/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.launcher3.graphics;
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import static com.android.launcher3.icons.GraphicsUtils.setColorAlphaBound;
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import android.app.Notification;
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import android.content.Context;
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import android.graphics.Color;
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import android.util.Log;
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import com.android.launcher3.R;
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import com.android.launcher3.util.Themes;
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import androidx.core.graphics.ColorUtils;
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/**
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* Contains colors based on the dominant color of an icon.
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*/
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public class IconPalette {
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private static final boolean DEBUG = false;
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private static final String TAG = "IconPalette";
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private static final float MIN_PRELOAD_COLOR_SATURATION = 0.2f;
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private static final float MIN_PRELOAD_COLOR_LIGHTNESS = 0.6f;
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/**
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* Returns a color suitable for the progress bar color of preload icon.
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*/
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public static int getPreloadProgressColor(Context context, int dominantColor) {
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int result = dominantColor;
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// Make sure that the dominant color has enough saturation to be visible properly.
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float[] hsv = new float[3];
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Color.colorToHSV(result, hsv);
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if (hsv[1] < MIN_PRELOAD_COLOR_SATURATION) {
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result = Themes.getColorAccent(context);
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} else {
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hsv[2] = Math.max(MIN_PRELOAD_COLOR_LIGHTNESS, hsv[2]);
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result = Color.HSVToColor(hsv);
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}
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return result;
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}
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/**
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* Resolves a color such that it has enough contrast to be used as the
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* color of an icon or text on the given background color.
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*
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* @return a color of the same hue with enough contrast against the background.
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*
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* This was copied from com.android.internal.util.NotificationColorUtil.
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*/
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public static int resolveContrastColor(Context context, int color, int background) {
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final int resolvedColor = resolveColor(context, color);
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int contrastingColor = ensureTextContrast(resolvedColor, background);
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if (contrastingColor != resolvedColor) {
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if (DEBUG){
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Log.w(TAG, String.format(
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"Enhanced contrast of notification for %s " +
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"%s (over background) by changing #%s to %s",
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context.getPackageName(),
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contrastChange(resolvedColor, contrastingColor, background),
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Integer.toHexString(resolvedColor), Integer.toHexString(contrastingColor)));
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}
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}
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return contrastingColor;
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}
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/**
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* Resolves {@param color} to an actual color if it is {@link Notification#COLOR_DEFAULT}
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*
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* This was copied from com.android.internal.util.NotificationColorUtil.
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*/
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private static int resolveColor(Context context, int color) {
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if (color == Notification.COLOR_DEFAULT) {
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return context.getColor(R.color.notification_icon_default_color);
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}
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return color;
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}
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/** For debugging. This was copied from com.android.internal.util.NotificationColorUtil. */
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private static String contrastChange(int colorOld, int colorNew, int bg) {
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return String.format("from %.2f:1 to %.2f:1",
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ColorUtils.calculateContrast(colorOld, bg),
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ColorUtils.calculateContrast(colorNew, bg));
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}
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/**
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* Finds a text color with sufficient contrast over bg that has the same hue as the original
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* color.
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*
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* This was copied from com.android.internal.util.NotificationColorUtil.
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*/
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private static int ensureTextContrast(int color, int bg) {
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return findContrastColor(color, bg, 4.5);
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}
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/**
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* Finds a suitable color such that there's enough contrast.
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*
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* @param fg the color to start searching from.
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* @param bg the color to ensure contrast against.
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* @param minRatio the minimum contrast ratio required.
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* @return a color with the same hue as {@param color}, potentially darkened to meet the
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* contrast ratio.
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*
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* This was copied from com.android.internal.util.NotificationColorUtil.
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*/
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private static int findContrastColor(int fg, int bg, double minRatio) {
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if (ColorUtils.calculateContrast(fg, bg) >= minRatio) {
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return fg;
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}
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double[] lab = new double[3];
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ColorUtils.colorToLAB(bg, lab);
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double bgL = lab[0];
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ColorUtils.colorToLAB(fg, lab);
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double fgL = lab[0];
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boolean isBgDark = bgL < 50;
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double low = isBgDark ? fgL : 0, high = isBgDark ? 100 : fgL;
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final double a = lab[1], b = lab[2];
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for (int i = 0; i < 15 && high - low > 0.00001; i++) {
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final double l = (low + high) / 2;
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fg = ColorUtils.LABToColor(l, a, b);
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if (ColorUtils.calculateContrast(fg, bg) > minRatio) {
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if (isBgDark) high = l; else low = l;
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} else {
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if (isBgDark) low = l; else high = l;
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}
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}
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return ColorUtils.LABToColor(low, a, b);
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}
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public static int getMutedColor(int color, float whiteScrimAlpha) {
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int whiteScrim = setColorAlphaBound(Color.WHITE, (int) (255 * whiteScrimAlpha));
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return ColorUtils.compositeColors(whiteScrim, color);
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}
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}
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