CaptureTool

CaptureTool is in the package ca.tecreations.apps.capturetool.CaptureTool
All of the code is within the directory for the project. @see: Magnifier

CaptureTool has very few options. 
You can save the Desktop.
You can capture the Desktop. (Hides the application window, captures, and restores the application window.)
You can save a rectangular or square portion within by adjusting the bound box.
And, if I remember correctly, Ctrl-Click to get to Magnifier, so you could follow that pattern, substitute your Magnifier, and go

Please refer to the code for the task.

Magnifier

Magnifier is accessed using a Ctrl-Click on a Graphics surface. You should make your applications follow that protocol if 
stating to be compatible with mine.

Using Magnifier, I forget, is it Ctrl-Wheel to scale? 
// sure...