content: /*
   * Copyright (C) 2006 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 android.graphics;
  
  import android.annotation.AnyThread;
  import android.annotation.ColorInt;
  import android.annotation.ColorLong;
  import android.annotation.HalfFloat;
  import android.annotation.IntRange;
  import android.annotation.NonNull;
  import android.annotation.Nullable;
  import android.annotation.Size;
  import android.annotation.SuppressAutoDoc;
  import android.util.Half;
  import com.android.internal.util.XmlUtils;
  
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.Locale;
  import java.util.function.DoubleUnaryOperator;
  
  /**
   * {@usesMathJax}
   *
   * <p>The <code>Color</code> class provides methods for creating, converting and
   * manipulating colors. Colors have three different representations:</p>
   * <ul>
   *     <li>Color ints, the most common representation</li>
   *     <li>Color longs</li>
   *     <li><code>Color</code> instances</li>
   * </ul>
   * <p>The section below describe each representation in detail.</p>
   *
   * <h3>Color ints</h3>
   * <p>Color ints are the most common representation of colors on Android and
   * have been used since {@link android.os.Build.VERSION_CODES#BASE API level 1}.</p>
   *
   * <p>A color int always defines a color in the {@link ColorSpace.Named#SRGB sRGB}
   * color space using 4 components packed in a single 32 bit integer value:</p>
   *
   * <table summary="Color int definition">
   *     <tr>
   *         <th>Component</th><th>Name</th><th>Size</th><th>Range</th>
   *     </tr>
   *     <tr><td>A</td><td>Alpha</td><td>8 bits</td><td>\([0..255]\)</td></tr>
   *     <tr><td>R</td><td>Red</td><td>8 bits</td><td>\([0..255]\)</td></tr>
   *     <tr><td>G</td><td>Green</td><td>8 bits</td><td>\([0..255]\)</td></tr>
   *     <tr><td>B</td><td>Blue</td><td>8 bits</td><td>\([0..255]\)</td></tr>
   * </table>
   *
   * <p>The components in this table are listed in encoding order (see below),
   * which is why color ints are called ARGB colors.</p>
   *
   * <h4>Usage in code</h4>
   * <p>To avoid confusing color ints with arbitrary integer values, it is a
   * good practice to annotate them with the <code>@ColorInt</code> annotation
   * found in the Android Support Library.</p>
   *
   * <h4>Encoding</h4>
   * <p>The four components of a color int are encoded in the following way:</p>
   * <pre class="prettyprint">
   * int color = (A & 0xff) << 24 | (R & 0xff) << 16 | (G & 0xff) << 8 | (B & 0xff);
   * </pre>
   *
   * <p>Because of this encoding, color ints can easily be described as an integer
   * constant in source. For instance, opaque blue is <code>0xff0000ff</code>
   * and yellow is <code>0xffffff00</code>.</p>
   *
   * <p>To easily encode color ints, it is recommended to use the static methods
   * {@link #argb(int, int, int, int)} and {@link #rgb(int, int, int)}. The second
   * method omits the alpha component and assumes the color is opaque (alpha is 255).
   * As a convenience this class also offers methods to encode color ints from components
   * defined in the \([0..1]\) range: {@link #argb(float, float, float, float)} and
   * {@link #rgb(float, float, float)}.</p>
   *
   * <p>Color longs (defined below) can be easily converted to color ints by invoking
   * the {@link #toArgb(long)} method. This method performs a color space conversion
   * if needed.</p>
   *
   * <p>It is also possible to create a color int by invoking the method {@link #toArgb()}
   * on a color instance.</p>
   *
   * <h4>Decoding</h4>
   * <p>The four ARGB components can be individually extracted from a color int
   * using the following expressions:</p>
   * <pre class="prettyprint">
   * int A = (color >> 24) & 0xff; // or color >>> 24
   * int R = (color >> 16) & 0xff;
   * int G = (color >>  8) & 0xff;
   * int B = (color      ) & 0xff;
   * </pre>
   *
   * <p>This class offers convenience methods to easily extract these components:</p>
   * <ul>
   *     <li>{@link #alpha(int)} to extract the alpha component</li>
   *     <li>{@link #red(int)} to extract the red component</li>
   *     <li>{@link #green(int)} to extract the green component</li>
   *     <li>{@link #blue(int)} to extract the blue component</li>
   * </ul>
   *
   * <h3>Color longs</h3>
   * <p>Color longs are a representation introduced in
   * {@link android.os.Build.VERSION_CODES#O Android O} to store colors in different
   * {@link ColorSpace color spaces}, with more precision than color ints.</p>
   *
   * <p>A color long always defines a color using 4 components packed in a single
   * 64 bit long value. One of these components is always alpha while the other
   * three components depend on the color space's {@link ColorSpace.Model color model}.
   * The most common color model is the {@link ColorSpace.Model#RGB RGB} model in
   * which the components represent red, green and blue values.</p>
   *
   * <p class="note"><b>Component ranges:</b> the ranges defined in the tables
   * below indicate the ranges that can be encoded in a color long. They do not
   * represent the actual ranges as they may differ per color space. For instance,
   * the RGB components of a color in the {@link ColorSpace.Named#DISPLAY_P3 Display P3}
   * color space use the \([0..1]\) range. Please refer to the documentation of the
   * various {@link ColorSpace.Named color spaces} to find their respective ranges.</p>
   *
   * <p class="note"><b>Alpha range:</b> while alpha is encoded in a color long using
   * a 10 bit integer (thus using a range of \([0..1023]\)), it is converted to and
   * from \([0..1]\) float values when decoding and encoding color longs.</p>
   *
   * <p class="note"><b>sRGB color space:</b> for compatibility reasons and ease of
   * use, color longs encoding {@link ColorSpace.Named#SRGB sRGB} colors do not
   * use the same encoding as other color longs.</p>
   *
   * <table summary="Color long definition">
   *     <tr>
   *         <th>Component</th><th>Name</th><th>Size</th><th>Range</th>
   *     </tr>
   *     <tr><td colspan="4">{@link ColorSpace.Model#RGB RGB} color model</td></tr>
   *     <tr><td>R</td><td>Red</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>G</td><td>Green</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>B</td><td>Blue</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>A</td><td>Alpha</td><td>10 bits</td><td>\([0..1023]\)</td></tr>
   *     <tr><td></td><td>Color space</td><td>6 bits</td><td>\([0..63]\)</td></tr>
   *     <tr><td colspan="4">{@link ColorSpace.Named#SRGB sRGB} color space</td></tr>
   *     <tr><td>A</td><td>Alpha</td><td>8 bits</td><td>\([0..255]\)</td></tr>
   *     <tr><td>R</td><td>Red</td><td>8 bits</td><td>\([0..255]\)</td></tr>
   *     <tr><td>G</td><td>Green</td><td>8 bits</td><td>\([0..255]\)</td></tr>
   *     <tr><td>B</td><td>Blue</td><td>8 bits</td><td>\([0..255]\)</td></tr>
   *     <tr><td>X</td><td>Unused</td><td>32 bits</td><td>\(0\)</td></tr>
   *     <tr><td colspan="4">{@link ColorSpace.Model#XYZ XYZ} color model</td></tr>
   *     <tr><td>X</td><td>X</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>Y</td><td>Y</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>Z</td><td>Z</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>A</td><td>Alpha</td><td>10 bits</td><td>\([0..1023]\)</td></tr>
   *     <tr><td></td><td>Color space</td><td>6 bits</td><td>\([0..63]\)</td></tr>
   *     <tr><td colspan="4">{@link ColorSpace.Model#XYZ Lab} color model</td></tr>
