Basic BlurTransformer for Square's Picasso

gistfile1.txt

import android.content.Context;
import android.graphics.Bitmap;
import android.renderscript.Allocation;
import android.renderscript.Element;
import android.renderscript.RenderScript;
import android.renderscript.ScriptIntrinsicBlur;

import com.squareup.picasso.Transformation;

public class BlurTransform implements Transformation {

    RenderScript rs;
    public BlurTransform(Context context) {
        super();
        rs = RenderScript.create(context);
    }

    @Override
    public Bitmap transform(Bitmap bitmap) {
        // Create another bitmap that will hold the results of the filter.
        Bitmap blurredBitmap = Bitmap.createBitmap(bitmap);

        // Allocate memory for Renderscript to work with
        Allocation input = Allocation.createFromBitmap(rs, bitmap, Allocation.MipmapControl.MIPMAP_FULL, Allocation.USAGE_SHARED);
        Allocation output = Allocation.createTyped(rs, input.getType());

        // Load up an instance of the specific script that we want to use.
        ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
        script.setInput(input);

        // Set the blur radius
        script.setRadius(10);

        // Start the ScriptIntrinisicBlur
        script.forEach(output);

        // Copy the output to the blurred bitmap
        output.copyTo(blurredBitmap);

        return blurredBitmap;
    }

    @Override
    public String key() {
        return "blur";
    }

}

It requires api level 17

Thanks for posting this up.

I had to change one line to get things working in my case:

val blurredBitmap = Bitmap.createBitmap(bitmap)

to

val blurredBitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true)

Problem was that BitMap.createBitmap() doesn't always create a copy - sometimes it reuses the bitmap. Looks like this was confusing Picasso's error checking in terms of whether or not the Transformation object correctly handled recycling.