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diff --git a/palettes/TonalPalette.java b/palettes/TonalPalette.java
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+/*
+ * 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 com.google.ux.material.libmonet.palettes;
+
+import com.google.ux.material.libmonet.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;
+  Hct keyColor;
+  double hue;
+  double 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 TonalPalette fromInt(int argb) {
+    return fromHct(Hct.fromInt(argb));
+  }
+
+  /**
+   * Create tones using a HCT color.
+   *
+   * @param hct HCT representation of a color.
+   * @return Tones matching that color's hue and chroma.
+   */
+  public static TonalPalette fromHct(Hct hct) {
+    return new TonalPalette(hct.getHue(), hct.getChroma(), hct);
+  }
+
+  /**
+   * 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 TonalPalette fromHueAndChroma(double hue, double chroma) {
+    return new TonalPalette(hue, chroma, createKeyColor(hue, chroma));
+  }
+
+  private TonalPalette(double hue, double chroma, Hct keyColor) {
+    cache = new HashMap<>();
+    this.hue = hue;
+    this.chroma = chroma;
+    this.keyColor = keyColor;
+  }
+
+  /** The key color is the first tone, starting from T50, matching the given hue and chroma. */
+  private static Hct createKeyColor(double hue, double chroma) {
+    double startTone = 50.0;
+    Hct smallestDeltaHct = Hct.from(hue, chroma, startTone);
+    double smallestDelta = Math.abs(smallestDeltaHct.getChroma() - chroma);
+    // Starting from T50, check T+/-delta to see if they match the requested
+    // chroma.
+    //
+    // Starts from T50 because T50 has the most chroma available, on
+    // average. Thus it is most likely to have a direct answer and minimize
+    // iteration.
+    for (double delta = 1.0; delta < 50.0; delta += 1.0) {
+      // Termination condition rounding instead of minimizing delta to avoid
+      // case where requested chroma is 16.51, and the closest chroma is 16.49.
+      // Error is minimized, but when rounded and displayed, requested chroma
+      // is 17, key color's chroma is 16.
+      if (Math.round(chroma) == Math.round(smallestDeltaHct.getChroma())) {
+        return smallestDeltaHct;
+      }
+
+      final Hct hctAdd = Hct.from(hue, chroma, startTone + delta);
+      final double hctAddDelta = Math.abs(hctAdd.getChroma() - chroma);
+      if (hctAddDelta < smallestDelta) {
+        smallestDelta = hctAddDelta;
+        smallestDeltaHct = hctAdd;
+      }
+
+      final Hct hctSubtract = Hct.from(hue, chroma, startTone - delta);
+      final double hctSubtractDelta = Math.abs(hctSubtract.getChroma() - chroma);
+      if (hctSubtractDelta < smallestDelta) {
+        smallestDelta = hctSubtractDelta;
+        smallestDeltaHct = hctSubtract;
+      }
+    }
+
+    return smallestDeltaHct;
+  }
+
+  /**
+   * 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;
+  }
+
+  /** Given a tone, use hue and chroma of palette to create a color, and return it as HCT. */
+  public Hct getHct(double tone) {
+    return Hct.from(this.hue, this.chroma, tone);
+  }
+
+  /** The chroma of the Tonal Palette, in HCT. Ranges from 0 to ~130 (for sRGB gamut). */
+  public double getChroma() {
+    return this.chroma;
+  }
+
+  /** The hue of the Tonal Palette, in HCT. Ranges from 0 to 360. */
+  public double getHue() {
+    return this.hue;
+  }
+
+  /** The key color is the first tone, starting from T50, that matches the palette's chroma. */
+  public Hct getKeyColor() {
+    return this.keyColor;
+  }
+}