Question

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()

Answer 1

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:

w = Canvas(master, width=150, height=40, bd=0, relief='ridge')
w.pack()

to:

w = Canvas(master, width=150, height=40, bd=0, highlightthickness=0, relief='ridge')
w.pack()

and this:

x0 = 2
y0 = 2
x1 = 151
y1 = 2

to:

x0 = 0
y0 = 0
x1 = 150
y1 = 0

Interestingly enough, the "borderwidth" attribute did not make a difference, but I left it in per the FAQ.

Running w.config() immediately after the Canvas initialization statement showed the defaults to be 2 for highlightthickness and 0 for border width.