Image Library

The image library provides useful functions for displaying and manipulating JPEG and PNG graphic files.  To use it, you need following in your program:

from image import *

This defines the Image class. The Image class is similar to the Icon class (seen in the GUI library), except an Image:

  • has its own window,
  • can be manipulated at the individual pixel level, and
  • can be written/saved to an external file.
Function Description
Image(filename) Reads in a .jpg or .png file called filename (a string)  and shows an image.  It returns the image, so it should be stored in a variable, e.g.,
img = Image(“sunset.jpg”)
Image(width, height) Returns an empty (blank) image with provided width and height.  It returns the image, so it should be stored in a variable, e.g.,
img = Image(200, 300)

One an image has been created, the following functions are available:

Function Description
img.show() Displays the image img in a window.
img.hide() Hides the image window.
img.getWidth() Returns the width of image img.
img.getHeight() Returns the height of image img.
img.getPixel(col, row) Returns this pixel’s RGB values (a list, e.g., [255, 0, 0]), where col is the image column, and row is the image row.  The image origin (0, 0) is at top left.
img.setPixel(col, row, RGBlist) Sets this pixel’s RGB values, e.g., [255, 0, 0], where col is the image column, and row is the image row.  The image origin (0, 0) is at top left.
img.getPixels() Returns all the pixels in this image in a list of rows. Each row is a list of pixels for that row. Each pixel is a list of RGB values, e.g., [255, 0, 0]. I.e., the image’s top-left pixel is at index [0][0].
img.setPixels(pixels) Sets all the pixels in this image, where pixels in a list of rows. Each row is a list of pixels for that row. Each pixel is a list of RGB values, e.g., [255, 0, 0]. I.e., the image’s top-left pixel is at index [0][0].
img.write(filename) Writes image img to the .jpg or .png filename.