EBoard 07: Transforming images (Section 1)

Please sit with your partner from Friday’s class.

Warning! You are being recorded (and transcribed) (provided the technology is working correctly).

Approximate overview

  • Administrative stuff
  • Lab 1: Transforming RGB colors (from Friday)
  • Lab 2: Transforming images (from Today)

Administrative stuff

Introductory Notes

  • Happy new year!

Quiz Notes

  • I have returned Friday’s quizzes. At least I will by the end of class; I just need to enter them on Gradescope.
  • Please do not write your name on the front of quizzes. I would prefer to grade without knowing your identity.
  • Please write first and last name on the back (print, don’t sign).
  • I will not be going over Friday’s quizzes in class. Please schedule office hours (https://bit.ly/book-samr), email Sam, TM Sam, visit with evening tutors, or attend the mentor sessions for details on the solutions.
  • Please don’t discuss how easy or difficult you find a quiz; others may have different experiences and your comment is unlikely to be useful to them.
  • This Friday, I would recommend you grab any quizzes you have not passed. Even if you leave them blank, that ensures you have a copy to study from.

Upcoming activities

Scholarly

  • Tuesday, 15 September 2026, Noon–1:00 p.m., CS Commons. CS Table: Opening Discussion
  • Thursday, 17 September 2026, 11:00 a.m., JRC 101. Scholars’ Convocation: Melissa Murray (Constitution Day Convo)
  • Thursday, 17 September 2026, 4:15–5:00 p.m., HSSC A1231. Melissa Murray Constitution Day Discussion
  • Friday, 18 September 2026, 4:10–5:00 p.m., Noyce 3830 (ELBICA). AI Coffee Chat: Spring MAPs

Artistic/Cultural

  • Thursday, 17 September 2026, 4:00–5:00 p.m., HSSC S1325. Writers@Grinnell Roundtable with Ananda Lina
  • Thursday, 17 September 2026, 5:00–7:00 p.m., GCMOA. Opening Reception: Abstraction Impressionists, the Women
  • Thursday, 17 September 2026, 8:00–9:30 p.m., Herrick Chapel. Writers@Grinnell Ananda Lina Reading

Multicultural

  • Friday, 18 September 2026, 4:10–5:00 p.m., HSSC N1170. Middle of Everywhere (???)

Peer

Musical, theatric, sporting, academic, and similar events involving this section’s students are welcome.

  • Wednesday, 16 September 2026, 7:00–9:00 p.m., Bob’s. Open Mic Night

Wellness

  • Monday, 14 September 2026, 6:30–8:00 p.m., Bear Dance Studio. Brazilian Jiu-Jitsu
  • Monday, 14 September 2026, 8:00–9:00 p.m., Prayer Garage. Meditation Group
  • Tuesday, 15 September 2026, 4:30–6:00 p.m., Bear P103. Wellness Yoga
  • Wednesday, 16 September 2026, 6:30–8:00 p.m., Bear Dance Studio. Brazilian Jiu-Jitsu
  • Wednesday, 16 September 2026, 4:15–5:45 p.m., Undisclosed Location. Forest Bathing
  • Friday, 18 September 2026, 6:30–8:00 p.m., Bear Dance Studio. Brazilian Jiu-Jitsu
  • Saturday, 10 October 2026, All Day, Somewhere. Mental Health Training.
    • Sign up on Handshake.
    • It’s all day, so you will earn 3 tokens.

Misc

  • Wednesday, 16 September 2026, 4:30–6:30 p.m., Central Campus. Student Involvement Fair
  • Wednesday, 16 September 2026, 8:00–9:00 p.m., Science 3820. Mentor Session
  • Thursday, 17 September 2026, 8:00–9:00 p.m., Science 3820. Mentor Session

Other good things

These do not earn tokens, but are worth your consideration.

  • Wednesday, 16 September 2026, 5:00–7:00 p.m., Springer Field. Men’s Soccer vs. Central
  • Saturday, 19 September 2026, 8:00 a.m–4:00 p.m., Mac and Ward Fields. Grinnelleanore Roosevelts Ultimate Tournament
  • Saturday, 19 September 2026, 9:00 a.m.–Noon, Tennis Courts. Women’s Tennis vs. Ripon
  • Saturday, 19 September 2026, 3:00–6:00 p.m., Tennis Courts. Women’s Tennis vs. Luther

Upcoming work

Administrative Q&A

I can’t make it to the opening at the gallery. Can I go another time and earn a token?

Yes. One visit to each GCMOA exhibition for 30 minutes or more counts, provided it is followed by a reflection.

I’ll have four quizzes to take this Friday. I don’t think I can do that in thirty minutes. What should I do?

I’d suggest that you start with the new one to see what it’s like, then pick one or two of the others that you think you are most likely to finish. You should be able to catch up.

Can I try the same quiz a second time in the same day?

No. That’s not equitable.

My partner is not here. What should I do?

Wait until the end of the administrivia and then we’ll reseat people.

How do I know how I’m doing in the class?

Mastery grading makes that a bit more difficult. If you have 2/3 of the LAs done correctly, you’re fine. If not? You may still be fine. I’ve seen lots of people get 0 for the first four weeks and then something clicks and they do well the rest of the semester.

I’d suggest looking at your percentage of LAs completed after week six.

I’ll send out grading checklists within the next few days.

How many trials do we have on the LAs?

LAs 1 & 2: Up to 15 (I think)

LA 3: Up to 14

Etc.

Always at least two.

Do we get more time for LAs throughout the semester?

No. Just 30 minutes each class. Plus the extra 30 minutes available at 7:30, 11:00, and 4:00.

Will I fail if I’m regularly late to class?

No. You’ll just make everyone sad.

How do we spend tokens?

Sam charges you tokens when appropriate.

How do we know how many tokens we have left?

It appears on the grading report.

MP1 Q&A

How do I know if my image for part 2 is interesting enough?

Does it have five named subimages?

Have you defined a procedure with at least one parameter that you use in creating the main image?

If so, your image is interesting enough.

Demo

(define thingy
  (lambda (color)
    (overlay (solid-circle 50 color)
             (outlined-square 50 "black" 5))))

(define northwest-part
  (thingy "blue"))

(define northeast-part
  (thingy (rgb-lighter (color->rgb "blue"))))

(define southwest-part
  (thingy (rgb 255 0 0)))

(define southeast-part
  (thingy (rgb 255 0 255)))

(define background
  (solid-square 200 "pink"))

(define my-image
  (overlay (above (beside northwest-part northeast-part)
                  (beside southwest-part southeast-part))
           background))

What happens if I get an N on MP1?

You’ll have a chance to redo it. MP redos are identical! Just fix the things that are not satisfactory and resubmit.

Redo date is tbd.

What happens if I get an N on an MP1 redo?

You’ll get another chance to redo it? This time, it costs you a token.

Re-Redo date is tbd.

Can I spend a token to turn in MP1 before Thursday night, but after Tuesday?

Yes.

Lab: Transforming RGB colors

Lab: Transforming images

If you have image-subtract in your supplied code, please change it to rgb-subtract. Sorry about that!