Translations with zoom in and zoom out?

["Bishop, Michael W. CONTR J9C880" <Mi...@je.jfcom.mil>]

OK, so I have the JSVGCanvas zooming in and zooming out.  Since I have a
whiteboard application, users can draw objects to the canvas.  Much like
typical art programs, you get an "outline" of what you're going to draw
before it's placed.  For a box, you click, drag the mouse to the desired
size and release.  I guess they call it "rubber-banding" or whatever.

 

On to my question.  When the canvas is zoomed in/zoomed out, how can I
get the translation correct on the glass pane?  The glass pane is
currently drawing based on the coordinates of the JSVGCanvas, but it
draws as if the JSVGCanvas isn't zoomed in or out.  In short, what the
glass pane is rendering is not zoomed, but what the JSVGCanvas is
rendering is.  So what you see isn't what you get when you let go of the
mouse.  How can I translate my shapes based on the zoom?  If I draw
something on a canvas that is zoomed in 20%, I'd like to scale the
outline 20%...etc.  That degree of scaling is what I don't know how to
get.

 

Michael Bishop