   *     <tr><td>L</td><td>L</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>a</td><td>a</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>b</td><td>b</td><td>16 bits</td><td>\([-65504.0, 65504.0]\)</td></tr>
   *     <tr><td>A</td><td>Alpha</td><td>10 bits</td><td>\([0..1023]\)</td></tr>
   *     <tr><td></td><td>Color space</td><td>6 bits</td><td>\([0..63]\)</td></tr>
   *     <tr><td colspan="4">{@link ColorSpace.Model#CMYK CMYK} color model</td></tr>
   *     <tr><td colspan="4">Unsupported</td></tr>
   * </table>
   *
   * <p>The components in this table are listed in encoding order (see below),
   * which is why color longs in the RGB model are called RGBA colors (even if
   * this doesn't quite hold for the special case of sRGB colors).</p>
   *
   * <p>The color long encoding relies on half-precision float values (fp16). If you
   * wish to know more about the limitations of half-precision float values, please
   * refer to the documentation of the {@link Half} class.</p>
   *
   * <h4>Usage in code</h4>
   * <p>To avoid confusing color longs with arbitrary long values, it is a
   * good practice to annotate them with the <code>@ColorLong</code> annotation
   * found in the Android Support Library.</p>
   *
   * <h4>Encoding</h4>
   *
   * <p>Given the complex nature of color longs, it is strongly encouraged to use
   * the various methods provided by this class to encode them.</p>
   *
   * <p>The most flexible way to encode a color long is to use the method
   * {@link #pack(float, float, float, float, ColorSpace)}. This method allows you
   * to specify three color components (typically RGB), an alpha component and a
   * color space. To encode sRGB colors, use {@link #pack(float, float, float)}
   * and {@link #pack(float, float, float, float)} which are the
   * equivalent of {@link #rgb(int, int, int)} and {@link #argb(int, int, int, int)}
   * for color ints. If you simply need to convert a color int into a color long,
   * use {@link #pack(int)}.</p>
   *
   * <p>It is also possible to create a color long value by invoking the method
   * {@link #pack()} on a color instance.</p>
   *
   * <h4>Decoding</h4>
   *
   * <p>This class offers convenience methods to easily extract the components
   * of a color long:</p>
   * <ul>
   *     <li>{@link #alpha(long)} to extract the alpha component</li>
   *     <li>{@link #red(long)} to extract the red/X/L component</li>
   *     <li>{@link #green(long)} to extract the green/Y/a component</li>
   *     <li>{@link #blue(long)} to extract the blue/Z/b component</li>
   * </ul>
   *
   * <p>The values returned by these methods depend on the color space encoded
   * in the color long. The values are however typically in the \([0..1]\) range
   * for RGB colors. Please refer to the documentation of the various
   * {@link ColorSpace.Named color spaces} for the exact ranges.</p>
   *
   * <h3>Color instances</h3>
   * <p>Color instances are a representation introduced in
   * {@link android.os.Build.VERSION_CODES#O Android O} to store colors in different
   * {@link ColorSpace color spaces}, with more precision than both color ints and
   * color longs. Color instances also offer the ability to store more than 4
   * components if necessary.</p>
   *
   * <p>Colors instances are immutable and can be created using one of the various
   * <code>valueOf</code> methods. For instance:</p>
   * <pre class="prettyprint">
   * // sRGB
   * Color opaqueRed = Color.valueOf(0xffff0000); // from a color int
   * Color translucentRed = Color.valueOf(1.0f, 0.0f, 0.0f, 0.5f);
   *
   * // Wide gamut color
   * {@literal @}ColorLong long p3 = pack(1.0f, 1.0f, 0.0f, 1.0f, colorSpaceP3);
   * Color opaqueYellow = Color.valueOf(p3); // from a color long
   *
   * // CIE L*a*b* color space
   * ColorSpace lab = ColorSpace.get(ColorSpace.Named.LAB);
   * Color green = Color.valueOf(100.0f, -128.0f, 128.0f, 1.0f, lab);
   * </pre>
   *
   * <p>Color instances can be converted to color ints ({@link #toArgb()}) or
   * color longs ({@link #pack()}). They also offer easy access to their various
   * components using the following methods:</p>
   * <ul>
   *     <li>{@link #alpha()}, returns the alpha component value</li>
   *     <li>{@link #red()}, returns the red component value (or first
   *     component value in non-RGB models)</li>
   *     <li>{@link #green()}, returns the green component value (or second
   *     component value in non-RGB models)</li>
   *     <li>{@link #blue()}, returns the blue component value (or third
   *     component value in non-RGB models)</li>
   *     <li>{@link #getComponent(int)}, returns a specific component value</li>
   *     <li>{@link #getComponents()}, returns all component values as an array</li>
   * </ul>
   *
   * <h3>Color space conversions</h3>
   * <p>You can convert colors from one color space to another using
   * {@link ColorSpace#connect(ColorSpace, ColorSpace)} and its variants. However,
   * the <code>Color</code> class provides a few convenience methods to simplify
   * the process. Here is a brief description of some of them:</p>
   * <ul>
   *     <li>{@link #convert(ColorSpace)} to convert a color instance in a color
   *     space to a new color instance in a different color space</li>
   *     <li>{@link #convert(float, float, float, float, ColorSpace, ColorSpace)} to
   *     convert a color from a source color space to a destination color space</li>
   *     <li>{@link #convert(long, ColorSpace)} to convert a color long from its
   *     built-in color space to a destination color space</li>
   *     <li>{@link #convert(int, ColorSpace)} to convert a color int from sRGB
   *     to a destination color space</li>
   * </ul>
   *
   * <p>Please refere to the {@link ColorSpace} documentation for more
   * information.</p>
   *
   * <h3>Alpha and transparency</h3>
   * <p>The alpha component of a color defines the level of transparency of a
   * color. When the alpha component is 0, the color is completely transparent.
   * When the alpha is component is 1 (in the \([0..1]\) range) or 255 (in the
   * \([0..255]\) range), the color is completely opaque.</p>
   *
   * <p>The color representations described above do not use pre-multiplied
   * color components (a pre-multiplied color component is a color component
   * that has been multiplied by the value of the alpha component).
   * For instance, the color int representation of opaque red is
   * <code>0xffff0000</code>. For semi-transparent (50%) red, the
   * representation becomes <code>0x80ff0000</code>. The equivalent color
   * instance representations would be <code>(1.0, 0.0, 0.0, 1.0)</code>
   * and <code>(1.0, 0.0, 0.0, 0.5)</code>.</p>
   */
  @AnyThread
  @SuppressAutoDoc
  public class Color {
      @ColorInt public static final int BLACK       = 0xFF000000;
      @ColorInt public static final int DKGRAY      = 0xFF444444;
      @ColorInt public static final int GRAY        = 0xFF888888;
      @ColorInt public static final int LTGRAY      = 0xFFCCCCCC;
      @ColorInt public static final int WHITE       = 0xFFFFFFFF;
      @ColorInt public static final int RED         = 0xFFFF0000;
      @ColorInt public static final int GREEN       = 0xFF00FF00;
      @ColorInt public static final int BLUE        = 0xFF0000FF;
      @ColorInt public static final int YELLOW      = 0xFFFFFF00;
      @ColorInt public static final int CYAN        = 0xFF00FFFF;
      @ColorInt public static final int MAGENTA     = 0xFFFF00FF;
      @ColorInt public static final int TRANSPARENT = 0;
  
      @NonNull
      @Size(min = 4, max = 5)
      private final float[] mComponents;
  
      @NonNull
      private final ColorSpace mColorSpace;
  
      /**
       * Creates a new color instance set to opaque black in the
       * {@link ColorSpace.Named#SRGB sRGB} color space.
       *
       * @see #valueOf(float, float, float)
       * @see #valueOf(float, float, float, float)
       * @see #valueOf(float, float, float, float, ColorSpace)
       * @see #valueOf(float[], ColorSpace)
       * @see #valueOf(int)
       * @see #valueOf(long)
       */
      public Color() {
          // This constructor is required for compatibility with previous APIs
          mComponents = new float[] { 0.0f, 0.0f, 0.0f, 1.0f };
          mColorSpace = ColorSpace.get(ColorSpace.Named.SRGB);
      }
  
      /**
       * Creates a new color instance in the {@link ColorSpace.Named#SRGB sRGB}
       * color space.
       *
       * @param r The value of the red channel, must be in [0..1] range
       * @param g The value of the green channel, must be in [0..1] range
       * @param b The value of the blue channel, must be in [0..1] range
       * @param a The value of the alpha channel, must be in [0..1] range
       */
      private Color(float r, float g, float b, float a) {
          this(r, g, b, a, ColorSpace.get(ColorSpace.Named.SRGB));
      }
  
      /**
       * Creates a new color instance in the specified color space. The color space
       * must have a 3 components model.
       *
       * @param r The value of the red channel, must be in the color space defined range
       * @param g The value of the green channel, must be in the color space defined range
       * @param b The value of the blue channel, must be in the color space defined range
       * @param a The value of the alpha channel, must be in [0..1] range
       * @param colorSpace This color's color space, cannot be null
       */
      private Color(float r, float g, float b, float a, @NonNull ColorSpace colorSpace) {
          mComponents = new float[] { r, g, b, a };
          mColorSpace = colorSpace;
      }
  
      /**
       * Creates a new color instance in the specified color space.
       *
       * @param components An array of color components, plus alpha
       * @param colorSpace This color's color space, cannot be null
       */
      private Color(@Size(min = 4, max = 5) float[] components, @NonNull ColorSpace colorSpace) {
          mComponents = components;
          mColorSpace = colorSpace;
      }
  
      /**
       * Returns this color's color space.
       *
       * @return A non-null instance of {@link ColorSpace}
       */
      @NonNull
      public ColorSpace getColorSpace() {
          return mColorSpace;
      }
  
      /**
       * Returns the color model of this color.
       *
       * @return A non-null {@link ColorSpace.Model}
       */
      public ColorSpace.Model getModel() {
          return mColorSpace.getModel();
      }
  
      /**
       * Indicates whether this color color is in a wide-gamut color space.
       * See {@link ColorSpace#isWideGamut()} for a definition of a wide-gamut
       * color space.
       *
       * @return True if this color is in a wide-gamut color space, false otherwise
       *
       * @see #isSrgb()
       * @see ColorSpace#isWideGamut()
       */
      public boolean isWideGamut() {
          return getColorSpace().isWideGamut();
      }
  
      /**
       * Indicates whether this color is in the {@link ColorSpace.Named#SRGB sRGB}
       * color space.
       *
       * @return True if this color is in the sRGB color space, false otherwise
       *
       * @see #isWideGamut()
       */
      public boolean isSrgb() {
          return getColorSpace().isSrgb();
      }
  
      /**
       * Returns the number of components that form a color value according
       * to this color space's color model, plus one extra component for
       * alpha.
       *
       * @return The integer 4 or 5
       */
      @IntRange(from = 4, to = 5)
      public int getComponentCount() {
          return mColorSpace.getComponentCount() + 1;
      }
  
      /**
       * Packs this color into a color long. See the documentation of this class
       * for a description of the color long format.
       *
       * @return A color long
       *
       * @throws IllegalArgumentException If this color's color space has the id
       * {@link ColorSpace#MIN_ID} or if this color has more than 4 components
       */
      @ColorLong
      public long pack() {
          return pack(mComponents[0], mComponents[1], mComponents[2], mComponents[3], mColorSpace);
      }
  
      /**
       * Converts this color from its color space to the specified color space.
       * The conversion is done using the default rendering intent as specified
       * by {@link ColorSpace#connect(ColorSpace, ColorSpace)}.
       *
       * @param colorSpace The destination color space, cannot be null
       *
       * @return A non-null color instance in the specified color space
       */
      @NonNull
      public Color convert(@NonNull ColorSpace colorSpace) {
          ColorSpace.Connector connector = ColorSpace.connect(mColorSpace, colorSpace);
          float[] color = new float[] {
                  mComponents[0], mComponents[1], mComponents[2], mComponents[3]
          };
          connector.transform(color);
          return new Color(color, colorSpace);
      }
  
      /**
       * Converts this color to an ARGB color int. A color int is always in
       * the {@link ColorSpace.Named#SRGB sRGB} color space. This implies
       * a color space conversion is applied if needed.
       *
       * @return An ARGB color in the sRGB color space
       */
      @ColorInt
      public int toArgb() {
          if (mColorSpace.isSrgb()) {
              return ((int) (mComponents[3] * 255.0f + 0.5f) << 24) |
                     ((int) (mComponents[0] * 255.0f + 0.5f) << 16) |
                     ((int) (mComponents[1] * 255.0f + 0.5f) <<  8) |
                      (int) (mComponents[2] * 255.0f + 0.5f);
          }
  
          float[] color = new float[] {
                  mComponents[0], mComponents[1], mComponents[2], mComponents[3]
          };
          // The transformation saturates the output
          ColorSpace.connect(mColorSpace).transform(color);
  
          return ((int) (color[3] * 255.0f + 0.5f) << 24) |
                 ((int) (color[0] * 255.0f + 0.5f) << 16) |
                 ((int) (color[1] * 255.0f + 0.5f) <<  8) |
                  (int) (color[2] * 255.0f + 0.5f);
      }
  
      /**
       * <p>Returns the value of the red component in the range defined by this
       * color's color space (see {@link ColorSpace#getMinValue(int)} and
       * {@link ColorSpace#getMaxValue(int)}).</p>
       *
       * <p>If this color's color model is not {@link ColorSpace.Model#RGB RGB},
       * calling this method is equivalent to <code>getComponent(0)</code>.</p>
       *
       * @see #alpha()
       * @see #red()
       * @see #green
       * @see #getComponents()
       */
      public float red() {
          return mComponents[0];
      }
  
      /**
       * <p>Returns the value of the green component in the range defined by this
       * color's color space (see {@link ColorSpace#getMinValue(int)} and
       * {@link ColorSpace#getMaxValue(int)}).</p>
       *
       * <p>If this color's color model is not {@link ColorSpace.Model#RGB RGB},
       * calling this method is equivalent to <code>getComponent(1)</code>.</p>
       *
       * @see #alpha()
       * @see #red()
       * @see #green
       * @see #getComponents()
       */
      public float green() {
          return mComponents[1];
      }
  
      /**
       * <p>Returns the value of the blue component in the range defined by this
       * color's color space (see {@link ColorSpace#getMinValue(int)} and
       * {@link ColorSpace#getMaxValue(int)}).</p>
       *
       * <p>If this color's color model is not {@link ColorSpace.Model#RGB RGB},
       * calling this method is equivalent to <code>getComponent(2)</code>.</p>
       *
       * @see #alpha()
       * @see #red()
       * @see #green
       * @see #getComponents()
       */
      public float blue() {
          return mComponents[2];
      }
  
