[Tkinter-discuss] Find_closest, bbox, and weirdness

[Jeff Cagle]

So I was trying to pretty up a GUI.  It took 20 minutes to write code to 
place names in a circle and draw arrows to the names that are related 
(actually, the names are filenames, and the arrows represent 'import' or 
'from ... import' statements).

It's taken a couple of hours to try to clean it up so that the arrows go 
up to the bounding box of the text, but not inside. 

Here was the plan: Compute the line that connects the centers of the 
text objects.  Figure out where that line intersects the bounding boxes 
of the texts, and draw the lines to the intersection points instead of 
center-to-center.

It all works ... except that I don't get the right bounding boxes.  
Here's the code:

----
# x0,y0 is one text object; x1,y1 is the other.
print "Center coords: (%.1f,%.1f) and (%.1f, %.1f)" % (x0,y0,x1,y1)
start_id = self.mainw.f.c.find_closest(x0,y0)[0]    # <---- should 
return the text object itself, right?
start_x0,start_y0,start_x1,start_y1 = self.mainw.f.c.bbox(start_id)
print "Bounding box near (x0,y0): (%.1f,%.1f) x (%.1f,%.1f)" % \
              (start_x0,start_y0,start_x1,start_y1)

end_id = self.mainw.f.c.find_closest(x1,y1)[0]     # <---- and the other 
one ...
end_x0,end_y0,end_x1,end_y1 = self.mainw.f.c.bbox(end_id)
print "Bounding box near (x1,y1): (%.1f,%.1f) x (%.1f,%.1f)" % \
              (end_x0,end_y0,end_x1,end_y1)
----

To my shock, find_closest returns the same start_id and end_id ... 
namely, 1 ... every single time.  Tkinter appears to be unable to 
capture the object closest to the coordinates, or else I'm not 
understanding how to use .find_closest().  Here's a typical result:

Center coords: (200.0,380.0) and (375.5, 240.1)   # (x0,y0) and (x1,y1)
start_id: 1
Bounding box near (x0,y0): (29.0,4.0) x (31.0,17.0)
end_id: 1
Bounding box near (x1,y1): (29.0,4.0) x (31.0,17.0)
Truncating around box near x0,y0
Testing point (29, 516.36794949889111)
Testing point (31, 514.77300272112632)
Testing point (671.48908696117667, 4)
Testing point (655.18760257156146, 17)
fall-through  # <---- Well, duh!  None of these points is on the 
bounding box.
Truncating around box near x1,y1
Testing point (29, 516.36794949889111)
Testing point (31, 514.77300272112632)
Testing point (671.48908696117667, 4)
Testing point (655.18760257156146, 17)
fall-through  # Ditto.

The bounding box in every single case is (29,4) x (31,17).  What's going 
on?  (Also, there isn't an object bounded by those coordinates on my 
screen!!)

Thanks,
Jeff Cagle