Tkinter font size only affects gap between letters on Raspberry pi

Question

I've got a weird problem here. I am setting the size of a text inside a canvas widget. Everything works fine on my laptop (arch linux x86_64). If I execute the same code on my Raspberry Pi (also arch linux armv6l) the font size just affects the gap between the letters. The size doesn't change.

class TextBild(tk.Canvas):
    def __init__(self, *args, **kwargs):
        tk.Canvas.__init__(self, *args, **kwargs)
        self.create_text(0, 
                         0, 
                         font = ('Helvetica', 30, 'bold'),
                         text = '000')

Do you have an idea why this is happening?

EDIT:

I found out that it works up to a size of 20. Also if I use a negative value for pixel size it only works lower than -20.

Answer 1

It sounds like you have bitmapped fonts in specific sizes, rather than scaleable fonts. Thus, when you request a font bigger than what is actually available, tkinter will pick the closest font and try to adjust the spacing to come as close as possible to what you're asking.