      /**
       * Returns the value of the alpha component in the range \([0..1]\).
       * Calling this method is equivalent to
       * <code>getComponent(getComponentCount() - 1)</code>.
       *
       * @see #red()
       * @see #green()
       * @see #blue()
       * @see #getComponents()
       * @see #getComponent(int)
       */
      public float alpha() {
          return mComponents[mComponents.length - 1];
      }
  
      /**
       * Returns this color's components as a new array. The last element of the
       * array is always the alpha component.
       *
       * @return A new, non-null array whose size is equal to {@link #getComponentCount()}
       *
       * @see #getComponent(int)
       */
      @NonNull
      @Size(min = 4, max = 5)
      public float[] getComponents() {
          return Arrays.copyOf(mComponents, mComponents.length);
      }
  
      /**
       * Copies this color's components in the supplied array. The last element of the
       * array is always the alpha component.
       *
       * @param components An array of floats whose size must be at least
       *                  {@link #getComponentCount()}, can be null
       * @return The array passed as a parameter if not null, or a new array of length
       *         {@link #getComponentCount()}
       *
       * @see #getComponent(int)
       *
       * @throws IllegalArgumentException If the specified array's length is less than
       * {@link #getComponentCount()}
       */
      @NonNull
      @Size(min = 4)
      public float[] getComponents(@Nullable @Size(min = 4) float[] components) {
          if (components == null) {
              return Arrays.copyOf(mComponents, mComponents.length);
          }
  
          if (components.length < mComponents.length) {
              throw new IllegalArgumentException("The specified array's length must be at "
                      + "least " + mComponents.length);
          }
  
          System.arraycopy(mComponents, 0, components, 0, mComponents.length);
          return components;
      }
  
      /**
       * <p>Returns the value of the specified component in the range defined by
       * this color's color space (see {@link ColorSpace#getMinValue(int)} and
       * {@link ColorSpace#getMaxValue(int)}).</p>
       *
       * <p>If the requested component index is {@link #getComponentCount()},
       * this method returns the alpha component, always in the range
       * \([0..1]\).</p>
       *
       * @see #getComponents()
       *
       * @throws ArrayIndexOutOfBoundsException If the specified component index
       * is < 0 or >= {@link #getComponentCount()}
       */
      public float getComponent(@IntRange(from = 0, to = 4) int component) {
          return mComponents[component];
      }
  
      /**
       * <p>Returns the relative luminance of this color.</p>
       *
       * <p>Based on the formula for relative luminance defined in WCAG 2.0,
       * W3C Recommendation 11 December 2008.</p>
       *
       * @return A value between 0 (darkest black) and 1 (lightest white)
       *
       * @throws IllegalArgumentException If the this color's color space
       * does not use the {@link ColorSpace.Model#RGB RGB} color model
       */
      public float luminance() {
          if (mColorSpace.getModel() != ColorSpace.Model.RGB) {
              throw new IllegalArgumentException("The specified color must be encoded in an RGB " +
                      "color space. The supplied color space is " + mColorSpace.getModel());
          }
  
          DoubleUnaryOperator eotf = ((ColorSpace.Rgb) mColorSpace).getEotf();
          double r = eotf.applyAsDouble(mComponents[0]);
          double g = eotf.applyAsDouble(mComponents[1]);
          double b = eotf.applyAsDouble(mComponents[2]);
  
          return saturate((float) ((0.2126 * r) + (0.7152 * g) + (0.0722 * b)));
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) return true;
          if (o == null || getClass() != o.getClass()) return false;
  
          Color color = (Color) o;
  
          //noinspection SimplifiableIfStatement
          if (!Arrays.equals(mComponents, color.mComponents)) return false;
          return mColorSpace.equals(color.mColorSpace);
      }
  
      @Override
      public int hashCode() {
          int result = Arrays.hashCode(mComponents);
          result = 31 * result + mColorSpace.hashCode();
          return result;
      }
  
      /**
       * <p>Returns a string representation of the object. This method returns
       * a string equal to the value of:</p>
       *
       * <pre class="prettyprint">
       * "Color(" + r + ", " + g + ", " + b + ", " + a +
       *         ", " + getColorSpace().getName + ')'
       * </pre>
       *
       * <p>For instance, the string representation of opaque black in the sRGB
       * color space is equal to the following value:</p>
       *
       * <pre>
       * Color(0.0, 0.0, 0.0, 1.0, sRGB IEC61966-2.1)
       * </pre>
       *
       * @return A non-null string representation of the object
       */
      @Override
      @NonNull
      public String toString() {
          StringBuilder b = new StringBuilder("Color(");
          for (float c : mComponents) {
              b.append(c).append(", ");
          }
          b.append(mColorSpace.getName());
          b.append(')');
          return b.toString();
      }
  
      /**
       * Returns the color space encoded in the specified color long.
       *
       * @param color The color long whose color space to extract
       * @return A non-null color space instance
       * @throws IllegalArgumentException If the encoded color space is invalid or unknown
       *
       * @see #red(long)
       * @see #green(long)
       * @see #blue(long)
       * @see #alpha(long)
       */
      @NonNull
      public static ColorSpace colorSpace(@ColorLong long color) {
          return ColorSpace.get((int) (color & 0x3fL));
      }
  
      /**
       * Returns the red component encoded in the specified color long.
       * The range of the returned value depends on the color space
       * associated with the specified color. The color space can be
       * queried by calling {@link #colorSpace(long)}.
       *
       * @param color The color long whose red channel to extract
       * @return A float value with a range defined by the specified color's
       * color space
       *
       * @see #colorSpace(long)
       * @see #green(long)
       * @see #blue(long)
       * @see #alpha(long)
       */
      public static float red(@ColorLong long color) {
          if ((color & 0x3fL) == 0L) return ((color >> 48) & 0xff) / 255.0f;
          return Half.toFloat((short) ((color >> 48) & 0xffff));
      }
  
      /**
       * Returns the green component encoded in the specified color long.
       * The range of the returned value depends on the color space
       * associated with the specified color. The color space can be
       * queried by calling {@link #colorSpace(long)}.
       *
       * @param color The color long whose green channel to extract
       * @return A float value with a range defined by the specified color's
       * color space
       *
       * @see #colorSpace(long)
       * @see #red(long)
       * @see #blue(long)
       * @see #alpha(long)
       */
      public static float green(@ColorLong long color) {
          if ((color & 0x3fL) == 0L) return ((color >> 40) & 0xff) / 255.0f;
          return Half.toFloat((short) ((color >> 32) & 0xffff));
      }
  
      /**
       * Returns the blue component encoded in the specified color long.
       * The range of the returned value depends on the color space
       * associated with the specified color. The color space can be
       * queried by calling {@link #colorSpace(long)}.
       *
       * @param color The color long whose blue channel to extract
       * @return A float value with a range defined by the specified color's
       * color space
       *
       * @see #colorSpace(long)
       * @see #red(long)
       * @see #green(long)
       * @see #alpha(long)
       */
      public static float blue(@ColorLong long color) {
          if ((color & 0x3fL) == 0L) return ((color >> 32) & 0xff) / 255.0f;
          return Half.toFloat((short) ((color >> 16) & 0xffff));
      }
  
