title: How to scale an image which should not smaller than a specified size
body: <p>I'm using a ImageView to dislay an image. There is a "Image--" button, when I click it, the ImageView will use a matrix to scale the image. The problem is, the image will finally too small to see.</p>
  
  <p>You can see my examples.</p>
  
  <p>Original Image:</p>
  
  <p><img src="https://i.stack.imgur.com/EJxz3.jpg" alt="enter image description here"></p>
  
  <p>After clicking button "Image--" 12 times:</p>
  
  <p><img src="https://i.stack.imgur.com/RacPv.jpg" alt="enter image description here"></p>
  
  <p>You can see the sofa image is so small that hard to see now.</p>
  
  <p>My "main.xml" content is:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout android:id="@+id/root" xmlns:android="http://schemas.android.com/apk/res/android"
                android:orientation="vertical"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
          &gt;
  
      &lt;LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content"
                    android:orientation="horizontal"&gt;
          &lt;!-- buttons --&gt;
      &lt;/LinearLayout&gt;
  
      &lt;ImageView android:id="@+id/imageView" android:layout_width="wrap_content" android:layout_height="wrap_content"
                 android:adjustViewBounds="true" android:background="#336699"
                 android:scaleType="matrix"/&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>And my java code is:</p>
  
  <pre><code>    this.btnImageZoomOut.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              Matrix matrix = new Matrix(imageView.getImageMatrix());
              matrix.postScale(0.8f, 0.8f);
              imageView.setImageMatrix(matrix);
              imageInfo();
          }
      });
  </code></pre>
  
  <p>My question is: how to let the sofa image will smaller a specified size? e.g. 1/5 of original size?</p>
  
  <hr>
  
  <p><strong>UPDATE</strong></p>
  
  <p>If I can get the size of scaled sofa image, it will be easy to check if the image is too small. But I tried a lot, still not get it, that's why I ask this question. Do I miss something?</p>