public class ThumbnailUtils {
private static final String TAG = "ThumbnailUtils";

/* Maximum pixels size for created bitmap. */
private static final int MAX_NUM_PIXELS_THUMBNAIL = 512 * 384;
private static final int MAX_NUM_PIXELS_MICRO_THUMBNAIL = 128 * 128;
private static final int UNCONSTRAINED = -1;

/* Options used internally. */
private static final int OPTIONS_NONE = 0x0;
private static final int OPTIONS_SCALE_UP = 0x1;

/**
* Constant used to indicate we should recycle the input in
* {@link #extractThumbnail(Bitmap, int, int, int)} unless the output is the input.
*/
public static final int OPTIONS_RECYCLE_INPUT = 0x2;

/**
* Constant used to indicate the dimension of mini thumbnail.
* @hide Only used by media framework and media provider internally.
*/
public static final int TARGET_SIZE_MINI_THUMBNAIL = 320;

/**
* Constant used to indicate the dimension of micro thumbnail.
* @hide Only used by media framework and media provider internally.
*/
public static final int TARGET_SIZE_MICRO_THUMBNAIL = 96;

/**
* This method first examines if the thumbnail embedded in EXIF is bigger than our target
* size. If not, then it'll create a thumbnail from original image. Due to efficiency
* consideration, we want to let MediaThumbRequest avoid calling this method twice for
* both kinds, so it only requests for MICRO_KIND and set saveImage to true.
*
* This method always returns a "square thumbnail" for MICRO_KIND thumbnail.
*
* @param filePath the path of image file
* @param kind could be MINI_KIND or MICRO_KIND
* @return Bitmap
*
* @hide This method is only used by media framework and media provider internally.
*/
public static Bitmap createImageThumbnail(String filePath, int kind) {
boolean wantMini = (kind == Images.Thumbnails.MINI_KIND);
int targetSize = wantMini
TARGET_SIZE_MINI_THUMBNAIL
: TARGET_SIZE_MICRO_THUMBNAIL;
int maxPixels = wantMini
MAX_NUM_PIXELS_THUMBNAIL
: MAX_NUM_PIXELS_MICRO_THUMBNAIL;
SizedThumbnailBitmap sizedThumbnailBitmap = new SizedThumbnailBitmap();
Bitmap bitmap = null;
MediaFileType fileType = MediaFile.getFileType(filePath);
if (fileType != null && fileType.fileType == MediaFile.FILE_TYPE_JPEG) {
createThumbnailFromEXIF(filePath, targetSize, maxPixels, sizedThumbnailBitmap);
bitmap = sizedThumbnailBitmap.mBitmap;
}

if (bitmap == null) {
try {
FileDescriptor fd = new FileInputStream(filePath).getFD();
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 1;
options.inJustDecodeBounds = true;
BitmapFactory.decodeFileDescriptor(fd, null, options);
if (options.mCancel || options.outWidth == -1
|| options.outHeight == -1) {
return null;
}
options.inSampleSize = computeSampleSize(
options, targetSize, maxPixels);
options.inJustDecodeBounds = false;