[M3][Color] Added the rest of the library for content color support.

PiperOrigin-RevId: 482801156

Author: Material Design Team

lib/java/com/google/android/material/color/utilities/CorePalette.java

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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.android.material.color.utilities;
+
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+import static java.lang.Math.max;
+import static java.lang.Math.min;
+
+import androidx.annotation.RestrictTo;
+
+// TODO(b/254603377): Use copybara to release material color utilities library directly to github.
+/**
+ * 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.
+ *
+ * @hide
+ */
+@RestrictTo(LIBRARY_GROUP)
+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, false);
+  }
+
+  /**
+   * Create content key tones from a color.
+   *
+   * @param argb ARGB representation of a color
+   */
+  public static CorePalette contentOf(int argb) {
+    return new CorePalette(argb, true);
+  }
+
+  private CorePalette(int argb, boolean isContent) {
+    Hct hct = Hct.fromInt(argb);
+    double hue = hct.getHue();
+    double chroma = hct.getChroma();
+    if (isContent) {
+      this.a1 = TonalPalette.fromHueAndChroma(hue, chroma);
+      this.a2 = TonalPalette.fromHueAndChroma(hue, chroma / 3.);
+      this.a3 = TonalPalette.fromHueAndChroma(hue + 60., chroma / 2.);
+      this.n1 = TonalPalette.fromHueAndChroma(hue, min(chroma / 12., 4.));
+      this.n2 = TonalPalette.fromHueAndChroma(hue, min(chroma / 6., 8.));
+    } else {
+      this.a1 = TonalPalette.fromHueAndChroma(hue, max(48., chroma));
+      this.a2 = TonalPalette.fromHueAndChroma(hue, 16.);
+      this.a3 = TonalPalette.fromHueAndChroma(hue + 60., 24.);
+      this.n1 = TonalPalette.fromHueAndChroma(hue, 4.);
+      this.n2 = TonalPalette.fromHueAndChroma(hue, 8.);
+    }
+    this.error = TonalPalette.fromHueAndChroma(25, 84.);
+  }
+}

lib/java/com/google/android/material/color/utilities/PointProvider.java

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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.android.material.color.utilities;
+
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+
+import androidx.annotation.RestrictTo;
+
+// TODO(b/254603377): Use copybara to release material color utilities library directly to github.
+/**
+ * An interface to allow use of different color spaces by quantizers.
+ *
+ * @hide
+ */
+@RestrictTo(LIBRARY_GROUP)
+public interface PointProvider {
+  public double[] fromInt(int argb);
+
+  public int toInt(double[] point);
+
+  public double distance(double[] a, double[] b);
+}

lib/java/com/google/android/material/color/utilities/PointProviderLab.java

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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.android.material.color.utilities;
+
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+
+import androidx.annotation.RestrictTo;
+
+// TODO(b/254603377): Use copybara to release material color utilities library directly to github.
+/**
+ * Provides conversions needed for K-Means quantization. Converting input to points, and converting
+ * the final state of the K-Means algorithm to colors.
+ *
+ * @hide
+ */
+@RestrictTo(LIBRARY_GROUP)
+public final class PointProviderLab implements PointProvider {
+  /**
+   * Convert a color represented in ARGB to a 3-element array of L*a*b* coordinates of the color.
+   */
+  @Override
+  public double[] fromInt(int argb) {
+    double[] lab = ColorUtils.labFromArgb(argb);
+    return new double[] {lab[0], lab[1], lab[2]};
+  }
+
+  /** Convert a 3-element array to a color represented in ARGB. */
+  @Override
+  public int toInt(double[] lab) {
+    return ColorUtils.argbFromLab(lab[0], lab[1], lab[2]);
+  }
+
+  /**
+   * Standard CIE 1976 delta E formula also takes the square root, unneeded here. This method is
+   * used by quantization algorithms to compare distance, and the relative ordering is the same,
+   * with or without a square root.
+   *
+   * <p>This relatively minor optimization is helpful because this method is called at least once
+   * for each pixel in an image.
+   */
+  @Override
+  public double distance(double[] one, double[] two) {
+    double dL = (one[0] - two[0]);
+    double dA = (one[1] - two[1]);
+    double dB = (one[2] - two[2]);
+    return (dL * dL + dA * dA + dB * dB);
+  }
+}

