Java Code Examples for android.graphics.BitmapRegionDecoder#decodeRegion()

/**
 * Reads and crops the bitmap.
 * @param outOptions Bitmap options, useful to determine {@code outMimeType}.
 */
private Bitmap crop(BitmapFactory.Options outOptions) throws IOException {
  InputStream inputStream = openBitmapInputStream();
  // Effeciently crops image without loading full resolution into memory
  // https://developer.android.com/reference/android/graphics/BitmapRegionDecoder.html
  BitmapRegionDecoder decoder = BitmapRegionDecoder.newInstance(inputStream, false);
  try {
    Rect rect = new Rect(mX, mY, mX + mWidth, mY + mHeight);
    return decoder.decodeRegion(rect, outOptions);
  } finally {
    if (inputStream != null) {
      inputStream.close();
    }
    decoder.recycle();
  }
}
 

/**
 * Reads and crops the bitmap.
 * @param outOptions Bitmap options, useful to determine {@code outMimeType}.
 */
private Bitmap crop(BitmapFactory.Options outOptions) throws IOException {
  InputStream inputStream = openBitmapInputStream();
  // Effeciently crops image without loading full resolution into memory
  // https://developer.android.com/reference/android/graphics/BitmapRegionDecoder.html
  BitmapRegionDecoder decoder = BitmapRegionDecoder.newInstance(inputStream, false);
  try {
    Rect rect = new Rect(mX, mY, mX + mWidth, mY + mHeight);
    return decoder.decodeRegion(rect, outOptions);
  } finally {
    if (inputStream != null) {
      inputStream.close();
    }
    decoder.recycle();
  }
}
 

private Bitmap readBitmap (final int scalePercentage, final Rect cropRect) throws IOException {
	if (100 % scalePercentage != 0) throw new IllegalArgumentException("scalePercentage " + scalePercentage + " is not a int ratio.");
	final Options opts = new Options();
	opts.inPurgeable = true;
	opts.inInputShareable = true;
	opts.inSampleSize = 100 / scalePercentage;

	if (cropRect != null) {
		final BitmapRegionDecoder dec = BitmapRegionDecoder.newInstance(openFileDescriptor().getFileDescriptor(), true);
		try {
			return dec.decodeRegion(cropRect, opts);
		}
		finally {
			dec.recycle();
		}
	}

	return BitmapFactory.decodeFileDescriptor(openFileDescriptor().getFileDescriptor(), null, opts);
}
 

private static byte[] transformByteArray(@NonNull byte[] data, @Nullable Rect cropRect, int rotation, boolean flip) throws IOException {
  Stopwatch stopwatch = new Stopwatch("transform");
  Bitmap in;

  if (cropRect != null) {
    BitmapRegionDecoder decoder = BitmapRegionDecoder.newInstance(data, 0, data.length, false);
    in = decoder.decodeRegion(cropRect, new BitmapFactory.Options());
    decoder.recycle();
    stopwatch.split("crop");
  } else {
    in = BitmapFactory.decodeByteArray(data, 0, data.length);
  }

  Bitmap out = in;

  if (rotation != 0 || flip) {
    Matrix matrix = new Matrix();
    matrix.postRotate(rotation);

    if (flip) {
      matrix.postScale(-1, 1);
      matrix.postTranslate(in.getWidth(), 0);
    }

    out = Bitmap.createBitmap(in, 0, 0, in.getWidth(), in.getHeight(), matrix, true);
  }

  byte[] transformedData = toJpegBytes(out);
  stopwatch.split("transcode");

  in.recycle();
  out.recycle();

  stopwatch.stop(TAG);

