Example to draw Bitmap with ShadowLayer

In the below screen capture, the background bitmap is draw normally, the upper left bitmap of Rubber Duck is draw using Paint with ShadowLayer, the middle one is the shadow layer of the Rubber Duck bitmap.

package com.test.androidimageprocessing;

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.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.example.androidimageprocessing.R;

public class MainActivity extends Activity {
 
 Button btnLoadImage1, btnLoadImage2;
 TextView textSource1, textSource2;
 Button btnProcessing;
 ImageView imageResult;
 
 final int RQS_IMAGE1 = 1;
 final int RQS_IMAGE2 = 2;
 
 Uri source1, source2;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  btnLoadImage1 = (Button)findViewById(R.id.loadimage1);
  btnLoadImage2 = (Button)findViewById(R.id.loadimage2);
  textSource1 = (TextView)findViewById(R.id.sourceuri1);
  textSource2 = (TextView)findViewById(R.id.sourceuri2);
  btnProcessing = (Button)findViewById(R.id.processing);
  imageResult = (ImageView)findViewById(R.id.result);
  
  btnLoadImage1.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);
   }});
  
  btnLoadImage2.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_IMAGE2);
   }});
  
  btnProcessing.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View v) {
    
    if(source1 != null && source2 != null){
     Bitmap processedBitmap = ProcessingBitmap();
     if(processedBitmap != null){
      imageResult.setImageBitmap(processedBitmap);
      Toast.makeText(getApplicationContext(), 
        "Done", 
        Toast.LENGTH_LONG).show();
     }else{
      Toast.makeText(getApplicationContext(), 
        "Something wrong in processing!", 
        Toast.LENGTH_LONG).show();
     }
    }else{
     Toast.makeText(getApplicationContext(), 
       "Select both image!", 
       Toast.LENGTH_LONG).show();
    }
    
   }});
 }

 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
  if(resultCode == RESULT_OK){
   switch (requestCode){
   case RQS_IMAGE1:
    source1 = data.getData();
    textSource1.setText(source1.toString());
    break;
   case RQS_IMAGE2:
    source2 = data.getData();
    textSource2.setText(source2.toString());
    break;
   }
  }
 }

 private Bitmap ProcessingBitmap(){
  Bitmap bm1 = null;
  Bitmap bm2 =  null;
  Bitmap newBitmap = null;
  
  try {
   bm1 = BitmapFactory.decodeStream(
     getContentResolver().openInputStream(source1));
   bm2 = BitmapFactory.decodeStream(
     getContentResolver().openInputStream(source2));
   
   int w;
   if(bm1.getWidth() >= bm2.getWidth()){
    w = bm1.getWidth();
   }else{
    w = bm2.getWidth();
   }
   
   int h;
   if(bm1.getHeight() >= bm2.getHeight()){
    h = bm1.getHeight();
   }else{
    h = bm2.getHeight();
   }
   
   Config config = bm1.getConfig();
   if(config == null){
    config = Bitmap.Config.ARGB_8888;
   }
   
   newBitmap = Bitmap.createBitmap(w, h, config);
   Canvas newCanvas = new Canvas(newBitmap);
   
   newCanvas.drawBitmap(bm1, 0, 0, null);
   
   Paint paint = new Paint();
   paint.setShadowLayer(50.0f, 200.0f, 100.0f, 0xFF000000);
   newCanvas.drawBitmap(bm2, 0, 0, paint);
   
  } catch (FileNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
  return newBitmap;
 }
 
}

The layout file refer to the post "Combine bitmap side-by-side".


Download the files.

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more: Something about processing images in Android