Class 03: An Introduction to the GIMP

Held: Wednesday, January 27, 2010

Summary: We begin our exploration of GIMP, the GNU Image Manipulation Program. GIMP is an open-source raster graphics editor, which is scriptable by a variant of the Scheme programming language.

Related Pages:

• EBoard.
• Lab: Getting Started with the GIMP.
• Reading: The GNU Image Manipulation Program.

Notes:

• The College asks that every student in this course fill out the RISC survey, available at http://www.grinnell.edu/academic/psychology/faculty/dl/risc/. It should take about fifteen minutes. (No, you don't get class time for it.) If you fill out the intro RISC survey at the start of the semester and the final RISC survey at the end of the semester, you'll get some extra credit in the class (beyond the normal EC).
• EC for attending Gene Gaub's concert, Thursday, 11am, Herrick.
• I'm still expecting to respond to assignment 1 by Friday.
• Three readings for Friday: The MediaScript Program-Development Environment & Beginning Scheme & How Scheme Evaluates Expressions (version 1)
• Someone had asked about connecting to MathLAN from a Windows laptop. The instructions were in the reading.
• Are there any questions on the reading?

Overview:

• What is GIMP?
• Why GIMP in 151?
• Short Demo.
• Lab + Reflection.

Some Notes from Yesterday's Class

See the previous outline for more details.

• Parts of an algorithm
• What we're doing in this course.

What is GIMP?

• GIMP (the GNU Image Manipulation Program) is free software. (Free software is related to open-source software, but with a particular political bent.)
• It allows you to create and edit a wide variety of images, all of which are pixel-based. Such images are called raster images.
  • A separate kind of graphics is based on drawing primitives, and is called vector graphics.
• It is intended as a more open alternative to photoshop.

So Why Study the GIMP in 151?

• This is An introduction to CS not Digital Art. So, why are we studying this GIMP thingy?
• The GIMP is scriptable, giving us the opportunity to write algorithms.
• About eight years ago, I added a short GIMP section to 151.
• About five years ago, I saw some evidence that introductory CS courses that emphasize image manipulation better served a wider variety of students, and decided to adapt that approach to our courses.
  • I applied for a grant, waited, waited some more, and finally got it.
• We had the first GIMP-based 151 two years ago, it had some success, so we continue to use and refine it.
• I built MediaScheme, the scripting software for the GIMP on my sabbatical last year. It was used for the first time last spring, and seemed more successful than the previous software we were using.

A Short Demo

• Not scripted.

Lab

• Do the lab.

Reflect

• We'll try a few of your algorithms.
• We'll also try to reflect a bit on what you learned or didn't learn.