  return transformedData;
}
 

@Override
protected Bitmap doInBackground (final Void... params) {
	LOG.i("Generating preview: s=%s q=%s.", this.dlg.getScale(), this.dlg.getQuality());
	try {
		final Bitmap scaled = this.srcMetadata.getBitmap(this.dlg.getScale().getPercentage());
		final ByteArrayOutputStream compOut = new ByteArrayOutputStream(512 * 1024);
		if (scaled.compress(Bitmap.CompressFormat.JPEG, this.dlg.getQuality().getPercentage(), compOut)) {
			this.summary
					.append(this.srcMetadata.getWidth()).append(" x ").append(this.srcMetadata.getHeight())
					.append(" (").append(IoHelper.readableFileSize(this.srcMetadata.getSize())).append(")")
					.append(" --> ").append(scaled.getWidth()).append(" x ").append(scaled.getHeight())
					.append(" (").append(IoHelper.readableFileSize(compOut.size())).append(")");
			final BitmapRegionDecoder dec = BitmapRegionDecoder.newInstance(compOut.toBufferedInputStream(), true);
			try {
				final int srcW = dec.getWidth();
				final int srcH = dec.getHeight();
				final int tgtW = this.dlg.getRootView().getWidth(); // FIXME Workaround for ImageView width issue.  Fix properly with something like FixedWidthImageView.
				final int tgtH = this.imgPreview.getHeight();
				final int left = srcW > tgtW ? (srcW - tgtW) / 2 : 0;
				final int top = srcH > tgtH ? (srcH - tgtH) / 2 : 0;
				final BitmapFactory.Options options = new BitmapFactory.Options();
				options.inPurgeable = true;
				options.inInputShareable = true;
				return dec.decodeRegion(new Rect(left, top, left + tgtW, top + tgtH), options);
			}
			finally {
				dec.recycle();
			}
		}
		this.summary.append("Failed to compress image."); //ES
		return null;
	}
	// XXX Many cases of OutOfMemoryError have been reported, particularly on low end hardware.
	// Try not to upset the user too much by not dying completely if possible.
	catch (final Throwable e) {
		LOG.e("Failed to generate preview image.", e);
		this.summary.append(e.toString());
		return null;
	}
}
 

@Override
protected Bitmap doInBackground(Void... params) {
    try {
        if (decoderRef != null && tileRef != null && viewRef != null) {
            final BitmapRegionDecoder decoder = decoderRef.get();
            final Object decoderLock = decoderLockRef.get();
            final Tile tile = tileRef.get();
            final SubsamplingScaleImageView view = viewRef.get();
            if (decoder != null && decoderLock != null && tile != null && view != null && !decoder.isRecycled()) {
                synchronized (decoderLock) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inSampleSize = tile.sampleSize;
                    options.inPreferredConfig = Config.RGB_565;
                    options.inDither = true;
                    Bitmap bitmap = decoder.decodeRegion(view.fileSRect(tile.sRect), options);
                    int rotation = view.getRequiredRotation();
                    if (rotation != 0) {
                        Matrix matrix = new Matrix();
                        matrix.postRotate(rotation);
                        bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
                    }
                    return bitmap;
                }
            } else if (tile != null) {
                tile.loading = false;
            }
        }
    } catch (Exception e) {
        Log.e(TAG, "Failed to decode tile", e);
    }
    return null;
}
 

/**
 * Acquire a read lock to prevent decoding overlapping with recycling, then check the pool still
 * exists and acquire a decoder to load the requested region. There is no check whether the pool
 * currently has decoders, because it's guaranteed to have one decoder after {@link #init(Context, Uri)}
 * is called and be null once {@link #recycle()} is called. In practice the view can't call this
 * method until after {@link #init(Context, Uri)}, so there will be no blocking on an empty pool.
 */
@Override
@NonNull
public Bitmap decodeRegion(@NonNull Rect sRect, int sampleSize) {
    debug("Decode region " + sRect + " on thread " + Thread.currentThread().getName());
    if (sRect.width() < imageDimensions.x || sRect.height() < imageDimensions.y) {
        lazyInit();
    }
    decoderLock.readLock().lock();
    try {
        if (decoderPool != null) {
            BitmapRegionDecoder decoder = decoderPool.acquire();
            try {
                // Decoder can't be null or recycled in practice
                if (decoder != null && !decoder.isRecycled()) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inSampleSize = sampleSize;
                    options.inPreferredConfig = bitmapConfig;
                    Bitmap bitmap = decoder.decodeRegion(sRect, options);
                    if (bitmap == null) {
                        throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported");
                    }
                    return bitmap;
                }
            } finally {
                if (decoder != null) {
                    decoderPool.release(decoder);
                }
            }
        }
        throw new IllegalStateException("Cannot decode region after decoder has been recycled");
    } finally {
        decoderLock.readLock().unlock();
    }
}
 

