(gA)));
+    float gC =
+        Math.signum(gA)
+            * (100.0f / viewingConditions.getFl())
+            * (float) Math.pow(gCBase, 1.0 / 0.42);
+    float bCBase = (float) max(0, (27.13 * Math.abs(bA)) / (400.0 - Math.abs(bA)));
+    float bC =
+        Math.signum(bA)
+            * (100.0f / viewingConditions.getFl())
+            * (float) Math.pow(bCBase, 1.0 / 0.42);
+    float rF = rC / viewingConditions.getRgbD()[0];
+    float gF = gC / viewingConditions.getRgbD()[1];
+    float bF = bC / viewingConditions.getRgbD()[2];
+
+    float[][] matrix = CAM16RGB_TO_XYZ;
+    float x = (rF * matrix[0][0]) + (gF * matrix[0][1]) + (bF * matrix[0][2]);
+    float y = (rF * matrix[1][0]) + (gF * matrix[1][1]) + (bF * matrix[1][2]);
+    float z = (rF * matrix[2][0]) + (gF * matrix[2][1]) + (bF * matrix[2][2]);
+
+    return ColorUtils.argbFromXyz(x, y, z);
+  }
+}

material-color-utilities/src/main/java/hct/Hct.java

@@ -0,0 +1,262 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package hct;
+
+import utils.ColorUtils;
+import utils.MathUtils;
+
+/**
+ * A color system built using CAM16 hue and chroma, and L* from L*a*b*.
+ *
+ * <p>Using L* creates a link between the color system, contrast, and thus accessibility. Contrast
+ * ratio depends on relative luminance, or Y in the XYZ color space. L*, or perceptual luminance can
+ * be calculated from Y.
+ *
+ * <p>Unlike Y, L* is linear to human perception, allowing trivial creation of accurate color tones.
+ *
+ * <p>Unlike contrast ratio, measuring contrast in L* is linear, and simple to calculate. A
+ * difference of 40 in HCT tone guarantees a contrast ratio >= 3.0, and a difference of 50
+ * guarantees a contrast ratio >= 4.5.
+ */
+
+/**
+ * HCT, hue, chroma, and tone. A color system that provides a perceptually accurate color
+ * measurement system that can also accurately render what colors will appear as in different
+ * lighting environments.
+ */
+public final class Hct {
+  private float hue;
+  private float chroma;
+  private float tone;
+
+  /**
+   * Create an HCT color from hue, chroma, and tone.
+   *
+   * @param hue 0 <= hue < 360; invalid values are corrected.
+   * @param chroma 0 <= chroma < ?; Informally, colorfulness. The color returned may be lower than
+   *     the requested chroma. Chroma has a different maximum for any given hue and tone.
+   * @param tone 0 <= tone <= 100; invalid values are corrected.
+   * @return HCT representation of a color in default viewing conditions.
+   */
+  public static Hct from(float hue, float chroma, float tone) {
+    return new Hct(hue, chroma, tone);
+  }
+
+  /**
+   * Create an HCT color from a color.
+   *
+   * @param argb ARGB representation of a color.
+   * @return HCT representation of a color in default viewing conditions
+   */
+  public static Hct fromInt(int argb) {
+    Cam16 cam = Cam16.fromInt(argb);
+    return new Hct(cam.getHue(), cam.getChroma(), (float) ColorUtils.lstarFromArgb(argb));
+  }
+
+  private Hct(float hue, float chroma, float tone) {
+    setInternalState(gamutMap(hue, chroma, tone));
+  }
+
+  public float getHue() {
+    return hue;
+  }
+
+  public float getChroma() {
+    return chroma;
+  }
+
+  public float getTone() {
+    return tone;
+  }
+
+  public int toInt() {
+    return gamutMap(hue, chroma, tone);
+  }
+
+  /**
+   * Set the hue of this color. Chroma may decrease because chroma has a different maximum for any
+   * given hue and tone.
+   *
+   * @param newHue 0 <= newHue < 360; invalid values are corrected.
+   */
+  public void setHue(float newHue) {
+    setInternalState(gamutMap((float) MathUtils.sanitizeDegreesDouble(newHue), chroma, tone));
+  }
+
+  /**
+   * Set the chroma of this color. Chroma may decrease because chroma has a different maximum for
+   * any given hue and tone.
+   *
+   * @param newChroma 0 <= newChroma < ?
+   */
+  public void setChroma(float newChroma) {
+    setInternalState(gamutMap(hue, newChroma, tone));
+  }
+
+  /**
+   * Set the tone of this color. Chroma may decrease because chroma has a different maximum for any
+   * given hue and tone.
+   *
+   * @param newTone 0 <= newTone <= 100; invalid valids are corrected.
+   */
+  public void setTone(float newTone) {
+    setInternalState(gamutMap(hue, chroma, newTone));
+  }
+
+  private void setInternalState(int argb) {
+    Cam16 cam = Cam16.fromInt(argb);
+    float tone = (float) ColorUtils.lstarFromArgb(argb);
+    hue = cam.getHue();
+    chroma = cam.getChroma();
+    this.tone = tone;
+  }
+
+  /**
+   * When the delta between the floor & ceiling of a binary search for maximum chroma at a hue and
+   * tone is less than this, the binary search terminates.
+   */
+  private static final float CHROMA_SEARCH_ENDPOINT = 0.4f;
+
+  /** The maximum color distance, in CAM16-UCS, between a requested color and the color returned. */
+  private static final float DE_MAX = 1.0f;
+
+  /** The maximum difference between the requested L* and the L* returned. */
+  private static final float DL_MAX = 0.2f;
+
+  /**
+   * The minimum color distance, in CAM16-UCS, between a requested color and an 'exact' match. This
+   * allows the binary search during gamut mapping to terminate much earlier when the error is
+   * infinitesimal.
+   */
+  private static final float DE_MAX_ERROR = 0.000000001f;
+
+  /**
+   * When the delta between the floor & ceiling of a binary search for J, lightness in CAM16, is
+   * less than this, the binary search terminates.
+   */
+  private static final float LIGHTNESS_SEARCH_ENDPOINT = 0.01f;
+
+  /**
+   * @param hue a number, in degrees, representing ex. red, orange, yellow, etc. Ranges from 0 <=
+   *     hue < 360.
+   * @param chroma Informally, colorfulness. Ranges from 0 to roughly 150. Like all perceptually
+   *     accurate color systems, chroma has a different maximum for any given hue and tone, so the
+   *     color returned may be lower than the requested chroma.
+   * @param tone Lightness. Ranges from 0 to 100.
+   * @return ARGB representation of a color in default viewing conditions
+   */
+  private static int gamutMap(float hue, float chroma, float tone) {
+    return gamutMapInViewingConditions(hue, chroma, tone, ViewingConditions.DEFAULT);
+  }
+
+  /**
+   * @param hue CAM16 hue.
+   * @param chroma CAM16 chroma.
+   * @param tone L*a*b* lightness.
+   * @param viewingConditions Information about the environment where the color was observed.
+   */
+  static int gamutMapInViewingConditions(
+      float hue, float chroma, float tone, ViewingConditions viewingConditions) {
+
+    if (chroma < 1.0 || Math.round(tone) <= 0.0 || Math.round(tone) >= 100.0) {
+      return ColorUtils.argbFromLstar(tone);
+    }
+
+    hue = (float) MathUtils.sanitizeDegreesDouble(hue);
+
+    float high = chroma;
+    float mid = chroma;
+    float low = 0.0f;
+    boolean isFirstLoop = true;
+
+    Cam16 answer = null;
+    while (Math.abs(low - high) >= CHROMA_SEARCH_ENDPOINT) {
+      Cam16 possibleAnswer = findCamByJ(hue, mid, tone);
+
+      if (isFirstLoop) {
+        if (possibleAnswer != null) {
+          return possibleAnswer.viewed(viewingConditions);
+        } else {
+          isFirstLoop = false;
+          mid = low + (high - low) / 2.0f;
+          continue;
+        }
+      }
+
+      if (possibleAnswer == null) {
+        high = mid;
+      } else {
+        answer = possibleAnswer;
+        low = mid;
+      }
+
+      mid = low + (high - low) / 2.0f;
+    }
+
+    if (answer == null) {
+      return ColorUtils.argbFromLstar(tone);
+    }
+
+    return answer.viewed(viewingConditions);
+  }
+
+  /**
+   * @param hue CAM16 hue
+   * @param chroma CAM16 chroma
+   * @param tone L*a*b* lightness
+   * @return CAM16 instance within error tolerance of the provided dimensions, or null.
+   */
+  private static Cam16 findCamByJ(float hue, float chroma, float tone) {
+    float low = 0.0f;
+    float high = 100.0f;
+    float mid = 0.0f;
+    float bestdL = 1000.0f;
+    float bestdE = 1000.0f;
+
+    Cam16 bestCam = null;
+    while (Math.abs(low - high) > LIGHTNESS_SEARCH_ENDPOINT) {
+      mid = low + (high - low) / 2;
+      Cam16 camBeforeClip = Cam16.fromJch(mid, chroma, hue);
+      int clipped = camBeforeClip.getInt();
+      float clippedLstar = (float) ColorUtils.lstarFromArgb(clipped);
+      float dL = Math.abs(tone - clippedLstar);
+
+      if (dL < DL_MAX) {
+        Cam16 camClipped = Cam16.fromInt(clipped);
+        float dE =
+            camClipped.distance(Cam16.fromJch(camClipped.getJ(), camClipped.getChroma(), hue));
+        if (dE <= DE_MAX && dE <= bestdE) {
+          bestdL = dL;
+          bestdE = dE;
+          bestCam = camClipped;
+        }
+      }
+
+      if (bestdL == 0 && bestdE < DE_MAX_ERROR) {
+        break;
+      }
+
+      if (clippedLstar < tone) {
+        low = mid;
+      } else {
+        high = mid;
+      }
+    }
+
+    return bestCam;
+  }
+}

