Held: Tuesday, 17 February 2015

Back to Outline 16 - Transforming Images. On to Outline 18 - Programming the GIMP Tools.

Summary

Today we explore Scheme's list data structure and some ways to use lists to make interesting images.

Related Pages

• Reading: Making and Manipulating Homogeneous Lists
• Lab: Making and Manipulating Lists of Drawings
• Morning EBoard 17 (Source a.m. 17)
• Afternoon EBoard 17 (Source p.m. 17)

Overview

• Context: What and why lists?
• Building lists.
• Mapping lists.
• Other list operations.

Administrivia

• Continue partners!
• Friday the 13th falls on Friday next month. Be careful.
• Exam 1 to be returned today.
  
  • I do not report averages or ranges or other statistics. You know what your grade means, there's no reason to hear the rest.
  • I recommend that you do not discuss your grade with a classmate. You can ask about solutions to problems, but there is no benefit to discussing what grade you got.
  • Do not post solutions anywhere.
  • Note that if you got under 70 before TMTL, I will fill in an APR for you. The APR serves as a note to your adviser and to academic advising that you are having difficulty. If you needed TMTL, then please talk to me and Prof. Weinman about getting an individual or small-group tutor. (Also please come see me today or next week.)
  • Some cover sheets are missing. I'll need some help identifying your exams. Random numbers (easy) or your program code (harder) will work.
  • Notes on the exam distributed via email. Please do not share.
• Tomorrow, you will have the choice whether or not to have a partner for the homework. One set of placement cards will be "no partner". One will be "with partner". I need an estimate of how many people want to work alone. (This time, your eyes, rather than mine, are closed.)

Upcoming Work

• Homework 4.
  • Due TONIGHT at 10:30 p.m.
• Lab writeup for today:
• Readings for Wednesday:
  • The GNU Image-Manipulation Program
  • Programming with GIMP Tools

Extra Credit Opportunities

Academic

• Pioneer Diversity Council Diversity Dialogue, 8:30 p.m. 19th, Main Quad "Academic Athletes and Academic Students".
• Any two talks from TEDx Grinnell, February 21, 1-5 pm. Live stream at http://tedxgrinnell.com.

Peer Support (Morning Section)

• Julia's radio show, "The Hot Box". Wednesday night/Thursday morning 1:00-2:00 a.m.

Peer Support (Afternoon Section)

• Men's Basketball vs. Knox, Wednesday at 7:30 p.m., New Darby

Other Good Things

• Women's Basketball vs. Knox on Wednesday.

Context: What Are Lists?

• Issue: We'd like to make images with lots and lots of similar shapes.
• Problem: How to do so systematically.
• Solution: Scheme's list data structure and some related procedures.
• We're learning a new type, so it's useful to figure out some basic issues.

Building Lists

• (list val1 val2 ... valn)
• (make-list n value)
• (iota n)

Mapping Lists

• Basic operation: (map func lst). Apply a function to each element of a list.
• For images, we'll find it easier to do something like
  (map drawing-transform list-of-drawings list-of-values)

Other List Operations

• (append *lst1* *lst2*) - join two lists
• (reverse *lst*) - just what it sounds like
• (list-take *lst* *n*) - take the first n elements of a list
• (list-drop *lst* *n*) - drop the first n elements of a list

Lab

• Do the lab.
• Be prepared to reflect.