      /**
       * Returns the alpha component encoded in the specified color long.
       * The returned value is always in the range \([0..1]\).
       *
       * @param color The color long whose blue channel to extract
       * @return A float value in the range \([0..1]\)
       *
       * @see #colorSpace(long)
       * @see #red(long)
       * @see #green(long)
       * @see #blue(long)
       */
      public static float alpha(@ColorLong long color) {
          if ((color & 0x3fL) == 0L) return ((color >> 56) & 0xff) / 255.0f;
          return ((color >> 6) & 0x3ff) / 1023.0f;
      }
  
      /**
       * Indicates whether the specified color is in the
       * {@link ColorSpace.Named#SRGB sRGB} color space.
       *
       * @param color The color to test
       * @return True if the color is in the sRGB color space, false otherwise
       * @throws IllegalArgumentException If the encoded color space is invalid or unknown
       *
       * @see #isInColorSpace(long, ColorSpace)
       * @see #isWideGamut(long)
       */
      public static boolean isSrgb(@ColorLong long color) {
          return colorSpace(color).isSrgb();
      }
  
      /**
       * Indicates whether the specified color is in a wide-gamut color space.
       * See {@link ColorSpace#isWideGamut()} for a definition of a wide-gamut
       * color space.
       *
       * @param color The color to test
       * @return True if the color is in a wide-gamut color space, false otherwise
       * @throws IllegalArgumentException If the encoded color space is invalid or unknown
       *
       * @see #isInColorSpace(long, ColorSpace)
       * @see #isSrgb(long)
       * @see ColorSpace#isWideGamut()
       */
      public static boolean isWideGamut(@ColorLong long color) {
          return colorSpace(color).isWideGamut();
      }
  
      /**
       * Indicates whether the specified color is in the specified color space.
       *
       * @param color The color to test
       * @param colorSpace The color space to test against
       * @return True if the color is in the specified color space, false otherwise
       *
       * @see #isSrgb(long)
       * @see #isWideGamut(long)
       */
      public static boolean isInColorSpace(@ColorLong long color, @NonNull ColorSpace colorSpace) {
          return (int) (color & 0x3fL) == colorSpace.getId();
      }
  
      /**
       * Converts the specified color long to an ARGB color int. A color int is
       * always in the {@link ColorSpace.Named#SRGB sRGB} color space. This implies
       * a color space conversion is applied if needed.
       *
       * @return An ARGB color in the sRGB color space
       * @throws IllegalArgumentException If the encoded color space is invalid or unknown
       */
      @ColorInt
      public static int toArgb(@ColorLong long color) {
          if ((color & 0x3fL) == 0L) return (int) (color >> 32);
  
          float r = red(color);
          float g = green(color);
          float b = blue(color);
          float a = alpha(color);
  
          // The transformation saturates the output
          float[] c = ColorSpace.connect(colorSpace(color)).transform(r, g, b);
  
          return ((int) (a    * 255.0f + 0.5f) << 24) |
                 ((int) (c[0] * 255.0f + 0.5f) << 16) |
                 ((int) (c[1] * 255.0f + 0.5f) <<  8) |
                  (int) (c[2] * 255.0f + 0.5f);
      }
  
      /**
       * Creates a new <code>Color</code> instance from an ARGB color int.
       * The resulting color is in the {@link ColorSpace.Named#SRGB sRGB}
       * color space.
       *
       * @param color The ARGB color int to create a <code>Color</code> from
       * @return A non-null instance of {@link Color}
       */
      @NonNull
      public static Color valueOf(@ColorInt int color) {
          float r = ((color >> 16) & 0xff) / 255.0f;
          float g = ((color >>  8) & 0xff) / 255.0f;
          float b = ((color      ) & 0xff) / 255.0f;
          float a = ((color >> 24) & 0xff) / 255.0f;
          return new Color(r, g, b, a, ColorSpace.get(ColorSpace.Named.SRGB));
      }
  
      /**
       * Creates a new <code>Color</code> instance from a color long.
       * The resulting color is in the same color space as the specified color long.
       *
       * @param color The color long to create a <code>Color</code> from
       * @return A non-null instance of {@link Color}
       * @throws IllegalArgumentException If the encoded color space is invalid or unknown
       */
      @NonNull
      public static Color valueOf(@ColorLong long color) {
          return new Color(red(color), green(color), blue(color), alpha(color), colorSpace(color));
      }
  
      /**
       * Creates a new opaque <code>Color</code> in the {@link ColorSpace.Named#SRGB sRGB}
       * color space with the specified red, green and blue component values. The component
       * values must be in the range \([0..1]\).
       *
       * @param r The red component of the opaque sRGB color to create, in \([0..1]\)
       * @param g The green component of the opaque sRGB color to create, in \([0..1]\)
       * @param b The blue component of the opaque sRGB color to create, in \([0..1]\)
       * @return A non-null instance of {@link Color}
       */
      @NonNull
      public static Color valueOf(float r, float g, float b) {
          return new Color(r, g, b, 1.0f);
      }
  
      /**
       * Creates a new <code>Color</code> in the {@link ColorSpace.Named#SRGB sRGB}
       * color space with the specified red, green, blue and alpha component values.
       * The component values must be in the range \([0..1]\).
       *
       * @param r The red component of the sRGB color to create, in \([0..1]\)
       * @param g The green component of the sRGB color to create, in \([0..1]\)
       * @param b The blue component of the sRGB color to create, in \([0..1]\)
       * @param a The alpha component of the sRGB color to create, in \([0..1]\)
       * @return A non-null instance of {@link Color}
       */
      @NonNull
      public static Color valueOf(float r, float g, float b, float a) {
          return new Color(saturate(r), saturate(g), saturate(b), saturate(a));
      }
  
      /**
       * Creates a new <code>Color</code> in the specified color space with the
       * specified red, green, blue and alpha component values. The range of the
       * components is defined by {@link ColorSpace#getMinValue(int)} and
       * {@link ColorSpace#getMaxValue(int)}. The values passed to this method
       * must be in the proper range.
       *
       * @param r The red component of the color to create
       * @param g The green component of the color to create
       * @param b The blue component of the color to create
       * @param a The alpha component of the color to create, in \([0..1]\)
       * @param colorSpace The color space of the color to create
       * @return A non-null instance of {@link Color}
       *
       * @throws IllegalArgumentException If the specified color space uses a
       * color model with more than 3 components
       */
      @NonNull
      public static Color valueOf(float r, float g, float b, float a, @NonNull ColorSpace colorSpace) {
          if (colorSpace.getComponentCount() > 3) {
              throw new IllegalArgumentException("The specified color space must use a color model " +
                      "with at most 3 color components");
          }
          return new Color(r, g, b, a, colorSpace);
      }
  
      /**
       * <p>Creates a new <code>Color</code> in the specified color space with the
       * specified component values. The range of the components is defined by
       * {@link ColorSpace#getMinValue(int)} and {@link ColorSpace#getMaxValue(int)}.
       * The values passed to this method must be in the proper range. The alpha
       * component is always in the range \([0..1]\).</p>
       *
       * <p>The length of the array of components must be at least
       * <code>{@link ColorSpace#getComponentCount()} + 1</code>. The component at index
       * {@link ColorSpace#getComponentCount()} is always alpha.</p>
       *
       * @param components The components of the color to create, with alpha as the last component
       * @param colorSpace The color space of the color to create
       * @return A non-null instance of {@link Color}
       *
       * @throws IllegalArgumentException If the array of components is smaller than
       * required by the color space
       */
      @NonNull
      public static Color valueOf(@NonNull @Size(min = 4, max = 5) float[] components,
              @NonNull ColorSpace colorSpace) {
          if (components.length < colorSpace.getComponentCount() + 1) {
              throw new IllegalArgumentException("Received a component array of length " +
                      components.length + " but the color model requires " +
                      (colorSpace.getComponentCount() + 1) + " (including alpha)");
          }
          return new Color(Arrays.copyOf(components, colorSpace.getComponentCount() + 1), colorSpace);
      }
  
