Picasso transformation that crops center the image to the specified dimensions and blurs it

BlurPicassoTransformation.java

public class BlurPicassoTransformation implements Transformation {

    private Context mContext;
    private int mWidth;
    private int mHeight;

    public BlurPicassoTransformation(Context context, int width, int height) {
        mContext = context;
        mWidth = width;
        mHeight = height;
    }

    @Override
    public Bitmap transform(Bitmap source) {
        // Scale center crop bitmap
        Bitmap scaledCenteredCroppedBitmap = scaleCenterCrop(source, mWidth, mHeight);
        // Blur bitmap and return it
        return blur(mContext, scaledCenteredCroppedBitmap, 25);
    }

    @Override
    public String key() {
        return "blur(width=" + mWidth + ",height=" + mHeight + ")";
    }

    private Bitmap scaleCenterCrop(Bitmap source, int newWidth, int newHeight) {
        int sourceWidth = source.getWidth();
        int sourceHeight = source.getHeight();

        // Compute the scaling factors to fit the new height and width, respectively.
        // To cover the final image, the final scaling will be the bigger
        // of these two.
        float xScale = (float) newWidth / sourceWidth;
        float yScale = (float) newHeight / sourceHeight;
        float scale = Math.max(xScale, yScale);

        // Now get the size of the source bitmap when scaled
        float scaledWidth = scale * sourceWidth;
        float scaledHeight = scale * sourceHeight;

        // Let's find out the upper left coordinates if the scaled bitmap
        // should be centered in the new size give by the parameters
        float left = (newWidth - scaledWidth) / 2;
        float top = (newHeight - scaledHeight) / 2;

        // The target rectangle for the new, scaled version of the source bitmap will now
        // be
        RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);

        // Finally, we create a new bitmap of the specified size and draw our new,
        // scaled bitmap onto it.
        Bitmap outBitmap = Bitmap.createBitmap(newWidth, newHeight, source.getConfig());
        Canvas canvas = new Canvas(outBitmap);
        canvas.drawBitmap(source, null, targetRect, null);

        // Recycle the original bitmap
        source.recycle();

        return outBitmap;
    }

    private Bitmap blur(Context context, Bitmap bitmap, float radius) {
        // Let's create an empty bitmap with the same size of the bitmap we want to blur
        Bitmap outBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), android.graphics.Bitmap.Config.ARGB_8888);

        // Instantiate a new Renderscript
        RenderScript rs = RenderScript.create(context);

        // Create an Intrinsic Blur Script using the Renderscript
        ScriptIntrinsicBlur blurScript = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));

        // Create the in/out Allocations with the Renderscript and the in/out bitmaps
        Allocation allIn = Allocation.createFromBitmap(rs, bitmap);
        Allocation allOut = Allocation.createFromBitmap(rs, outBitmap);

        // Set the radius of the blur
        blurScript.setRadius(radius);

        // Perform the Renderscript
        blurScript.setInput(allIn);
        blurScript.forEach(allOut);

        // Copy the final bitmap created by the out Allocation to the outBitmap
        allOut.copyTo(outBitmap);

        // recycle the original bitmap
        bitmap.recycle();

        // After finishing everything, we destroy the Renderscript.
        rs.destroy();

        return outBitmap;
    }
}