Hi Richard,
Thanks for choosing syncfusion product.
We have used VisualTreeHelper to get the grid Height and Width. Please refer to the attached sample.
Colud you please send us the snapshot or other information about the semi-parent square thus helps us to work on this.
Let me know, If you have any queries.
Regards
Sujitha S
ZoomingAnd Scrolling_de494b63.zip