      /**
       * Converts the specified ARGB color int to an RGBA color long in the sRGB
       * color space. See the documentation of this class for a description of
       * the color long format.
       *
       * @param color The ARGB color int to convert to an RGBA color long in sRGB
       *
       * @return A color long
       */
      @ColorLong
      public static long pack(@ColorInt int color) {
          return (color & 0xffffffffL) << 32;
      }
  
      /**
       * Packs the sRGB color defined by the specified red, green and blue component
       * values into an RGBA color long in the sRGB color space. The alpha component
       * is set to 1.0. See the documentation of this class for a description of the
       * color long format.
       *
       * @param red The red component of the sRGB color to create, in \([0..1]\)
       * @param green The green component of the sRGB color to create, in \([0..1]\)
       * @param blue The blue component of the sRGB color to create, in \([0..1]\)
       *
       * @return A color long
       */
      @ColorLong
      public static long pack(float red, float green, float blue) {
          return pack(red, green, blue, 1.0f, ColorSpace.get(ColorSpace.Named.SRGB));
      }
  
      /**
       * Packs the sRGB color defined by the specified red, green, blue and alpha
       * component values into an RGBA color long in the sRGB color space. See the
       * documentation of this class for a description of the color long format.
       *
       * @param red The red component of the sRGB color to create, in \([0..1]\)
       * @param green The green component of the sRGB color to create, in \([0..1]\)
       * @param blue The blue component of the sRGB color to create, in \([0..1]\)
       * @param alpha The alpha component of the sRGB color to create, in \([0..1]\)
       *
       * @return A color long
       */
      @ColorLong
      public static long pack(float red, float green, float blue, float alpha) {
          return pack(red, green, blue, alpha, ColorSpace.get(ColorSpace.Named.SRGB));
      }
  
      /**
       * <p>Packs the 3 component color defined by the specified red, green, blue and
       * alpha component values into a color long in the specified color space. See the
       * documentation of this class for a description of the color long format.</p>
       *
       * <p>The red, green and blue components must be in the range defined by the
       * specified color space. See {@link ColorSpace#getMinValue(int)} and
       * {@link ColorSpace#getMaxValue(int)}.</p>
       *
       * @param red The red component of the color to create
       * @param green The green component of the color to create
       * @param blue The blue component of the color to create
       * @param alpha The alpha component of the color to create, in \([0..1]\)
       *
       * @return A color long
       *
       * @throws IllegalArgumentException If the color space's id is {@link ColorSpace#MIN_ID}
       * or if the color space's color model has more than 3 components
       */
      @ColorLong
      public static long pack(float red, float green, float blue, float alpha,
              @NonNull ColorSpace colorSpace) {
          if (colorSpace.isSrgb()) {
              int argb =
                      ((int) (alpha * 255.0f + 0.5f) << 24) |
                      ((int) (red   * 255.0f + 0.5f) << 16) |
                      ((int) (green * 255.0f + 0.5f) <<  8) |
                       (int) (blue  * 255.0f + 0.5f);
              return (argb & 0xffffffffL) << 32;
          }
  
          int id = colorSpace.getId();
          if (id == ColorSpace.MIN_ID) {
              throw new IllegalArgumentException(
                      "Unknown color space, please use a color space returned by ColorSpace.get()");
          }
          if (colorSpace.getComponentCount() > 3) {
              throw new IllegalArgumentException(
                      "The color space must use a color model with at most 3 components");
          }
  
          @HalfFloat short r = Half.toHalf(red);
          @HalfFloat short g = Half.toHalf(green);
          @HalfFloat short b = Half.toHalf(blue);
  
          int a = (int) (Math.max(0.0f, Math.min(alpha, 1.0f)) * 1023.0f + 0.5f);
  
          // Suppress sign extension
          return  (r & 0xffffL) << 48 |
                  (g & 0xffffL) << 32 |
                  (b & 0xffffL) << 16 |
                  (a & 0x3ffL ) <<  6 |
                  id & 0x3fL;
      }
  
      /**
       * Converts the specified ARGB color int from the {@link ColorSpace.Named#SRGB sRGB}
       * color space into the specified destination color space. The resulting color is
       * returned as a color long. See the documentation of this class for a description
       * of the color long format.
       *
       * @param color The sRGB color int to convert
       * @param colorSpace The destination color space
       * @return A color long in the destination color space
       */
      @ColorLong
      public static long convert(@ColorInt int color, @NonNull ColorSpace colorSpace) {
          float r = ((color >> 16) & 0xff) / 255.0f;
          float g = ((color >>  8) & 0xff) / 255.0f;
          float b = ((color      ) & 0xff) / 255.0f;
          float a = ((color >> 24) & 0xff) / 255.0f;
          ColorSpace source = ColorSpace.get(ColorSpace.Named.SRGB);
          return convert(r, g, b, a, source, colorSpace);
      }
  
      /**
       * <p>Converts the specified color long from its color space into the specified
       * destination color space. The resulting color is returned as a color long. See
       * the documentation of this class for a description of the color long format.</p>
       *
       * <p>When converting several colors in a row, it is recommended to use
       * {@link #convert(long, ColorSpace.Connector)} instead to
       * avoid the creation of a {@link ColorSpace.Connector} on every invocation.</p>
       *
       * @param color The color long to convert
       * @param colorSpace The destination color space
       * @return A color long in the destination color space
       * @throws IllegalArgumentException If the encoded color space is invalid or unknown
       */
      @ColorLong
      public static long convert(@ColorLong long color, @NonNull ColorSpace colorSpace) {
          float r = red(color);
          float g = green(color);
          float b = blue(color);
          float a = alpha(color);
          ColorSpace source = colorSpace(color);
          return convert(r, g, b, a, source, colorSpace);
      }
  
      /**
       * <p>Converts the specified 3 component color from the source color space to the
       * destination color space. The resulting color is returned as a color long. See
       * the documentation of this class for a description of the color long format.</p>
       *
       * <p>When converting multiple colors in a row, it is recommended to use
       * {@link #convert(float, float, float, float, ColorSpace.Connector)} instead to
       * avoid the creation of a {@link ColorSpace.Connector} on every invocation.</p>
       *
       * <p>The red, green and blue components must be in the range defined by the
       * specified color space. See {@link ColorSpace#getMinValue(int)} and
       * {@link ColorSpace#getMaxValue(int)}.</p>
       *
       * @param r The red component of the color to convert
       * @param g The green component of the color to convert
       * @param b The blue component of the color to convert
       * @param a The alpha component of the color to convert, in \([0..1]\)
       * @param source The source color space, cannot be null
       * @param destination The destination color space, cannot be null
       * @return A color long in the destination color space
       *
       * @see #convert(float, float, float, float, ColorSpace.Connector)
       */
      @ColorLong
      public static long convert(float r, float g, float b, float a,
              @NonNull ColorSpace source, @NonNull ColorSpace destination) {
          float[] c = ColorSpace.connect(source, destination).transform(r, g, b);
          return pack(c[0], c[1], c[2], a, destination);
      }
  
