| /* |
| * Copyright (C) 2017 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.cts.utils; |
| |
| import android.graphics.Color; |
| |
| /** |
| * Copied from frameworks/base/core to support CAM library for SystemPalette CTS test |
| * |
| * A set of color-related utility methods, building upon those available in {@code Color}. |
| */ |
| public final class ColorUtils { |
| |
| private static final double XYZ_WHITE_REFERENCE_X = 95.047; |
| private static final double XYZ_WHITE_REFERENCE_Y = 100; |
| private static final double XYZ_WHITE_REFERENCE_Z = 108.883; |
| private static final double XYZ_EPSILON = 0.008856; |
| private static final double XYZ_KAPPA = 903.3; |
| |
| /** |
| * Converts a color from CIE XYZ to its RGB representation. |
| * |
| * <p>This method expects the XYZ representation to use the D65 illuminant and the CIE |
| * 2° Standard Observer (1931).</p> |
| * |
| * @param x X component value [0...95.047) |
| * @param y Y component value [0...100) |
| * @param z Z component value [0...108.883) |
| * @return int containing the RGB representation |
| */ |
| public static int xyzToColor(double x, double y, double z) { |
| double r = (x * 3.2406 + y * -1.5372 + z * -0.4986) / 100; |
| double g = (x * -0.9689 + y * 1.8758 + z * 0.0415) / 100; |
| double b = (x * 0.0557 + y * -0.2040 + z * 1.0570) / 100; |
| |
| r = r > 0.0031308 ? 1.055 * Math.pow(r, 1 / 2.4) - 0.055 : 12.92 * r; |
| g = g > 0.0031308 ? 1.055 * Math.pow(g, 1 / 2.4) - 0.055 : 12.92 * g; |
| b = b > 0.0031308 ? 1.055 * Math.pow(b, 1 / 2.4) - 0.055 : 12.92 * b; |
| |
| return Color.rgb( |
| (int) constrain((int) Math.round(r * 255), 0, 255), |
| (int) constrain((int) Math.round(g * 255), 0, 255), |
| (int) constrain((int) Math.round(b * 255), 0, 255)); |
| } |
| |
| private static float constrain(float amount, float low, float high) { |
| return amount < low ? low : (amount > high ? high : amount); |
| } |
| } |