Problem displaying Numeric Array as image

[Les Schaffer]

Eric Frey said:
> I a trying to display a floating point Numeric (NumPy) array as a
> grayscale image via Tkinter.

this example code works for me. its an amalgam of stuff i have found
on the net... normalize takes a floating point image and scales it to
1 and returns byte values suitable for a greyscale image. with a
little cleaning up this should do what you want......

les schaffer

==================================

#!/usr/bin/python


from Tkinter import *
from ImageTk import PhotoImage
import Image

from Numeric import *
from RandomArray import random

def normalize(a):
    a = array(a, copy=1)
    a = (a - min(a.flat))/(max(a.flat) - min(a.flat)) 
    return ( a*254 ).astype('b')

def ArrayToImage(a, height=200, scale=1):
    a = normalize(a)
    i = Image.new("L", (a.shape[1], a.shape[0]), color=255)
    i.fromstring(a.tostring())
    if scale != 1:
	i = i.resize((i.size[0]*scale, i.size[1]*scale))
    return i

def ImageToArray(i):
    a = fromstring(i.tostring(), 'b')
    a.shape = i.im.size[1], i.im.size[0]
    return a


class MatrixDisplay:

    def __init__(self, master):

        frame = Frame(master)
        frame.pack()
        self.button = Button(frame, text="QUIT", fg="red", 
                             command=frame.quit)
        self.button.pack(side=TOP)
        self.test_B = Button(frame, text="Update", command=self.update)
        self.test_B.pack(side=TOP)
        self.img = Image.new("L",(100,100))
        self.photo = PhotoImage(image=self.img)
        self.canvas = Canvas(frame, width=100, height=100)
        self.canvas.create_image(0, 0, anchor=NW, image=self.photo)
        self.canvas.pack()

    def update(self):
        ra = fromfunction(self.func, (101, 101))
        #ra = random((101, 101))
        
        self.img = ArrayToImage(ra)
        #self.photo = PhotoImage(self.img)
        self.photo.paste(self.img)
        self.canvas.create_image(0, 0, anchor=NW, image=self.photo)
        self.canvas.update()

    def func(self, i,j):
        return cos( 4*2*3.1415926*i / 100. ) * cos( 4*2*3.1415926*(j / 100. ))
    
    

root = Tk()
app = MatrixDisplay(root)
root.mainloop()