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_large_image_view);

    mImageView = (ImageView) findViewById(R.id.id_imageview);
    try
    {
        InputStream inputStream = getAssets().open("tangyan.jpg");

        //获得图片的宽、高
        BitmapFactory.Options tmpOptions = new BitmapFactory.Options();
        tmpOptions.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(inputStream, null, tmpOptions);
        int width = tmpOptions.outWidth;
        int height = tmpOptions.outHeight;

        //设置显示图片的中心区域
        BitmapRegionDecoder bitmapRegionDecoder = BitmapRegionDecoder.newInstance(inputStream, false);
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inPreferredConfig = Bitmap.Config.RGB_565;
        Bitmap bitmap = bitmapRegionDecoder.decodeRegion(new Rect(width / 2 - 100, height / 2 - 100, width / 2 + 100, height / 2 + 100), options);
        mImageView.setImageBitmap(bitmap);


    } catch (IOException e)
    {
        e.printStackTrace();
    }


}
 

/**
 * Acquire a read lock to prevent decoding overlapping with recycling, then check the pool still
 * exists and acquire a decoder to load the requested region. There is no check whether the pool
 * currently has decoders, because it's guaranteed to have one decoder after {@link #init(Context, Uri)}
 * is called and be null once {@link #recycle()} is called. In practice the view can't call this
 * method until after {@link #init(Context, Uri)}, so there will be no blocking on an empty pool.
 */
@Override
@NonNull
public Bitmap decodeRegion(@NonNull Rect sRect, int sampleSize) {
    debug("Decode region " + sRect + " on thread " + Thread.currentThread().getName());
    if (sRect.width() < imageDimensions.x || sRect.height() < imageDimensions.y) {
        lazyInit();
    }
    decoderLock.readLock().lock();
    try {
        if (decoderPool != null) {
            BitmapRegionDecoder decoder = decoderPool.acquire();
            try {
                // Decoder can't be null or recycled in practice
                if (decoder != null && !decoder.isRecycled()) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inSampleSize = sampleSize;
                    options.inPreferredConfig = bitmapConfig;
                    // If that is not set, some PNGs are read with a ColorSpace of code "Unknown" (-1),
                    // which makes resizing buggy (generates a black picture)
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
                        options.inPreferredColorSpace = ColorSpace.get(ColorSpace.Named.SRGB);

                    Bitmap bitmap = decoder.decodeRegion(sRect, options);
                    if (bitmap == null) {
                        throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported");
                    }
                    return bitmap;
                }
            } finally {
                if (decoder != null) {
                    decoderPool.release(decoder);
                }
            }
        }
        throw new IllegalStateException("Cannot decode region after decoder has been recycled");
    } finally {
        decoderLock.readLock().unlock();
    }
}
 

private Bitmap readBitmapInternal(BitmapFactory.Options options, boolean mayUseRegionDecoder,
		boolean mayUseWebViewDecoder) {
	ImageData imageData = getImageData();
	if (imageData.type == ImageType.NOT_IMAGE) {
		return null;
	}
	if (imageData.type != ImageType.IMAGE_SVG) {
		Bitmap bitmap = readBitmapSimple(options);
		if (bitmap != null) {
			return bitmap;
		}
		if (mayUseRegionDecoder && isRegionDecoderSupported()) {
			InputStream input = null;
			BitmapRegionDecoder decoder = null;
			try {
				input = openInputStream();
				decoder = BitmapRegionDecoder.newInstance(input, false);
				return decoder.decodeRegion(new Rect(0, 0, decoder.getWidth(), decoder.getHeight()), options);
			} catch (IOException e) {
				Log.persistent().stack(e);
			} finally {
				IOUtils.close(input);
				if (decoder != null) {
					decoder.recycle();
				}
			}
		}
	}
	if (mayUseWebViewDecoder) {
		return WebViewBitmapDecoder.loadBitmap(this, options);
	}
	return null;
}
 