      /**
       * <p>Converts the specified color long from a color space to another using the
       * specified color space {@link ColorSpace.Connector connector}. The resulting
       * color is returned as a color long. See the documentation of this class for a
       * description of the color long format.</p>
       *
       * <p>When converting several colors in a row, this method is preferable to
       * {@link #convert(long, ColorSpace)} as it prevents a new connector from being
       * created on every invocation.</p>
       *
       * <p class="note">The connector's source color space should match the color long's
       * color space.</p>
       *
       * @param color The color long to convert
       * @param connector A color space connector, cannot be null
       * @return A color long in the destination color space of the connector
       */
      @ColorLong
      public static long convert(@ColorLong long color, @NonNull ColorSpace.Connector connector) {
          float r = red(color);
          float g = green(color);
          float b = blue(color);
          float a = alpha(color);
          return convert(r, g, b, a, connector);
      }
  
      /**
       * <p>Converts the specified 3 component color from a color space to another using
       * the specified color space {@link ColorSpace.Connector connector}. The resulting
       * color is returned as a color long. See the documentation of this class for a
       * description of the color long format.</p>
       *
       * <p>When converting several colors in a row, this method is preferable to
       * {@link #convert(float, float, float, float, ColorSpace, ColorSpace)} as
       * it prevents a new connector from being created on every invocation.</p>
       *
       * <p>The red, green and blue components must be in the range defined by the
       * source color space of the connector. See {@link ColorSpace#getMinValue(int)}
       * and {@link ColorSpace#getMaxValue(int)}.</p>
       *
       * @param r The red component of the color to convert
       * @param g The green component of the color to convert
       * @param b The blue component of the color to convert
       * @param a The alpha component of the color to convert, in \([0..1]\)
       * @param connector A color space connector, cannot be null
       * @return A color long in the destination color space of the connector
       *
       * @see #convert(float, float, float, float, ColorSpace, ColorSpace)
       */
      @ColorLong
      public static long convert(float r, float g, float b, float a,
              @NonNull ColorSpace.Connector connector) {
          float[] c = connector.transform(r, g, b);
          return pack(c[0], c[1], c[2], a, connector.getDestination());
      }
  
      /**
       * <p>Returns the relative luminance of a color.</p>
       *
       * <p>Based on the formula for relative luminance defined in WCAG 2.0,
       * W3C Recommendation 11 December 2008.</p>
       *
       * @return A value between 0 (darkest black) and 1 (lightest white)
       *
       * @throws IllegalArgumentException If the specified color's color space
       * is unknown or does not use the {@link ColorSpace.Model#RGB RGB} color model
       */
      public static float luminance(@ColorLong long color) {
          ColorSpace colorSpace = colorSpace(color);
          if (colorSpace.getModel() != ColorSpace.Model.RGB) {
              throw new IllegalArgumentException("The specified color must be encoded in an RGB " +
                      "color space. The supplied color space is " + colorSpace.getModel());
          }
  
          DoubleUnaryOperator eotf = ((ColorSpace.Rgb) colorSpace).getEotf();
          double r = eotf.applyAsDouble(red(color));
          double g = eotf.applyAsDouble(green(color));
          double b = eotf.applyAsDouble(blue(color));
  
          return saturate((float) ((0.2126 * r) + (0.7152 * g) + (0.0722 * b)));
      }
  
      private static float saturate(float v) {
          return v <= 0.0f ? 0.0f : (v >= 1.0f ? 1.0f : v);
      }
  
      /**
       * Return the alpha component of a color int. This is the same as saying
       * color >>> 24
       */
      @IntRange(from = 0, to = 255)
      public static int alpha(int color) {
          return color >>> 24;
      }
  
      /**
       * Return the red component of a color int. This is the same as saying
       * (color >> 16) & 0xFF
       */
      @IntRange(from = 0, to = 255)
      public static int red(int color) {
          return (color >> 16) & 0xFF;
      }
  
      /**
       * Return the green component of a color int. This is the same as saying
       * (color >> 8) & 0xFF
       */
      @IntRange(from = 0, to = 255)
      public static int green(int color) {
          return (color >> 8) & 0xFF;
      }
  
      /**
       * Return the blue component of a color int. This is the same as saying
       * color & 0xFF
       */
      @IntRange(from = 0, to = 255)
      public static int blue(int color) {
          return color & 0xFF;
      }
  
      /**
       * Return a color-int from red, green, blue components.
       * The alpha component is implicitly 255 (fully opaque).
       * These component values should be \([0..255]\), but there is no
       * range check performed, so if they are out of range, the
       * returned color is undefined.
       *
       * @param red  Red component \([0..255]\) of the color
       * @param green Green component \([0..255]\) of the color
       * @param blue  Blue component \([0..255]\) of the color
       */
      @ColorInt
      public static int rgb(
              @IntRange(from = 0, to = 255) int red,
              @IntRange(from = 0, to = 255) int green,
              @IntRange(from = 0, to = 255) int blue) {
          return 0xff000000 | (red << 16) | (green << 8) | blue;
      }
  
      /**
       * Return a color-int from red, green, blue float components
       * in the range \([0..1]\). The alpha component is implicitly
       * 1.0 (fully opaque). If the components are out of range, the
       * returned color is undefined.
       *
       * @param red Red component \([0..1]\) of the color
       * @param green Green component \([0..1]\) of the color
       * @param blue Blue component \([0..1]\) of the color
       */
      @ColorInt
      public static int rgb(float red, float green, float blue) {
          return 0xff000000 |
                 ((int) (red   * 255.0f + 0.5f) << 16) |
                 ((int) (green * 255.0f + 0.5f) <<  8) |
                  (int) (blue  * 255.0f + 0.5f);
      }
  
      /**
       * Return a color-int from alpha, red, green, blue components.
       * These component values should be \([0..255]\), but there is no
       * range check performed, so if they are out of range, the
       * returned color is undefined.
       * @param alpha Alpha component \([0..255]\) of the color
       * @param red Red component \([0..255]\) of the color
       * @param green Green component \([0..255]\) of the color
       * @param blue Blue component \([0..255]\) of the color
       */
      @ColorInt
      public static int argb(
              @IntRange(from = 0, to = 255) int alpha,
              @IntRange(from = 0, to = 255) int red,
              @IntRange(from = 0, to = 255) int green,
              @IntRange(from = 0, to = 255) int blue) {
          return (alpha << 24) | (red << 16) | (green << 8) | blue;
      }
  
      /**
       * Return a color-int from alpha, red, green, blue float components
       * in the range \([0..1]\). If the components are out of range, the
       * returned color is undefined.
       *
       * @param alpha Alpha component \([0..1]\) of the color
       * @param red Red component \([0..1]\) of the color
       * @param green Green component \([0..1]\) of the color
       * @param blue Blue component \([0..1]\) of the color
       */
      @ColorInt
      public static int argb(float alpha, float red, float green, float blue) {
          return ((int) (alpha * 255.0f + 0.5f) << 24) |
                 ((int) (red   * 255.0f + 0.5f) << 16) |
                 ((int) (green * 255.0f + 0.5f) <<  8) |
                  (int) (blue  * 255.0f + 0.5f);
      }
  