material-color-utilities/src/main/java/hct/ViewingConditions.java

@@ -0,0 +1,198 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package hct;
+
+import utils.ColorUtils;
+import utils.MathUtils;
+
+/**
+ * In traditional color spaces, a color can be identified solely by the observer's measurement of
+ * the color. Color appearance models such as CAM16 also use information about the environment where
+ * the color was observed, known as the viewing conditions.
+ *
+ * <p>For example, white under the traditional assumption of a midday sun white point is accurately
+ * measured as a slightly chromatic blue by CAM16. (roughly, hue 203, chroma 3, lightness 100)
+ *
+ * <p>This class caches intermediate values of the CAM16 conversion process that depend only on
+ * viewing conditions, enabling speed ups.
+ */
+public final class ViewingConditions {
+  /** sRGB-like viewing conditions. */
+  public static final ViewingConditions DEFAULT =
+      ViewingConditions.make(
+          new float[] {
+            (float) ColorUtils.whitePointD65()[0],
+            (float) ColorUtils.whitePointD65()[1],
+            (float) ColorUtils.whitePointD65()[2]
+          },
+          (float) (200.0f / Math.PI * ColorUtils.yFromLstar(50.0f) / 100.f),
+          50.0f,
+          2.0f,
+          false);
+
+  private final float aw;
+  private final float nbb;
+  private final float ncb;
+  private final float c;
+  private final float nc;
+  private final float n;
+  private final float[] rgbD;
+  private final float fl;
+  private final float flRoot;
+  private final float z;
+
+  public float getAw() {
+    return aw;
+  }
+
+  public float getN() {
+    return n;
+  }
+
+  public float getNbb() {
+    return nbb;
+  }
+
+  float getNcb() {
+    return ncb;
+  }
+
+  float getC() {
+    return c;
+  }
+
+  float getNc() {
+    return nc;
+  }
+
+  public float[] getRgbD() {
+    return rgbD;
+  }
+
+  float getFl() {
+    return fl;
+  }
+
+  public float getFlRoot() {
+    return flRoot;
+  }
+
+  float getZ() {
+    return z;
+  }
+
+  /**
+   * Create ViewingConditions from a simple, physically relevant, set of parameters.
+   *
+   * @param whitePoint White point, measured in the XYZ color space. default = D65, or sunny day
+   *     afternoon
+   * @param adaptingLuminance The luminance of the adapting field. Informally, how bright it is in
+   *     the room where the color is viewed. Can be calculated from lux by multiplying lux by
+   *     0.0586. default = 11.72, or 200 lux.
+   * @param backgroundLstar The lightness of the area surrounding the color. measured by L* in
+   *     L*a*b*. default = 50.0
+   * @param surround A general description of the lighting surrounding the color. 0 is pitch dark,
+   *     like watching a movie in a theater. 1.0 is a dimly light room, like watching TV at home at
+   *     night. 2.0 means there is no difference between the lighting on the color and around it.
+   *     default = 2.0
+   * @param discountingIlluminant Whether the eye accounts for the tint of the ambient lighting,
+   *     such as knowing an apple is still red in green light. default = false, the eye does not
+   *     perform this process on self-luminous objects like displays.
+   */
+  static ViewingConditions make(
+      float[] whitePoint,
+      float adaptingLuminance,
+      float backgroundLstar,
+      float surround,
+      boolean discountingIlluminant) {
+    // Transform white point XYZ to 'cone'/'rgb' responses
+    float[][] matrix = Cam16.XYZ_TO_CAM16RGB;
+    float[] xyz = whitePoint;
+    float rW = (xyz[0] * matrix[0][0]) + (xyz[1] * matrix[0][1]) + (xyz[2] * matrix[0][2]);
+    float gW = (xyz[0] * matrix[1][0]) + (xyz[1] * matrix[1][1]) + (xyz[2] * matrix[1][2]);
+    float bW = (xyz[0] * matrix[2][0]) + (xyz[1] * matrix[2][1]) + (xyz[2] * matrix[2][2]);
+    float f = 0.8f + (surround / 10.0f);
+    float c =
+        (f >= 0.9)
+            ? (float) MathUtils.lerp(0.59f, 0.69f, ((f - 0.9f) * 10.0f))
+            : (float) MathUtils.lerp(0.525f, 0.59f, ((f - 0.8f) * 10.0f));
+    float d =
+        discountingIlluminant
+            ? 1.0f
+            : f * (1.0f - ((1.0f / 3.6f) * (float) Math.exp((-adaptingLuminance - 42.0f) / 92.0f)));
+    d = (d > 1.0) ? 1.0f : (d < 0.0) ? 0.0f : d;
+    float nc = f;
+    float[] rgbD =
+        new float[] {
+          d * (100.0f / rW) + 1.0f - d, d * (100.0f / gW) + 1.0f - d, d * (100.0f / bW) + 1.0f - d
+        };
+    float k = 1.0f / (5.0f * adaptingLuminance + 1.0f);
+    float k4 = k * k * k * k;
+    float k4F = 1.0f - k4;
+    float fl =
+        (k4 * adaptingLuminance) + (0.1f * k4F * k4F * (float) Math.cbrt(5.0 * adaptingLuminance));
+    float n = (float) (ColorUtils.yFromLstar(backgroundLstar) / whitePoint[1]);
+    float z = 1.48f + (float) Math.sqrt(n);
+    float nbb = 0.725f / (float) Math.pow(n, 0.2);
+    float ncb = nbb;
+    float[] rgbAFactors =
+        new float[] {
+          (float) Math.pow(fl * rgbD[0] * rW / 100.0, 0.42),
+          (float) Math.pow(fl * rgbD[1] * gW / 100.0, 0.42),
+          (float) Math.pow(fl * rgbD[2] * bW / 100.0, 0.42)
+        };
+
+    float[] rgbA =
+        new float[] {
+          (400.0f * rgbAFactors[0]) / (rgbAFactors[0] + 27.13f),
+          (400.0f * rgbAFactors[1]) / (rgbAFactors[1] + 27.13f),
+          (400.0f * rgbAFactors[2]) / (rgbAFactors[2] + 27.13f)
+        };
+
+    float aw = ((2.0f * rgbA[0]) + rgbA[1] + (0.05f * rgbA[2])) * nbb;
+    return new ViewingConditions(n, aw, nbb, ncb, c, nc, rgbD, fl, (float) Math.pow(fl, 0.25), z);
+  }
+
+  /**
+   * Parameters are intermediate values of the CAM16 conversion process. Their names are shorthand
+   * for technical color science terminology, this class would not benefit from documenting them
+   * individually. A brief overview is available in the CAM16 specification, and a complete overview
+   * requires a color science textbook, such as Fairchild's Color Appearance Models.
+   */
+  private ViewingConditions(
+      float n,
+      float aw,
+      float nbb,
+      float ncb,
+      float c,
+      float nc,
+      float[] rgbD,
+      float fl,
+      float flRoot,
+      float z) {
+    this.n = n;
+    this.aw = aw;
+    this.nbb = nbb;
+    this.ncb = ncb;
+    this.c = c;
+    this.nc = nc;
+    this.rgbD = rgbD;
+    this.fl = fl;
+    this.flRoot = flRoot;
+    this.z = z;
+  }
+}

