At the beginning the area selector covers the whole image. In our case we would like to select the right half of the image. For that we should be able to set the X1 with the value of the half of the image width.
We also remarked that the methods areaInfo.getPixelHeight() and areaInfo.getPixelWidth() are swapped.
yes, the value are currently passed from client side only.
But: we can extend this, so that they are also considered from server side. Is part of next update (or immediately... just tell us, if you require an interim build).
...thanks for the hint on swapping width/height. We will correct this in the next update. Of course this correction may cause some compatibility-issues, if already processing the width/height...