@Override
@NonNull
public Bitmap decodeRegion(@NonNull Rect sRect, int sampleSize) {
    debug("Decode region " + sRect + " on thread " + Thread.currentThread().getName());
    if (sRect.width() < imageDimensions.x || sRect.height() < imageDimensions.y) {
        lazyInit();
    }
    decoderLock.readLock().lock();
    try {
        if (decoderPool != null) {
            BitmapRegionDecoder decoder = decoderPool.acquire();
            try {
                // Decoder can't be null or recycled in practice
                if (decoder != null && !decoder.isRecycled()) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inSampleSize = sampleSize;
                    options.inPreferredConfig = bitmapConfig;
                    Bitmap bitmap = decoder.decodeRegion(sRect, options);
                    if (bitmap == null) {
                        throw new RuntimeException(
                                "null bitmap - image format may not be supported");
                    }
                    return bitmap;
                }
            } finally {
                if (decoder != null) {
                    decoderPool.release(decoder);
                }
            }
        }
        throw new IllegalStateException("Cannot decode region after decoder has been recycled");
    } finally {
        decoderLock.readLock().unlock();
    }
}
 

/**
 * Acquire a read lock to prevent decoding overlapping with recycling, then check the pool still
 * exists and acquire a decoder to load the requested region. There is no check whether the pool
 * currently has decoders, because it's guaranteed to have one decoder after {@link #init(Context, Uri)}
 * is called and be null once {@link #recycle()} is called. In practice the view can't call this
 * method until after {@link #init(Context, Uri)}, so there will be no blocking on an empty pool.
 */
@Override
public Bitmap decodeRegion(Rect sRect, int sampleSize) {
    debug("Decode region " + sRect + " on thread " + Thread.currentThread().getName());
    if (sRect.width() < imageDimensions.x || sRect.height() < imageDimensions.y) {
        lazyInit();
    }
    decoderLock.readLock().lock();
    try {
        if (decoderPool != null) {
            BitmapRegionDecoder decoder = decoderPool.acquire();
            try {
                // Decoder can't be null or recycled in practice
                if (decoder != null && !decoder.isRecycled()) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inSampleSize = sampleSize;
                    options.inPreferredConfig = bitmapConfig;
                    Bitmap bitmap = decoder.decodeRegion(sRect, options);
                    if (bitmap == null) {
                        throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported");
                    }
                    return bitmap;
                }
            } finally {
                if (decoder != null) {
                    decoderPool.release(decoder);
                }
            }
        }
        throw new IllegalStateException("Cannot decode region after decoder has been recycled");
    } finally {
        decoderLock.readLock().unlock();
    }
}
 

public static Bitmap loadBitmapRegion(Path path,int sampleSize,Rect regionRect) throws IOException
{
	BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = sampleSize;
    InputStream data = path.getFile().getInputStream();
	try
	{
		if(Build.VERSION.SDK_INT>= Build.VERSION_CODES.GINGERBREAD_MR1)
		{
			BitmapRegionDecoder decoder = BitmapRegionDecoder.newInstance(data, true);
			try
			{
				return decoder.decodeRegion(regionRect, options);
			}
			finally
			{
				decoder.recycle();
			}
		}
		else
			return BitmapFactory.decodeStream(data, null, options);
	}
	finally
	{
		data.close();
	}
}
 

