Lawnchair/quickstep/src/com/android/launcher3/taskbar/StashedHandleView.java

/*
 * Copyright (C) 2021 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.taskbar;

import static com.android.launcher3.LauncherAnimUtils.SCALE_PROPERTY;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.animation.PropertyValuesHolder;
import android.annotation.Nullable;
import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.ColorInt;
import androidx.core.content.ContextCompat;

import com.android.launcher3.LauncherAnimUtils;
import com.android.launcher3.R;

/**
 * View to render a handle that changes color based on the background to ensure contrast. Used for
 * the taskbar when stashed as well as the bubble bar when stashed.
 */
public class StashedHandleView extends View {

    private static final long COLOR_CHANGE_DURATION = 120;

    private final @ColorInt int mStashedHandleLightColor;
    private final @ColorInt int mStashedHandleDarkColor;
    private final Rect mSampledRegion = new Rect();
    private final int[] mTmpArr = new int[2];

    private @Nullable ObjectAnimator mColorChangeAnim;
    private Boolean mIsRegionDark;

    public StashedHandleView(Context context) {
        this(context, null);
    }

    public StashedHandleView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public StashedHandleView(Context context, AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    public StashedHandleView(Context context, AttributeSet attrs, int defStyleAttr,
            int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);

        mStashedHandleLightColor = ContextCompat.getColor(context,
                R.color.taskbar_stashed_handle_light_color);
        mStashedHandleDarkColor = ContextCompat.getColor(context,
                R.color.taskbar_stashed_handle_dark_color);
    }

    /**
     * Updates mSampledRegion to be the location of the stashedHandleBounds relative to the screen.
     * @see #getSampledRegion()
     */
    public void updateSampledRegion(Rect stashedHandleBounds) {
        getLocationOnScreen(mTmpArr);
        // Translations are temporary due to animations, remove them for the purpose of determining
        // the final region we want sampled.
        mTmpArr[0] -= Math.round(getTranslationX());
        mTmpArr[1] -= Math.round(getTranslationY());
        mSampledRegion.set(stashedHandleBounds);
        mSampledRegion.offset(mTmpArr[0], mTmpArr[1]);
    }

    public Rect getSampledRegion() {
        return mSampledRegion;
    }

    /**
     * Updates the handle color.
     * @param isRegionDark Whether the background behind the handle is dark, and thus the handle
     *                     should be light (and vice versa).
     * @param animate Whether to animate the change, or apply it immediately.
     */
    public void updateHandleColor(boolean isRegionDark, boolean animate) {
        if (mIsRegionDark != null && mIsRegionDark == isRegionDark) {
            return;
        }
        int newColor = isRegionDark ? mStashedHandleLightColor : mStashedHandleDarkColor;
        mIsRegionDark = isRegionDark;
        if (mColorChangeAnim != null) {
            mColorChangeAnim.cancel();
        }
        if (animate) {
            mColorChangeAnim = ObjectAnimator.ofArgb(this,
                    LauncherAnimUtils.VIEW_BACKGROUND_COLOR, newColor);
            mColorChangeAnim.addListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mColorChangeAnim = null;
                }
            });
            mColorChangeAnim.setDuration(COLOR_CHANGE_DURATION);
            mColorChangeAnim.start();
        } else {
            setBackgroundColor(newColor);
        }
    }

    /**
     * Updates the handle scale.
     *
     * @param scale target scale to animate towards (starting from current scale)
     * @param durationMs milliseconds for the animation to take
     */
    public void animateScale(float scale, long durationMs) {
        ObjectAnimator scaleAnim = ObjectAnimator.ofPropertyValuesHolder(this,
                PropertyValuesHolder.ofFloat(SCALE_PROPERTY, scale));
        scaleAnim.setDuration(durationMs).setAutoCancel(true);
        scaleAnim.start();
    }
}