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

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package palettes;
+
+import static java.lang.Math.max;
+
+import hct.Hct;
+
+/**
+ * An intermediate concept between the key color for a UI theme, and a full color scheme. 5 sets of
+ * tones are generated, all except one use the same hue as the key color, and all vary in chroma.
+ */
+public final class CorePalette {
+  public TonalPalette a1;
+  public TonalPalette a2;
+  public TonalPalette a3;
+  public TonalPalette n1;
+  public TonalPalette n2;
+  public TonalPalette error;
+
+  /**
+   * Create key tones from a color.
+   *
+   * @param argb ARGB representation of a color
+   */
+  public static CorePalette of(int argb) {
+    return new CorePalette(argb);
+  }
+
+  private CorePalette(int argb) {
+    Hct hct = Hct.fromInt(argb);
+    float hue = hct.getHue();
+    this.a1 = TonalPalette.fromHueAndChroma(hue, max(48f, hct.getChroma()));
+    this.a2 = TonalPalette.fromHueAndChroma(hue, 16f);
+    this.a3 = TonalPalette.fromHueAndChroma(hue + 60f, 24f);
+    this.n1 = TonalPalette.fromHueAndChroma(hue, 4f);
+    this.n2 = TonalPalette.fromHueAndChroma(hue, 8f);
+    this.error = TonalPalette.fromHueAndChroma(25, 84f);
+  }
+}

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

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package palettes;
+
+import hct.Hct;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A convenience class for retrieving colors that are constant in hue and chroma, but vary in tone.
+ */
+public final class TonalPalette {
+  Map<Integer, Integer> cache;
+  float hue;
+  float chroma;
+
+  /**
+   * Create tones using the HCT hue and chroma from a color.
+   *
+   * @param argb ARGB representation of a color
+   * @return Tones matching that color's hue and chroma.
+   */
+  public static final TonalPalette fromInt(int argb) {
+    Hct hct = Hct.fromInt(argb);
+    return TonalPalette.fromHueAndChroma(hct.getHue(), hct.getChroma());
+  }
+
+  /**
+   * Create tones from a defined HCT hue and chroma.
+   *
+   * @param hue HCT hue
+   * @param chroma HCT chroma
+   * @return Tones matching hue and chroma.
+   */
+  public static final TonalPalette fromHueAndChroma(float hue, float chroma) {
+    return new TonalPalette(hue, chroma);
+  }
+
+  private TonalPalette(float hue, float chroma) {
+    cache = new HashMap<>();
+    this.hue = hue;
+    this.chroma = chroma;
+  }
+
+  /**
+   * Create an ARGB color with HCT hue and chroma of this Tones instance, and the provided HCT tone.
+   *
+   * @param tone HCT tone, measured from 0 to 100.
+   * @return ARGB representation of a color with that tone.
+   */
+  // AndroidJdkLibsChecker is higher priority than ComputeIfAbsentUseValue (b/119581923)
+  @SuppressWarnings("ComputeIfAbsentUseValue")
+  public int tone(int tone) {
+    Integer color = cache.get(tone);
+    if (color == null) {
+      color = Hct.from(this.hue, this.chroma, tone).toInt();
+      cache.put(tone, color);
+    }
+    return color;
+  }
+}