      /**
       * Returns the relative luminance of a color.
       * <p>
       * Assumes sRGB encoding. Based on the formula for relative luminance
       * defined in WCAG 2.0, W3C Recommendation 11 December 2008.
       *
       * @return a value between 0 (darkest black) and 1 (lightest white)
       */
      public static float luminance(@ColorInt int color) {
          ColorSpace.Rgb cs = (ColorSpace.Rgb) ColorSpace.get(ColorSpace.Named.SRGB);
          DoubleUnaryOperator eotf = cs.getEotf();
  
          double r = eotf.applyAsDouble(red(color) / 255.0);
          double g = eotf.applyAsDouble(green(color) / 255.0);
          double b = eotf.applyAsDouble(blue(color) / 255.0);
  
          return (float) ((0.2126 * r) + (0.7152 * g) + (0.0722 * b));
      }
  
      /**
       * </p>Parse the color string, and return the corresponding color-int.
       * If the string cannot be parsed, throws an IllegalArgumentException
       * exception. Supported formats are:</p>
       *
       * <ul>
       *   <li><code>#RRGGBB</code></li>
       *   <li><code>#AARRGGBB</code></li>
       * </ul>
       *
       * <p>The following names are also accepted: <code>red</code>, <code>blue</code>,
       * <code>green</code>, <code>black</code>, <code>white</code>, <code>gray</code>,
       * <code>cyan</code>, <code>magenta</code>, <code>yellow</code>, <code>lightgray</code>,
       * <code>darkgray</code>, <code>grey</code>, <code>lightgrey</code>, <code>darkgrey</code>,
       * <code>aqua</code>, <code>fuchsia</code>, <code>lime</code>, <code>maroon</code>,
       * <code>navy</code>, <code>olive</code>, <code>purple</code>, <code>silver</code>,
       * and <code>teal</code>.</p>
       */
      @ColorInt
      public static int parseColor(@Size(min=1) String colorString) {
          if (colorString.charAt(0) == '#') {
              // Use a long to avoid rollovers on #ffXXXXXX
              long color = Long.parseLong(colorString.substring(1), 16);
              if (colorString.length() == 7) {
                  // Set the alpha value
                  color |= 0x00000000ff000000;
              } else if (colorString.length() != 9) {
                  throw new IllegalArgumentException("Unknown color");
              }
              return (int)color;
          } else {
              Integer color = sColorNameMap.get(colorString.toLowerCase(Locale.ROOT));
              if (color != null) {
                  return color;
              }
          }
          throw new IllegalArgumentException("Unknown color");
      }
  
      /**
       * Convert RGB components to HSV.
       * <ul>
       *   <li><code>hsv[0]</code> is Hue \([0..360[\)</li>
       *   <li><code>hsv[1]</code> is Saturation \([0...1]\)</li>
       *   <li><code>hsv[2]</code> is Value \([0...1]\)</li>
       * </ul>
       * @param red  red component value \([0..255]\)
       * @param green  green component value \([0..255]\)
       * @param blue  blue component value \([0..255]\)
       * @param hsv  3 element array which holds the resulting HSV components.
       */
      public static void RGBToHSV(
              @IntRange(from = 0, to = 255) int red,
              @IntRange(from = 0, to = 255) int green,
              @IntRange(from = 0, to = 255) int blue, @Size(3) float hsv[]) {
          if (hsv.length < 3) {
              throw new RuntimeException("3 components required for hsv");
          }
          nativeRGBToHSV(red, green, blue, hsv);
      }
  
      /**
       * Convert the ARGB color to its HSV components.
       * <ul>
       *   <li><code>hsv[0]</code> is Hue \([0..360[\)</li>
       *   <li><code>hsv[1]</code> is Saturation \([0...1]\)</li>
       *   <li><code>hsv[2]</code> is Value \([0...1]\)</li>
       * </ul>
       * @param color the argb color to convert. The alpha component is ignored.
       * @param hsv  3 element array which holds the resulting HSV components.
       */
      public static void colorToHSV(@ColorInt int color, @Size(3) float hsv[]) {
          RGBToHSV((color >> 16) & 0xFF, (color >> 8) & 0xFF, color & 0xFF, hsv);
      }
  
      /**
       * Convert HSV components to an ARGB color. Alpha set to 0xFF.
       * <ul>
       *   <li><code>hsv[0]</code> is Hue \([0..360[\)</li>
       *   <li><code>hsv[1]</code> is Saturation \([0...1]\)</li>
       *   <li><code>hsv[2]</code> is Value \([0...1]\)</li>
       * </ul>
       * If hsv values are out of range, they are pinned.
       * @param hsv  3 element array which holds the input HSV components.
       * @return the resulting argb color
      */
      @ColorInt
      public static int HSVToColor(@Size(3) float hsv[]) {
          return HSVToColor(0xFF, hsv);
      }
  
      /**
       * Convert HSV components to an ARGB color. The alpha component is passed
       * through unchanged.
       * <ul>
       *   <li><code>hsv[0]</code> is Hue \([0..360[\)</li>
       *   <li><code>hsv[1]</code> is Saturation \([0...1]\)</li>
       *   <li><code>hsv[2]</code> is Value \([0...1]\)</li>
       * </ul>
       * If hsv values are out of range, they are pinned.
       * @param alpha the alpha component of the returned argb color.
       * @param hsv  3 element array which holds the input HSV components.
       * @return the resulting argb color
       */
      @ColorInt
      public static int HSVToColor(@IntRange(from = 0, to = 255) int alpha, @Size(3) float hsv[]) {
          if (hsv.length < 3) {
              throw new RuntimeException("3 components required for hsv");
          }
          return nativeHSVToColor(alpha, hsv);
      }
  
      private static native void nativeRGBToHSV(int red, int greed, int blue, float hsv[]);
      private static native int nativeHSVToColor(int alpha, float hsv[]);
  
      /**
       * Converts an HTML color (named or numeric) to an integer RGB value.
       *
       * @param color Non-null color string.
       *
       * @return A color value, or {@code -1} if the color string could not be interpreted.
       *
       * @hide
       */
      @ColorInt
      public static int getHtmlColor(@NonNull String color) {
          Integer i = sColorNameMap.get(color.toLowerCase(Locale.ROOT));
          if (i != null) {
              return i;
          } else {
              try {
                  return XmlUtils.convertValueToInt(color, -1);
              } catch (NumberFormatException nfe) {
                  return -1;
              }
          }
      }
  
      private static final HashMap<String, Integer> sColorNameMap;
      static {
          sColorNameMap = new HashMap<>();
          sColorNameMap.put("black", BLACK);
          sColorNameMap.put("darkgray", DKGRAY);
          sColorNameMap.put("gray", GRAY);
          sColorNameMap.put("lightgray", LTGRAY);
          sColorNameMap.put("white", WHITE);
          sColorNameMap.put("red", RED);
          sColorNameMap.put("green", GREEN);
          sColorNameMap.put("blue", BLUE);
          sColorNameMap.put("yellow", YELLOW);
          sColorNameMap.put("cyan", CYAN);
          sColorNameMap.put("magenta", MAGENTA);
          sColorNameMap.put("aqua", 0xFF00FFFF);
          sColorNameMap.put("fuchsia", 0xFFFF00FF);
          sColorNameMap.put("darkgrey", DKGRAY);
          sColorNameMap.put("grey", GRAY);
          sColorNameMap.put("lightgrey", LTGRAY);
          sColorNameMap.put("lime", 0xFF00FF00);
          sColorNameMap.put("maroon", 0xFF800000);
          sColorNameMap.put("navy", 0xFF000080);
          sColorNameMap.put("olive", 0xFF808000);
          sColorNameMap.put("purple", 0xFF800080);
          sColorNameMap.put("silver", 0xFFC0C0C0);
          sColorNameMap.put("teal", 0xFF008080);
  
      }
  }
  