Friday, 4 January 2013

Image zoomin and zoomout in android


Normal Image Screen


Zoomout Image Screen

Zoomin Image Screen

MainActivity.java

package com.example.image_zoomin_zoomout;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.FloatMath;
import android.util.Log;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;

public class MainActivity extends Activity  implements  OnTouchListener{

/**Variables Declaration*/
private static final String TAG = "Touch";
    @SuppressWarnings("unused")
    private static final float MIN_ZOOM = 1f,MAX_ZOOM = 1f;

    // These matrices will be used to scale points of the image
    Matrix matrix = new Matrix();
    Matrix savedMatrix = new Matrix();

    // The 3 states (events) which the user is trying to perform
    static final int NONE = 0;
    static final int DRAG = 1;
    static final int ZOOM = 2;
    int mode = NONE;

    // these PointF objects are used to record the point(s) the user is touching
    PointF start = new PointF();
    PointF mid = new PointF();
    float oldDist = 1f;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        ImageView imv = (ImageView)findViewById(R.id.imageView1);
        imv.setOnTouchListener(this);
    }
    
    public boolean onTouch(View v, MotionEvent event)
    {
    ImageView imv = (ImageView) v ;
    imv.setScaleType(ImageView.ScaleType.MATRIX);
    float scale;
   
    dumpEvent(event);
   
    switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG,"Mode =Drage");
mode = DRAG;
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode =NONE;
Log.d(TAG, "Mode = None");
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if(oldDist > 10f)
{
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM");
}
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) 
{
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);
}
else if (mode == ZOOM) 
{
float newDist = spacing (event);
Log.d(TAG, "newDistance=" +newDist);
if (newDist > 5f) 
{
matrix.set(savedMatrix);
scale = newDist / oldDist;
// setting the scaling of the matrix...if scale > 1 means zoom in...if scale < 1 means zoom out
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;

}
    imv.setImageMatrix(matrix);
   
return true;
   
    }

/*
     * --------------------------------------------------------------------------
     * Method: spacing Parameters: MotionEvent Returns: float Description:
     * checks the spacing between the two fingers on touch
     * ----------------------------------------------------
     */
    
    private float spacing(MotionEvent event) {
// TODO Auto-generated method stub
    float x = event.getX(0) - event.getX(1);
    float y = event.getY(0) - event.getY(1);
   
    return FloatMath.sqrt(x * x + y *y);
}
    
    /*
     * --------------------------------------------------------------------------
     * Method: midPoint Parameters: PointF object, MotionEvent Returns: void
     * Description: calculates the midpoint between the two fingers
     * ------------------------------------------------------------
     */
    
    private void midPoint(PointF point, MotionEvent event) {
// TODO Auto-generated method stub
   
    float x = event.getX(0) + event.getX(1);
    float y = event.getY(0) + event.getY(1);
   
    point.set(x/2, y/2);    
    }
    
    /** Show an event in the LogCat view, for debugging */
private void dumpEvent(MotionEvent event) {
// TODO Auto-generated method stub
String names[] = {"DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE","POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
StringBuilder sb = new  StringBuilder();
int action = event.getAction();
int actionCode =  action & MotionEvent.ACTION_MASK;
sb.append("event ACTION_").append(names[actionCode]);
if (actionCode == MotionEvent.ACTION_POINTER_DOWN || actionCode == MotionEvent.ACTION_POINTER_UP) 
{
sb.append("(paid").append(action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
sb.append(")");
}
sb.append("[");
for (int i = 0; i < event.getPointerCount(); i++) 
{
sb.append("#").append(i);
sb.append("(pid ").append(event.getPointerId(i));
       sb.append(")=").append((int) event.getX(i));
       sb.append(",").append((int) event.getY(i));
           if (i + 1 < event.getPointerCount())
               sb.append(";");
}
sb.append("]");
        Log.d("Touch Events ---------", sb.toString());
}

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }    
}


Layout : activity_main.xml

<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="wrap_content"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="fill_parent"
        android:layout_height="422dp"
        android:src="@drawable/android" />

</LinearLayout>
Download : Source