Programming Python, 3rd Edition

Viewing and Processing Images with PIL

As mentioned earlier, Python Tkinter scripts show images by associating independently created image objects with real widget objects. At this writing, Tkinter GUIs can display photo image files in GIF, PPM, and PGM formats by creating a PhotoImage object, as well as X11-style bitmap files (usually suffixed with an .xbm extension) by creating a BitmapImage object.

This set of supported file formats is limited by the underlying Tk library, not by Tkinter itself, and may expand in the future. But if you want to display files in other formats today (e.g., the popular JPEG format), you can either convert your files to one of the supported formats with an image-processing program, or install the PIL Python extension package mentioned at the start of Chapter 8.

PIL, the Python Imaging Library, is an open source system that supports nearly 30 graphics file formats (including GIF, JPEG, TIFF, and BMP). In addition to allowing your scripts to display a much wider variety of image types than standard Tkinter, PIL also provides tools for image processing, including geometric transforms, thumbnail creation, format conversions, and much more.

PIL Basics

To use its tools, you must first fetch and install the PIL package: see http://www.pythonware.com (or search for “PIL” on Google). Then, simply use special PhotoImage and BitmapImage objects imported from the PIL ImageTk module to open files in other graphic formats. These are compatible replacements for the ...