src/com/android/launcher3/dynamicui/ExtractedColors.java

/*
 * 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.app.WallpaperManager;
import android.content.Context;
import android.graphics.Color;
import android.support.annotation.Nullable;
import android.support.v4.graphics.ColorUtils;
import android.support.v7.graphics.Palette;
import android.util.Log;

import com.android.launcher3.Utilities;
import com.android.launcher3.config.FeatureFlags;

import java.util.ArrayList;
import java.util.Arrays;

/**
 * Saves and loads colors extracted from the wallpaper, as well as the associated wallpaper id.
 */
public class ExtractedColors {
    private static final String TAG = "ExtractedColors";

    public static final int DEFAULT_LIGHT = Color.WHITE;
    public static final int DEFAULT_DARK = Color.BLACK;

    // These color profile indices should NOT be changed, since they are used when saving and
    // loading extracted colors. New colors should always be added at the end.
    public static final int VERSION_INDEX = 0;
    public static final int HOTSEAT_INDEX = 1;
    public static final int STATUS_BAR_INDEX = 2;
    public static final int WALLPAPER_VIBRANT_INDEX = 3;
    public static final int ALLAPPS_GRADIENT_MAIN_INDEX = 4;
    public static final int ALLAPPS_GRADIENT_SECONDARY_INDEX = 5;

    private static final int VERSION;
    private static final int[] DEFAULT_VALUES;

    static {
        if (FeatureFlags.LAUNCHER3_GRADIENT_ALL_APPS) {
            VERSION = 3;
            DEFAULT_VALUES = new int[] {
                    VERSION,            // VERSION_INDEX
                    0x40FFFFFF,         // HOTSEAT_INDEX: White with 25% alpha
                    DEFAULT_DARK,       // STATUS_BAR_INDEX
                    0xFFCCCCCC,         // WALLPAPER_VIBRANT_INDEX
                    0xFF000000,         // ALLAPPS_GRADIENT_MAIN_INDEX
                    0xFF000000          // ALLAPPS_GRADIENT_SECONDARY_INDEX
            };
        } else if (FeatureFlags.QSB_IN_HOTSEAT) {
            VERSION = 2;
            DEFAULT_VALUES = new int[] {
                    VERSION,            // VERSION_INDEX
                    0x40FFFFFF,         // HOTSEAT_INDEX: White with 25% alpha
                    DEFAULT_DARK,       // STATUS_BAR_INDEX
                    0xFFCCCCCC,         // WALLPAPER_VIBRANT_INDEX
            };
        } else {
            VERSION = 1;
            DEFAULT_VALUES = new int[] {
                    VERSION,            // VERSION_INDEX
                    0x40FFFFFF,         // HOTSEAT_INDEX: White with 25% alpha
                    DEFAULT_DARK,       // STATUS_BAR_INDEX
            };
        }
    }

    private static final String COLOR_SEPARATOR = ",";

    private final ArrayList<OnChangeListener> mListeners = new ArrayList<>();
    private final int[] mColors;

    public ExtractedColors() {
        // The first entry is reserved for the version number.
        mColors = Arrays.copyOf(DEFAULT_VALUES, DEFAULT_VALUES.length);
    }

    public void setColorAtIndex(int index, int color) {
        if (index > VERSION_INDEX && index < mColors.length) {
            mColors[index] = color;
        } else {
            Log.e(TAG, "Attempted to set a color at an invalid index " + index);
        }
    }

    /**
     * Encodes {@link #mColors} as a comma-separated String.
     */
    String encodeAsString() {
        StringBuilder colorsStringBuilder = new StringBuilder();
        for (int color : mColors) {
            colorsStringBuilder.append(color).append(COLOR_SEPARATOR);
        }
        return colorsStringBuilder.toString();
    }

    /**
     * Loads colors and wallpaper id from {@link Utilities#getPrefs(Context)}.
     * These were saved there in {@link ColorExtractionService}.
     */
    public void load(Context context) {
        String encodedString = Utilities.getPrefs(context).getString(
                ExtractionUtils.EXTRACTED_COLORS_PREFERENCE_KEY, VERSION + "");

        String[] splitColorsString = encodedString.split(COLOR_SEPARATOR);
        if (splitColorsString.length == DEFAULT_VALUES.length &&
                Integer.parseInt(splitColorsString[VERSION_INDEX]) == VERSION) {
            // Parse and apply the saved values.
            for (int i = 0; i < mColors.length; i++) {
                mColors[i] = Integer.parseInt(splitColorsString[i]);
            }
        } else {
            // Leave the values as default values as the saved values may not be compatible.
            ExtractionUtils.startColorExtractionService(context);
        }
    }

    /** @param index must be one of the index values defined at the top of this class. */
    public int getColor(int index) {
        return mColors[index];
    }

    /**
     * The hotseat's color is defined as follows:
     * - 12% black for super light wallpaper
     * - 18% white for super dark
     * - 25% white otherwise
     */
    public void updateHotseatPalette(Palette hotseatPalette) {
        int hotseatColor;
        if (hotseatPalette != null && ExtractionUtils.isSuperLight(hotseatPalette)) {
            hotseatColor = ColorUtils.setAlphaComponent(Color.BLACK, (int) (0.12f * 255));
        } else if (hotseatPalette != null && ExtractionUtils.isSuperDark(hotseatPalette)) {
            hotseatColor = ColorUtils.setAlphaComponent(Color.WHITE, (int) (0.18f * 255));
        } else {
            hotseatColor = DEFAULT_VALUES[HOTSEAT_INDEX];
        }
        setColorAtIndex(HOTSEAT_INDEX, hotseatColor);
    }

    public void updateStatusBarPalette(Palette statusBarPalette) {
        setColorAtIndex(STATUS_BAR_INDEX, ExtractionUtils.isSuperLight(statusBarPalette) ?
                DEFAULT_LIGHT : DEFAULT_DARK);
    }

    public void updateWallpaperThemePalette(@Nullable Palette wallpaperPalette) {
        int defaultColor = DEFAULT_VALUES[WALLPAPER_VIBRANT_INDEX];
        setColorAtIndex(WALLPAPER_VIBRANT_INDEX, wallpaperPalette == null
                ? defaultColor : wallpaperPalette.getVibrantColor(defaultColor));
    }

    public void addOnChangeListener(OnChangeListener listener) {
        mListeners.add(listener);
    }

    public void notifyChange() {
        for (OnChangeListener listener : mListeners) {
            listener.onExtractedColorsChanged();
        }
    }

    /**
     * Interface for listening for extracted color changes
     */
    public interface OnChangeListener {

        void onExtractedColorsChanged();
    }
}