/* * 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.ColorInt; import android.annotation.Size; import android.util.MathUtils; import com.android.internal.util.XmlUtils; import java.util.HashMap; import java.util.Locale; /** * The Color class defines methods for creating and converting color ints. * Colors are represented as packed ints, made up of 4 bytes: alpha, red, * green, blue. The values are unpremultiplied, meaning any transparency is * stored solely in the alpha component, and not in the color components. The * components are stored as follows (alpha << 24) | (red << 16) | * (green << 8) | blue. Each component ranges between 0..255 with 0 * meaning no contribution for that component, and 255 meaning 100% * contribution. Thus opaque-black would be 0xFF000000 (100% opaque but * no contributions from red, green, or blue), and opaque-white would be * 0xFFFFFFFF */ 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; /** * Return the alpha component of a color int. This is the same as saying * color >>> 24 */ 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 */ 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 */ 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 */ public static int blue(int color) { return color & 0xFF; } /** * Return a color-int from red, green, blue components. * The alpha component is implicity 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(int red, int green, int blue) { return (0xFF << 24) | (red << 16) | (green << 8) | blue; } /** * 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(int alpha, int red, int green, int blue) { return (alpha << 24) | (red << 16) | (green << 8) | blue; } /** * Returns the relative luminance of a color. *

* 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) { double red = Color.red(color) / 255.0; red = red < 0.03928 ? red / 12.92 : Math.pow((red + 0.055) / 1.055, 2.4); double green = Color.green(color) / 255.0; green = green < 0.03928 ? green / 12.92 : Math.pow((green + 0.055) / 1.055, 2.4); double blue = Color.blue(color) / 255.0; blue = blue < 0.03928 ? blue / 12.92 : Math.pow((blue + 0.055) / 1.055, 2.4); return (float) ((0.2126 * red) + (0.7152 * green) + (0.0722 * blue)); } /** * Parse the color string, and return the corresponding color-int. * If the string cannot be parsed, throws an IllegalArgumentException * exception. Supported formats are: * #RRGGBB * #AARRGGBB * or one of the following names: * 'red', 'blue', 'green', 'black', 'white', 'gray', 'cyan', 'magenta', * 'yellow', 'lightgray', 'darkgray', 'grey', 'lightgrey', 'darkgrey', * 'aqua', 'fuchsia', 'lime', 'maroon', 'navy', 'olive', 'purple', * 'silver', 'teal'. */ @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. * hsv[0] is Hue [0 .. 360) * hsv[1] is Saturation [0...1] * hsv[2] is Value [0...1] * @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(int red, int green, 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. * hsv[0] is Hue [0 .. 360) * hsv[1] is Saturation [0...1] * hsv[2] is Value [0...1] * @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. * hsv[0] is Hue [0 .. 360) * hsv[1] is Saturation [0...1] * hsv[2] is Value [0...1] * 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 */ 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. * hsv[0] is Hue [0 .. 360) * hsv[1] is Saturation [0...1] * hsv[2] is Value [0...1] * 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 */ public static int HSVToColor(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(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 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); } }