# Tk_gridmap.py

# Tk_gridmap.py

import sys
import Tkinter


def make_canvas(width, height):
    top = Tkinter.Tk()
    top.minsize(width=width + 10, height=height + 10)

    canvas = Tkinter.Canvas(top, width=width, height=height)
    canvas.pack()
    canvas.xview_scroll(6, 'units')  # hack so (0, 0) works correctly
    canvas.yview_scroll(6, 'units')

    # draw blue boundaries - sides
    canvas.create_line(width - 1, 0, width - 1, height - 1, fill='blue')
    # top to bottom
    canvas.create_line(0, height - 1, width - 1, height - 1, fill='blue')
    return canvas


def draw_grid(width, height, n):
    canvas = make_canvas(width, height)

    # Vertical lines at 1/n, 2/n, .. n-1/n
    for i in range(1, n+1):
        x = int(width * i/n)
        if i < n:
            canvas.create_line(x, 0, x, height - 1, fill='red')
        canvas.create_text(x+3, 16, text=str(x), anchor=Tkinter.SW)
        print x

    # b. horizontal lines + text
    for i in range(1, n+1):
        y = int(height * i/n)
        if i < n:
            canvas.create_line(0, y, width - 1, y, fill='red')
        canvas.create_text(3, y, text=str(y), anchor=Tkinter.SW)

    # required last line puts the canvas-window up on screen
    Tkinter.mainloop()


# Default canvas size
WIDTH = 900
HEIGHT = 500

draw_grid(WIDTH, HEIGHT, 10)