material-color-utilities/src/main/java/scheme/Scheme.java

@@ -0,0 +1,717 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package scheme;
+
+import palettes.CorePalette;
+
+/** Represents a Material color scheme, a mapping of color roles to colors. */
+public class Scheme {
+  private int primary;
+  private int onPrimary;
+  private int primaryContainer;
+  private int onPrimaryContainer;
+  private int secondary;
+  private int onSecondary;
+  private int secondaryContainer;
+  private int onSecondaryContainer;
+  private int tertiary;
+  private int onTertiary;
+  private int tertiaryContainer;
+  private int onTertiaryContainer;
+  private int error;
+  private int onError;
+  private int errorContainer;
+  private int onErrorContainer;
+  private int background;
+  private int onBackground;
+  private int surface;
+  private int onSurface;
+  private int surfaceVariant;
+  private int onSurfaceVariant;
+  private int outline;
+  private int shadow;
+  private int inverseSurface;
+  private int inverseOnSurface;
+  private int inversePrimary;
+
+  public Scheme() {}
+
+  public Scheme(
+      int primary,
+      int onPrimary,
+      int primaryContainer,
+      int onPrimaryContainer,
+      int secondary,
+      int onSecondary,
+      int secondaryContainer,
+      int onSecondaryContainer,
+      int tertiary,
+      int onTertiary,
+      int tertiaryContainer,
+      int onTertiaryContainer,
+      int error,
+      int onError,
+      int errorContainer,
+      int onErrorContainer,
+      int background,
+      int onBackground,
+      int surface,
+      int onSurface,
+      int surfaceVariant,
+      int onSurfaceVariant,
+      int outline,
+      int shadow,
+      int inverseSurface,
+      int inverseOnSurface,
+      int inversePrimary) {
+    super();
+    this.primary = primary;
+    this.onPrimary = onPrimary;
+    this.primaryContainer = primaryContainer;
+    this.onPrimaryContainer = onPrimaryContainer;
+    this.secondary = secondary;
+    this.onSecondary = onSecondary;
+    this.secondaryContainer = secondaryContainer;
+    this.onSecondaryContainer = onSecondaryContainer;
+    this.tertiary = tertiary;
+    this.onTertiary = onTertiary;
+    this.tertiaryContainer = tertiaryContainer;
+    this.onTertiaryContainer = onTertiaryContainer;
+    this.error = error;
+    this.onError = onError;
+    this.errorContainer = errorContainer;
+    this.onErrorContainer = onErrorContainer;
+    this.background = background;
+    this.onBackground = onBackground;
+    this.surface = surface;
+    this.onSurface = onSurface;
+    this.surfaceVariant = surfaceVariant;
+    this.onSurfaceVariant = onSurfaceVariant;
+    this.outline = outline;
+    this.shadow = shadow;
+    this.inverseSurface = inverseSurface;
+    this.inverseOnSurface = inverseOnSurface;
+    this.inversePrimary = inversePrimary;
+  }
+
+  public static Scheme light(int argb) {
+    CorePalette core = CorePalette.of(argb);
+    return new Scheme()
+        .withPrimary(core.a1.tone(40))
+        .withOnPrimary(core.a1.tone(100))
+        .withPrimaryContainer(core.a1.tone(90))
+        .withOnPrimaryContainer(core.a1.tone(10))
+        .withSecondary(core.a2.tone(40))
+        .withOnSecondary(core.a2.tone(100))
+        .withSecondaryContainer(core.a2.tone(90))
+        .withOnSecondaryContainer(core.a2.tone(10))
+        .withTertiary(core.a3.tone(40))
+        .withOnTertiary(core.a3.tone(100))
+        .withTertiaryContainer(core.a3.tone(90))
+        .withOnTertiaryContainer(core.a3.tone(10))
+        .withError(core.error.tone(40))
+        .withOnError(core.error.tone(100))
+        .withErrorContainer(core.error.tone(90))
+        .withOnErrorContainer(core.error.tone(10))
+        .withBackground(core.n1.tone(99))
+        .withOnBackground(core.n1.tone(10))
+        .withSurface(core.n1.tone(99))
+        .withOnSurface(core.n1.tone(10))
+        .withSurfaceVariant(core.n2.tone(90))
+        .withOnSurfaceVariant(core.n2.tone(30))
+        .withOutline(core.n2.tone(50))
+        .withShadow(core.n1.tone(0))
+        .withInverseSurface(core.n1.tone(20))
+        .withInverseOnSurface(core.n1.tone(95))
+        .withInversePrimary(core.a1.tone(80));
+  }
+
+  public static Scheme dark(int argb) {
+    CorePalette core = CorePalette.of(argb);
+    return new Scheme()
+        .withPrimary(core.a1.tone(80))
+        .withOnPrimary(core.a1.tone(20))
+        .withPrimaryContainer(core.a1.tone(30))
+        .withOnPrimaryContainer(core.a1.tone(90))
+        .withSecondary(core.a2.tone(80))
+        .withOnSecondary(core.a2.tone(20))
+        .withSecondaryContainer(core.a2.tone(30))
+        .withOnSecondaryContainer(core.a2.tone(90))
+        .withTertiary(core.a3.tone(80))
+        .withOnTertiary(core.a3.tone(20))
+        .withTertiaryContainer(core.a3.tone(30))
+        .withOnTertiaryContainer(core.a3.tone(90))
+        .withError(core.error.tone(80))
+        .withOnError(core.error.tone(20))
+        .withErrorContainer(core.error.tone(30))
+        .withOnErrorContainer(core.error.tone(80))
+        .withBackground(core.n1.tone(10))
+        .withOnBackground(core.n1.tone(90))
+        .withSurface(core.n1.tone(10))
+        .withOnSurface(core.n1.tone(90))
+        .withSurfaceVariant(core.n2.tone(30))
+        .withOnSurfaceVariant(core.n2.tone(80))
+        .withOutline(core.n2.tone(60))
+        .withShadow(core.n1.tone(0))
+        .withInverseSurface(core.n1.tone(90))
+        .withInverseOnSurface(core.n1.tone(20))
+        .withInversePrimary(core.a1.tone(40));
+  }
+
+  public int getPrimary() {
+    return primary;
+  }
+
+  public void setPrimary(int primary) {
+    this.primary = primary;
+  }
+
+  public Scheme withPrimary(int primary) {
+    this.primary = primary;
+    return this;
+  }
+
+  public int getOnPrimary() {
+    return onPrimary;
+  }
+
+  public void setOnPrimary(int onPrimary) {
+    this.onPrimary = onPrimary;
+  }
+
+  public Scheme withOnPrimary(int onPrimary) {
+    this.onPrimary = onPrimary;
+    return this;
+  }
+
+  public int getPrimaryContainer() {
+    return primaryContainer;
+  }
+
+  public void setPrimaryContainer(int primaryContainer) {
+    this.primaryContainer = primaryContainer;
+  }
+
+  public Scheme withPrimaryContainer(int primaryContainer) {
+    this.primaryContainer = primaryContainer;
+    return this;
+  }
+
+  public int getOnPrimaryContainer() {
+    return onPrimaryContainer;
+  }
+
+  public void setOnPrimaryContainer(int onPrimaryContainer) {
+    this.onPrimaryContainer = onPrimaryContainer;
+  }
+
+  public Scheme withOnPrimaryContainer(int onPrimaryContainer) {
+    this.onPrimaryContainer = onPrimaryContainer;
+    return this;
+  }
+
+  public int getSecondary() {
+    return secondary;
+  }
+
+  public void setSecondary(int secondary) {
+    this.secondary = secondary;
+  }
+
+  public Scheme withSecondary(int secondary) {
+    this.secondary = secondary;
+    return this;
+  }
+
+  public int getOnSecondary() {
+    return onSecondary;
+  }
+
+  public void setOnSecondary(int onSecondary) {
+    this.onSecondary = onSecondary;
+  }
+
+  public Scheme withOnSecondary(int onSecondary) {
+    this.onSecondary = onSecondary;
+    return this;
+  }
+
+  public int getSecondaryContainer() {
+    return secondaryContainer;
+  }
+
+  public void setSecondaryContainer(int secondaryContainer) {
+    this.secondaryContainer = secondaryContainer;
+  }
+
+  public Scheme withSecondaryContainer(int secondaryContainer) {
+    this.secondaryContainer = secondaryContainer;
+    return this;
+  }
+
+  public int getOnSecondaryContainer() {
+    return onSecondaryContainer;
+  }
+
+  public void setOnSecondaryContainer(int onSecondaryContainer) {
+    this.onSecondaryContainer = onSecondaryContainer;
+  }
+
+  public Scheme withOnSecondaryContainer(int onSecondaryContainer) {
+    this.onSecondaryContainer = onSecondaryContainer;
+    return this;
+  }
+
+  public int getTertiary() {
+    return tertiary;
+  }
+
+  public void setTertiary(int tertiary) {
+    this.tertiary = tertiary;
+  }
+
+  public Scheme withTertiary(int tertiary) {
+    this.tertiary = tertiary;
+    return this;
+  }
+
+  public int getOnTertiary() {
+    return onTertiary;
+  }
+
+  public void setOnTertiary(int onTertiary) {
+    this.onTertiary = onTertiary;
+  }
+
+  public Scheme withOnTertiary(int onTertiary) {
+    this.onTertiary = onTertiary;
+    return this;
+  }
+
+  public int getTertiaryContainer() {
+    return tertiaryContainer;
+  }
+
+  public void setTertiaryContainer(int tertiaryContainer) {
+    this.tertiaryContainer = tertiaryContainer;
+  }
+
+  public Scheme withTertiaryContainer(int tertiaryContainer) {
+    this.tertiaryContainer = tertiaryContainer;
+    return this;
+  }
+
+  public int getOnTertiaryContainer() {
+    return onTertiaryContainer;
+  }
+
+  public void setOnTertiaryContainer(int onTertiaryContainer) {
+    this.onTertiaryContainer = onTertiaryContainer;
+  }
+
+  public Scheme withOnTertiaryContainer(int onTertiaryContainer) {
+    this.onTertiaryContainer = onTertiaryContainer;
+    return this;
+  }
+
+  public int getError() {
