content: /* Copyright (C) 2010 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.UnsupportedAppUsage;
  import android.content.res.AssetManager;
  import android.os.Build;
  
  import java.io.FileDescriptor;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * BitmapRegionDecoder can be used to decode a rectangle region from an image.
   * BitmapRegionDecoder is particularly useful when an original image is large and
   * you only need parts of the image.
   *
   * <p>To create a BitmapRegionDecoder, call newInstance(...).
   * Given a BitmapRegionDecoder, users can call decodeRegion() repeatedly
   * to get a decoded Bitmap of the specified region.
   *
   */
  public final class BitmapRegionDecoder {
      private long mNativeBitmapRegionDecoder;
      private boolean mRecycled;
      // ensures that the native decoder object exists and that only one decode can
      // occur at a time.
      private final Object mNativeLock = new Object();
  
      /**
       * Create a BitmapRegionDecoder from the specified byte array.
       * Currently only the JPEG and PNG formats are supported.
       *
       * @param data byte array of compressed image data.
       * @param offset offset into data for where the decoder should begin
       *               parsing.
       * @param length the number of bytes, beginning at offset, to parse
       * @param isShareable If this is true, then the BitmapRegionDecoder may keep a
       *                    shallow reference to the input. If this is false,
       *                    then the BitmapRegionDecoder will explicitly make a copy of the
       *                    input data, and keep that. Even if sharing is allowed,
       *                    the implementation may still decide to make a deep
       *                    copy of the input data. If an image is progressively encoded,
       *                    allowing sharing may degrade the decoding speed.
       * @return BitmapRegionDecoder, or null if the image data could not be decoded.
       * @throws IOException if the image format is not supported or can not be decoded.
       */
      public static BitmapRegionDecoder newInstance(byte[] data,
              int offset, int length, boolean isShareable) throws IOException {
          if ((offset | length) < 0 || data.length < offset + length) {
              throw new ArrayIndexOutOfBoundsException();
          }
          return nativeNewInstance(data, offset, length, isShareable);
      }
  
      /**
       * Create a BitmapRegionDecoder from the file descriptor.
       * The position within the descriptor will not be changed when
       * this returns, so the descriptor can be used again as is.
       * Currently only the JPEG and PNG formats are supported.
       *
       * @param fd The file descriptor containing the data to decode
       * @param isShareable If this is true, then the BitmapRegionDecoder may keep a
       *                    shallow reference to the input. If this is false,
       *                    then the BitmapRegionDecoder will explicitly make a copy of the
       *                    input data, and keep that. Even if sharing is allowed,
       *                    the implementation may still decide to make a deep
       *                    copy of the input data. If an image is progressively encoded,
       *                    allowing sharing may degrade the decoding speed.
       * @return BitmapRegionDecoder, or null if the image data could not be decoded.
       * @throws IOException if the image format is not supported or can not be decoded.
       */
      public static BitmapRegionDecoder newInstance(
              FileDescriptor fd, boolean isShareable) throws IOException {
          return nativeNewInstance(fd, isShareable);
      }
  
      /**
       * Create a BitmapRegionDecoder from an input stream.
       * The stream's position will be where ever it was after the encoded data
       * was read.
       * Currently only the JPEG and PNG formats are supported.
       *
       * @param is The input stream that holds the raw data to be decoded into a
       *           BitmapRegionDecoder.
       * @param isShareable If this is true, then the BitmapRegionDecoder may keep a
       *                    shallow reference to the input. If this is false,
       *                    then the BitmapRegionDecoder will explicitly make a copy of the
       *                    input data, and keep that. Even if sharing is allowed,
       *                    the implementation may still decide to make a deep
       *                    copy of the input data. If an image is progressively encoded,
       *                    allowing sharing may degrade the decoding speed.
       * @return BitmapRegionDecoder, or null if the image data could not be decoded.
       * @throws IOException if the image format is not supported or can not be decoded.
       *
       * <p class="note">Prior to {@link android.os.Build.VERSION_CODES#KITKAT},
       * if {@link InputStream#markSupported is.markSupported()} returns true,
       * <code>is.mark(1024)</code> would be called. As of
       * {@link android.os.Build.VERSION_CODES#KITKAT}, this is no longer the case.</p>
       */
      public static BitmapRegionDecoder newInstance(InputStream is,
              boolean isShareable) throws IOException {
          if (is instanceof AssetManager.AssetInputStream) {
              return nativeNewInstance(
                      ((AssetManager.AssetInputStream) is).getNativeAsset(),
                      isShareable);
          } else {
              // pass some temp storage down to the native code. 1024 is made up,
              // but should be large enough to avoid too many small calls back
              // into is.read(...).
              byte [] tempStorage = new byte[16 * 1024];
              return nativeNewInstance(is, tempStorage, isShareable);
          }
      }
  
