title: what's the difference between Path.quadTo and Path.lineTo in the case of finger paint?
body: <p>There is a FingerPaint demo in APIDemos of Android.
  Below is the code when finger moving on the screen.</p>
  
  <pre><code>private void touch_move(float x, float y) {
      float dx = Math.abs(x - mX);
      float dy = Math.abs(y - mY);
      if (dx &gt;= TOUCH_TOLERANCE || dy &gt;= TOUCH_TOLERANCE) {
          mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
          mX = x;
          mY = y;
      }
  }
  </code></pre>
  
  <p>I notice this the demo use mPath.quadTo which I thought should be mPath.lineTo, and I tried. Below is my code:</p>
  
  <pre><code>private void touch_move(float x, float y) {
      float dx = Math.abs(x - mX);
      float dy = Math.abs(y - mY);
      if (dx &gt;= TOUCH_TOLERANCE || dy &gt;= TOUCH_TOLERANCE) {
          mPath.lineTo(x, y);
          mX = x;
          mY = y;
      }
  }
  </code></pre>
  
  <p>Then I tried again, seems no difference, why Google use quadTo?</p>
  
  <p>I heard in Game Program, they use quadTo to draw finger paint, but why?
  Plz help...thx</p>