@TargetApi(Build.VERSION_CODES.N)
private Palette getStatusBarPalette() {
    WallpaperManager wallpaperManager = WallpaperManager.getInstance(this);
    int statusBarHeight = getResources()
            .getDimensionPixelSize(R.dimen.status_bar_height);

    if (AndroidVersion.isAtLeastNougat) {
        try (ParcelFileDescriptor fd = wallpaperManager
                .getWallpaperFile(WallpaperManager.FLAG_SYSTEM)) {
            BitmapRegionDecoder decoder = BitmapRegionDecoder
                    .newInstance(fd.getFileDescriptor(), false);
            Rect decodeRegion = new Rect(0, 0,
                    decoder.getWidth(), statusBarHeight);
            Bitmap bitmap = decoder.decodeRegion(decodeRegion, null);
            decoder.recycle();
            if (bitmap != null) {
                return Palette.from(bitmap).clearFilters().generate();
            }
        } catch (IOException | NullPointerException e) {
            e.printStackTrace();
        }
    }

    Bitmap wallpaper = ((BitmapDrawable) wallpaperManager.getDrawable()).getBitmap();
    return Palette.from(wallpaper)
            .setRegion(0, 0, wallpaper.getWidth(), statusBarHeight)
            .clearFilters()
            .generate();
}
 

/**
 * Acquire a read lock to prevent decoding overlapping with recycling, then check the pool still
 * exists and acquire a decoder to load the requested region. There is no check whether the pool
 * currently has decoders, because it's guaranteed to have one decoder after {@link #init(Context, Uri)}
 * is called and be null once {@link #recycle()} is called. In practice the view can't call this
 * method until after {@link #init(Context, Uri)}, so there will be no blocking on an empty pool.
 */
@Override
@NonNull
public Bitmap decodeRegion(@NonNull Rect sRect, int sampleSize) {
    debug("Decode region " + sRect + " on thread " + Thread.currentThread().getName());
    if (sRect.width() < imageDimensions.x || sRect.height() < imageDimensions.y) {
        lazyInit();
    }
    decoderLock.readLock().lock();
    try {
        if (decoderPool != null) {
            BitmapRegionDecoder decoder = decoderPool.acquire();
            try {
                // Decoder can't be null or recycled in practice
                if (decoder != null && !decoder.isRecycled()) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inSampleSize = sampleSize;
                    options.inPreferredConfig = bitmapConfig;
                    Bitmap bitmap = decoder.decodeRegion(sRect, options);
                    if (bitmap == null) {
                        throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported");
                    }
                    return bitmap;
                }
            } finally {
                if (decoder != null) {
                    decoderPool.release(decoder);
                }
            }
        }
        throw new IllegalStateException("Cannot decode region after decoder has been recycled");
    } finally {
        decoderLock.readLock().unlock();
    }
}
 

/**
 * Acquire a read lock to prevent decoding overlapping with recycling, then check the pool still
 * exists and acquire a decoder to load the requested region. There is no check whether the pool
 * currently has decoders, because it's guaranteed to have one decoder after {@link #init(Context, Uri)}
 * is called and be null once {@link #recycle()} is called. In practice the view can't call this
 * method until after {@link #init(Context, Uri)}, so there will be no blocking on an empty pool.
 */
@Override
@NonNull
public Bitmap decodeRegion(@NonNull Rect sRect, int sampleSize) {
    debug("Decode region " + sRect + " on thread " + Thread.currentThread().getName());
    if (sRect.width() < imageDimensions.x || sRect.height() < imageDimensions.y) {
        lazyInit();
    }
    decoderLock.readLock().lock();
    try {
        if (decoderPool != null) {
            BitmapRegionDecoder decoder = decoderPool.acquire();
            try {
                // Decoder can't be null or recycled in practice
                if (decoder != null && !decoder.isRecycled()) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inSampleSize = sampleSize;
                    options.inPreferredConfig = bitmapConfig;
                    Bitmap bitmap = decoder.decodeRegion(sRect, options);
                    if (bitmap == null) {
                        throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported");
                    }
                    return bitmap;
                }
            } finally {
                if (decoder != null) {
                    decoderPool.release(decoder);
                }
            }
        }
        throw new IllegalStateException("Cannot decode region after decoder has been recycled");
    } finally {
        decoderLock.readLock().unlock();
    }
}
 

