Slightly improve Taskbar animations to launcher

- Move Taskbar scale to LauncherState
- Rename TaskbarVisibilityController to TaskbarAnimationController and
  add mTaskbarScaleForLauncherState to TaskbarAnimationController
- Set OverviewState#getTaskbarScale() = 1f so Taskbar doesn't scale
  up when going from an app to Overview
- Increase home animation duration so Taskbar animation aligns better

Test: Taskbar scales up when going home, doesn't scale up when going
to overview
Bug: 182512211

Change-Id: I6f448e76de98d7ff337ae93234d4bb7ce6254d50

quickstep/src/com/android/launcher3/taskbar/TaskbarAnimationController.java

@@ -0,0 +1,126 @@
+/*
+ * 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.LauncherState.TASKBAR;
+
+import android.animation.Animator;
+
+import com.android.launcher3.BaseQuickstepLauncher;
+import com.android.launcher3.Utilities;
+import com.android.quickstep.AnimatedFloat;
+import com.android.quickstep.SystemUiProxy;
+import com.android.systemui.shared.system.QuickStepContract;
+
+/**
+ * Works with TaskbarController to update the TaskbarView's visual properties based on factors such
+ * as LauncherState, whether Launcher is in the foreground, etc.
+ */
+public class TaskbarAnimationController {
+
+    private static final long IME_VISIBILITY_ALPHA_DURATION = 120;
+
+    private final BaseQuickstepLauncher mLauncher;
+    private final TaskbarController.TaskbarAnimationControllerCallbacks mTaskbarCallbacks;
+
+    // Background alpha.
+    private final AnimatedFloat mTaskbarBackgroundAlpha = new AnimatedFloat(
+            this::onTaskbarBackgroundAlphaChanged);
+
+    // Overall visibility.
+    private final AnimatedFloat mTaskbarVisibilityAlphaForLauncherState = new AnimatedFloat(
+            this::updateVisibilityAlpha);
+    private final AnimatedFloat mTaskbarVisibilityAlphaForIme = new AnimatedFloat(
+            this::updateVisibilityAlpha);
+
+    // Scale.
+    private final AnimatedFloat mTaskbarScaleForLauncherState = new AnimatedFloat(
+            this::updateScale);
+
+    public TaskbarAnimationController(BaseQuickstepLauncher launcher,
+            TaskbarController.TaskbarAnimationControllerCallbacks taskbarCallbacks) {
+        mLauncher = launcher;
+        mTaskbarCallbacks = taskbarCallbacks;
+    }
+
+    protected void init() {
+        mTaskbarBackgroundAlpha.updateValue(mLauncher.hasBeenResumed() ? 0f : 1f);
+        boolean isVisibleForLauncherState = (mLauncher.getStateManager().getState()
+                .getVisibleElements(mLauncher) & TASKBAR) != 0;
+        mTaskbarVisibilityAlphaForLauncherState.updateValue(isVisibleForLauncherState ? 1f : 0f);
+        boolean isImeVisible = (SystemUiProxy.INSTANCE.get(mLauncher).getLastSystemUiStateFlags()
+                & QuickStepContract.SYSUI_STATE_IME_SHOWING) != 0;
+        mTaskbarVisibilityAlphaForIme.updateValue(isImeVisible ? 0f : 1f);
+
+        onTaskbarBackgroundAlphaChanged();
+        updateVisibilityAlpha();
+    }
+
+    protected void cleanup() {
+        setNavBarButtonAlpha(1f);
+    }
+
+    protected AnimatedFloat getTaskbarVisibilityForLauncherState() {
+        return mTaskbarVisibilityAlphaForLauncherState;
+    }
+
+    protected AnimatedFloat getTaskbarScaleForLauncherState() {
+        return mTaskbarScaleForLauncherState;
+    }
+
+    protected Animator createAnimToBackgroundAlpha(float toAlpha, long duration) {
+        return mTaskbarBackgroundAlpha.animateToValue(mTaskbarBackgroundAlpha.value, toAlpha)
+                .setDuration(duration);
+    }
+
+    protected void animateToVisibilityForIme(float toAlpha) {
+        mTaskbarVisibilityAlphaForIme.animateToValue(mTaskbarVisibilityAlphaForIme.value, toAlpha)
+                .setDuration(IME_VISIBILITY_ALPHA_DURATION).start();
+    }
+
+    private void onTaskbarBackgroundAlphaChanged() {
+        mTaskbarCallbacks.updateTaskbarBackgroundAlpha(mTaskbarBackgroundAlpha.value);
+        updateVisibilityAlpha();
+        updateScale();
+    }
+
+    private void updateVisibilityAlpha() {
+        // We use mTaskbarBackgroundAlpha as a proxy for whether Launcher is resumed/paused, the
+        // assumption being that Taskbar should always be visible regardless of the current
+        // LauncherState if Launcher is paused.
+        float alphaDueToLauncher = Math.max(mTaskbarBackgroundAlpha.value,
+                mTaskbarVisibilityAlphaForLauncherState.value);
+        float alphaDueToOther = mTaskbarVisibilityAlphaForIme.value;
+        float taskbarAlpha = alphaDueToLauncher * alphaDueToOther;
+        mTaskbarCallbacks.updateTaskbarVisibilityAlpha(taskbarAlpha);
+
+        // Make the nav bar invisible if taskbar is visible.
+        setNavBarButtonAlpha(1f - taskbarAlpha);
+    }
+
+    private void updateScale() {
+        // We use mTaskbarBackgroundAlpha as a proxy for whether Launcher is resumed/paused, the
+        // assumption being that Taskbar should always be at scale 1f regardless of the current
+        // LauncherState if Launcher is paused.
+        float scale = mTaskbarScaleForLauncherState.value;
+        scale = Utilities.mapRange(mTaskbarBackgroundAlpha.value, scale, 1f);
+        mTaskbarCallbacks.updateTaskbarScale(scale);
+    }
+
+    private void setNavBarButtonAlpha(float navBarAlpha) {
+        SystemUiProxy.INSTANCE.get(mLauncher).setNavBarButtonAlpha(navBarAlpha, false);
+    }
+}