Bitmap b2 = Bitmap.createBitmap(
b1,
dx1 / 2,
dy1 / 2,
targetWidth,
targetHeight);

if (b2 != b1) {
if (recycle || b1 != source) {
b1.recycle();
}
}

return b2;
}

/**
* SizedThumbnailBitmap contains the bitmap, which is downsampled either from
* the thumbnail in exif or the full image.
* mThumbnailData, mThumbnailWidth and mThumbnailHeight are set together only if mThumbnail
* is not null.
*
* The width/height of the sized bitmap may be different from mThumbnailWidth/mThumbnailHeight.
*/
private static class SizedThumbnailBitmap {
public byte[] mThumbnailData;
public Bitmap mBitmap;
public int mThumbnailWidth;
public int mThumbnailHeight;
}

/**
* Creates a bitmap by either downsampling from the thumbnail in EXIF or the full image.
* The functions returns a SizedThumbnailBitmap,
* which contains a downsampled bitmap and the thumbnail data in EXIF if exists.
*/
private static void createThumbnailFromEXIF(String filePath, int targetSize,
int maxPixels, SizedThumbnailBitmap sizedThumbBitmap) {
if (filePath == null) return;

ExifInterface exif = null;
byte [] thumbData = null;
try {
exif = new ExifInterface(filePath);
if (exif != null) {
thumbData = exif.getThumbnail();
}
} catch (IOException ex) {
Log.w(TAG, ex);
}

BitmapFactory.Options fullOptions = new BitmapFactory.Options();
BitmapFactory.Options exifOptions = new BitmapFactory.Options();
int exifThumbWidth = 0;
int fullThumbWidth = 0;

// Compute exifThumbWidth.
if (thumbData != null) {
exifOptions.inJustDecodeBounds = true;
BitmapFactory.decodeByteArray(thumbData, 0, thumbData.length, exifOptions);
exifOptions.inSampleSize = computeSampleSize(exifOptions, targetSize, maxPixels);
exifThumbWidth = exifOptions.outWidth / exifOptions.inSampleSize;
}

// Compute fullThumbWidth.
fullOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filePath, fullOptions);
fullOptions.inSampleSize = computeSampleSize(fullOptions, targetSize, maxPixels);
fullThumbWidth = fullOptions.outWidth / fullOptions.inSampleSize;