## creates ASCII random character stereograms
## 03/2006 Wolfgang.Urban@schule.at
##
## example:
## >>> stereogram("image.gif")
## where image is a depth file approx 70x30 pixels for screen viewing.
## Adjust sizes and font sizes (courier type) to fit your needs.
##
## Have fun.

import random

class AsciiStereogram:

    ## setup character sets
    def __init__(self,patternwidth=10):
        self.patternwidth = patternwidth
        self.textchars = "               ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        self.fillchars = "123456789abcdefghijklmnopq"
        self.output = ""
        self.line = ""

    ## start a new line
    def newline(self):
        if self.line: self.output += self.line+"\n"

        t = list(self.textchars[:])
        random.shuffle(t)
        self.pattern = "".join(t[:self.patternwidth])

        f = list(self.fillchars[:])
        random.shuffle(f)
        self.fill = "".join(f)

        self.line = self.pattern[:]   # start with a pattern
        self.depth = 0
        

    ## add one char representing depth
    def add(self,depth):
        if depth > self.depth:      # go to front, shorten pattern
            self.pattern = self.pattern[(depth-self.depth):]
            self.depth = depth
        elif depth < self.depth:    # go sdeeper, lengthen pattern 
            self.pattern = self.fill[:(self.depth-depth)]+self.pattern
            self.fill = self.fill[(self.depth-depth):]
            self.depth = depth

        ## append first pattern char and recycle it for later use
        self.line += self.pattern[0]
        self.pattern = self.pattern[1:]+self.pattern[0]

    ## return whole text including last line
    def get(self):
        return self.output+self.line+"\n"

    ## two circles as a focussing aid
    def focusline(self,n):
        n += self.patternwidth
        mid = " "*((n-self.patternwidth)/2)+"O"+" "*(self.patternwidth-2)+"O"
        return mid

## use given text as pattern in lines
class AsciTextogram(AsciiStereogram):
    def __init__(self):
        AsciiStereogram.__init__(self)
        text = ["erstes","zweites","drittes","viertes","fünftes"]


##############################################################################

def stereogram(name="ellipse4.gif"):
    depthimage = loaddepthimage(name)

    a = AsciiStereogram()
    for line in depthimage:
        a.newline()
        for d in line: a.add(int(d))

    stereo = a.focusline(70)+"\n"+a.get()

    # print stereo      ## text output in IDLE

    savedepth(depthimage,"depth.txt")   # save depth as text
    savestereogram(stereo,"stereo.txt") # save stereogram as text

    # show text in a Tk Window
    s = TkStereoText()
    s.write(stereo,0,0)
    

from Tkinter import *

## load a gif as a depth image
def loaddepthimage(name):
    root = Tk()
    pic = PhotoImage(file=name)
    t = []
    for y in range(pic.height()):
        line = ""
        for x in range(pic.width()):
            h = pic.get(x,y).split()[0]
            line += str(int(h)/64)
        t.append(line)
    root.destroy()
    return t

## save depth image as ascii-file
def savedepth(depth,name="depth.txt"):
    f = open(name,"w")
    for y in depth:
        f.write(y+"\n")
    f.close()

## save stereogram as ascii-file
def savestereogram(pic,name="stereo.txt"):
    f = open(name,"w")
    f.write(pic)
    f.close()


class TkStereoText:

    def __init__(self):
        self.root = Tk()

        self.c = Canvas(self.root, width=880+6,height=660+6)
        self.c.pack()

    def write(self,text,x,y):
        font = ("Courier",10,"bold")
        self.c.create_text(x+440+3,y+330+3,text=text,font=font)
        self.c.update()