+    return error;
+  }
+
+  public void setError(int error) {
+    this.error = error;
+  }
+
+  public Scheme withError(int error) {
+    this.error = error;
+    return this;
+  }
+
+  public int getOnError() {
+    return onError;
+  }
+
+  public void setOnError(int onError) {
+    this.onError = onError;
+  }
+
+  public Scheme withOnError(int onError) {
+    this.onError = onError;
+    return this;
+  }
+
+  public int getErrorContainer() {
+    return errorContainer;
+  }
+
+  public void setErrorContainer(int errorContainer) {
+    this.errorContainer = errorContainer;
+  }
+
+  public Scheme withErrorContainer(int errorContainer) {
+    this.errorContainer = errorContainer;
+    return this;
+  }
+
+  public int getOnErrorContainer() {
+    return onErrorContainer;
+  }
+
+  public void setOnErrorContainer(int onErrorContainer) {
+    this.onErrorContainer = onErrorContainer;
+  }
+
+  public Scheme withOnErrorContainer(int onErrorContainer) {
+    this.onErrorContainer = onErrorContainer;
+    return this;
+  }
+
+  public int getBackground() {
+    return background;
+  }
+
+  public void setBackground(int background) {
+    this.background = background;
+  }
+
+  public Scheme withBackground(int background) {
+    this.background = background;
+    return this;
+  }
+
+  public int getOnBackground() {
+    return onBackground;
+  }
+
+  public void setOnBackground(int onBackground) {
+    this.onBackground = onBackground;
+  }
+
+  public Scheme withOnBackground(int onBackground) {
+    this.onBackground = onBackground;
+    return this;
+  }
+
+  public int getSurface() {
+    return surface;
+  }
+
+  public void setSurface(int surface) {
+    this.surface = surface;
+  }
+
+  public Scheme withSurface(int surface) {
+    this.surface = surface;
+    return this;
+  }
+
+  public int getOnSurface() {
+    return onSurface;
+  }
+
+  public void setOnSurface(int onSurface) {
+    this.onSurface = onSurface;
+  }
+
+  public Scheme withOnSurface(int onSurface) {
+    this.onSurface = onSurface;
+    return this;
+  }
+
+  public int getSurfaceVariant() {
+    return surfaceVariant;
+  }
+
+  public void setSurfaceVariant(int surfaceVariant) {
+    this.surfaceVariant = surfaceVariant;
+  }
+
+  public Scheme withSurfaceVariant(int surfaceVariant) {
+    this.surfaceVariant = surfaceVariant;
+    return this;
+  }
+
+  public int getOnSurfaceVariant() {
+    return onSurfaceVariant;
+  }
+
+  public void setOnSurfaceVariant(int onSurfaceVariant) {
+    this.onSurfaceVariant = onSurfaceVariant;
+  }
+
+  public Scheme withOnSurfaceVariant(int onSurfaceVariant) {
+    this.onSurfaceVariant = onSurfaceVariant;
+    return this;
+  }
+
+  public int getOutline() {
+    return outline;
+  }
+
+  public void setOutline(int outline) {
+    this.outline = outline;
+  }
+
+  public Scheme withOutline(int outline) {
+    this.outline = outline;
+    return this;
+  }
+
+  public int getShadow() {
+    return shadow;
+  }
+
+  public void setShadow(int shadow) {
+    this.shadow = shadow;
+  }
+
+  public Scheme withShadow(int shadow) {
+    this.shadow = shadow;
+    return this;
+  }
+
+  public int getInverseSurface() {
+    return inverseSurface;
+  }
+
+  public void setInverseSurface(int inverseSurface) {
+    this.inverseSurface = inverseSurface;
+  }
+
+  public Scheme withInverseSurface(int inverseSurface) {
+    this.inverseSurface = inverseSurface;
+    return this;
+  }
+
+  public int getInverseOnSurface() {
+    return inverseOnSurface;
+  }
+
+  public void setInverseOnSurface(int inverseOnSurface) {
+    this.inverseOnSurface = inverseOnSurface;
+  }
+
+  public Scheme withInverseOnSurface(int inverseOnSurface) {
+    this.inverseOnSurface = inverseOnSurface;
+    return this;
+  }
+
+  public int getInversePrimary() {
+    return inversePrimary;
+  }
+
+  public void setInversePrimary(int inversePrimary) {
+    this.inversePrimary = inversePrimary;
+  }
+
+  public Scheme withInversePrimary(int inversePrimary) {
+    this.inversePrimary = inversePrimary;
+    return this;
+  }
+
+  @Override
+  public String toString() {
+    return "Scheme{"
+        + "primary="
+        + primary
+        + ", onPrimary="
+        + onPrimary
+        + ", primaryContainer="
+        + primaryContainer
+        + ", onPrimaryContainer="
+        + onPrimaryContainer
+        + ", secondary="
+        + secondary
+        + ", onSecondary="
+        + onSecondary
+        + ", secondaryContainer="
+        + secondaryContainer
+        + ", onSecondaryContainer="
+        + onSecondaryContainer
+        + ", tertiary="
+        + tertiary
+        + ", onTertiary="
+        + onTertiary
+        + ", tertiaryContainer="
+        + tertiaryContainer
+        + ", onTertiaryContainer="
+        + onTertiaryContainer
+        + ", error="
+        + error
+        + ", onError="
+        + onError
+        + ", errorContainer="
+        + errorContainer
+        + ", onErrorContainer="
+        + onErrorContainer
+        + ", background="
+        + background
+        + ", onBackground="
+        + onBackground
+        + ", surface="
+        + surface
+        + ", onSurface="
+        + onSurface
+        + ", surfaceVariant="
+        + surfaceVariant
+        + ", onSurfaceVariant="
+        + onSurfaceVariant
+        + ", outline="
+        + outline
+        + ", shadow="
+        + shadow
+        + ", inverseSurface="
+        + inverseSurface
+        + ", inverseOnSurface="
+        + inverseOnSurface
+        + ", inversePrimary="
+        + inversePrimary
+        + '}';
+  }
+
+  @Override
+  public boolean equals(Object object) {
+    if (this == object) {
+      return true;
+    }
+    if (!(object instanceof Scheme)) {
+      return false;
+    }
+    if (!super.equals(object)) {
+      return false;
+    }
+
+    Scheme scheme = (Scheme) object;
+
+    if (primary != scheme.primary) {
+      return false;
+    }
+    if (onPrimary != scheme.onPrimary) {
+      return false;
+    }
+    if (primaryContainer != scheme.primaryContainer) {
+      return false;
+    }
+    if (onPrimaryContainer != scheme.onPrimaryContainer) {
+      return false;
+    }
+    if (secondary != scheme.secondary) {
+      return false;
+    }
+    if (onSecondary != scheme.onSecondary) {
+      return false;
+    }
+    if (secondaryContainer != scheme.secondaryContainer) {
+      return false;
+    }
+    if (onSecondaryContainer != scheme.onSecondaryContainer) {
+      return false;
+    }
+    if (tertiary != scheme.tertiary) {
+      return false;
+    }
+    if (onTertiary != scheme.onTertiary) {
+      return false;
+    }
+    if (tertiaryContainer != scheme.tertiaryContainer) {
+      return false;
+    }
+    if (onTertiaryContainer != scheme.onTertiaryContainer) {
+      return false;
+    }
+    if (error != scheme.error) {
+      return false;
+    }
+    if (onError != scheme.onError) {
+      return false;
+    }
+    if (errorContainer != scheme.errorContainer) {
+      return false;
+    }
+    if (onErrorContainer != scheme.onErrorContainer) {
+      return false;
+    }
+    if (background != scheme.background) {
+      return false;
+    }
+    if (onBackground != scheme.onBackground) {
+      return false;
+    }
+    if (surface != scheme.surface) {
+      return false;
+    }
+    if (onSurface != scheme.onSurface) {
+      return false;
+    }
+    if (surfaceVariant != scheme.surfaceVariant) {
+      return false;
+    }
+    if (onSurfaceVariant != scheme.onSurfaceVariant) {
+      return false;
+    }
+    if (outline != scheme.outline) {
+      return false;
+    }
+    if (shadow != scheme.shadow) {
+      return false;
+    }
+    if (inverseSurface != scheme.inverseSurface) {
+      return false;
+    }
+    if (inverseOnSurface != scheme.inverseOnSurface) {
+      return false;
+    }
+    if (inversePrimary != scheme.inversePrimary) {
+      return false;
+    }
+
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = super.hashCode();
+    result = 31 * result + primary;
+    result = 31 * result + onPrimary;
+    result = 31 * result + primaryContainer;
+    result = 31 * result + onPrimaryContainer;
+    result = 31 * result + secondary;
+    result = 31 * result + onSecondary;
+    result = 31 * result + secondaryContainer;
+    result = 31 * result + onSecondaryContainer;
+    result = 31 * result + tertiary;
+    result = 31 * result + onTertiary;
+    result = 31 * result + tertiaryContainer;
+    result = 31 * result + onTertiaryContainer;
+    result = 31 * result + error;
+    result = 31 * result + onError;
+    result = 31 * result + errorContainer;
+    result = 31 * result + onErrorContainer;
+    result = 31 * result + background;
+    result = 31 * result + onBackground;
+    result = 31 * result + surface;
+    result = 31 * result + onSurface;
+    result = 31 * result + surfaceVariant;
+    result = 31 * result + onSurfaceVariant;
+    result = 31 * result + outline;
+    result = 31 * result + shadow;
+    result = 31 * result + inverseSurface;
+    result = 31 * result + inverseOnSurface;
+    result = 31 * result + inversePrimary;
+    return result;
+  }
+}