lib/java/com/google/android/material/color/utilities/Quantizer.java

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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.android.material.color.utilities;
+
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+
+import androidx.annotation.RestrictTo;
+
+// TODO(b/254603377): Use copybara to release material color utilities library directly to github.
+/** @hide */
+@RestrictTo(LIBRARY_GROUP)
+interface Quantizer {
+  public QuantizerResult quantize(int[] pixels, int maxColors);
+}

lib/java/com/google/android/material/color/utilities/QuantizerCelebi.java

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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.android.material.color.utilities;
+
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+
+import androidx.annotation.RestrictTo;
+import java.util.Map;
+import java.util.Set;
+
+// TODO(b/254603377): Use copybara to release material color utilities library directly to github.
+/**
+ * An image quantizer that improves on the quality of a standard K-Means algorithm by setting the
+ * K-Means initial state to the output of a Wu quantizer, instead of random centroids. Improves on
+ * speed by several optimizations, as implemented in Wsmeans, or Weighted Square Means, K-Means with
+ * those optimizations.
+ *
+ * <p>This algorithm was designed by M. Emre Celebi, and was found in their 2011 paper, Improving
+ * the Performance of K-Means for Color Quantization. https://arxiv.org/abs/1101.0395
+ *
+ * @hide
+ */
+@RestrictTo(LIBRARY_GROUP)
+public final class QuantizerCelebi {
+  private QuantizerCelebi() {}
+
+  /**
+   * Reduce the number of colors needed to represented the input, minimizing the difference between
+   * the original image and the recolored image.
+   *
+   * @param pixels Colors in ARGB format.
+   * @param maxColors The number of colors to divide the image into. A lower number of colors may be
+   *     returned.
+   * @return Map with keys of colors in ARGB format, and values of number of pixels in the original
+   *     image that correspond to the color in the quantized image.
+   */
+  public static Map<Integer, Integer> quantize(int[] pixels, int maxColors) {
+    QuantizerWu wu = new QuantizerWu();
+    QuantizerResult wuResult = wu.quantize(pixels, maxColors);
+
+    Set<Integer> wuClustersAsObjects = wuResult.colorToCount.keySet();
+    int index = 0;
+    int[] wuClusters = new int[wuClustersAsObjects.size()];
+    for (Integer argb : wuClustersAsObjects) {
+      wuClusters[index++] = argb;
+    }
+
+    return QuantizerWsmeans.quantize(pixels, wuClusters, maxColors);
+  }
+}

lib/java/com/google/android/material/color/utilities/QuantizerMap.java

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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.android.material.color.utilities;
+
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+
+import androidx.annotation.RestrictTo;
+import java.util.HashMap;
+import java.util.Map;
+
+// TODO(b/254603377): Use copybara to release material color utilities library directly to github.
+/**
+ * Creates a dictionary with keys of colors, and values of count of the color
+ *
+ * @hide
+ */
+@RestrictTo(LIBRARY_GROUP)
+public final class QuantizerMap implements Quantizer {
+  Map<Integer, Integer> colorToCount;
+
+  @Override
+  public QuantizerResult quantize(int[] pixels, int colorCount) {
+    final HashMap<Integer, Integer> pixelByCount = new HashMap<>();
+    for (int pixel : pixels) {
+      final Integer currentPixelCount = pixelByCount.get(pixel);
+      final int newPixelCount = currentPixelCount == null ? 1 : currentPixelCount + 1;
+      pixelByCount.put(pixel, newPixelCount);
+    }
+    colorToCount = pixelByCount;
+    return new QuantizerResult(pixelByCount);
+  }
+
+  public Map<Integer, Integer> getColorToCount() {
+    return colorToCount;
+  }
+}

lib/java/com/google/android/material/color/utilities/QuantizerResult.java

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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.android.material.color.utilities;
+
+import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+
+import androidx.annotation.RestrictTo;
+import java.util.Map;
+
+// TODO(b/254603377): Use copybara to release material color utilities library directly to github.
+/**
+ * Represents result of a quantizer run
+ *
+ * @hide
+ */
+@RestrictTo(LIBRARY_GROUP)
+public final class QuantizerResult {
+  public final Map<Integer, Integer> colorToCount;
+
+  QuantizerResult(Map<Integer, Integer> colorToCount) {
+    this.colorToCount = colorToCount;
+  }
+}