| /* |
| * Copyright (C) 2018 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.android.systemui.shared.recents.utilities; |
| |
| import android.graphics.Color; |
| import android.os.Handler; |
| import android.os.Message; |
| |
| /* Common code */ |
| public class Utilities { |
| |
| /** |
| * Posts a runnable on a handler at the front of the queue ignoring any sync barriers. |
| */ |
| public static void postAtFrontOfQueueAsynchronously(Handler h, Runnable r) { |
| Message msg = h.obtainMessage().setCallback(r); |
| h.sendMessageAtFrontOfQueue(msg); |
| } |
| |
| /** Calculates the constrast between two colors, using the algorithm provided by the WCAG v2. */ |
| public static float computeContrastBetweenColors(int bg, int fg) { |
| float bgR = Color.red(bg) / 255f; |
| float bgG = Color.green(bg) / 255f; |
| float bgB = Color.blue(bg) / 255f; |
| bgR = (bgR < 0.03928f) ? bgR / 12.92f : (float) Math.pow((bgR + 0.055f) / 1.055f, 2.4f); |
| bgG = (bgG < 0.03928f) ? bgG / 12.92f : (float) Math.pow((bgG + 0.055f) / 1.055f, 2.4f); |
| bgB = (bgB < 0.03928f) ? bgB / 12.92f : (float) Math.pow((bgB + 0.055f) / 1.055f, 2.4f); |
| float bgL = 0.2126f * bgR + 0.7152f * bgG + 0.0722f * bgB; |
| |
| float fgR = Color.red(fg) / 255f; |
| float fgG = Color.green(fg) / 255f; |
| float fgB = Color.blue(fg) / 255f; |
| fgR = (fgR < 0.03928f) ? fgR / 12.92f : (float) Math.pow((fgR + 0.055f) / 1.055f, 2.4f); |
| fgG = (fgG < 0.03928f) ? fgG / 12.92f : (float) Math.pow((fgG + 0.055f) / 1.055f, 2.4f); |
| fgB = (fgB < 0.03928f) ? fgB / 12.92f : (float) Math.pow((fgB + 0.055f) / 1.055f, 2.4f); |
| float fgL = 0.2126f * fgR + 0.7152f * fgG + 0.0722f * fgB; |
| |
| return Math.abs((fgL + 0.05f) / (bgL + 0.05f)); |
| } |
| |
| /** |
| * @return the clamped {@param value} between the provided {@param min} and {@param max}. |
| */ |
| public static float clamp(float value, float min, float max) { |
| return Math.max(min, Math.min(max, value)); |
| } |
| } |