Example
BlurBitmapTask.java
public class BlurBitmapTask extends AsyncTask<Bitmap, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference;
private final RenderScript renderScript;
private boolean shouldRecycleSource = false;
public BlurBitmapTask(@NonNull Context context, @NonNull ImageView imageView) {
// Use a WeakReference to ensure
// the ImageView can be garbage collected
imageViewReference = new WeakReference<>(imageView);
renderScript = RenderScript.create(context);
}
// Decode image in background.
@Override
protected Bitmap doInBackground(Bitmap... params) {
Bitmap bitmap = params[0];
return blurBitmap(bitmap);
}
// Once complete, see if ImageView is still around and set bitmap.
@Override
protected void onPostExecute(Bitmap bitmap) {
if (bitmap == null || isCancelled()) {
return;
}
final ImageView imageView = imageViewReference.get();
if (imageView == null) {
return;
}
imageView.setImageBitmap(bitmap);
}
public Bitmap blurBitmap(Bitmap bitmap) {
// https://plus.google.com/+MarioViviani/posts/fhuzYkji9zz
//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(),
Bitmap.Config.ARGB_8888);
//Instantiate a new Renderscript
//Create an Intrinsic Blur Script using the Renderscript
ScriptIntrinsicBlur blurScript = ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript));
//Create the in/out Allocations with the Renderscript and the in/out bitmaps
Allocation allIn = Allocation.createFromBitmap(renderScript, bitmap);
Allocation allOut = Allocation.createFromBitmap(renderScript, outBitmap);
//Set the radius of the blur
blurScript.setRadius(25.f);
//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
// nope, we are using the original bitmap as well :/
if (shouldRecycleSource) {
bitmap.recycle();
}
//After finishing everything, we destroy the Renderscript.
renderScript.destroy();
return outBitmap;
}
public boolean isShouldRecycleSource() {
return shouldRecycleSource;
}
public void setShouldRecycleSource(boolean shouldRecycleSource) {
this.shouldRecycleSource = shouldRecycleSource;
}
}
Usage:
ImageView imageViewOverlayOnViewToBeBlurred
.setImageDrawable(ContextCompat.getDrawable(this, android.R.color.transparent));
View viewToBeBlurred.setDrawingCacheQuality(View.DRAWING_CACHE_QUALITY_LOW);
viewToBeBlurred.setDrawingCacheEnabled(true);
BlurBitmapTask blurBitmapTask = new BlurBitmapTask(this, imageViewOverlayOnViewToBeBlurred);
blurBitmapTask.execute(Bitmap.createBitmap(viewToBeBlurred.getDrawingCache()));
viewToBeBlurred.setDrawingCacheEnabled(false);