/**
 * Acquire a read lock to prevent decoding overlapping with recycling, then check the pool still
 * exists and acquire a decoder to load the requested region. There is no check whether the pool
 * currently has decoders, because it's guaranteed to have one decoder after {@link #init(Context, Uri)}
 * is called and be null once {@link #recycle()} is called. In practice the view can't call this
 * method until after {@link #init(Context, Uri)}, so there will be no blocking on an empty pool.
 */
@Override
@NonNull
public Bitmap decodeRegion(@NonNull Rect sRect, int sampleSize) {
    debug("Decode region " + sRect + " on thread " + Thread.currentThread().getName());
    if (sRect.width() < imageDimensions.x || sRect.height() < imageDimensions.y) {
        lazyInit();
    }
    decoderLock.readLock().lock();
    try {
        if (decoderPool != null) {
            BitmapRegionDecoder decoder = decoderPool.acquire();
            try {
                // Decoder can't be null or recycled in practice
                if (decoder != null && !decoder.isRecycled()) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inSampleSize = sampleSize;
                    options.inPreferredConfig = bitmapConfig;
                    Bitmap bitmap = decoder.decodeRegion(sRect, options);
                    if (bitmap == null) {
                        throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported");
                    }
                    return bitmap;
                }
            } finally {
                if (decoder != null) {
                    decoderPool.release(decoder);
                }
            }
        }
        throw new IllegalStateException("Cannot decode region after decoder has been recycled");
    } finally {
        decoderLock.readLock().unlock();
    }
}
 

private Bitmap createClippedBitmap() {
    if (mSampleSize <= 1) {
        return mClipImageView.clip();
    }

    // 获取缩放位移后的矩阵值
    final float[] matrixValues = mClipImageView.getClipMatrixValues();
    final float scale = matrixValues[Matrix.MSCALE_X];
    final float transX = matrixValues[Matrix.MTRANS_X];
    final float transY = matrixValues[Matrix.MTRANS_Y];

    // 获取在显示的图片中裁剪的位置
    final Rect border = mClipImageView.getClipBorder();
    final float cropX = ((-transX + border.left) / scale) * mSampleSize;
    final float cropY = ((-transY + border.top) / scale) * mSampleSize;
    final float cropWidth = (border.width() / scale) * mSampleSize;
    final float cropHeight = (border.height() / scale) * mSampleSize;

    // 获取在旋转之前的裁剪位置
    final RectF srcRect = new RectF(cropX, cropY, cropX + cropWidth, cropY + cropHeight);
    final Rect clipRect = getRealRect(srcRect);

    final BitmapFactory.Options ops = new BitmapFactory.Options();
    final Matrix outputMatrix = new Matrix();

    outputMatrix.setRotate(mDegree);
    // 如果裁剪之后的图片宽高仍然太大,则进行缩小
    if (mMaxWidth > 0 && cropWidth > mMaxWidth) {
        ops.inSampleSize = findBestSample((int) cropWidth, mMaxWidth);

        final float outputScale = mMaxWidth / (cropWidth / ops.inSampleSize);
        outputMatrix.postScale(outputScale, outputScale);
    }

    // 裁剪
    BitmapRegionDecoder decoder = null;
    try {
        decoder = BitmapRegionDecoder.newInstance(mInput, false);
        final Bitmap source = decoder.decodeRegion(clipRect, ops);
        recycleImageViewBitmap();
        return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), outputMatrix, false);
    } catch (Exception e) {
        return mClipImageView.clip();
    } finally {
        if (decoder != null && !decoder.isRecycled()) {
            decoder.recycle();
        }
    }
}
 

