[Tkinter-discuss] Re: How to change font sizes in a Tkinter app?

[Martin Franklin]

On Fri, 10 Sep 2004 21:53:33 -0600, <stewart at midtoad.homelinux.org> wrote:

> Quoting Michael Lange <klappnase at freenet.de>:
>
>> maybe the easiest would be to put all the widgets that use the font in  
>> a list
>> and then do something like:
>>
>> for widget in widgetlist:
>>     widget.configure(font=newFont)
>>
>> when the user changes the font.
>
> I want to change all my menu entries to use the new font.  But,I don't  
> see how
> to get the right name for those items to use in the list since each menu  
> entry
> doesn't have a discrete object name, like say a button would
> (btn=Tkinter.Button, so you could have widgetlist=[btn,lbl,btn2].  I read
> something about using component() to achieve this, but the exact  
> implementation
> escapes me - the example I saw related to notebook tabs rather than menu  
> entries.
>
>> I think the usual way to do this is to use an option database which  
>> allows to
>> override default tk options
>> like fonts and colors (in case you want to change the default font for  
>> the
>> whole app). Entries in an option database
>> look like this:
>
> thanks for this useful detail.   I'll give it a try on Monday.  I did  
> try a
> similar idea, putting the current font name into another module which I  
> called
> basefont.py.  I built a test app and was able to change the font this  
> way (the
> user has to quit and restart the app, but that's okay).   The strange  
> thing is,
> when I copy the methods into my real app, it doesn't work due to a  
> scoping
> problem in the lambda function I use. I'll post the details on that on  
> Monday.
>


You could try this little snippet...:

 from Tkinter import *

class WidgetWalker:
     def __init__(self, parent):
         self.parent = parent

     def __call__(self):
         self.walk(self.parent)

     def update(self, widget):
         try:
             widget["font"] = "Helvetica 18"
         except:
             pass

         try:
             widget["fg"] = "pink"
         except:
             pass

     def walk(self, top):
         self.update(top)
         for child in top.children.values():
             self.walk(child)




if __name__=="__main__":
     root = Tk()
     f = Frame(root)
     l = Label(f, text="Label")
     l.pack()
     b = Button(f, text="Button", command=WidgetWalker(root))
     b.pack()
     inf = Frame(f)
     l2 = Label(inf, text="Label 2")
     l2.pack()
     inf2 = Frame(inf)
     l3 = Label(inf2, text="Label 3")
     l3.pack()
     inf2.pack()
     inf.pack()
     f.pack()
     root.mainloop()


It relys on the children dictionary every Tkinter widget has.


Cheers
Martin