Create blur bitmap using RenderScript and ScriptIntrinsicBlur

ScriptIntrinsicBlur, added in API Level 17, is a Intrinsic Gausian blur filter. Applies a gaussian blur of the specified radius to all elements of an allocation.

Here is a example show how to create blur bitmap with RenderScript and ScriptIntrinsicBlur.

package com.example.androidimageview;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.renderscript.Allocation;
import android.renderscript.Element;
import android.renderscript.RenderScript;
import android.renderscript.ScriptIntrinsicBlur;
import android.support.v7.app.ActionBarActivity;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

 TextView textTitle;
 ImageView image1, image2, image3;
 SeekBar seekbarBlurRadius;
 
 Bitmap bitmapOriginal;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  textTitle = (TextView) findViewById(R.id.title);
  image1 = (ImageView) findViewById(R.id.image1);
  image2 = (ImageView) findViewById(R.id.image2);
  image3 = (ImageView) findViewById(R.id.image3);

  bitmapOriginal = BitmapFactory.decodeResource(getResources(),
    R.drawable.ic_launcher);

  image1.setImageBitmap(bitmapOriginal);

  // create blur bitmaps
  image2.setImageBitmap(createBitmap_ScriptIntrinsicBlur(bitmapOriginal, 25.0f));
  image3.setImageBitmap(createBitmap_ScriptIntrinsicBlur(bitmapOriginal, 25.0f));
  
  seekbarBlurRadius = (SeekBar)findViewById(R.id.blurradius);

  seekbarBlurRadius.setOnSeekBarChangeListener(new OnSeekBarChangeListener(){

   @Override
   public void onProgressChanged(SeekBar seekBar, int progress,
     boolean fromUser) {
    
   }

   @Override
   public void onStartTrackingTouch(SeekBar seekBar) {
    // TODO Auto-generated method stub
    
   }

   @Override
   public void onStopTrackingTouch(SeekBar seekBar) {
    float radius = (float)seekbarBlurRadius.getProgress();
    image2.setImageBitmap(createBitmap_ScriptIntrinsicBlur(bitmapOriginal, radius));
    image3.setImageBitmap(createBitmap_ScriptIntrinsicBlur(bitmapOriginal, radius));
   }});

 }

 private Bitmap createBitmap_ScriptIntrinsicBlur(Bitmap src, float r) {
  
  //Radius range (0 < r <= 25)
  if(r <= 0){
   r = 0.1f;
  }else if(r > 25){
   r = 25.0f;
  }

  Bitmap bitmap = Bitmap.createBitmap(
    src.getWidth(), src.getHeight(),
    Bitmap.Config.ARGB_8888);

  RenderScript renderScript = RenderScript.create(this);

  Allocation blurInput = Allocation.createFromBitmap(renderScript, src);
  Allocation blurOutput = Allocation.createFromBitmap(renderScript, bitmap);

  ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(renderScript,
    Element.U8_4(renderScript));
  blur.setInput(blurInput);
  blur.setRadius(r);
  blur.forEach(blurOutput);

  blurOutput.copyTo(bitmap);
  renderScript.destroy();
  return bitmap;
 }

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.androidimageview.MainActivity" >

    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />
    
    <SeekBar
        android:id="@+id/blurradius"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="25"
        android:progress="25" />

    <ImageView
        android:id="@+id/image1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    
    <ImageView
        android:id="@+id/image2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <ImageView
        android:id="@+id/image3"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />


</LinearLayout>