[Tkinter-discuss] (0,0) off the visible area of a Canvas

[Fredrik Lundh]

Bill Barksdale wrote:

> I am sure this must be a common question but I couldn't find anything
> about it.
>
> When I run the following on my system, the first line appears cut off
> and the second line doesn't appear at all.  I believe this is because
> (0,0) is not part of the visible area of a canvas, and that it starts
> instead at (3,3) or thereabouts.  How can I fix this?
>
> import Tkinter as TK
> root = TK.Tk()
> canv = TK.Canvas(root,width=100,height=100,bg='red')
> canv.pack()
> canv.create_line(0,100,100,0)
> canv.create_line(0,0,0,100)

stock answer:

    by default, the coordinate system is aligned with the widget's upper
    left corner, which means that things you draw will be covered by the
    inner border.

    to fix this, you can either set the border width to zero, add scrollbars
    to the widget (this fixes the coordinate system), or explicitly reset the
    coordinate system:

    w.xview_moveto(0)
    w.yview_moveto(0)

</F>