/* * Copyright (C) 2017 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 android.widget; import android.annotation.FloatRange; import android.annotation.NonNull; import android.annotation.Nullable; import android.annotation.TestApi; import android.annotation.UiThread; import android.content.Context; import android.content.res.Resources; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.Color; import android.graphics.Outline; import android.graphics.Paint; import android.graphics.PixelFormat; import android.graphics.Point; import android.graphics.PointF; import android.graphics.Rect; import android.os.Handler; import android.os.HandlerThread; import android.os.Message; import android.view.ContextThemeWrapper; import android.view.Display; import android.view.DisplayListCanvas; import android.view.LayoutInflater; import android.view.PixelCopy; import android.view.RenderNode; import android.view.Surface; import android.view.SurfaceControl; import android.view.SurfaceHolder; import android.view.SurfaceSession; import android.view.SurfaceView; import android.view.ThreadedRenderer; import android.view.View; import android.view.ViewRootImpl; import com.android.internal.R; import com.android.internal.util.Preconditions; /** * Android magnifier widget. Can be used by any view which is attached to a window. */ @UiThread public final class Magnifier { // Use this to specify that a previous configuration value does not exist. private static final int NONEXISTENT_PREVIOUS_CONFIG_VALUE = -1; // The callbacks of the pixel copy requests will be invoked on // the Handler of this Thread when the copy is finished. private static final HandlerThread sPixelCopyHandlerThread = new HandlerThread("magnifier pixel copy result handler"); // The view to which this magnifier is attached. private final View mView; // The coordinates of the view in the surface. private final int[] mViewCoordinatesInSurface; // The window containing the magnifier. private InternalPopupWindow mWindow; // The center coordinates of the window containing the magnifier. private final Point mWindowCoords = new Point(); // The width of the window containing the magnifier. private final int mWindowWidth; // The height of the window containing the magnifier. private final int mWindowHeight; // The zoom applied to the view region copied to the magnifier window. private final float mZoom; // The width of the bitmaps where the magnifier content is copied. private final int mBitmapWidth; // The height of the bitmaps where the magnifier content is copied. private final int mBitmapHeight; // The elevation of the window containing the magnifier. private final float mWindowElevation; // The corner radius of the window containing the magnifier. private final float mWindowCornerRadius; // The center coordinates of the content that is to be magnified. private final Point mCenterZoomCoords = new Point(); // Variables holding previous states, used for detecting redundant calls and invalidation. private final Point mPrevStartCoordsInSurface = new Point( NONEXISTENT_PREVIOUS_CONFIG_VALUE, NONEXISTENT_PREVIOUS_CONFIG_VALUE); private final PointF mPrevPosInView = new PointF( NONEXISTENT_PREVIOUS_CONFIG_VALUE, NONEXISTENT_PREVIOUS_CONFIG_VALUE); // Rectangle defining the view surface area we pixel copy content from. private final Rect mPixelCopyRequestRect = new Rect(); // Lock to synchronize between the UI thread and the thread that handles pixel copy results. // Only sync mWindow writes from UI thread with mWindow reads from sPixelCopyHandlerThread. private final Object mLock = new Object(); /** * Initializes a magnifier. * * @param view the view for which this magnifier is attached */ public Magnifier(@NonNull View view) { mView = Preconditions.checkNotNull(view); final Context context = mView.getContext(); final View content = LayoutInflater.from(context).inflate(R.layout.magnifier, null); content.findViewById(R.id.magnifier_inner).setClipToOutline(true); mWindowWidth = context.getResources().getDimensionPixelSize(R.dimen.magnifier_width); mWindowHeight = context.getResources().getDimensionPixelSize(R.dimen.magnifier_height); mWindowElevation = context.getResources().getDimension(R.dimen.magnifier_elevation); mWindowCornerRadius = getDeviceDefaultDialogCornerRadius(); mZoom = context.getResources().getFloat(R.dimen.magnifier_zoom_scale); mBitmapWidth = Math.round(mWindowWidth / mZoom); mBitmapHeight = Math.round(mWindowHeight / mZoom); // The view's surface coordinates will not be updated until the magnifier is first shown. mViewCoordinatesInSurface = new int[2]; } static { sPixelCopyHandlerThread.start(); } /** * Returns the device default theme dialog corner radius attribute. * We retrieve this from the device default theme to avoid * using the values set in the custom application themes. */ private float getDeviceDefaultDialogCornerRadius() { final Context deviceDefaultContext = new ContextThemeWrapper(mView.getContext(), R.style.Theme_DeviceDefault); final TypedArray ta = deviceDefaultContext.obtainStyledAttributes( new int[]{android.R.attr.dialogCornerRadius}); final float dialogCornerRadius = ta.getDimension(0, 0); ta.recycle(); return dialogCornerRadius; } /** * Shows the magnifier on the screen. * * @param xPosInView horizontal coordinate of the center point of the magnifier source relative * to the view. The lower end is clamped to 0 and the higher end is clamped to the view * width. * @param yPosInView vertical coordinate of the center point of the magnifier source * relative to the view. The lower end is clamped to 0 and the higher end is clamped to * the view height. */ public void show(@FloatRange(from = 0) float xPosInView, @FloatRange(from = 0) float yPosInView) { xPosInView = Math.max(0, Math.min(xPosInView, mView.getWidth())); yPosInView = Math.max(0, Math.min(yPosInView, mView.getHeight())); configureCoordinates(xPosInView, yPosInView); // Clamp the startX location to avoid magnifying content which does not belong // to the magnified view. This will not take into account overlapping views. final Rect viewVisibleRegion = new Rect(); mView.getGlobalVisibleRect(viewVisibleRegion); final int startX = Math.max(viewVisibleRegion.left, Math.min( mCenterZoomCoords.x - mBitmapWidth / 2, viewVisibleRegion.right - mBitmapWidth)); final int startY = mCenterZoomCoords.y - mBitmapHeight / 2; if (xPosInView != mPrevPosInView.x || yPosInView != mPrevPosInView.y) { if (mWindow == null) { synchronized (mLock) { mWindow = new InternalPopupWindow(mView.getContext(), mView.getDisplay(), getValidViewSurface(), mWindowWidth, mWindowHeight, mWindowElevation, mWindowCornerRadius, Handler.getMain() /* draw the magnifier on the UI thread */, mLock, mCallback); } } performPixelCopy(startX, startY, true /* update window position */); mPrevPosInView.x = xPosInView; mPrevPosInView.y = yPosInView; } } /** * Dismisses the magnifier from the screen. Calling this on a dismissed magnifier is a no-op. */ public void dismiss() { if (mWindow != null) { synchronized (mLock) { mWindow.destroy(); mWindow = null; } mPrevPosInView.x = NONEXISTENT_PREVIOUS_CONFIG_VALUE; mPrevPosInView.y = NONEXISTENT_PREVIOUS_CONFIG_VALUE; mPrevStartCoordsInSurface.x = NONEXISTENT_PREVIOUS_CONFIG_VALUE; mPrevStartCoordsInSurface.y = NONEXISTENT_PREVIOUS_CONFIG_VALUE; } } /** * Forces the magnifier to update its content. It uses the previous coordinates passed to * {@link #show(float, float)}. This only happens if the magnifier is currently showing. */ public void update() { if (mWindow != null) { // Update the content shown in the magnifier. performPixelCopy(mPrevStartCoordsInSurface.x, mPrevStartCoordsInSurface.y, false /* update window position */); } } /** * @return The width of the magnifier window, in pixels. */ public int getWidth() { return