Input a binary file.

A binary file is a file that is not a text file. Examples include image files, sound files, and video files. A binary file contains a sequence of bytes, not a string of characters, and therefore contains no lines to loop through. Since the bytes do not represent characters, the binary file must not be decoded.

Inputting an entire file all at once is called slurping the file. Line 26 demonstrates how to call read to slurp a binary file and store it as a sequence of bytes. Line 27 demonstrates how to close the file.

The most familiar example of a binary file is an image file. Now that we have input the image file, the simplest way to demonstrate that we have input it correctly is to display it with a tkinter PhotoImage. A PhotoImage can display gif or png, so I’m using a gif file as our example of a binary file.

Download the binary file escalus.gif to your Desktop. In the script, change myname to your name.

image.py

The image is of type gif.
len(sequenceOfBytes) = 239,095

cd /Users/myname/Desktop
ls -l escalus.gif
-rw-r--r--@ 1 myname  mygroup  239095 Aug 24 17:52 escalus.gif

You could also download the binary file escalus.png to your Desktop. In the script, change the filename to escalus.png.

Things to try

Don’t hardcode the dimensions into the script. Get the dimensions from the image file. Change

root.geometry("720x480")

width = photoImage.width()
height = photoImage.height()
root.geometry(f"{width}x{height}")

Don’t hardcode the path of the Desktop into the script. Change

filename = "/Users/myname/Desktop/escalus.gif"

import os

#macOS
filename = os.path.expanduser("~/Desktop/escalus.gif")

#Microsoft Windows
filename = os.path.expanduser(r"~\Desktop\escalus.gif")

Get the image file from the web. Change

#macOS
filename = "/Users/myname/Desktop/escalus.gif"
#Microsoft Windows
#filename = r"C:\Users\Myname\Desktop\escalus.gif"

try:
    binaryFile = open(filename, "rb")        #read binary
except FileNotFoundError as error:
    print(error, file = sys.stderr)
    sys.exit(1)
except PermissionError as error:
    print(error, file = sys.stderr)
    sys.exit(1)

url = "http://oit2.scps.nyu.edu/~meretzkm/python/string/escalus.gif" #or .png

try:
    binaryFile = urllib.request.urlopen(url)
except urllib.error.URLError as error:
    print(error, file = sys.stderr)
    sys.exit(1)

and import urllib.request.

Convert the photoImage to black and white before displaying it on the screen. Insert the following code after creating the photoImage, width and height, but before calling create_image. The three ints in the tuple are the amount of red, green, and blue (in the range 0 to 255 inclusive) in the pixel at row y, column x.

for y in range(height):
    for x in range(width):
        t = photoImage.get(x, y)   #t is a tuple containing 3 ints.
        average = sum(t) // len(t)
        gray = f"#{average:02X}{average:02X}{average:02X}"   #a shade of gray
        photoImage.put(data = gray, to = (x, y))

Any color that has equal amounts of red, green, blue is a shade of gray. For example,

3 ints	written in hex	name
`( 0, 0, 0)`	`#000000`	black
`( 64, 64, 64)`	`#404040`
`(128, 128, 128)`	`#808080`	gray
`(192, 192, 192)`	`#C0C0C0`	silver
`(255, 255, 255)`	`#FFFFFF`	white

Double the width and height of the photoImage. Insert the following code after creating the photoImage, but before creating width and height.
```
photoImage = photoImage.zoom(2, 2)
```

The gif and png formats are built into tkinter, but jpg is not. To display a jpg image image, install Pillow. The Pil stands for Python Imaging Library.

pip3 list
pip3 install pillow

pip3 list
Package         Version
--------------- --------
Pillow          6.1.0

pip3 show pillow
Name: Pillow
Version: 6.1.0
Summary: Python Imaging Library (Fork)
Home-page: http://python-pillow.org
Author: Alex Clark (Fork Author)
Author-email: aclark@aclark.net
License: UNKNOWN
Location: /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages
Requires:
Required-by:

Here is the complete program. This time I decided to display the PhotoImage in a Canvas, not a Label.

"""
Download and display a jpg file.
"""

import sys
import tkinter
import urllib.request
import imghdr      #image header
import PIL.ImageTk #Python Imaging Library

url = "http://oit2.scps.nyu.edu/~meretzkm/python/string/escalus.jpg"

try:
    binaryFile = urllib.request.urlopen(url)
except urllib.error.URLError as error:
    print(error, file = sys.stderr)
    sys.exit(1)

sequenceOfBytes = binaryFile.read()
binaryFile.close()
print(f"The image is of type {imghdr.what(None, h = sequenceOfBytes)}.")
print(f"len(sequenceOfBytes) = {len(sequenceOfBytes):,}")

root = tkinter.Tk()

try:
    #The following statement cannot come before the tkinter.Tk().
    photoImage = PIL.ImageTk.PhotoImage(data = sequenceOfBytes)
except:
    print(f"Can't create PhotoImage: {sys.exc_info()[1]}")
    sys.exit(1)

width = photoImage.width()
height = photoImage.height()
root.geometry(f"{width}x{height}")
root.title("Prince Escalus")

#Put the center of the image at the center of the canvas.
canvas = tkinter.Canvas(root, highlightthickness = 0)
canvas.create_image(width / 2, height / 2, image = photoImage)
canvas.pack(expand = tkinter.YES, fill = "both")

root.mainloop()

The image is of type jpeg.
len(sequenceOfBytes) = 575,357

Convert the photoImage from the jpg file to black and white before displaying it on the screen. Insert the following code after creating the photoImage, width and height, but before calling create_image. The three ints in the tuple are the amount of red, green, and blue (in the range 0 to 255 inclusive) in the pixel at row y, column x.

for y in range(height):
    for x in range(width):
        t = photoImage._PhotoImage__photo.get(x, y) #t is a tuple containing 3 ints.
        average = sum(t) // len(t)
        gray = f"#{average:02X}{average:02X}{average:02X}"   #a shade of gray
        photoImage._PhotoImage__photo.put(data = gray, to = (x, y))

Double the width and height of the photoImage form the jpg file. Insert the following code after creating the photoImage, but before creating width and height.
```
photoImage = photoImage._PhotoImage__photo.zoom(2, 2)
```