material-color-utilities/src/main/java/utils/ColorUtils.java

@@ -0,0 +1,265 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// This file is automatically generated. Do not modify it.
+
+package utils;
+
+/**
+ * Color science utilities.
+ *
+ * <p>Utility methods for color science constants and color space conversions that aren't HCT or
+ * CAM16.
+ */
+public class ColorUtils {
+  private ColorUtils() {}
+
+  static final double[][] SRGB_TO_XYZ =
+      new double[][] {
+        new double[] {0.41233895, 0.35762064, 0.18051042},
+        new double[] {0.2126, 0.7152, 0.0722},
+        new double[] {0.01932141, 0.11916382, 0.95034478},
+      };
+
+  static final double[][] XYZ_TO_SRGB =
+      new double[][] {
+        new double[] {
+          3.2413774792388685, -1.5376652402851851, -0.49885366846268053,
+        },
+        new double[] {
+          -0.9691452513005321, 1.8758853451067872, 0.04156585616912061,
+        },
+        new double[] {
+          0.05562093689691305, -0.20395524564742123, 1.0571799111220335,
+        },
+      };
+
+  static final double[] WHITE_POINT_D65 = new double[] {95.047, 100.0, 108.883};
+
+  /** Converts a color from RGB components to ARGB format. */
+  public static int argbFromRgb(int red, int green, int blue) {
+    return (255 << 24) | ((red & 255) << 16) | ((green & 255) << 8) | (blue & 255);
+  }
+
+  /** Returns the alpha component of a color in ARGB format. */
+  public static int alphaFromArgb(int argb) {
+    return (argb >> 24) & 255;
+  }
+
+  /** Returns the red component of a color in ARGB format. */
+  public static int redFromArgb(int argb) {
+    return (argb >> 16) & 255;
+  }
+
+  /** Returns the green component of a color in ARGB format. */
+  public static int greenFromArgb(int argb) {
+    return (argb >> 8) & 255;
+  }
+
+  /** Returns the blue component of a color in ARGB format. */
+  public static int blueFromArgb(int argb) {
+    return argb & 255;
+  }
+
+  /** Returns whether a color in ARGB format is opaque. */
+  public static boolean isOpaque(int argb) {
+    return alphaFromArgb(argb) >= 255;
+  }
+
+  /** Converts a color from ARGB to XYZ. */
+  public static int argbFromXyz(double x, double y, double z) {
+    double[][] matrix = XYZ_TO_SRGB;
+    double linearR = matrix[0][0] * x + matrix[0][1] * y + matrix[0][2] * z;
+    double linearG = matrix[1][0] * x + matrix[1][1] * y + matrix[1][2] * z;
+    double linearB = matrix[2][0] * x + matrix[2][1] * y + matrix[2][2] * z;
+    int r = delinearized(linearR);
+    int g = delinearized(linearG);
+    int b = delinearized(linearB);
+    return argbFromRgb(r, g, b);
+  }
+
+  /** Converts a color from XYZ to ARGB. */
+  public static double[] xyzFromArgb(int argb) {
+    double r = linearized(redFromArgb(argb));
+    double g = linearized(greenFromArgb(argb));
+    double b = linearized(blueFromArgb(argb));
+    return MathUtils.matrixMultiply(new double[] {r, g, b}, SRGB_TO_XYZ);
+  }
+
+  /** Converts a color represented in Lab color space into an ARGB integer. */
+  public static int argbFromLab(double l, double a, double b) {
+    double[] whitePoint = WHITE_POINT_D65;
+    double fy = (l + 16.0) / 116.0;
+    double fx = a / 500.0 + fy;
+    double fz = fy - b / 200.0;
+    double xNormalized = labInvf(fx);
+    double yNormalized = labInvf(fy);
+    double zNormalized = labInvf(fz);
+    double x = xNormalized * whitePoint[0];
+    double y = yNormalized * whitePoint[1];
+    double z = zNormalized * whitePoint[2];
+    return argbFromXyz(x, y, z);
+  }
+
+  /**
+   * Converts a color from ARGB representation to L*a*b* representation.
+   *
+   * @param argb the ARGB representation of a color
+   * @return a Lab object representing the color
+   */
+  public static double[] labFromArgb(int argb) {
+    double linearR = linearized(redFromArgb(argb));
+    double linearG = linearized(greenFromArgb(argb));
+    double linearB = linearized(blueFromArgb(argb));
+    double[][] matrix = SRGB_TO_XYZ;
+    double x = matrix[0][0] * linearR + matrix[0][1] * linearG + matrix[0][2] * linearB;
+    double y = matrix[1][0] * linearR + matrix[1][1] * linearG + matrix[1][2] * linearB;
+    double z = matrix[2][0] * linearR + matrix[2][1] * linearG + matrix[2][2] * linearB;
+    double[] whitePoint = WHITE_POINT_D65;
+    double xNormalized = x / whitePoint[0];
+    double yNormalized = y / whitePoint[1];
+    double zNormalized = z / whitePoint[2];
+    double fx = labF(xNormalized);
+    double fy = labF(yNormalized);
+    double fz = labF(zNormalized);
+    double l = 116.0 * fy - 16;
+    double a = 500.0 * (fx - fy);
+    double b = 200.0 * (fy - fz);
+    return new double[] {l, a, b};
+  }
+
+  /**
+   * Converts an L* value to an ARGB representation.
+   *
+   * @param lstar L* in L*a*b*
+   * @return ARGB representation of grayscale color with lightness matching L*
+   */
+  public static int argbFromLstar(double lstar) {
+    double fy = (lstar + 16.0) / 116.0;
+    double fz = fy;
+    double fx = fy;
+    double kappa = 24389.0 / 27.0;
+    double epsilon = 216.0 / 24389.0;
+    boolean lExceedsEpsilonKappa = lstar > 8.0;
+    double y = lExceedsEpsilonKappa ? fy * fy * fy : lstar / kappa;
+    boolean cubeExceedEpsilon = fy * fy * fy > epsilon;
+    double x = cubeExceedEpsilon ? fx * fx * fx : lstar / kappa;
+    double z = cubeExceedEpsilon ? fz * fz * fz : lstar / kappa;
+    double[] whitePoint = WHITE_POINT_D65;
+    return argbFromXyz(x * whitePoint[0], y * whitePoint[1], z * whitePoint[2]);
+  }
+
+  /**
+   * Computes the L* value of a color in ARGB representation.
+   *
+   * @param argb ARGB representation of a color
+   * @return L*, from L*a*b*, coordinate of the color
+   */
+  public static double lstarFromArgb(int argb) {
+    double y = xyzFromArgb(argb)[1] / 100.0;
+    double e = 216.0 / 24389.0;
+    if (y <= e) {
+      return 24389.0 / 27.0 * y;
+    } else {
+      double yIntermediate = Math.pow(y, 1.0 / 3.0);
+      return 116.0 * yIntermediate - 16.0;
+    }
+  }
+
+  /**
+   * Converts an L* value to a Y value.
+   *
+   * <p>L* in L*a*b* and Y in XYZ measure the same quantity, luminance.
+   *
+   * <p>L* measures perceptual luminance, a linear scale. Y in XYZ measures relative luminance, a
+   * logarithmic scale.
+   *
+   * @param lstar L* in L*a*b*
+   * @return Y in XYZ
+   */
+  public static double yFromLstar(double lstar) {
+    double ke = 8.0;
+    if (lstar > ke) {
+      return Math.pow((lstar + 16.0) / 116.0, 3.0) * 100.0;
+    } else {
+      return lstar / 24389.0 / 27.0 * 100.0;
+    }
+  }
+
+  /**
+   * Linearizes an RGB component.
+   *
+   * @param rgbComponent 0 <= rgb_component <= 255, represents R/G/B channel
+   * @return 0.0 <= output <= 100.0, color channel converted to linear RGB space
+   */
+  public static double linearized(int rgbComponent) {
+    double normalized = rgbComponent / 255.0;
+    if (normalized <= 0.040449936) {
+      return normalized / 12.92 * 100.0;
+    } else {
+      return Math.pow((normalized + 0.055) / 1.055, 2.4) * 100.0;
+    }
+  }
+
+  /**
+   * Delinearizes an RGB component.
+   *
+   * @param rgbComponent 0.0 <= rgb_component <= 100.0, represents linear R/G/B channel
+   * @return 0 <= output <= 255, color channel converted to regular RGB space
+   */
+  public static int delinearized(double rgbComponent) {
+    double normalized = rgbComponent / 100.0;
+    double delinearized = 0.0;
+    if (normalized <= 0.0031308) {
+      delinearized = normalized * 12.92;
+    } else {
+      delinearized = 1.055 * Math.pow(normalized, 1.0 / 2.4) - 0.055;
+    }
+    return MathUtils.clampInt(0, 255, (int) Math.round(delinearized * 255.0));
+  }
+
+  /**
+   * Returns the standard white point; white on a sunny day.
+   *
+   * @return The white point
+   */
+  public static double[] whitePointD65() {
+    return WHITE_POINT_D65;
+  }
+
+  static double labF(double t) {
+    double e = 216.0 / 24389.0;
+    double kappa = 24389.0 / 27.0;
+    if (t > e) {
+      return Math.pow(t, 1.0 / 3.0);
+    } else {
+      return (kappa * t + 16) / 116;
+    }
+  }
+
+  static double labInvf(double ft) {
+    double e = 216.0 / 24389.0;
+    double kappa = 24389.0 / 27.0;
+    double ft3 = ft * ft * ft;
+    if (ft3 > e) {
+      return ft3;
+    } else {
+      return (116 * ft - 16) / kappa;
+    }
+  }
+
+}
+

material-color-utilities/src/main/java/utils/MathUtils.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// This file is automatically generated. Do not modify it.
+
+package utils;
+
+/** Utility methods for mathematical operations. */
+public class MathUtils {
+  private MathUtils() {}
+
+  /**
+   * The signum function.
+   *
+   * @return 1 if num > 0, -1 if num < 0, and 0 if num = 0
+   */
+  public static int signum(double num) {
+    if (num < 0) {
+      return -1;
+    } else if (num == 0) {
+      return 0;
+    } else {
+      return 1;
+    }
+  }
+
+  /**
+   * The linear interpolation function.
+   *
+   * @return start if amount = 0 and stop if amount = 1
+   */
+  public static double lerp(double start, double stop, double amount) {
+    return (1.0 - amount) * start + amount * stop;
+  }
+
+  /**
+   * Clamps an integer between two integers.
+   *
+   * @return input when min <= input <= max, and either min or max otherwise.
+   */
+  public static int clampInt(int min, int max, int input) {
+    if (input < min) {
+      return min;
+    } else if (input > max) {
+      return max;
+    }
+
+    return input;
+  }
+
+  /**
+   * Clamps an integer between two floating-point numbers.
+   *
+   * @return input when min <= input <= max, and either min or max otherwise.
+   */
+  public static double clampDouble(double min, double max, double input) {
+    if (input < min) {
+      return min;
+    } else if (input > max) {
+      return max;
+    }
+
+    return input;
+  }
+
+  /**
+   * Sanitizes a degree measure as an integer.
+   *
+   * @return a degree measure between 0 (inclusive) and 360 (exclusive).
+   */
+  public static int sanitizeDegreesInt(int degrees) {
+    degrees = degrees % 360;
+    if (degrees < 0) {
+      degrees = degrees + 360;
+    }
+    return degrees;
+  }
+
+  /**
+   * Sanitizes a degree measure as a floating-point number.
+   *
+   * @return a degree measure between 0.0 (inclusive) and 360.0 (exclusive).
+   */
+  public static double sanitizeDegreesDouble(double degrees) {
+    degrees = degrees % 360.0;
+    if (degrees < 0) {
+      degrees = degrees + 360.0;
+    }
+    return degrees;
+  }
+
+  /** Distance of two points on a circle, represented using degrees. */
+  public static double differenceDegrees(double a, double b) {
+    return 180.0 - Math.abs(Math.abs(a - b) - 180.0);
+  }
+
+  /** Multiplies a 1x3 row vector with a 3x3 matrix. */
+  public static double[] matrixMultiply(double[] row, double[][] matrix) {
+    double a = row[0] * matrix[0][0] + row[1] * matrix[0][1] + row[2] * matrix[0][2];
+    double b = row[0] * matrix[1][0] + row[1] * matrix[1][1] + row[2] * matrix[1][2];
+    double c = row[0] * matrix[2][0] + row[1] * matrix[2][1] + row[2] * matrix[2][2];
+    return new double[] {a, b, c};
+  }
+
+}
+

