move graphics entities to the origin

[srhoads]

I have written a TCL application which places graphics on a canvas and allows the user to zoom in, out, and pan. I record the scaling info so I am able to restore the canvas items to the original scale but I don't know how to restore them to the original position.

If I could query the screen coordinates of a line I create with the tag "Origin" I could then figure out how far to move all the items.

Anybody know a solution for either of these techniques?

 

[ulis]

Sounds like you need to register and restore the scrollregion and the position in it.

Registering :

set sr [.canvas config -scrollregion]
set xpos [.canvas xview]
set ypos [.canvas yview]

Restoring:

.canvas config -scrollregion $sr
.canvas xview moveto [lindex $xpos 0]
.canvas yview moveto [lindex $ypos 0]

I've not tested this code but you got the idea.

ulis