/**
 * Takes an inputstream, loads a bitmap optimized of space and then crops it for the view.
 * @param iStream Inputstream to the image.
 * @param containerHeight Height of the image holder container. 
 * @param containerWidth Width of the image holder container.
 * @return Cropped/masked bitmap.
 */
public static Bitmap loadMaskedBitmap(InputStream iStream, int containerHeight, int containerWidth){
	
	// Load image data before loading the image itself.
	BitmapFactory.Options bmOptions = new BitmapFactory.Options();
	bmOptions.inJustDecodeBounds = true;
	
	BitmapFactory.decodeStream(iStream,null,bmOptions);
	
	int photoH = bmOptions.outHeight;
	int photoW = bmOptions.outWidth;
	
	// Find a suitable scalefactor to load the smaller bitmap, and then set the options.
	int scaleFactor = Math.min(photoH/containerHeight, photoW/containerHeight);
	bmOptions.inJustDecodeBounds = false;
	bmOptions.inSampleSize = scaleFactor;
	bmOptions.inPurgeable = true;

	// Load the square region out of the bitmap.
	Bitmap bmap=null;
	BitmapRegionDecoder decoder;
	try {
		iStream.reset();
		decoder = BitmapRegionDecoder.newInstance(iStream, false);
		bmap = decoder.decodeRegion(new Rect(0, 0, Math.min(photoH, photoW), Math.min(photoH, photoW)),bmOptions);
	} catch (IOException e) {
		e.printStackTrace();
	}
	
	// Calculate new width of the bitmap based on the width of the container
	int bitmapNewWidth = (bmap.getWidth()*containerWidth)/containerHeight;   
	
	// Produce clipping mask on the canvas and draw the bitmap 
	Bitmap targetBitmap = Bitmap.createBitmap(bitmapNewWidth, bmap.getHeight(), bmap.getConfig());
	Canvas canvas = new Canvas(targetBitmap);
	Path path = new Path();
	path.addCircle(bmap.getWidth() / 2, bmap.getHeight() / 2, bmap.getWidth() / 2, Path.Direction.CCW);
	canvas.clipPath(path);
	canvas.drawBitmap(bmap, 0, 0, null);

	// Retrieve the clipped bitmap and return
	return targetBitmap;
}
 

private Bitmap createClippedBitmap() {
    //if (mSampleSize <= 1) {
    // TODO has problem, this method is not useful on some picture
    //    return mClipImageView.clip();
    //}

    final float[] matrixValues = mClipImageView.getClipMatrixValues();
    final float scale = matrixValues[Matrix.MSCALE_X];
    final float transX = matrixValues[Matrix.MTRANS_X];
    final float transY = matrixValues[Matrix.MTRANS_Y];

    final Rect border = mClipImageView.getClipBorder();
    final float cropX = ((-transX + border.left) / scale) * mSampleSize;
    final float cropY = ((-transY + border.top) / scale) * mSampleSize;
    final float cropWidth = (border.width() / scale) * mSampleSize;
    final float cropHeight = (border.height() / scale) * mSampleSize;

    final RectF srcRect = new RectF(cropX, cropY, cropX + cropWidth, cropY + cropHeight);
    final Rect clipRect = getRealRect(srcRect);

    final BitmapFactory.Options ops = new BitmapFactory.Options();
    final Matrix outputMatrix = new Matrix();

    outputMatrix.setRotate(mDegree);
    if (mMaxWidth > 0 && cropWidth > mMaxWidth) {
        ops.inSampleSize = findBestSample((int) cropWidth, mMaxWidth);

        final float outputScale = mMaxWidth / (cropWidth / ops.inSampleSize);
        outputMatrix.postScale(outputScale, outputScale);
    }

    BitmapRegionDecoder decoder = null;
    try {
        decoder = BitmapRegionDecoder.newInstance(mInput, false);
        final Bitmap source = decoder.decodeRegion(clipRect, ops);
        recycleImageViewBitmap();
        return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(),
            outputMatrix, false);
    } catch (Exception e) {
        return mClipImageView.clip();
    } finally {
        if (decoder != null && !decoder.isRecycled()) {
            decoder.recycle();
        }
    }
}