import os, random
try:
    import Image, ImageDraw
except:
    try:
        from PIL import Image, ImageDraw
    except:
        raise Error("Error: cannot image Image, ImageDraw from PIL")

import tempfile

# Graphics for the Ising model

# -----------------------------------------------------------------------

# image display

def Display(image_file='tmpf.jpg'):
    """Display(image_file) attempts to display the specified image_file on
    the screen, using the Preview application on Mac OS X, the ImageMagick
    display utility on other posix platforms (e.g., Linux)
    and the Microsoft mspaint utility on Windows platforms."""
    os_name = os.name
    if os_name == 'nt': # Windows
        try:
            os.system('mspaint %s &' % image_file)
        except:
            raise OSError("Cannot display %s with Windows mspaint" % \
                  image_file)
    else:
      os_uname = os.uname()
      if os_uname[0] == 'Darwin':  # Mac OS X, assume no X server running
        try:
            os.system('open /Applications/Preview.app %s &' % image_file)
        except:
            raise OSError("Cannot display %s with Preview application" % \
                  image_file)

      elif os_name == 'posix':  # Linux, Unix, etc.
        try:
            os.system('display %s &' % image_file)
        except:
            raise OSError("Cannot display %s with ImageMagick display. ImageMagick display requires a running X server." % \
                  image_file)
      else:
        raise OSError("no known display function for OS %s" % os_name)


# -----------------------------------------------------------------------


def DrawIsingLattice(lattice, scale=0, imsize=800, 
                           imfile=None):
    """DrawIsingLattice(lattice) will draw an image file of the 2D LxL
    square--lattice Ising model, and then will display the result.
    By default, the image file will be stored in a uniquely named png file
    in /tmp, although the image file name can be supplied optionally with
    the imfile argument."""
    # Set up image file
    if imfile is None:
        imfile = tempfile.mktemp()  # make unique filename in /tmp
        imfile += "_square_network_sites.png"
    L = len(lattice) 
    if (scale==0):
        scale = max(1,int(imsize/L)) # Size of squares for each node
    # Background white (in case some nodes missing)
    white = (255,255,255)
    im = Image.new('RGB', (scale*L, scale*L), white)
    if (scale>1):
        draw = ImageDraw.Draw(im)
    black = (0,0,0) # starting color
    # Draw up spins black
    for i in range(L):
        for j in range(L):
            if lattice[i,j]==1:
                if (scale==1):
                    im.putpixel((i,j), black)
                else:
                    x = i*scale
                    y = j*scale
                    draw.rectangle(((x,y),(x+scale,y+scale)), fill=black)
    im.save(imfile)
    Display(imfile)
    return im

# Copyright (C) Cornell University
# All rights reserved.
# Apache License, Version 2.0