scale animation android
<p>hello i saw this code that make a scale animation for a list view </p>

<pre><code>public class ViewAnimation extends Animation {
float centerX, centerY;
public ViewAnimation3(){}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
centerX = width/2.0f;
centerY = height/2.0f;
setDuration(2500);
setFillAfter(true);
setInterpolator(new LinearInterpolator());
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final Matrix matrix = t.getMatrix();
matrix.setScale(interpolatedTime, interpolatedTime);
matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);
}
}
</code></pre>

<p>i know that this will make the animation from the center of the Activity not from the top-left point  but i don't understand where is these points are( -centerX,-centerY) and respect to what to the animation top-left corner or view !! </p>
