com/android/systemui/statusbar/policy/TintedKeyButtonDrawable.java

/*
 * 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.statusbar.policy;

import android.annotation.ColorInt;
import android.graphics.Color;
import android.graphics.drawable.Drawable;

import com.android.internal.graphics.ColorUtils;

/**
 * Drawable for {@link KeyButtonView}s which contains a single asset and colors for light and dark
 * navigation bar mode.
 */
public class TintedKeyButtonDrawable extends KeyButtonDrawable {

    private final int mLightColor;
    private final int mDarkColor;

    public static final float DARK_INTENSITY_NOT_SET = -1f;
    private float mDarkIntensity = DARK_INTENSITY_NOT_SET;

    public static TintedKeyButtonDrawable create(Drawable drawable, @ColorInt int lightColor,
            @ColorInt int darkColor) {
        return new TintedKeyButtonDrawable(new Drawable[] { drawable }, lightColor, darkColor);
    }

    private TintedKeyButtonDrawable(Drawable[] drawables, int lightColor, int darkColor){
        super(drawables);
        mLightColor = lightColor;
        mDarkColor = darkColor;
        setDarkIntensity(0f); // Set initial coloration
    }

    @Override
    public void setDarkIntensity(float intensity) {
        // Duplicate intensity scaling from KeyButtonDrawable
        mDarkIntensity = intensity;

        // Dark and light colors may have an alpha component
        final int intermediateColor = ColorUtils.compositeColors(
                blendAlpha(mDarkColor, intensity),
                blendAlpha(mLightColor, (1f - intensity)));

        getDrawable(0).setTint(intermediateColor);
        invalidateSelf();
    }

    private int blendAlpha(int color, float alpha) {
        final float newAlpha = alpha < 0f ? 0f : (alpha > 1f ? 1f : alpha);
        final float colorAlpha = Color.alpha(color) / 255f;
        final int alphaInt = (int) (255 * newAlpha * colorAlpha); // Blend by multiplying
        // Ensure alpha is clamped [0-255] or ColorUtils will crash
        return ColorUtils.setAlphaComponent(color, alphaInt);
    }

    public boolean isDarkIntensitySet() {
        return mDarkIntensity != DARK_INTENSITY_NOT_SET;
    }

    public float getDarkIntensity() {
        return mDarkIntensity;
    }
}