Android: Bitmaps loaded from gallery are rotated in ImageView

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When I load an image from the media gallery into a Bitmap, everything is working fine, except that pictures that were shot with the camera while holding the phone vertically, are rotated so that I always get a horizontal picture even though it appears vertical in the gallery. Why is that and how can I load it correctly?

19 Answers

Kotlin code:

if (file.exists()){
    val bitmap = BitmapFactory.decodeFile(file.absolutePath)

    val exif = ExifInterface(file.absoluteFile.toString())
    val orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL)
    val matrix = Matrix()

    when(orientation){
        ExifInterface.ORIENTATION_ROTATE_90 -> matrix.postRotate(90F)
        ExifInterface.ORIENTATION_ROTATE_180 -> matrix.postRotate(180F)
        ExifInterface.ORIENTATION_ROTATE_270 -> matrix.postRotate(270F)
    }

    val rotatedBitmap = Bitmap.createBitmap(bitmap, 0,0 , bitmap.width, bitmap.height, matrix, true)
    bitmap.recycle()
    iv_capture.setImageBitmap(rotatedBitmap)
}

The methods below scales AND rotates the bitmap according to the orientation:

public Bitmap scaleAndRotateImage(String path, int orientation, final int targetWidth, final int targetHeight)
{
    Bitmap bitmap = null;

    try
    {
        // Check the dimensions of the Image
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(path, options);

        // Adjust the Width and Height
        int sourceWidth, sourceHeight;
        if (orientation == 90 || orientation == 270)
        {
            sourceWidth = options.outHeight;
            sourceHeight = options.outWidth;
        }
        else
        {
            sourceWidth = options.outWidth;
            sourceHeight = options.outHeight;
        }

        // Calculate the maximum required scaling ratio if required and load the bitmap
        if (sourceWidth > targetWidth || sourceHeight > targetHeight)
        {
            float widthRatio = (float)sourceWidth / (float)targetWidth;
            float heightRatio = (float)sourceHeight / (float)targetHeight;
            float maxRatio = Math.max(widthRatio, heightRatio);
            options.inJustDecodeBounds = false;
            options.inSampleSize = (int)maxRatio;
            bitmap = BitmapFactory.decodeFile(path, options);
        }
        else
        {
            bitmap = BitmapFactory.decodeFile(path);
        }

        // We need to rotate the bitmap (if required)
        int orientationInDegrees = exifToDegrees(orientation);
        if (orientation > 0)
        {
            Matrix matrix = new Matrix();
            if (orientation != 0f)
            {
                matrix.preRotate(orientationInDegrees);
            };

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

        // Re-scale the bitmap if necessary
        sourceWidth = bitmap.getWidth();
        sourceHeight = bitmap.getHeight();

        if (sourceWidth != targetWidth || sourceHeight != targetHeight)
        {
            float widthRatio = (float)sourceWidth / (float)targetWidth;
            float heightRatio = (float)sourceHeight / (float)targetHeight;
            float maxRatio = Math.max(widthRatio, heightRatio);
            sourceWidth = (int)((float)sourceWidth / maxRatio);
            sourceHeight = (int)((float)sourceHeight / maxRatio);
            bitmap = Bitmap.createScaledBitmap(bitmap, sourceWidth, sourceHeight, true);
        }
    }
    catch (Exception e)
    {
        Logger.d("Could not rotate the image");
        Logger.d(e.getMessage());
    }
    return bitmap;
}

Example:

public void getPictureFromDevice(Uri Uri,ImageView imageView)
{
    try
    {
        ExifInterface exifInterface = new ExifInterface(Uri.getPath());
        int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);

        Bitmap bitmap = scaleAndRotateImage(Uri.getPath(), orientation, imageView.getWidth(), imageView.getHeight());
        imageView.setImageBitmap(bitmap);
    }
    catch (OutOfMemoryError outOfMemoryError)
    {
        Logger.d(outOfMemoryError.getLocalizedMessage());
        Logger.d("Failed to load image from filePath (out of memory)");
        Logger.d(Uri.toString());
    }
    catch (Exception e)
    {
        Logger.d("Failed to load image from filePath");
        Logger.d(Uri.toString());
    }
}

Use the following code to rotate an image correctly:

private Bitmap rotateImage(Bitmap bitmap, String filePath)
{
    Bitmap resultBitmap = bitmap;

    try
    {
        ExifInterface exifInterface = new ExifInterface(filePath);
        int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);

        Matrix matrix = new Matrix();

        if (orientation == ExifInterface.ORIENTATION_ROTATE_90)
        {
            matrix.postRotate(ExifInterface.ORIENTATION_ROTATE_90);
        }
        else if (orientation == ExifInterface.ORIENTATION_ROTATE_180)
        {
            matrix.postRotate(ExifInterface.ORIENTATION_ROTATE_180);
        }
        else if (orientation == ExifInterface.ORIENTATION_ROTATE_270)
        {
            matrix.postRotate(ExifInterface.ORIENTATION_ROTATE_270);
        }

        // Rotate the bitmap
        resultBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
    }
    catch (Exception exception)
    {
        Logger.d("Could not rotate the image");
    }
    return resultBitmap;
}

I solved the problem with the following workaround. Note that I am also scaling the image, which was necessary to avoid OutOfMemoryExceptions.

Beware that this solution will not work properly with portrait images or opside-down images (thank you Timmmm for noting). Timmmm's solution above might be the better choice if that is required and it looks more elegant, too: https://stackoverflow.com/a/8914291/449918

File path = // ... location of your bitmap file
int w = 512; int h = 384; // size that does not lead to OutOfMemoryException on Nexus One
Bitmap b = BitmapFactory.decodeFile(path);


// Hack to determine whether the image is rotated
boolean rotated = b.getWidth() > b.getHeight();

Bitmap resultBmp = null;

// If not rotated, just scale it
if (!rotated) {
    resultBmp = Bitmap.createScaledBitmap(b, w, h, true);
    b.recycle();
    b = null;

// If rotated, scale it by switching width and height and then rotated it
} else {
    Bitmap scaledBmp = Bitmap.createScaledBitmap(b, h, w, true);
    b.recycle();
    b = null;

    Matrix mat = new Matrix();
    mat.postRotate(90);
    resultBmp = Bitmap.createBitmap(scaledBmp, 0, 0, h, w, mat, true);

    // Release image resources
    scaledBmp.recycle();
    scaledBmp = null;
}

// resultBmp now contains the scaled and rotated image

Cheers

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