material-color-utilities/src/main/java/utils/StringUtils.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package utils;
+
+/** Utility methods for string representations of colors. */
+final class StringUtils {
+  private StringUtils() {}
+
+  /**
+   * Hex string representing color, ex. #ff0000 for red.
+   *
+   * @param argb ARGB representation of a color.
+   */
+  public static String hexFromArgb(int argb) {
+    int red = ColorUtils.redFromArgb(argb);
+    int blue = ColorUtils.blueFromArgb(argb);
+    int green = ColorUtils.greenFromArgb(argb);
+    return String.format("#%02x%02x%02x", red, green, blue);
+  }
+}

preferences/src/main/proto/settings.proto

@@ -15,6 +15,7 @@ message Settings {
     enum ColorScheme {
       Default = 0;
       BlackAndWhite = 1;
+      Wallpaper = 2;
     }
     ColorScheme color_scheme = 6;
     bool dim_wallpaper = 7;

settings.gradle.kts

@@ -385,3 +385,4 @@ dependencyResolutionManagement {
 include(":notifications")
 include(":accounts")
 include(":appshortcuts")
+include(":material-color-utilities")

ui/build.gradle.kts

@@ -104,6 +104,8 @@ dependencies {
     implementation(libs.coil.core)
     implementation(libs.coil.compose)
 
+    implementation(project(":material-color-utilities"))
+
     implementation(project(":base"))
     implementation(project(":i18n"))
     implementation(project(":compat"))

ui/src/main/java/de/mm20/launcher2/ui/settings/appearance/AppearanceSettingsScreen.kt

@@ -71,6 +71,7 @@ fun AppearanceSettingsScreen() {
                     summary = when (colorScheme) {
                         ColorScheme.Default -> stringResource(R.string.preference_colors_default)
                         ColorScheme.BlackAndWhite -> stringResource(R.string.preference_colors_bw)
+                        ColorScheme.Wallpaper -> stringResource(R.string.preference_colors_wallpaper)
                         else -> null
                     },
                     onClick = {

ui/src/main/java/de/mm20/launcher2/ui/settings/colorscheme/ColorSchemeSettingsScreen.kt

@@ -1,5 +1,6 @@
 package de.mm20.launcher2.ui.settings.colorscheme
 
+import android.os.Build
 import androidx.compose.foundation.background
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.*
@@ -7,6 +8,7 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.rounded.RadioButtonChecked
 import androidx.compose.material.icons.rounded.RadioButtonUnchecked
 import androidx.compose.material3.ColorScheme
+import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
@@ -17,44 +19,42 @@ import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.viewmodel.compose.viewModel
+import de.mm20.launcher2.ktx.isAtLeastApiLevel
 import de.mm20.launcher2.preferences.Settings.AppearanceSettings
 import de.mm20.launcher2.ui.R
 import de.mm20.launcher2.ui.component.preferences.Preference
 import de.mm20.launcher2.ui.component.preferences.PreferenceCategory
 import de.mm20.launcher2.ui.component.preferences.PreferenceScreen
-import de.mm20.launcher2.ui.theme.getColorScheme
+import de.mm20.launcher2.ui.theme.colorSchemeAsState
 
 @Composable
 fun ColorSchemeSettingsScreen() {
     val viewModel: ColorSchemeSettingsScreenVM = viewModel()
-    val context = LocalContext.current
 
     PreferenceScreen(title = stringResource(R.string.preference_screen_colors)) {
         item {
             PreferenceCategory {
-                val theme by viewModel.theme.observeAsState()
-                val darkTheme =
-                    theme == AppearanceSettings.Theme.Dark || theme == AppearanceSettings.Theme.System && isSystemInDarkTheme()
                 val colorScheme by viewModel.colorScheme.observeAsState()
 
-                val items = listOf(
+                val items = mutableListOf(
                     AppearanceSettings.ColorScheme.Default to R.string.preference_colors_default,
-                    AppearanceSettings.ColorScheme.BlackAndWhite to R.string.preference_colors_bw
+                    AppearanceSettings.ColorScheme.BlackAndWhite to R.string.preference_colors_bw,
                 )
 
+                if (isAtLeastApiLevel(Build.VERSION_CODES.O_MR1)) {
+                    items.add(
+                        AppearanceSettings.ColorScheme.Wallpaper to R.string.preference_colors_wallpaper
+                    )
+                }
+
                 for (cs in items) {
+                    val scheme by colorSchemeAsState(cs.first)
                     Preference(
                         title = stringResource(cs.second),
                         icon = if (colorScheme == cs.first) Icons.Rounded.RadioButtonChecked else Icons.Rounded.RadioButtonUnchecked,
                         onClick = { viewModel.setColorScheme(cs.first) },
                         controls = {
-                            ColorSchemePreview(
-                                getColorScheme(
-                                    LocalContext.current,
-                                    cs.first,
-                                    darkTheme,
-                                )
-                            )
+                            ColorSchemePreview(scheme)
                         }
                     )
                 }
@@ -65,51 +65,54 @@ fun ColorSchemeSettingsScreen() {
 
 @Composable
 fun ColorSchemePreview(colorScheme: ColorScheme) {
-    Box(
-        modifier = Modifier
-            .padding(vertical = 12.dp)
-            .width(72.dp)
-            .height(36.dp),
-        contentAlignment = Alignment.Center
-    ) {
-        Row(
-            verticalAlignment = Alignment.CenterVertically
+    MaterialTheme(colorScheme = colorScheme) {
+        Box(
+            modifier = Modifier
+                .padding(vertical = 12.dp)
+                .width(72.dp)
+                .height(36.dp),
+            contentAlignment = Alignment.Center
         ) {
-            Surface(
-                tonalElevation = 1.dp,
-                color = colorScheme.surface,
-                modifier = Modifier
-                    .size(36.dp)
-            ) {}
-            Surface(
-                tonalElevation = 1.dp,
-                color = colorScheme.surfaceVariant,
-                modifier = Modifier
-                    .size(36.dp)
-            ) {}
-        }
-        Row(
-            verticalAlignment = Alignment.CenterVertically
-        ) {
-            Surface(
-                tonalElevation = 1.dp,
-                color = colorScheme.primary,
-                modifier = Modifier
-                    .size(16.dp)
-            ) {}
-            Surface(
-                tonalElevation = 1.dp,
-                color = colorScheme.secondary,
-                modifier = Modifier
-                    .padding(horizontal = 8.dp)
-                    .size(16.dp)
-            ) {}
-            Surface(
-                tonalElevation = 1.dp,
-                color = colorScheme.tertiary,
-                modifier = Modifier
-                    .size(16.dp)
-            ) {}
+            Row(
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                Surface(
+                    tonalElevation = 1.dp,
+                    color = MaterialTheme.colorScheme.surface,
+                    modifier = Modifier
+                        .size(36.dp)
+                ) {}
+                Surface(
+                    tonalElevation = 1.dp,
+                    color = MaterialTheme.colorScheme.surfaceVariant,
+                    modifier = Modifier
+                        .size(36.dp)
+                ) {}
+            }
+            Row(
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                Surface(
+                    tonalElevation = 1.dp,
+                    color = MaterialTheme.colorScheme.primary,
+                    modifier = Modifier
+                        .size(16.dp)
+                ) {}
+                Surface(
+                    tonalElevation = 1.dp,
+                    color = MaterialTheme.colorScheme.secondary,
+                    modifier = Modifier
+                        .padding(horizontal = 8.dp)
+                        .size(16.dp)
+                ) {}
+                Surface(
+                    tonalElevation = 1.dp,
+                    color = MaterialTheme.colorScheme.tertiary,
+                    modifier = Modifier
+                        .size(16.dp)
+                ) {}
+            }
         }
     }
+
 }

