| /* |
| * 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.server.wm; |
| |
| import static android.app.ActivityManager.ENABLE_TASK_SNAPSHOTS; |
| import static android.graphics.Bitmap.Config.ARGB_8888; |
| import static android.graphics.GraphicBuffer.USAGE_HW_TEXTURE; |
| import static android.graphics.GraphicBuffer.USAGE_SW_READ_NEVER; |
| import static android.graphics.GraphicBuffer.USAGE_SW_WRITE_NEVER; |
| import static android.graphics.PixelFormat.RGBA_8888; |
| |
| import android.annotation.Nullable; |
| import android.app.ActivityManager.StackId; |
| import android.graphics.Bitmap; |
| import android.graphics.Canvas; |
| import android.graphics.GraphicBuffer; |
| import android.util.ArraySet; |
| import android.view.WindowManagerPolicy.StartingSurface; |
| |
| import com.android.internal.annotations.VisibleForTesting; |
| |
| /** |
| * When an app token becomes invisible, we take a snapshot (bitmap) of the corresponding task and |
| * put it into our cache. Internally we use gralloc buffers to be able to draw them wherever we |
| * like without any copying. |
| * <p> |
| * System applications may retrieve a snapshot to represent the current state of a task, and draw |
| * them in their own process. |
| * <p> |
| * When we task becomes visible again, we show a starting window with the snapshot as the content to |
| * make app transitions more responsive. |
| * <p> |
| * To access this class, acquire the global window manager lock. |
| */ |
| class TaskSnapshotController { |
| |
| private final WindowManagerService mService; |
| private final TaskSnapshotCache mCache = new TaskSnapshotCache(); |
| |
| private final ArraySet<Task> mTmpTasks = new ArraySet<>(); |
| |
| TaskSnapshotController(WindowManagerService service) { |
| mService = service; |
| } |
| |
| void onTransitionStarting() { |
| if (!ENABLE_TASK_SNAPSHOTS) { |
| return; |
| } |
| |
| // We need to take a snapshot of the task if and only if all activities of the task are |
| // either closing or hidden. |
| getClosingTasks(mService.mClosingApps, mTmpTasks); |
| for (int i = mTmpTasks.size() - 1; i >= 0; i--) { |
| final Task task = mTmpTasks.valueAt(i); |
| if (!canSnapshotTask(task)) { |
| continue; |
| } |
| final GraphicBuffer graphicBuffer = snapshotTask(task); |
| if (graphicBuffer != null) { |
| mCache.putSnapshot(task, graphicBuffer); |
| } |
| } |
| } |
| |
| @Nullable GraphicBuffer getSnapshot(Task task) { |
| return mCache.getSnapshot(task); |
| } |
| |
| /** |
| * Creates a starting surface for {@param token} with {@param snapshot}. DO NOT HOLD THE WINDOW |
| * MANAGER LOCK WHEN CALLING THIS METHOD! |
| */ |
| StartingSurface createStartingSurface(AppWindowToken token, |
| GraphicBuffer snapshot) { |
| return TaskSnapshotSurface.create(mService, token, snapshot); |
| } |
| |
| private GraphicBuffer snapshotTask(Task task) { |
| final AppWindowToken top = (AppWindowToken) task.getTop(); |
| if (top == null) { |
| return null; |
| } |
| final Bitmap bmp = top.mDisplayContent.screenshotApplications(top.token, -1, -1, false, |
| 1.0f, ARGB_8888, false, true, false); |
| if (bmp == null) { |
| return null; |
| } |
| // TODO: Already use a GraphicBuffer when snapshotting the content. |
| final GraphicBuffer buffer = GraphicBuffer.create(bmp.getWidth(), bmp.getHeight(), |
| RGBA_8888, USAGE_HW_TEXTURE | USAGE_SW_WRITE_NEVER | USAGE_SW_READ_NEVER); |
| final Canvas c = buffer.lockCanvas(); |
| c.drawBitmap(bmp, 0, 0, null); |
| buffer.unlockCanvasAndPost(c); |
| return buffer; |
| } |
| |
| /** |
| * Retrieves all closing tasks based on the list of closing apps during an app transition. |
| */ |
| @VisibleForTesting |
| void getClosingTasks(ArraySet<AppWindowToken> closingApps, ArraySet<Task> outClosingTasks) { |
| outClosingTasks.clear(); |
| for (int i = closingApps.size() - 1; i >= 0; i--) { |
| final AppWindowToken atoken = closingApps.valueAt(i); |
| |
| // If the task of the app is not visible anymore, it means no other app in that task |
| // is opening. Thus, the task is closing. |
| if (atoken.mTask != null && !atoken.mTask.isVisible()) { |
| outClosingTasks.add(closingApps.valueAt(i).mTask); |
| } |
| } |
| } |
| |
| private boolean canSnapshotTask(Task task) { |
| return !StackId.isHomeOrRecentsStack(task.mStack.mStackId); |
| } |
| } |