| /* |
| * Copyright (C) 2016 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.launcher3.dynamicui; |
| |
| import android.annotation.TargetApi; |
| import android.app.WallpaperManager; |
| import android.content.Context; |
| import android.content.Intent; |
| import android.content.SharedPreferences; |
| import android.graphics.Color; |
| import android.os.Build; |
| import android.support.v4.graphics.ColorUtils; |
| import android.support.v7.graphics.Palette; |
| |
| import com.android.launcher3.Utilities; |
| |
| import java.util.List; |
| |
| /** |
| * Contains helper fields and methods related to extracting colors from the wallpaper. |
| */ |
| public class ExtractionUtils { |
| public static final String EXTRACTED_COLORS_PREFERENCE_KEY = "pref_extractedColors"; |
| public static final String WALLPAPER_ID_PREFERENCE_KEY = "pref_wallpaperId"; |
| |
| private static final float MIN_CONTRAST_RATIO = 2f; |
| |
| /** |
| * Extract colors in the :wallpaper-chooser process, if the wallpaper id has changed. |
| * When the new colors are saved in the LauncherProvider, |
| * Launcher will be notified in Launcher#onSettingsChanged(String, String). |
| */ |
| public static void startColorExtractionServiceIfNecessary(final Context context) { |
| // Run on a background thread, since the service is asynchronous anyway. |
| Utilities.THREAD_POOL_EXECUTOR.execute(new Runnable() { |
| @Override |
| public void run() { |
| if (hasWallpaperIdChanged(context)) { |
| startColorExtractionService(context); |
| } |
| } |
| }); |
| } |
| |
| /** Starts the {@link ColorExtractionService} without checking the wallpaper id */ |
| public static void startColorExtractionService(Context context) { |
| context.startService(new Intent(context, ColorExtractionService.class)); |
| } |
| |
| private static boolean hasWallpaperIdChanged(Context context) { |
| if (!Utilities.ATLEAST_NOUGAT) { |
| // TODO: update an id in sharedprefs in onWallpaperChanged broadcast, and read it here. |
| return false; |
| } |
| final SharedPreferences sharedPrefs = Utilities.getPrefs(context); |
| int wallpaperId = getWallpaperId(WallpaperManager.getInstance(context)); |
| int savedWallpaperId = sharedPrefs.getInt(ExtractionUtils.WALLPAPER_ID_PREFERENCE_KEY, -1); |
| return wallpaperId != savedWallpaperId; |
| } |
| |
| @TargetApi(Build.VERSION_CODES.N) |
| public static int getWallpaperId(WallpaperManager wallpaperManager) { |
| return Utilities.ATLEAST_NOUGAT ? |
| wallpaperManager.getWallpaperId(WallpaperManager.FLAG_SYSTEM) : -1; |
| } |
| |
| public static boolean isSuperLight(Palette p) { |
| return !isLegibleOnWallpaper(Color.WHITE, p.getSwatches()); |
| } |
| |
| public static boolean isSuperDark(Palette p) { |
| return !isLegibleOnWallpaper(Color.BLACK, p.getSwatches()); |
| } |
| |
| /** |
| * Given a color, returns true if that color is legible on |
| * the given wallpaper color swatches, else returns false. |
| */ |
| private static boolean isLegibleOnWallpaper(int color, List<Palette.Swatch> wallpaperSwatches) { |
| int legiblePopulation = 0; |
| int illegiblePopulation = 0; |
| for (Palette.Swatch swatch : wallpaperSwatches) { |
| if (isLegible(color, swatch.getRgb())) { |
| legiblePopulation += swatch.getPopulation(); |
| } else { |
| illegiblePopulation += swatch.getPopulation(); |
| } |
| } |
| return legiblePopulation > illegiblePopulation; |
| } |
| |
| /** @return Whether the foreground color is legible on the background color. */ |
| private static boolean isLegible(int foreground, int background) { |
| background = ColorUtils.setAlphaComponent(background, 255); |
| return ColorUtils.calculateContrast(foreground, background) >= MIN_CONTRAST_RATIO; |
| } |
| |
| } |