Blur bitmap

This exercise generate a blur bitmap by changing each pixel to the average of its surrounding 5x5 pixel.

package com.example.androiddrawbitmap;

import java.io.FileNotFoundException;

import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends Activity {

 Button btnLoadImage;
 ImageView imageResult, imageOriginal;
 TextView textDur;

 final int RQS_IMAGE1 = 1;

 Uri source;
 Bitmap bitmapMaster;
 Canvas canvasMaster;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  btnLoadImage = (Button) findViewById(R.id.loadimage);
  imageResult = (ImageView) findViewById(R.id.result);
  imageOriginal = (ImageView)findViewById(R.id.original);
  textDur = (TextView)findViewById(R.id.dur);

  btnLoadImage.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View arg0) {
    Intent intent = new Intent(
      Intent.ACTION_PICK,
      android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
    startActivityForResult(intent, RQS_IMAGE1);
   }
  });
 }

 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);

  if (resultCode == RESULT_OK) {
   switch (requestCode) {
   case RQS_IMAGE1:
    source = data.getData();

    try {
     bitmapMaster = BitmapFactory
       .decodeStream(getContentResolver().openInputStream(
         source));
     
     imageOriginal.setImageBitmap(bitmapMaster);
     loadBlurBitmap(bitmapMaster);

    } catch (FileNotFoundException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }

    break;
   }
  }
 }

 private void loadBlurBitmap(Bitmap src) {
  if (src != null) {
   
   Bitmap bmBlur;
   
   long startTime = System.currentTimeMillis();
   bmBlur = getBlurBitmap(src);
   long duration = System.currentTimeMillis() - startTime;
   
   imageResult.setImageBitmap(bmBlur);
   textDur.setText("processing duration(ms): " + duration);
  }
 }

 private Bitmap getBlurBitmap(Bitmap src) {
  
  final int widthKernal = 5;
  final int heightKernal = 5;

  int w = src.getWidth();
  int h = src.getHeight();

  Bitmap blurBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);

  for (int x = 0; x < w; x++) {
   for (int y = 0; y < h; y++) {

    int r = 0;
    int g = 0;
    int b = 0;
    int a = 0;
    
    for (int xk = 0; xk < widthKernal; xk++) {
     for (int yk = 0; yk < heightKernal; yk++) {
      int px = x + xk -2;
      int py = y + yk -2;

      if(px < 0){
       px = 0;
      }else if(px >= w){
       px = w-1;
      }
      
      if(py < 0){
       py = 0;
      }else if(py >= h){
       py = h-1;
      }
      
      int intColor = src.getPixel(px, py);
      r += Color.red(intColor);
      g += Color.green(intColor);
      b += Color.blue(intColor);
      a += Color.alpha(intColor);
      
     }
    }
    
    blurBitmap.setPixel(x, y, Color.argb(a/25, r/25, g/25, b/25));

   }
  }

  return blurBitmap;
 }

}

<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:background="@android:color/background_dark"
    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=".MainActivity" >

    <TextView
        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" />

    <Button
        android:id="@+id/loadimage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Load Image 1" />

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical" >
            <ImageView
                android:id="@+id/original"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:adjustViewBounds="true"
                android:scaleType="fitXY" />
            <ImageView
                android:id="@+id/result"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:adjustViewBounds="true"
                android:scaleType="fitXY" />
            <TextView 
                android:id="@+id/dur"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"/>
        </LinearLayout>
    </ScrollView>
</LinearLayout>

Download the files.

Download and try the APK.

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