Glide shadow transformation

gistfile1.txt

/**
 * Quick and hacky way, tested under SDK19 and newer.
 * How to use (key: in conjunction with CircleCrop):
 * <code>transform(new CircleCrop(), new CircleShadowTransformation())</code>
 */
public class CircleShadowTransformation extends BitmapTransformation {
    private static final int SHADOW_RADIUS = 10;
    private static final String ID = "a.b.c.transformations.CircleShadowTransformation";
    private static final byte[] ID_BYTES = ID.getBytes(Charset.forName(STRING_CHARSET_NAME));

    @Override
    protected Bitmap transform(BitmapPool pool, Bitmap sourceBitmap, int outWidth, int outHeight) {
        int size = sourceBitmap.getWidth();

        Bitmap outputBitmap = Bitmap.createBitmap(
                size + SHADOW_RADIUS * 2,
                size + SHADOW_RADIUS * 2,
                Bitmap.Config.ARGB_8888);

        Canvas outputCanvas = new Canvas(outputBitmap);

        Paint shadow = new Paint(Paint.ANTI_ALIAS_FLAG);
        shadow.setShadowLayer(SHADOW_RADIUS, 0, 0, Color.BLACK);

        outputCanvas.drawCircle(
                (size + SHADOW_RADIUS * 2) / 2,
                (size + SHADOW_RADIUS * 2) / 2,
                (size) / 2,
                shadow);

        outputCanvas.drawBitmap(sourceBitmap, SHADOW_RADIUS, SHADOW_RADIUS, null);

        return outputBitmap;
    }

    @Override
    public boolean equals(Object obj) {
        return obj instanceof CircleShadowTransformation;
    }

    @Override
    public int hashCode() {
        return ID.hashCode();
    }

    @Override
    public void updateDiskCacheKey(MessageDigest messageDigest) {
        messageDigest.update(ID_BYTES);
    }
}

Here is the sample (simple ImageView, 100x100dp)

This is the original image: