[Tutor] Tkinter Expanding Canvas with AutoScrollBar

[Alexander Grant]

Well.  I solved my own problem.  Mainly I wasn't using the grid manager
everywhere, and I think that's what was messing it up!
Thanks anyways!

Al

On Mon, Feb 9, 2009 at 12:29 PM, Alexander Grant <a.n.grant at gmail.com>wrote:

> Hi Tutors,
> Thanks in advance for all the advice you've already given to others... it
> has been extremely useful!
>
> I'm working on a project, and I wanted to have a header, a footer and an
> expanding canvas with  (possibly) many widgets inside it.
>
> I simply modified Fred Lundh's auto-hiding scrollbar code found here -
> http://effbot.org/zone/tkinter-autoscrollbar.htm
> It is almost working as hoped - but I have the problem that the canvas only
> resizes smaller, not larger - even when the canvas is too large to display
> in the original window!
>
> I'll attach my code... I'm just not sure what's going wrong:
>
>
> #################################################
> from Tkinter import *
>
> class AutoScrollbar(Scrollbar):
>     # a scrollbar that hides itself if it's not needed.  only
>     # works if you use the grid geometry manager.
>     def set(self, lo, hi):
>         if float(lo) <= 0.0 and float(hi) >= 1.0:
>             # grid_remove is currently missing from Tkinter!
>             self.tk.call("grid", "remove", self)
>         else:
>             self.grid()
>         Scrollbar.set(self, lo, hi)
>     def pack(self, **kw):
>         raise TclError, "cannot use pack with this widget"
>     def place(self, **kw):
>         raise TclError, "cannot use place with this widget"
>
> #
> # create scrolled canvas
>
> al = Tk()
> al.columnconfigure(0,weight=1)
> al.rowconfigure(0,weight=1)
>
> header = Frame(al)
> header.pack(side= TOP, expand = YES)
>
> htxt = Label(header,text='TOP TOP TOP... this is the TOP')
> htxt.pack()
>
> footer = Frame(al)
> footer.pack(side = BOTTOM, expand = YES)
>
> ftxt = Label(footer,text='BOTTOM BOTTOM BOTTOM... this is the BOTTOM!')
> ftxt.pack()
>
> root = LabelFrame(al, bd=2, text='Data',relief='groove',padx=5, pady=5)
> root.pack(side = TOP, expand = YES)
>
> vscrollbar = AutoScrollbar(root)
> vscrollbar.grid(row=0, column=1, sticky=N+S)
> hscrollbar = AutoScrollbar(root, orient=HORIZONTAL)
> hscrollbar.grid(row=1, column=0, sticky=E+W)
>
> canvas = Canvas(root,
>                 yscrollcommand=vscrollbar.set,
>                 xscrollcommand=hscrollbar.set)
> canvas.grid(row=0, column=0, sticky=N+S+E+W)
>
> vscrollbar.config(command=canvas.yview)
> hscrollbar.config(command=canvas.xview)
>
> # make the canvas expandable
> root.grid_rowconfigure(0, weight=1)
> root.grid_columnconfigure(0, weight=1)
>
> # create canvas contents
>
> frame = Frame(canvas)
> frame.rowconfigure(1, weight=1)
> frame.columnconfigure(1, weight=1)
>
> rows = 20
> for i in range(1,rows):
>     for j in range(1,20):
>         button = Button(frame, padx=7, pady=7, text="[%d,%d]" % (i,j))
>         button.grid(row=i, column=j, sticky='news')
>
> canvas.create_window(0, 0, anchor=NW, window=frame)
>
> frame.update_idletasks()
>
> canvas.config(scrollregion=canvas.bbox("all"))
>
> root.mainloop()
> #################################################
>
>
>
> Thanks,
>
> Al
>
>
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