title: Rotate zoom drag image in android imageview
body: <p>I want to be able to rotate, zoom and move an image in android framelayout and imageview. With the following code I am able to do it. But the view sometimes gets out of UI. As you can c I handle the rotation in ACTION_UP(90 degree rotation for each ACTION_UP) motionevent. following is my main.xml:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;FrameLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" &gt;
     &lt;ImageView android:id="@+id/imageView"
           android:layout_width="fill_parent"
           android:layout_height="fill_parent"
           android:src="@drawable/csf6a4_flipped"
           android:scaleType="matrix" &gt;
     &lt;/ImageView&gt;
  &lt;/FrameLayout&gt;
  </code></pre>
  
  <p>and following is my java file:</p>
  
  <pre><code>package com.example.rotatezoommove;
  
  
  
  import android.app.Activity;
  import android.graphics.Bitmap;
  import android.graphics.BitmapFactory;
  import android.graphics.Matrix;
  import android.graphics.PointF;
  import android.os.Bundle;
  import android.util.FloatMath;
  import android.util.Log;
  import android.view.MotionEvent;
  import android.view.View;
  import android.view.View.OnTouchListener;
  import android.widget.ImageView;
  
  public class RotateZoomMove extends Activity implements OnTouchListener {
     private static final String TAG = "Touch";
     // These matrices will be used to move and zoom image
     Matrix matrix = new Matrix();
     Matrix savedMatrix = new Matrix();
  
     // We can be in one of these 3 states
     static final int NONE = 0;
     static final int DRAG = 1;
     static final int ZOOM = 2;
     int mode = NONE;
  
     // Remember some things for zooming
     PointF start = new PointF();
     PointF mid = new PointF();
     float oldDist = 1f;
  
     @Override
     public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        ImageView view = (ImageView) findViewById(R.id.imageView);
        view.setOnTouchListener(this);
     }
  
     @Override
     public boolean onTouch(View v, MotionEvent event) {
        ImageView view = (ImageView) v;
        int rotation = 25;
        // Dump touch event to log
        dumpEvent(event);
  
        // Handle touch events here...
        switch (event.getAction() &amp; MotionEvent.ACTION_MASK) {
        case MotionEvent.ACTION_DOWN:
           savedMatrix.set(matrix);
           start.set(event.getX(), event.getY());
           Log.d(TAG, "mode=DRAG");
           mode = DRAG;
           break;
  
  
  
        case MotionEvent.ACTION_POINTER_DOWN:
           oldDist = spacing(event);
           Log.d(TAG, "oldDist=" + oldDist);
           if (oldDist &gt; 10f) {
              savedMatrix.set(matrix);
              midPoint(mid, event);
              mode = ZOOM;
              Log.d(TAG, "mode=ZOOM");
           }
           break;
  
       case MotionEvent.ACTION_UP:
  
           mode = NONE;
           Log.d(TAG, "mode=NONE");
           savedMatrix.set(matrix);
           matrix.postRotate(90);
  
           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, "newDist=" + newDist);
              if (newDist &gt; 10f) {
                 matrix.set(savedMatrix);
                 float scale = newDist / oldDist;
                 matrix.postScale(scale, scale, mid.x, mid.y);
              }
           }
           break;
        }
  
        view.setImageMatrix(matrix);
        return true; // indicate event was handled
     }
  
  
  
  /** Show an event in the LogCat view, for debugging */
     private void dumpEvent(MotionEvent event) {
        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 &amp; MotionEvent.ACTION_MASK;
        sb.append("event ACTION_").append(names[actionCode]);
        if (actionCode == MotionEvent.ACTION_POINTER_DOWN
              || actionCode == MotionEvent.ACTION_POINTER_UP) {
           sb.append("(pid ").append(
                 action &gt;&gt; MotionEvent.ACTION_POINTER_ID_SHIFT);
           sb.append(")");
        }
        sb.append("[");
        for (int i = 0; i &lt; 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 &lt; event.getPointerCount())
              sb.append(";");
        }
        sb.append("]");
        Log.d(TAG, sb.toString());
     }
  
     /** Determine the space between the first two fingers */
     private float spacing(MotionEvent event) {
        float x = event.getX(0) - event.getX(1);
        float y = event.getY(0) - event.getY(1);
        return FloatMath.sqrt(x * x + y * y);
     }
  
     /** Calculate the mid point of the first two fingers */
     private void midPoint(PointF point, MotionEvent event) {
        float x = event.getX(0) + event.getX(1);
        float y = event.getY(0) + event.getY(1);
        point.set(x / 2, y / 2);
     }
  }
  </code></pre>
  
  <p>I guess I'm almost there. Can anyone suggest any solutions so that I can rotate, drag and zoom the image and keep the image within UI all the time?  </p>