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Display large Images with Scrollbars with Python, Tk, and PIL

I wrote a program to display extremely large images in Python using TK. It's interesting how simple this program is, yet frustrating how long it took me to figure out.

This little Python program will load an image (pretty much any format) using the Python Imaging Library (PIL, which must be installed) and allows you to see it on a scrollable canvas (in two directions) with Tkinter and ImageTk. The above screenshot is of the program viewing the image below:

What is that image? I won't get ahead of myself, but it's about 5kHz of audio from 10.140mHz which includes a popular QRSS calling frequency. The image displays an hour of data. My ultimate goal is to have it scroll in the TK window, with slide-adjustable brightness/contrast/etc.

from Tkinter import *
import Image, ImageTk

class ScrolledCanvas(Frame):
     def __init__(self, parent=None):
          Frame.__init__(self, parent)
          self.master.title("Spectrogram Viewer")
          self.pack(expand=YES, fill=BOTH)
          canv = Canvas(self, relief=SUNKEN)
          canv.config(width=400, height=200)
          canv.config(highlightthickness=0)

          sbarV = Scrollbar(self, orient=VERTICAL)
          sbarH = Scrollbar(self, orient=HORIZONTAL)

          sbarV.config(command=canv.yview)
          sbarH.config(command=canv.xview)

          canv.config(yscrollcommand=sbarV.set)
          canv.config(xscrollcommand=sbarH.set)

          sbarV.pack(side=RIGHT, fill=Y)
          sbarH.pack(side=BOTTOM, fill=X)

          canv.pack(side=LEFT, expand=YES, fill=BOTH)
          self.im=Image.open("./1hr_original.jpg")
          width,height=self.im.size
          canv.config(scrollregion=(0,0,width,height))
          self.im2=ImageTk.PhotoImage(self.im)
          self.imgtag=canv.create_image(0,0,anchor="nw",image=self.im2)

ScrolledCanvas().mainloop()
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