mWindowWidth; } /** * @return The height of the magnifier window, in pixels. */ public int getHeight() { return mWindowHeight; } /** * @return The zoom applied to the magnified view region copied to the magnifier window. * If the zoom is x and the magnifier window size is (width, height), the original size * of the content copied in the magnifier will be (width / x, height / x). */ public float getZoom() { return mZoom; } /** * @hide */ @Nullable public Point getWindowCoords() { if (mWindow == null) { return null; } return new Point(mWindow.mLastDrawContentPositionX, mWindow.mLastDrawContentPositionY); } @Nullable private Surface getValidViewSurface() { // TODO: deduplicate this against the first part of #performPixelCopy final Surface surface; if (mView instanceof SurfaceView) { surface = ((SurfaceView) mView).getHolder().getSurface(); } else if (mView.getViewRootImpl() != null) { surface = mView.getViewRootImpl().mSurface; } else { surface = null; } return (surface != null && surface.isValid()) ? surface : null; } private void configureCoordinates(final float xPosInView, final float yPosInView) { // Compute the coordinates of the center of the content going to be displayed in the // magnifier. These are relative to the surface the content is copied from. final float posX; final float posY; if (mView instanceof SurfaceView) { // No offset required if the backing Surface matches the size of the SurfaceView. posX = xPosInView; posY = yPosInView; } else { mView.getLocationInSurface(mViewCoordinatesInSurface); posX = xPosInView + mViewCoordinatesInSurface[0]; posY = yPosInView + mViewCoordinatesInSurface[1]; } mCenterZoomCoords.x = Math.round(posX); mCenterZoomCoords.y = Math.round(posY); // Compute the position of the magnifier window. Again, this has to be relative to the // surface of the magnified view, as this surface is the parent of the magnifier surface. final int verticalOffset = mView.getContext().getResources().getDimensionPixelSize( R.dimen.magnifier_offset); mWindowCoords.x = mCenterZoomCoords.x - mWindowWidth / 2; mWindowCoords.y = mCenterZoomCoords.y - mWindowHeight / 2 - verticalOffset; } private void performPixelCopy(final int startXInSurface, final int startYInSurface, final boolean updateWindowPosition) { // Get the view surface where the content will be copied from. final Surface surface; final int surfaceWidth; final int surfaceHeight; if (mView instanceof SurfaceView) { final SurfaceHolder surfaceHolder = ((SurfaceView) mView).getHolder(); surface = surfaceHolder.getSurface(); surfaceWidth = surfaceHolder.getSurfaceFrame().right; surfaceHeight = surfaceHolder.getSurfaceFrame().bottom; } else if (mView.getViewRootImpl() != null) { final ViewRootImpl viewRootImpl = mView.getViewRootImpl(); surface = viewRootImpl.mSurface; surfaceWidth = viewRootImpl.getWidth(); surfaceHeight = viewRootImpl.getHeight(); } else { surface = null; surfaceWidth = NONEXISTENT_PREVIOUS_CONFIG_VALUE; surfaceHeight = NONEXISTENT_PREVIOUS_CONFIG_VALUE; } if (surface == null || !surface.isValid()) { return; } // Clamp copy coordinates inside the surface to avoid displaying distorted content. final int clampedStartXInSurface = Math.max(0, Math.min(startXInSurface, surfaceWidth - mBitmapWidth)); final int clampedStartYInSurface = Math.max(0, Math.min(startYInSurface, surfaceHeight - mBitmapHeight)); // Clamp window coordinates inside the parent surface, to avoid displaying // the magnifier out of screen or overlapping with system insets. final Rect insets = mView.getRootWindowInsets().getSystemWindowInsets(); final int windowCoordsX = Math.max(insets.left, Math.min(surfaceWidth - mWindowWidth - insets.right, mWindowCoords.x)); final int windowCoordsY = Math.max(insets.top, Math.min(surfaceHeight - mWindowHeight - insets.bottom, mWindowCoords.y)); // Perform the pixel copy. mPixelCopyRequestRect.set(clampedStartXInSurface, clampedStartYInSurface, clampedStartXInSurface + mBitmapWidth, clampedStartYInSurface + mBitmapHeight); final InternalPopupWindow currentWindowInstance = mWindow; final Bitmap bitmap = Bitmap.createBitmap(mBitmapWidth, mBitmapHeight, Bitmap.Config.ARGB_8888); PixelCopy.request(surface, mPixelCopyRequestRect, bitmap, result -> { synchronized (mLock) { if (mWindow != currentWindowInstance) { // The magnifier was dismissed (and maybe shown again) in the meantime. return; } if (updateWindowPosition) { // TODO: pull the position update outside #performPixelCopy mWindow.setContentPositionForNextDraw(windowCoordsX, windowCoordsY); } mWindow.updateContent(bitmap); } }, sPixelCopyHandlerThread.getThreadHandler()); mPrevStartCoordsInSurface.x = startXInSurface; mPrevStartCoordsInSurface.y = startYInSurface; } /** * Magnifier's own implementation of PopupWindow-similar floating window. * This exists to ensure frame-synchronization between window position updates and window * content updates. By using a PopupWindow, these events would happen in different frames, * producing a shakiness effect for the magnifier content. */ private static class InternalPopupWindow { // The alpha set on the magnifier's content, which defines how // prominent the white background is. private static final int CONTENT_BITMAP_ALPHA = 242; // Display associated to the view the magnifier is attached to. private final Display mDisplay; // The size of the content of the magnifier. private final int mContentWidth; private final int mContentHeight; // The size of the allocated surface. private final int mSurfaceWidth; private final int mSurfaceHeight; // The insets of the content inside the allocated surface. private final int mOffsetX; private final int mOffsetY; // The surface we allocate for the magnifier content + shadow. private final SurfaceSession mSurfaceSession; private final SurfaceControl mSurfaceControl; private final Surface mSurface; // The renderer used for the allocated surface. private final ThreadedRenderer.SimpleRenderer mRenderer; // The RenderNode used to draw the magnifier content in the surface. private final RenderNode mBitmapRenderNode; // The job that will be post'd to apply the pending magnifier updates to the surface. private final Runnable mMagnifierUpdater; // The handler where the magnifier updater jobs will be post'd. private final Handler mHandler; // The callback to be run after the next draw. private Callback mCallback; // The position of the magnifier content when the last draw was requested. private int mLastDrawContentPositionX; private int mLastDrawContentPositionY; // Members below describe the state of the magnifier. Reads/writes to them // have to be synchronized between the UI thread and the thread that handles // the pixel copy results. This is the purpose of mLock. private final Object mLock; // Whether a magnifier frame draw is currently pending in the UI thread queue. private boolean mFrameDrawScheduled; // The content bitmap. private Bitmap mBitmap; // Whether the next draw will be the first one for the current instance. private boolean mFirstDraw = true; // The window position in the parent surface. Might be applied during the next draw, // when mPendingWindowPositionUpdate is true. private int mWindowPositionX; private int mWindowPositionY; private boolean mPendingWindowPositionUpdate; // The lock used to synchronize the UI and render threads when a #destroy // is performed on the UI thread and a frame callback on the render thread. // When both mLock and mDestroyLock need to be held at the same time, // mDestroyLock should be acquired before mLock in order to avoid deadlocks. private final Object mDestroyLock = new Object(); InternalPopupWindow(final Context context, final Display display, final Surface parentSurface, final int width, final int height, final float elevation, final float cornerRadius, final Handler handler, final Object lock, final Callback