Blaginations

This is a first solution of code that does this. It doesn’t yet take care of the fact a Label takes whitespace into account, but it does look like a good start. The real work is in lin.count (), the other code is just enough to exercise lin.count ().

import Tkinter as Tk
import tkFont
import random
import sys

def genstr (j):
    rno = random.randint(4,50)
    ret_val = str(j) + ":"
    for i in range (0, rno):
        ret_val += "hello" + str(i)
    return ret_val

def gendata (lh):
    ret_val = []
    for i in range(0,lh):
        ret_val.append (genstr (i))
    return ret_val

data = gendata (100)

root = Tk.Tk()
font = tkFont.Font(family='times', size=13)

class lines:
    def __init__ (self):
        self.lastct = 1   # remember where the cutoff was last work from there

    def count (self, text, cutoff = 400):
        global font
        no_lines = 1
        start_idx = 0
        idx = self.lastct

        while True:
            if idx > len (text):
                idx = len (text)

            # shrink from guessed value
            while font.measure (text[start_idx:idx - 1]) > cutoff:
                if idx <= start_idx:
                    print "error"
                    sys.exit ()
                else:
                    idx -= 1
                    self.lastct = idx - start_idx # adjust since was too big

            # increase from guessed value (note: if first shrunk then done)
            while (idx < len (text)
                   and font.measure (text[start_idx:idx]) < cutoff):
                idx += 1
                self.lastct = idx - start_idx     # adjust since was too small

            # next line has been determined
            print "*" + text[start_idx:idx-1] + "*"
            if idx == len(text) and font.measure (text[start_idx:]) < cutoff:
                return no_lines
            elif idx == len(text):
                return no_lines + 1
            else:
                no_lines += 1
                start_idx = idx - 1
                idx = start_idx + self.lastct

lin = lines()

for i in range(0,len(data)):
    lin.count(data[i], 450)

for i in range(0,min(len(data),10)):
    l = Tk.Label(root)
    l.pack()
    l['text'] = data[i]
    print i
    no = lin.count (data[i], 450)
    print "computed lines", no
    l['width'] = 50
    l['justify'] = Tk.LEFT
    l['anchor'] = 'w'
    l['wraplength'] = 450
    l['padx']=10
    l['pady'] = 5
    l['height'] = no
    l['font'] = font
    if i % 2 == 0:
        l['background'] = 'grey80'
    else:
        l['background'] = 'grey70'

root.mainloop()