tkinter: displaying a square grid

Question

I'm trying to use tkinter to periodically refresh a square grid. Each square in the grid is painted a certain color (say obtained from a given function); in the center of each square, a smaller circle is drawn (the color is also obtained from a function).

If I have to do it from scratch, perhaps there's an example or a standard recipe I can use?

Answer 1

Here's a quick hack showing how to draw a grid of rectangles and circles, and how to update the display once a second. If you've never programmed in tk before, it uses concepts that are no doubt foreign to you. You'll need to read up on canvas object ids and tags, as well as what the after command does.

import Tkinter as tk
import random

class App(tk.Tk):
    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)
        self.canvas = tk.Canvas(self, width=500, height=500, borderwidth=0, highlightthickness=0)
        self.canvas.pack(side="top", fill="both", expand="true")
        self.rows = 100
        self.columns = 100
        self.cellwidth = 25
        self.cellheight = 25

        self.rect = {}
        self.oval = {}
        for column in range(20):
            for row in range(20):
                x1 = column*self.cellwidth
                y1 = row * self.cellheight
                x2 = x1 + self.cellwidth
                y2 = y1 + self.cellheight
                self.rect[row,column] = self.canvas.create_rectangle(x1,y1,x2,y2, fill="blue", tags="rect")
                self.oval[row,column] = self.canvas.create_oval(x1+2,y1+2,x2-2,y2-2, fill="blue", tags="oval")

        self.redraw(1000)

    def redraw(self, delay):
        self.canvas.itemconfig("rect", fill="blue")
        self.canvas.itemconfig("oval", fill="blue")
        for i in range(10):
            row = random.randint(0,19)
            col = random.randint(0,19)
            item_id = self.oval[row,col]
            self.canvas.itemconfig(item_id, fill="green")
        self.after(delay, lambda: self.redraw(delay))

if __name__ == "__main__":
    app = App()
    app.mainloop()