Pinch Zoom patch, enable users to zoom x, y or both.

The current library zooms in/out on x and y axes at the same time.

As far as I know, we can set the graph zoomable on which axis by
 renderer.setZoomEnabled(enabledX, enabledY);

But it is fixed. I think it will be handy if we can do:

1.If pinch is diagonal, then zoom both axes
2.If pinch is horizontal, then zoom X axis
3.If pinch is vertical, then zoom Y axis 

Attached is the patch implementing what described above.

Notice that I've deleted two if statements in apply() (Zoom.java), it is 
nothing to do with pinch zoom, but without doing this, the zoom out button 
won't work. Please see issue 172:
 http://code.google.com/p/achartengine/issues/detail?id=172

Original issue reported on code.google.com by renws1990@gmail.com on 2 Feb 2012 at 12:56

Attachments:

achartengine_independent_zoom.patch

wangyao5 / achartengine

Pinch Zoom patch, enable users to zoom x, y or both. #176