callback) { mDisplay = display; mLock = lock; mCallback = callback; mContentWidth = width; mContentHeight = height; mOffsetX = (int) (0.1f * width); mOffsetY = (int) (0.1f * height); // Setup the surface we will use for drawing the content and shadow. mSurfaceWidth = mContentWidth + 2 * mOffsetX; mSurfaceHeight = mContentHeight + 2 * mOffsetY; mSurfaceSession = new SurfaceSession(parentSurface); mSurfaceControl = new SurfaceControl.Builder(mSurfaceSession) .setFormat(PixelFormat.TRANSLUCENT) .setSize(mSurfaceWidth, mSurfaceHeight) .setName("magnifier surface") .setFlags(SurfaceControl.HIDDEN) .build(); mSurface = new Surface(); mSurface.copyFrom(mSurfaceControl); // Setup the RenderNode tree. The root has only one child, which contains the bitmap. mRenderer = new ThreadedRenderer.SimpleRenderer( context, "magnifier renderer", mSurface ); mBitmapRenderNode = createRenderNodeForBitmap( "magnifier content", elevation, cornerRadius ); final DisplayListCanvas canvas = mRenderer.getRootNode().start(width, height); try { canvas.insertReorderBarrier(); canvas.drawRenderNode(mBitmapRenderNode); canvas.insertInorderBarrier(); } finally { mRenderer.getRootNode().end(canvas); } // Initialize the update job and the handler where this will be post'd. mHandler = handler; mMagnifierUpdater = this::doDraw; mFrameDrawScheduled = false; } private RenderNode createRenderNodeForBitmap(final String name, final float elevation, final float cornerRadius) { final RenderNode bitmapRenderNode = RenderNode.create(name, null); // Define the position of the bitmap in the parent render node. The surface regions // outside the bitmap are used to draw elevation. bitmapRenderNode.setLeftTopRightBottom(mOffsetX, mOffsetY, mOffsetX + mContentWidth, mOffsetY + mContentHeight); bitmapRenderNode.setElevation(elevation); final Outline outline = new Outline(); outline.setRoundRect(0, 0, mContentWidth, mContentHeight, cornerRadius); outline.setAlpha(1.0f); bitmapRenderNode.setOutline(outline); bitmapRenderNode.setClipToOutline(true); // Create a dummy draw, which will be replaced later with real drawing. final DisplayListCanvas canvas = bitmapRenderNode.start(mContentWidth, mContentHeight); try { canvas.drawColor(0xFF00FF00); } finally { bitmapRenderNode.end(canvas); } return bitmapRenderNode; } /** * Sets the position of the magnifier content relative to the parent surface. * The position update will happen in the same frame with the next draw. * The method has to be called in a context that holds {@link #mLock}. * * @param contentX the x coordinate of the content * @param contentY the y coordinate of the content */ public void setContentPositionForNextDraw(final int contentX, final int contentY) { mWindowPositionX = contentX - mOffsetX; mWindowPositionY = contentY - mOffsetY; mPendingWindowPositionUpdate = true; requestUpdate(); } /** * Sets the content that should be displayed in the magnifier. * The update happens immediately, and possibly triggers a pending window movement set * by {@link #setContentPositionForNextDraw(int, int)}. * The method has to be called in a context that holds {@link #mLock}. * * @param bitmap the content bitmap */ public void updateContent(final @NonNull Bitmap bitmap) { if (mBitmap != null) { mBitmap.recycle(); } mBitmap = bitmap; requestUpdate(); } private void requestUpdate() { if (mFrameDrawScheduled) { return; } final Message request = Message.obtain(mHandler, mMagnifierUpdater); request.setAsynchronous(true); request.sendToTarget(); mFrameDrawScheduled = true; } /** * Destroys this instance. */ public void destroy() { synchronized (mDestroyLock) { mSurface.destroy(); } synchronized (mLock) { mRenderer.destroy(); mSurfaceControl.destroy(); mSurfaceSession.kill(); mBitmapRenderNode.destroy(); mHandler.removeCallbacks(mMagnifierUpdater); if (mBitmap != null) { mBitmap.recycle(); } } } private void doDraw() { final ThreadedRenderer.FrameDrawingCallback