content: /*
   * Copyright (C) 2007 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.graphics;
  
  import android.annotation.NonNull;
  import android.annotation.UnsupportedAppUsage;
  
  import java.io.InputStream;
  import java.io.OutputStream;
  
  /**
   * A Picture records drawing calls (via the canvas returned by beginRecording)
   * and can then play them back into Canvas (via {@link Picture#draw(Canvas)} or
   * {@link Canvas#drawPicture(Picture)}).For most content (e.g. text, lines, rectangles),
   * drawing a sequence from a picture can be faster than the equivalent API
   * calls, since the picture performs its playback without incurring any
   * method-call overhead.
   *
   * <p class="note"><strong>Note:</strong> Prior to API level 23 a picture cannot
   * be replayed on a hardware accelerated canvas.</p>
   */
  public class Picture {
      private PictureCanvas mRecordingCanvas;
      // TODO: Figure out if this was a false-positive
      @UnsupportedAppUsage(maxTargetSdk = 28)
      private long mNativePicture;
      private boolean mRequiresHwAcceleration;
  
      private static final int WORKING_STREAM_STORAGE = 16 * 1024;
  
      /**
       * Creates an empty picture that is ready to record.
       */
      public Picture() {
          this(nativeConstructor(0));
      }
  
      /**
       * Create a picture by making a copy of what has already been recorded in
       * src. The contents of src are unchanged, and if src changes later, those
       * changes will not be reflected in this picture.
       */
      public Picture(Picture src) {
          this(nativeConstructor(src != null ? src.mNativePicture : 0));
      }
  
      /** @hide */
      public Picture(long nativePicture) {
          if (nativePicture == 0) {
              throw new IllegalArgumentException();
          }
          mNativePicture = nativePicture;
      }
  
      /**
       * Immediately releases the backing data of the Picture. This object will no longer
       * be usable after calling this, and any further calls on the Picture will throw an
       * IllegalStateException.
       * // TODO: Support?
       * @hide
       */
      public void close() {
          if (mNativePicture != 0) {
              nativeDestructor(mNativePicture);
              mNativePicture = 0;
          }
      }
  
      @Override
      protected void finalize() throws Throwable {
          try {
              close();
          } finally {
              super.finalize();
          }
      }
  
      private void verifyValid() {
          if (mNativePicture == 0) {
              throw new IllegalStateException("Picture is destroyed");
          }
      }
  
      /**
       * To record a picture, call beginRecording() and then draw into the Canvas
       * that is returned. Nothing we appear on screen, but all of the draw
       * commands (e.g. {@link Canvas#drawRect(Rect, Paint)}) will be recorded.
       * To stop recording, call endRecording(). After endRecording() the Canvas
       * that was returned must no longer be used, and nothing should be drawn
       * into it.
       */
      @NonNull
      public Canvas beginRecording(int width, int height) {
          verifyValid();
          if (mRecordingCanvas != null) {
              throw new IllegalStateException("Picture already recording, must call #endRecording()");
          }
          long ni = nativeBeginRecording(mNativePicture, width, height);
          mRecordingCanvas = new PictureCanvas(this, ni);
          mRequiresHwAcceleration = false;
          return mRecordingCanvas;
      }
  
      /**
       * Call endRecording when the picture is built. After this call, the picture
       * may be drawn, but the canvas that was returned by beginRecording must not
       * be used anymore. This is automatically called if {@link Picture#draw}
       * or {@link Canvas#drawPicture(Picture)} is called.
       */
      public void endRecording() {
          verifyValid();
          if (mRecordingCanvas != null) {
              mRequiresHwAcceleration = mRecordingCanvas.mHoldsHwBitmap;
              mRecordingCanvas = null;
              nativeEndRecording(mNativePicture);
          }
      }
  
      /**
       * Get the width of the picture as passed to beginRecording. This
       * does not reflect (per se) the content of the picture.
       */
      public int getWidth() {
          verifyValid();
          return nativeGetWidth(mNativePicture);
      }
  
      /**
       * Get the height of the picture as passed to beginRecording. This
       * does not reflect (per se) the content of the picture.
       */
      public int getHeight() {
          verifyValid();
          return nativeGetHeight(mNativePicture);
      }
  
      /**
       * Indicates whether or not this Picture contains recorded commands that only work when
       * drawn to a hardware-accelerated canvas. If this returns true then this Picture can only
       * be drawn to another Picture or to a Canvas where canvas.isHardwareAccelerated() is true.
       *
       * Note this value is only updated after recording has finished by a call to
       * {@link #endRecording()}. Prior to that it will be the default value of false.
       *
       * @return true if the Picture can only be drawn to a hardware-accelerated canvas,
       *         false otherwise.
       */
      public boolean requiresHardwareAcceleration() {
          verifyValid();
          return mRequiresHwAcceleration;
      }
  
      /**
       * Draw this picture on the canvas.
       * <p>
       * Prior to {@link android.os.Build.VERSION_CODES#LOLLIPOP}, this call could
       * have the side effect of changing the matrix and clip of the canvas
       * if this picture had imbalanced saves/restores.
       *
       * <p>
       * <strong>Note:</strong> This forces the picture to internally call
       * {@link Picture#endRecording()} in order to prepare for playback.
       *
       * @param canvas  The picture is drawn to this canvas
       */
      public void draw(@NonNull Canvas canvas) {
          verifyValid();
          if (mRecordingCanvas != null) {
              endRecording();
          }
          if (mRequiresHwAcceleration && !canvas.isHardwareAccelerated()) {
              canvas.onHwBitmapInSwMode();
          }
          nativeDraw(canvas.getNativeCanvasWrapper(), mNativePicture);
      }
  
      /**
       * Create a new picture (already recorded) from the data in the stream. This
       * data was generated by a previous call to writeToStream(). Pictures that
       * have been persisted across device restarts are not guaranteed to decode
       * properly and are highly discouraged.
       *
       * @see #writeToStream(java.io.OutputStream)
       * @removed
       * @deprecated The recommended alternative is to not use writeToStream and
       * instead draw the picture into a Bitmap from which you can persist it as
       * raw or compressed pixels.
       */
      @Deprecated
      public static Picture createFromStream(@NonNull InputStream stream) {
          return new Picture(nativeCreateFromStream(stream, new byte[WORKING_STREAM_STORAGE]));
      }
  
      /**
       * Write the picture contents to a stream. The data can be used to recreate
       * the picture in this or another process by calling createFromStream(...)
       * The resulting stream is NOT to be persisted across device restarts as
       * there is no guarantee that the Picture can be successfully reconstructed.
       *
       * @see #createFromStream(java.io.InputStream)
       * @removed
       * @deprecated The recommended alternative is to draw the picture into a
       * Bitmap from which you can persist it as raw or compressed pixels.
       */
      @Deprecated
      public void writeToStream(@NonNull OutputStream stream) {
          verifyValid();
          // do explicit check before calling the native method
          if (stream == null) {
              throw new IllegalArgumentException("stream cannot be null");
          }
          if (!nativeWriteToStream(mNativePicture, stream, new byte[WORKING_STREAM_STORAGE])) {
              throw new RuntimeException();
          }
      }
  
      // return empty picture if src is 0, or a copy of the native src
      private static native long nativeConstructor(long nativeSrcOr0);
      private static native long nativeCreateFromStream(InputStream stream, byte[] storage);
      private static native int nativeGetWidth(long nativePicture);
      private static native int nativeGetHeight(long nativePicture);
      private static native long nativeBeginRecording(long nativeCanvas, int w, int h);
      private static native void nativeEndRecording(long nativeCanvas);
      private static native void nativeDraw(long nativeCanvas, long nativePicture);
      private static native boolean nativeWriteToStream(long nativePicture,
                                             OutputStream stream, byte[] storage);
      private static native void nativeDestructor(long nativePicture);
  
      private static class PictureCanvas extends Canvas {
          private final Picture mPicture;
          boolean mHoldsHwBitmap;
  
          public PictureCanvas(Picture pict, long nativeCanvas) {
              super(nativeCanvas);
              mPicture = pict;
              // Disable bitmap density scaling. This matches RecordingCanvas.
              mDensity = 0;
          }
  
          @Override
          public void setBitmap(Bitmap bitmap) {
              throw new RuntimeException("Cannot call setBitmap on a picture canvas");
          }
  
          @Override
          public void drawPicture(Picture picture) {
              if (mPicture == picture) {
                  throw new RuntimeException("Cannot draw a picture into its recording canvas");
              }
              super.drawPicture(picture);
          }
  
          @Override
          protected void onHwBitmapInSwMode() {
              mHoldsHwBitmap = true;
          }
      }
  }
  