Helpful code snippets for Page

28 May 2018

First, it is Memorial Day in the U.S. so Happy Memorial Day.

For months now, I’ve been keeping some tricks and tips in a text file that make programming User Interfaces easier. For my Python UI work, I use Page which is a wonderful Drag-N-Drop GUI designer for Python that uses the Tkinter toolkit. Don Rozenberg has done a wonderful job creating and maintaining Page. The latest version is 4.13, but 4.14 is due out any time. You can find it here.

One of the standard “go to” functions I like to use is one that centers the form in the screen horizontally and vertically. Here is the code…

def centre_screen(w, h):
    ws = root.winfo_screenwidth()
    hs = root.winfo_screenheight()
    x = (ws/2) - (w/2)
    y = (hs/2) - (h/2)
    root.geometry('%dx%d+%d+%d' % (w, h, x, y))

This should be placed in the yourprojectname_support.py file and called from the init() function. When you did your actual UI design in Page, you should have noticed and written down (at least somewhere temporary) the width and height of the topmost widget that makes up the form.

Note: For those who are not that familiar with Page, there are three files created for each “form” that is designed. These are:

• filename.tcl
• filename.py
• filename_support.py You should never hand edit the filename.tcl file and will hopefully not edit the filename.py file. The only file you should under normal circumstances is the filename_support.py file.

You call the function like this:

    centre_screen(300, 200)

where 300 is the width of the topmost form and 200 is the height of the topmost form.

I hope this function is helpful in your day-to-day coding.

Greg