callback; // Draw the current bitmap to the surface, and prepare the callback which updates the // surface position. These have to be in the same synchronized block, in order to // guarantee the consistency between the bitmap content and the surface position. synchronized (mLock) { if (!mSurface.isValid()) { // Probably #destroy() was called for the current instance, so we skip the draw. return; } final DisplayListCanvas canvas = mBitmapRenderNode.start(mContentWidth, mContentHeight); try { canvas.drawColor(Color.WHITE); final Rect srcRect = new Rect(0, 0, mBitmap.getWidth(), mBitmap.getHeight()); final Rect dstRect = new Rect(0, 0, mContentWidth, mContentHeight); final Paint paint = new Paint(); paint.setFilterBitmap(true); paint.setAlpha(CONTENT_BITMAP_ALPHA); canvas.drawBitmap(mBitmap, srcRect, dstRect, paint); } finally { mBitmapRenderNode.end(canvas); } if (mPendingWindowPositionUpdate || mFirstDraw) { // If the window has to be shown or moved, defer this until the next draw. final boolean firstDraw = mFirstDraw; mFirstDraw = false; final boolean updateWindowPosition = mPendingWindowPositionUpdate; mPendingWindowPositionUpdate = false; final int pendingX = mWindowPositionX; final int pendingY = mWindowPositionY; callback = frame -> { synchronized (mDestroyLock) { if (!mSurface.isValid()) { return; } synchronized (mLock) { mRenderer.setLightCenter(mDisplay, pendingX, pendingY); // Show or move the window at the content draw frame. SurfaceControl.openTransaction(); mSurfaceControl.deferTransactionUntil(mSurface, frame); if (updateWindowPosition) { mSurfaceControl.setPosition(pendingX, pendingY); } if (firstDraw) { mSurfaceControl.show(); } SurfaceControl.closeTransaction(); } } }; } else { callback = null; } mLastDrawContentPositionX = mWindowPositionX + mOffsetX; mLastDrawContentPositionY = mWindowPositionY + mOffsetY; mFrameDrawScheduled = false; } mRenderer.draw(callback); if (mCallback != null) { mCallback.onOperationComplete(); } } } // The rest of the file consists of test APIs. /** * See {@link #setOnOperationCompleteCallback(Callback)}. */ @TestApi private Callback mCallback; /** * Sets a callback which will be invoked at the end of the next * {@link #show(float, float)} or {@link #update()} operation. * * @hide */ @TestApi public void setOnOperationCompleteCallback(final Callback callback) { mCallback = callback; if (mWindow != null) { mWindow.mCallback = callback; } } /** * @return the content being currently displayed in the magnifier, as bitmap * * @hide */ @TestApi public @Nullable Bitmap getContent() { if (mWindow == null) { return null; } synchronized (mWindow.mLock) { return Bitmap.createScaledBitmap(mWindow.mBitmap, mWindowWidth, mWindowHeight, true); } } /** * @return the position of the magnifier window relative to the screen * * @hide */ @TestApi public Rect getWindowPositionOnScreen() { final int[] viewLocationOnScreen = new int[2]; mView.getLocationOnScreen(viewLocationOnScreen); final int[] viewLocationInSurface = new int[2]; mView.getLocationInSurface(viewLocationInSurface); final int left = mWindowCoords.x + viewLocationOnScreen[0] - viewLocationInSurface[0]; final int top = mWindowCoords.y + viewLocationOnScreen[1] - viewLocationInSurface[1]; return new Rect(left, top, left + mWindowWidth, top + mWindowHeight); } /** * @return the size of the magnifier window in dp * * @hide */ @TestApi public static PointF getMagnifierDefaultSize() { final Resources resources = Resources.getSystem(); final float density = resources.getDisplayMetrics().density; final PointF size = new PointF(); size.x = resources.getDimension(R.dimen.magnifier_width) / density; size.y = resources.getDimension(R.dimen.magnifier_height) / density; return size; } /** * @hide */ @TestApi public interface Callback { /** * Callback called after the drawing for a magnifier update has happened. */ void onOperationComplete(); } }