Android snippet: EXIF orientation to Bitmap transformation Matrix

ExifToMat.java

import android.graphics.Matrix;
import android.media.ExifInterface;

// Some reference: https://msdn.microsoft.com/library/windows/apps/windows.storage.fileproperties.photoorientation
public class ExifToMat {

    public static Matrix fromOrientation(final int pExifOrientation) {

        Matrix matrix = new Matrix();
        switch (pExifOrientation) {

            case ExifInterface.ORIENTATION_ROTATE_270: {

                matrix.postRotate(270);

                break;
            }

            case ExifInterface.ORIENTATION_ROTATE_180: {

                matrix.postRotate(180);

                break;
            }

            case ExifInterface.ORIENTATION_ROTATE_90: {

                matrix.postRotate(90);

                break;
            }

            case ExifInterface.ORIENTATION_FLIP_HORIZONTAL: {

                matrix.preScale(-1.0f, 1.0f);

                break;
            }

            case ExifInterface.ORIENTATION_FLIP_VERTICAL: {

                matrix.preScale(1.0f, -1.0f);

                break;
            }

            case ExifInterface.ORIENTATION_TRANSPOSE: {

                matrix.preRotate(-90);
                matrix.preScale(-1.0f, 1.0f);

                break;
            }

            case ExifInterface.ORIENTATION_TRANSVERSE: {

                matrix.preRotate(90);
                matrix.preScale(-1.0f, 1.0f);

                break;
            }

        }

        return matrix;
    }

    private ExifToMat() {}

}

Usage.java

// Usage

final File file = getJpegFile();

final Bitmap raw = BitmapFactory.decodeFile(file.getAbsolutePath());

Matrix matrix = null;

try {

    final ExifInterface exif = new ExifInterface(file.getAbsolutePath());

    final int exifOrientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);

    matrix = ExifToMat.fromOrientation(exifOrientation);

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

// At this point the matrix is the transformation matrix for image file with EXIF orientation attribute
// So you can create a correctly transformed Bitmap now
final Bitmap transformedBitmap = Bitmap.createBitmap(raw, 0, 0, raw.getWidth(), raw.getHeight(), matrix, true);