I've been messing with the Tkinter Canvas
widget in order to see if I could make some aesthetically pleasing widgets, and I have a few questions.
First, why is there a light grey border around my Canvas widget, and how do I get rid of it?
Secondly, why is the top left most position in the Canvas (2,2)? It seems like it should be (0,0).
My current script:
from Tkinter import *
master = Tk()
master.configure(bg='black')
master.wm_attributes("-topmost", 1)
w = Canvas(master, width=150, height=40, bd=0,relief='ridge',)
w.pack()
color = 100
x0 = 2
y0 = 2
x1 = 151
y1 = 2
while y0 < 20 :
r = color
g = color
b = color
rgb = r, g, b
Hex = '#%02x%02x%02x' % rgb
w.create_line(x0, y0, x1, y1,fill=str(Hex), width=1)
color = color - 2
y0 = y0 + 1
y1 = y1 + 1
color = 10
while y0 < 40 :
r = color
g = color
b = color
rgb = r, g, b
Hex = '#%02x%02x%02x' % rgb
w.create_line(x0, y0, x1, y1,fill=str(Hex), width=1)
color = color + 4
y0 = y0 + 1
y1 = y1 + 1
mainloop()
The short answer is, the Canvas has two components which affect the edges: the border (
borderwidth
attribute) and highlight ring (highlightthickness
attribute).If you have a border width of zero and a highlight thickness of zero, the canvas coordinates will begin at 0,0. Otherwise, these two components of the canvas infringe upon the coordinate space.
What I most often do is set these attributes to zero. Then, if I actually want a border I'll put that canvas inside a frame and give the frame a border.
Section 6.8 Why doesn't the canvas seem to start at 0,0? of the Tk Usage FAQ describes the phenomenon.
I was able to eliminate the border artefact with slight changes to the posted source...
Change this:
to:
and this:
to:
Interestingly enough, the
"borderwidth"
attribute did not make a difference, but I left it in per the FAQ.Running
w.config()
immediately after theCanvas
initialization statement showed the defaults to be 2 forhighlightthickness
and 0 forborder width
.