[Tutor] Tkinter image with "hyperregions"

Koen Bossers koen@behindthesofa.dhs.org
Sat, 18 Aug 2001 11:17:18 +0200

Hi everybody,

I'm trying some stuff with Tkinter. Right now, I'm writing a class 
MakeMap that displays an image. The user can select different regions 
within that image and assign functions to them.  Makemap then writes a 
class that contains the image with the "hyperregions" and its 
corresponding function calls as event bindings (OK this might be a bit 
unclear, imagine a picture of a calculator. the user selects a square 
around the "1" button and assigns a function to it).

If I use Canvas Rectangles for example for the region selection, I can 
use canvas.find_overlapping() to determine which rectangle is clicked. 
Unfortunately, this only works if the rectangle is visible, for example 
a rectangle with transparent fill and outline will NOT work with this 

To avoid this, I wrote a funtion that determines if the mouse click is 
in a "hyperregion", knowing the positions and sizes of the rectangles 
that make up the "hyperregions". This is easy for rectangles and 
probably also for ellipses, but I also like to add functionality for 
polygons. I have no idea how to determine all the pixels that make up 
the polygon, so I don't know whether a user clicked on the polygon or not.

So the question is, is there another method of determining if a user 
clicked a canvas.rectangle than canvas.find_overlapping(), or is there a 
way to determine all the pixels that a polygon contains, or is there a 
way to use a COMPLETELY transparent canvas.rectangle so that 
canvas.find_overlapping() works?

Sorry for the long ang probably unclear questions. Hope somebody can 

Cheers, Koen Bossers