ui/src/main/java/de/mm20/launcher2/ui/theme/LauncherTheme.kt

@@ -1,24 +1,18 @@
 package de.mm20.launcher2.ui.theme
 
-import android.content.Context
+import android.os.Build
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material3.ColorScheme
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.dynamicDarkColorScheme
 import androidx.compose.material3.dynamicLightColorScheme
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.collectAsState
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.remember
+import androidx.compose.runtime.*
 import androidx.compose.ui.platform.LocalContext
 import de.mm20.launcher2.ktx.isAtLeastApiLevel
 import de.mm20.launcher2.preferences.LauncherDataStore
 import de.mm20.launcher2.preferences.Settings.AppearanceSettings
 import de.mm20.launcher2.preferences.Settings.AppearanceSettings.Theme
-import de.mm20.launcher2.ui.theme.colorscheme.DarkBlackAndWhiteColorScheme
-import de.mm20.launcher2.ui.theme.colorscheme.DarkPre31DefaultColorScheme
-import de.mm20.launcher2.ui.theme.colorscheme.LightBlackAndWhiteColorScheme
-import de.mm20.launcher2.ui.theme.colorscheme.LightPre31DefaultColorScheme
+import de.mm20.launcher2.ui.theme.colorscheme.*
 import de.mm20.launcher2.ui.theme.typography.DefaultTypography
 import kotlinx.coroutines.flow.map
 import org.koin.androidx.compose.inject
@@ -34,34 +28,52 @@ fun LauncherTheme(
     val colorSchemePreference by remember { dataStore.data.map { it.appearance.colorScheme } }.collectAsState(
         AppearanceSettings.ColorScheme.Default
     )
-    val themePreference by remember { dataStore.data.map { it.appearance.theme } }.collectAsState(
-        Theme.System
-    )
 
-    val darkTheme =
-        themePreference == Theme.Dark || themePreference == Theme.System && isSystemInDarkTheme()
+    val colorScheme by colorSchemeAsState(colorSchemePreference)
 
     MaterialTheme(
-        colorScheme = getColorScheme(LocalContext.current, colorSchemePreference, darkTheme),
+        colorScheme = colorScheme,
         typography = DefaultTypography,
         content = content
     )
 }
 
-fun getColorScheme(context: Context, colorScheme: AppearanceSettings.ColorScheme, darkTheme: Boolean): ColorScheme {
-    return when (colorScheme) {
-        AppearanceSettings.ColorScheme.BlackAndWhite -> {
-            if (darkTheme) DarkBlackAndWhiteColorScheme
-            else LightBlackAndWhiteColorScheme
-        }
-        else -> {
-            if (darkTheme) {
-                if (isAtLeastApiLevel(31)) dynamicDarkColorScheme(context)
-                else DarkPre31DefaultColorScheme
-            } else {
-                if (isAtLeastApiLevel(31)) dynamicLightColorScheme(context)
-                else LightPre31DefaultColorScheme
+@Composable
+fun colorSchemeAsState(colorScheme: AppearanceSettings.ColorScheme): MutableState<ColorScheme> {
+    val context = LocalContext.current
+    val dataStore: LauncherDataStore by inject()
+
+    val themePreference by remember { dataStore.data.map { it.appearance.theme } }.collectAsState(
+        Theme.System
+    )
+    val darkTheme =
+        themePreference == Theme.Dark || themePreference == Theme.System && isSystemInDarkTheme()
+
+    val state = remember(colorScheme, darkTheme) {
+        mutableStateOf(
+            when (colorScheme) {
+                AppearanceSettings.ColorScheme.BlackAndWhite -> {
+                    if (darkTheme) DarkBlackAndWhiteColorScheme else LightBlackAndWhiteColorScheme
+                }
+                else -> {
+                    if (darkTheme) {
+                        if (isAtLeastApiLevel(31)) dynamicDarkColorScheme(context)
+                        else DarkPre31DefaultColorScheme
+                    } else {
+                        if (isAtLeastApiLevel(31)) dynamicLightColorScheme(context)
+                        else LightPre31DefaultColorScheme
+                    }
+                }
             }
+        )
+    }
+
+    if (colorScheme == AppearanceSettings.ColorScheme.Wallpaper && Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
+        val wallpaperColors by wallpaperColorsAsState()
+        LaunchedEffect(wallpaperColors, darkTheme) {
+            state.value = WallpaperColorScheme(wallpaperColors, darkTheme)
         }
     }
-}
+
+    return state
+}

ui/src/main/java/de/mm20/launcher2/ui/theme/WallpaperColors.kt

@@ -4,6 +4,7 @@ import android.app.WallpaperManager
 import android.os.Build
 import android.os.Handler
 import android.os.Looper
+import android.util.Log
 import androidx.annotation.RequiresApi
 import androidx.compose.runtime.*
 import androidx.compose.ui.graphics.Color

ui/src/main/java/de/mm20/launcher2/ui/theme/colorscheme/Wallpaper.kt

@@ -0,0 +1,69 @@
+package de.mm20.launcher2.ui.theme.colorscheme
+
+import androidx.compose.material3.ColorScheme
+import androidx.compose.material3.darkColorScheme
+import androidx.compose.material3.lightColorScheme
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.toArgb
+import de.mm20.launcher2.ui.theme.WallpaperColors
+import palettes.TonalPalette
+
+fun WallpaperColorScheme(wallpaperColors: WallpaperColors, darkTheme: Boolean): ColorScheme {
+    val primary = TonalPalette.fromInt(wallpaperColors.primary.toArgb())
+    val secondary = TonalPalette.fromInt((wallpaperColors.secondary ?: wallpaperColors.primary).toArgb())
+    val tertiary = TonalPalette.fromInt((wallpaperColors.tertiary ?: wallpaperColors.primary).toArgb())
+
+    val neutral1 = TonalPalette.fromInt(Color.Black.toArgb())
+    val neutral2 = TonalPalette.fromInt(Color.Black.toArgb())
+
+    return if(darkTheme) {
+         darkColorScheme(
+             primary = Color(primary.tone(80)),
+             onPrimary = Color(primary.tone(20)),
+             primaryContainer = Color(primary.tone(30)),
+             onPrimaryContainer = Color(primary.tone(90)),
+             secondary = Color(secondary.tone(80)),
+             onSecondary = Color(secondary.tone(20)),
+             secondaryContainer = Color(secondary.tone(30)),
+             onSecondaryContainer = Color(secondary.tone(90)),
+             tertiary = Color(tertiary.tone(80)),
+             onTertiary = Color(tertiary.tone(20)),
+             tertiaryContainer = Color(tertiary.tone(30)),
+             onTertiaryContainer = Color(tertiary.tone(90)),
+             background = Color(neutral1.tone(10)),
+             onBackground = Color(neutral1.tone(90)),
+             surface = Color(neutral1.tone(10)),
+             onSurface = Color(neutral1.tone(90)),
+             surfaceVariant = Color(neutral2.tone(30)),
+             onSurfaceVariant = Color(neutral2.tone(80)),
+             outline = Color(neutral2.tone(60)),
+             inverseSurface = Color(neutral1.tone(90)),
+             inverseOnSurface = Color(neutral1.tone(20)),
+             inversePrimary = Color(primary.tone(40)),
+         )
+    } else {
+        lightColorScheme(
+            primary = Color(primary.tone(40)),
+            onPrimary = Color(primary.tone(100)),
+            primaryContainer = Color(primary.tone(90)),
+            onPrimaryContainer = Color(primary.tone(10)),
+            secondary = Color(secondary.tone(40)),
+            onSecondary = Color(secondary.tone(100)),
+            secondaryContainer = Color(secondary.tone(90)),
+            onSecondaryContainer = Color(secondary.tone(10)),
+            tertiary = Color(tertiary.tone(40)),
+            onTertiary = Color(tertiary.tone(100)),
+            tertiaryContainer = Color(tertiary.tone(90)),
+            onTertiaryContainer = Color(tertiary.tone(10)),
+            background = Color(neutral1.tone(99)),
+            onBackground = Color(neutral1.tone(10)),
+            surface = Color(neutral1.tone(99)),
+            onSurface = Color(neutral1.tone(10)),
+            surfaceVariant = Color(neutral2.tone(90)),
+            onSurfaceVariant = Color(neutral2.tone(30)),
+            outline = Color(neutral2.tone(50)),
+            inverseSurface = Color(neutral1.tone(20)),
+            inverseOnSurface = Color(neutral1.tone(95)),
+            inversePrimary = Color(primary.tone(80)),)
+    }
+}