More on Generate a mirror image using Matrix.postConcat()

More function of mirror image, such as mirror about X axis, mirror about center, will be as in this exercise; base on the last exercise "Generate a mirror image using Matrix.postConcat()".



main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
<Spinner
 android:id="@+id/mirrorselection"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 />
<ImageView
  android:id="@+id/imageview"
  android:layout_gravity="center"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:scaleType="center"
  />
</LinearLayout>

AndroidMirrorImage.java

package com.exercise.AndroidMirrorImage;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.Spinner;

public class AndroidMirrorImage extends Activity {
 
 private final String imageInSD = "/sdcard/google.png";
 
 private static final String[] optionMirror =
  {"Normal", "Mirror about X", "Mirror about Y", "Mirror about Center"};
  private ArrayAdapter<String> adapter;
 
 Spinner mirrorSelection;
 ImageView myImageView;
 
 Bitmap bitmap;
 int bmpWidth, bmpHeight;
 
 Matrix matrixMirrorNormal, matrixMirrorX, matrixMirrorY, matrixMirrorC;
 
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
      
       myImageView = (ImageView)findViewById(R.id.imageview);
       mirrorSelection = (Spinner)findViewById(R.id.mirrorselection);
      
       adapter = new ArrayAdapter<String>(this,
         android.R.layout.simple_spinner_item, optionMirror);
       adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
       mirrorSelection.setAdapter(adapter);
      
       mirrorSelection.setSelection(0);
      
       mirrorSelection.setOnItemSelectedListener(new Spinner.OnItemSelectedListener(){

   @Override
   public void onItemSelected(AdapterView<?> arg0, View arg1,
     int arg2, long arg3) {
    // TODO Auto-generated method stub
    drawMatrix();
   }

   @Override
   public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub
    mirrorSelection.setSelection(0);
   }});
      
       bitmap = BitmapFactory.decodeFile(imageInSD);
       bmpWidth = bitmap.getWidth();
       bmpHeight = bitmap.getHeight();
      
       initMirrorMatrix();
     
       drawMatrix();
   }
  
   private void initMirrorMatrix()
   {
    float[] mirrorNormal =
    {   1, 0, 0,
     0, 1, 0, 
     0, 0, 1    
    };
    
    float[] mirrorX =
    {   1, 0, 0,
     0, -1, 0, 
     0, 0, 1    
    };
    
    float[] mirrorY =
    {  -1, 0, 0,
     0, 1, 0, 
     0, 0, 1    
    };
    
    float[] mirrorC =
    {  -1, 0, 0,
     0, -1, 0, 
     0, 0, 1    
    };
    matrixMirrorNormal = new Matrix();
    matrixMirrorNormal.setValues(mirrorNormal);
    matrixMirrorX = new Matrix();
    matrixMirrorX.setValues(mirrorX);
    matrixMirrorY = new Matrix();
    matrixMirrorY.setValues(mirrorY);
    matrixMirrorC = new Matrix();
    matrixMirrorC.setValues(mirrorC);
   }
  
   private void drawMatrix()
   {
    Matrix matrix = new Matrix();
    switch (mirrorSelection.getSelectedItemPosition()){
    case 0: //Normal
      matrix.postConcat(matrixMirrorNormal);
      break;
    case 1: //Mirror about X
      matrix.postConcat(matrixMirrorX);
      break;
    case 2: //Mirror about Y
      matrix.postConcat(matrixMirrorY);
      break;
    case 3: //Mirror about Center
      matrix.postConcat(matrixMirrorC);
      break;  
    }
    Bitmap mirrorBitmap = Bitmap.createBitmap(bitmap, 0, 0, bmpWidth, bmpHeight, matrix, true);
  myImageView.setImageBitmap(mirrorBitmap);  
   }
}

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