      /**
       * Create a BitmapRegionDecoder from a file path.
       * Currently only the JPEG and PNG formats are supported.
       *
       * @param pathName complete path name for the file to be decoded.
       * @param isShareable If this is true, then the BitmapRegionDecoder may keep a
       *                    shallow reference to the input. If this is false,
       *                    then the BitmapRegionDecoder will explicitly make a copy of the
       *                    input data, and keep that. Even if sharing is allowed,
       *                    the implementation may still decide to make a deep
       *                    copy of the input data. If an image is progressively encoded,
       *                    allowing sharing may degrade the decoding speed.
       * @return BitmapRegionDecoder, or null if the image data could not be decoded.
       * @throws IOException if the image format is not supported or can not be decoded.
       */
      public static BitmapRegionDecoder newInstance(String pathName,
              boolean isShareable) throws IOException {
          BitmapRegionDecoder decoder = null;
          InputStream stream = null;
  
          try {
              stream = new FileInputStream(pathName);
              decoder = newInstance(stream, isShareable);
          } finally {
              if (stream != null) {
                  try {
                      stream.close();
                  } catch (IOException e) {
                      // do nothing here
                  }
              }
          }
          return decoder;
      }
  
      /*  Private constructor that must receive an already allocated native
          region decoder int (pointer).
  
          This can be called from JNI code.
      */
      @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
      private BitmapRegionDecoder(long decoder) {
          mNativeBitmapRegionDecoder = decoder;
          mRecycled = false;
      }
  
      /**
       * Decodes a rectangle region in the image specified by rect.
       *
       * @param rect The rectangle that specified the region to be decode.
       * @param options null-ok; Options that control downsampling.
       *             inPurgeable is not supported.
       * @return The decoded bitmap, or null if the image data could not be
       *         decoded.
       * @throws IllegalArgumentException if {@link BitmapFactory.Options#inPreferredConfig}
       *         is {@link android.graphics.Bitmap.Config#HARDWARE}
       *         and {@link BitmapFactory.Options#inMutable} is set, if the specified color space
       *         is not {@link ColorSpace.Model#RGB RGB}, or if the specified color space's transfer
       *         function is not an {@link ColorSpace.Rgb.TransferParameters ICC parametric curve}
       */
      public Bitmap decodeRegion(Rect rect, BitmapFactory.Options options) {
          BitmapFactory.Options.validate(options);
          synchronized (mNativeLock) {
              checkRecycled("decodeRegion called on recycled region decoder");
              if (rect.right <= 0 || rect.bottom <= 0 || rect.left >= getWidth()
                      || rect.top >= getHeight())
                  throw new IllegalArgumentException("rectangle is outside the image");
              return nativeDecodeRegion(mNativeBitmapRegionDecoder, rect.left, rect.top,
                      rect.right - rect.left, rect.bottom - rect.top, options,
                      BitmapFactory.Options.nativeInBitmap(options),
                      BitmapFactory.Options.nativeColorSpace(options));
          }
      }
  
      /** Returns the original image's width */
      public int getWidth() {
          synchronized (mNativeLock) {
              checkRecycled("getWidth called on recycled region decoder");
              return nativeGetWidth(mNativeBitmapRegionDecoder);
          }
      }
  
      /** Returns the original image's height */
      public int getHeight() {
          synchronized (mNativeLock) {
              checkRecycled("getHeight called on recycled region decoder");
              return nativeGetHeight(mNativeBitmapRegionDecoder);
          }
      }
  
      /**
       * Frees up the memory associated with this region decoder, and mark the
       * region decoder as "dead", meaning it will throw an exception if decodeRegion(),
       * getWidth() or getHeight() is called.
       *
       * <p>This operation cannot be reversed, so it should only be called if you are
       * sure there are no further uses for the region decoder. This is an advanced call,
       * and normally need not be called, since the normal GC process will free up this
       * memory when there are no more references to this region decoder.
       */
      public void recycle() {
          synchronized (mNativeLock) {
              if (!mRecycled) {
                  nativeClean(mNativeBitmapRegionDecoder);
                  mRecycled = true;
              }
          }
      }
  
      /**
       * Returns true if this region decoder has been recycled.
       * If so, then it is an error to try use its method.
       *
       * @return true if the region decoder has been recycled
       */
      public final boolean isRecycled() {
          return mRecycled;
      }
  
      /**
       * Called by methods that want to throw an exception if the region decoder
       * has already been recycled.
       */
      private void checkRecycled(String errorMessage) {
          if (mRecycled) {
              throw new IllegalStateException(errorMessage);
          }
      }
  
      @Override
      protected void finalize() throws Throwable {
          try {
              recycle();
          } finally {
              super.finalize();
          }
      }
  
      private static native Bitmap nativeDecodeRegion(long lbm,
              int start_x, int start_y, int width, int height,
              BitmapFactory.Options options, long inBitmapHandle,
              long colorSpaceHandle);
      private static native int nativeGetWidth(long lbm);
      private static native int nativeGetHeight(long lbm);
      private static native void nativeClean(long lbm);
  
      @UnsupportedAppUsage
      private static native BitmapRegionDecoder nativeNewInstance(
              byte[] data, int offset, int length, boolean isShareable);
      private static native BitmapRegionDecoder nativeNewInstance(
              FileDescriptor fd, boolean isShareable);
      private static native BitmapRegionDecoder nativeNewInstance(
              InputStream is, byte[] storage, boolean isShareable);
      private static native BitmapRegionDecoder nativeNewInstance(
              long asset, boolean isShareable);
  }
  