CSC151.02 2016S, Class 07: Transforming Images ============================================== * New partners! You should know the drill. _Overview_ * Preliminaries. * Admin. * Upcoming Work. * Extra Credit. * Questions. * Quick Summary. * Lab. Preliminaries ------------- ### Admin * Yes, I forgot to update the lab page. Sorry. Should be fixed now. ### Reminders * Office hours: MTWF 10-11, Tu 1-2. * Sign up at . * Also feel free to stop by when my door is open. * Or to email me for an appointment. * Tutor hours * Sunday, 3-5 p.m. * Sunday-Thursday, 7-10 p.m. * Weekly review sessions: * Wednesday at 8pm in the CS Commons with Sarah * Thursday at 10am in this room with SamR * Thursday at 8pm in the CS Commons with Kumar ### Upcoming Work: * Quiz Friday * Topics * Scheme's order of evaluation and sequencing. * Definitions (in Scheme). * Arithmetic operations, including things like `max`, `min`, `floor`, `ceiling`, `round`, `quotient`, and `remainder`. * RGB colors, and the operations on integer-encoded RGB colors. * Basic RGB transforms (although we will remind you of what they do): `irgb-redder`, `irgb-greener`, `irgb-bluer`, `irgb-darker`, `irgb-lighter`, `irgb-complement`, `irgb-rotate`, `irgb->string` * Function composition. * Form * Closed book * Possibly: "evaluate this expression (or series of expressions)" * Possibly: "using composition, write a procedure to compute ..." * Possibly: "given this definition, what does this procedure do?" * Readings for Friday: * [Writing Your Own Procedures](../readings/procedures-rgb-reading.html) * [How Scheme Evaluates Expressions (v2)](../readings/scheme-eval-2.html) * [Assignment 3](../assignments/assignment.03.html) due next Tuesday at 10:30 p.m. (Your assignment partner is your partner from today.) * Lab Writeup: Exercise _____ * Send email titled __CSC 151 Lab Writeup _ (Your Names)__ * Do not include the underscores. * Send to * Due before class on Monday. ### Extra Credit _If you know of other events, please suggest them! (I might not always agree, but it never hurts to ask.)_ Send email to with a subject of "CSC 151 Extra Credit (Your Name)" I try to respond within a week. You'll have a report of grades by next Monday. #### Academic * 4 pm Thursday in this room: LaTeX * 4 pm Thursday in JRC 209 - Funding for unfunded internships * Next week's Rosenfield Symposium on Campaign Finance Reform. * noon Tuesday in the White PDR: Bowie, Mickey, and more: Copyright in the 21st century (copies of the reading outside Sam's office) * 7:30 pm next Tuesday in ARH 131 - Funding for unfunded internships #### Peer * Track and Field Grinnell Invite February 6. (10 a.m.) * Swimming February 6 vs. UN and IAState. (1 p.m.) #### Regular Peer * Social Dance Workshop Tuesdays 7:00-8:00 in Bucksbaum Dance Studio (starting next week) * Pun club Saturdays at 4pm in Younker (max 2) * Socrates Cafe' Saturdays (max 2) * Electrronic Potpourri on KDIC Frridays at Five ### Questions _Why do you have so many web pages?_ > To clarify or confuse or both _Why so many links at the top of each page?_ > Once you're used to it it speeds navigation. Quick Summary ------------- What are the important topics from yesterday's class and today's class? Monday * Colors are represented in Scheme as combinations of red, green, and blue which are put together into a single integer that most of us can't read. * (by multiplying the red component by 256*256, multiplying the green component by 256, and then adding the three values together.) * We can preview colors with things like (image-show (color-palette ...)) * When you nest operations, you get things in one neat line and the work is done inside-out Yesterday * Colors can be transformed by complementing the components (the pseudocomplement of a color, when added to a color, gives you 255 for each); enhancing the red, green, or blue component; and more. * We can make colors lighter by increasing all three components. * We can build new functions by composing other functions. If we write `(define irgb-evan (o irgb-complement irgb-bluer irgb-complement))` `irgb-evan` makes a color less blue. Today * You can load images and play with them by applying a color transformation to all of the pixels, using `image-variant`. * We have this magic thing called sectioning that builds functions from other functions by filling in some of the parameters to the procedure. * For example, we can eliminate red, green, or blue components * For example, if we write `(define st (section expt <> 3))`, `st` ... Lab --- Lab writeup: