| /* |
| * 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.UiThread; |
| import android.content.Context; |
| import android.graphics.Bitmap; |
| import android.graphics.Point; |
| import android.graphics.PointF; |
| import android.graphics.Rect; |
| import android.os.Handler; |
| import android.view.Gravity; |
| import android.view.LayoutInflater; |
| import android.view.PixelCopy; |
| import android.view.Surface; |
| import android.view.SurfaceHolder; |
| import android.view.SurfaceView; |
| import android.view.View; |
| import android.view.ViewParent; |
| import android.view.ViewRootImpl; |
| |
| 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 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 final PopupWindow 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 bitmap used to display the contents of the magnifier. |
| private final Bitmap mBitmap; |
| // The center coordinates of the content that is to be magnified. |
| private final Point mCenterZoomCoords = new Point(); |
| // The callback of the pixel copy request will be invoked on this Handler when |
| // the copy is finished. |
| private final Handler mPixelCopyHandler = Handler.getMain(); |
| // Current magnification scale. |
| private final float mZoomScale; |
| // 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); |
| private final Rect mPixelCopyRequestRect = new Rect(); |
| |
| /** |
| * 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 float elevation = context.getResources().getDimension( |
| com.android.internal.R.dimen.magnifier_elevation); |
| final View content = LayoutInflater.from(context).inflate( |
| com.android.internal.R.layout.magnifier, null); |
| content.findViewById(com.android.internal.R.id.magnifier_inner).setClipToOutline(true); |
| mWindowWidth = context.getResources().getDimensionPixelSize( |
| com.android.internal.R.dimen.magnifier_width); |
| mWindowHeight = context.getResources().getDimensionPixelSize( |
| com.android.internal.R.dimen.magnifier_height); |
| mZoomScale = context.getResources().getFloat( |
| com.android.internal.R.dimen.magnifier_zoom_scale); |
| // The view's surface coordinates will not be updated until the magnifier is first shown. |
| mViewCoordinatesInSurface = new int[2]; |
| |
| mWindow = new PopupWindow(context); |
| mWindow.setContentView(content); |
| mWindow.setWidth(mWindowWidth); |
| mWindow.setHeight(mWindowHeight); |
| mWindow.setElevation(elevation); |
| mWindow.setTouchable(false); |
| mWindow.setBackgroundDrawable(null); |
| |
| final int bitmapWidth = Math.round(mWindowWidth / mZoomScale); |
| final int bitmapHeight = Math.round(mWindowHeight / mZoomScale); |
| mBitmap = Bitmap.createBitmap(bitmapWidth, bitmapHeight, Bitmap.Config.ARGB_8888); |
| getImageView().setImageBitmap(mBitmap); |
| } |
| |
| /** |
| * 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 value to avoid magnifying content which does not belong to the magnified |
| // view. This will not take into account overlapping views. |
| // For this, we compute: |
| // - zeroScrollXInSurface: this is the start x of mView, where this is not masked by a |
| // potential scrolling container. For example, if mView is a |
| // TextView contained in a HorizontalScrollView, |
| // mViewCoordinatesInSurface will reflect the surface position of |
| // the first text character, rather than the position of the first |
| // visible one. Therefore, we need to add back the amount of |
| // scrolling from the parent containers. |
| // - actualWidth: similarly, the width of a View will be larger than its actually visible |
| // width when it is contained in a scrolling container. We need to use |
| // the minimum width of a scrolling container which contains this view. |
| int zeroScrollXInSurface = mViewCoordinatesInSurface[0]; |
| int actualWidth = mView.getWidth(); |
| ViewParent viewParent = mView.getParent(); |
| while (viewParent instanceof View) { |
| final View container = (View) viewParent; |
| if (container.canScrollHorizontally(-1 /* left scroll */) |
| || container.canScrollHorizontally(1 /* right scroll */)) { |
| zeroScrollXInSurface += container.getScrollX(); |
| actualWidth = Math.min(actualWidth, container.getWidth() |
| - container.getPaddingLeft() - container.getPaddingRight()); |
| } |
| viewParent = viewParent.getParent(); |
| } |
| |
| final int startX = Math.max(zeroScrollXInSurface, Math.min( |
| mCenterZoomCoords.x - mBitmap.getWidth() / 2, |
| zeroScrollXInSurface + actualWidth - mBitmap.getWidth())); |
| final int startY = mCenterZoomCoords.y - mBitmap.getHeight() / 2; |
| |
| if (xPosInView != mPrevPosInView.x || yPosInView != mPrevPosInView.y) { |
| performPixelCopy(startX, startY); |
| |
| mPrevPosInView.x = xPosInView; |
| mPrevPosInView.y = yPosInView; |
| |
| if (mWindow.isShowing()) { |
| mWindow.update(mWindowCoords.x, mWindowCoords.y, mWindow.getWidth(), |
| mWindow.getHeight()); |
| } else { |
| mWindow.showAtLocation(mView, Gravity.NO_GRAVITY, mWindowCoords.x, mWindowCoords.y); |
| } |
| } |
| } |
| |
| /** |
| * Dismisses the magnifier from the screen. Calling this on a dismissed magnifier is a no-op. |
| */ |
| public void dismiss() { |
| mWindow.dismiss(); |
| } |
| |
| /** |
| * 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.isShowing()) { |
| // Update the contents shown in the magnifier. |
| performPixelCopy(mPrevStartCoordsInSurface.x, mPrevStartCoordsInSurface.y); |
| } |
| } |
| |
| 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 contentPosX; |
| final float contentPosY; |
| if (mView instanceof SurfaceView) { |
| // No offset required if the backing Surface matches the size of the SurfaceView. |
| contentPosX = xPosInView; |
| contentPosY = yPosInView; |
| } else { |
| mView.getLocationInSurface(mViewCoordinatesInSurface); |
| contentPosX = xPosInView + mViewCoordinatesInSurface[0]; |
| contentPosY = yPosInView + mViewCoordinatesInSurface[1]; |
| } |
| mCenterZoomCoords.x = Math.round(contentPosX); |
| mCenterZoomCoords.y = Math.round(contentPosY); |
| |
| // Compute the position of the magnifier window. These have to be relative to the window |
| // of the view the magnifier is attached to, as the magnifier popup is a panel window |
| // attached to that window. |
| final int[] viewCoordinatesInWindow = new int[2]; |
| mView.getLocationInWindow(viewCoordinatesInWindow); |
| final int verticalOffset = mView.getContext().getResources().getDimensionPixelSize( |
| com.android.internal.R.dimen.magnifier_offset); |
| final float magnifierPosX = xPosInView + viewCoordinatesInWindow[0]; |
| final float magnifierPosY = yPosInView + viewCoordinatesInWindow[1] - verticalOffset; |
| mWindowCoords.x = Math.round(magnifierPosX - mWindowWidth / 2); |
| mWindowCoords.y = Math.round(magnifierPosY - mWindowHeight / 2); |
| } |
| |
| private void performPixelCopy(final int startXInSurface, final int startYInSurface) { |
| // 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 - mWindowWidth)); |
| final int clampedStartYInSurface = Math.max(0, |
| Math.min(startYInSurface, surfaceHeight - mWindowHeight)); |
| |
| // Perform the pixel copy. |
| mPixelCopyRequestRect.set(clampedStartXInSurface, |
| clampedStartYInSurface, |
| clampedStartXInSurface + mBitmap.getWidth(), |
| clampedStartYInSurface + mBitmap.getHeight()); |
| PixelCopy.request(surface, mPixelCopyRequestRect, mBitmap, |
| result -> { |
| getImageView().invalidate(); |
| mPrevStartCoordsInSurface.x = startXInSurface; |
| mPrevStartCoordsInSurface.y = startYInSurface; |
| }, |
| mPixelCopyHandler); |
| } |
| |
| private ImageView getImageView() { |
| return mWindow.getContentView().findViewById( |
| com.android.internal.R.id.magnifier_image); |
| } |
| } |