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Basic BlurTransformer for Square's Picasso
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";
}
}
@tadfisher

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commented Jan 9, 2014

You can make this a LOT faster by setting Allocation.USAGE_SHARED and removing the bitmap.recycle() call.

@akhy

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commented Apr 7, 2014

Just a note, most methods in ScriptIntrinsicBlur used in this snippet require API level 17.

@ryanbateman

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Owner Author

commented May 2, 2014

Thanks, Tad - noted and updated.

@rajuashok

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commented Oct 15, 2014

Note that if you don't call bitmap.recycle than the following call will fail:

Picasso.with(getActivity())
.load(mClip.getImageUrl(app))
.resize(width, height)
.centerCrop()
.transform(new BlurTransform(getActivity()))
.into(mImageView);

with the following error: "Transformation blur mutated input Bitmap but failed to recycle the original."

So in this case I've re-added the .recycle() call.

@rajuashok

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commented Oct 23, 2014

Hmm, so I realize that be re-adding the recycle() call my image is not getting cached. So if I don't want to recycle I get the error mentioned above ("Transformation blur mutated input Bitmap but failed to recycle the original.").

Any idea how I can avoid this? Or is there no way to resize and blur an image at the same time?

@tokudu

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commented Oct 23, 2014

Quick note: you shouldn't creating a new RS instance in the constructor, which gets called every time - even when the blurred image is being loaded from memory. Instead, store a WeakReference<Context> and create RenderScript inside of the transform method.

@dp-singh

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commented Nov 6, 2014

It requires api level 17

@TommyVisic

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commented Nov 4, 2015

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.

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