EBoard 06: Transforming colors and images (Section 1)

Today’s start-of-class procedure

  • Grab one or two quizzes.
  • Take one of the business cards from OUTSIDE the jar.
  • Identify where the named computer is.
  • Drop the business card in the jar.
  • Navigate to that computer.
  • If you are first, log in, but do not start the lab.
  • When a second person arrives, introduce yourselves.

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

Approximate optimistic overview

  • Quiz [15 min]
  • Administrative stuff [5 min]
  • Questions [5 min]
  • Lab [50 min]
  • Turn in lab [5 min]

Administrative stuff

Introductory notes

  • I’m going to try to keep intro stuff short so that you have more time for lab.
  • If you can’t make it to class, for whatever reason, please send me a note (email or Teams Message), preferably in advance of class. You need not explain why.
    • Missing class, no note: Two tokens charged.
    • Missing class, with note: No charge.
  • I tend to have a bimodal response rate for email and DMs: Either I respond quickly or I forget about the message and never respond. If I haven’t responded to your email or DM within 24 hours, feel free to send me a reminder.
  • Please read your comments for quizzes and such on Gradescope, even if you get credit for them. We try to provide useful feedback.

Upcoming activities

Scholarly

  • Tuesday, 11 February 2025, Noon–12:50 p.m., PDR 224C (White Dining Room). CS Table: ???
  • Thursday, 13 February 2025, 11:00 a.m.–Noon, JRC 101. Grinnell Lecture: Darrius Hills on “The Achievement of Identity: Soul Work, Salvation, and Black Manhood in the Religious Imagination of James Baldwin”.

Artistic

Multicultural

  • Friday, 7 February 2025, 4:00-5:00 p.m., HSSC N1170 (Global Living Room) Middle of Everywhere: How to Order a Coffee in Singapore.

Peer

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

Wellness

  • Friday, 7 February 2025, 5:30–8:00 p.m., Downtown Grinnell. The Sweet Stroll.
  • Tuesday, 11 February 2025, 12:15–12:50 p.m., GCMoA. Yoga in the Museum.
  • Tuesday, 11 February 2025, 4:30–6:30 p.m., BRAC P103 (Multipurpose Dance Studio). Wellness Yoga.

Misc

  • Wednesday, 5 February 2025, Noon–12:45 p.m., Science 2021. Learn about the UIowa U2G (aka 4+1) program.
  • Thursday, 6 February 2025, 4:15–5:00 p.m., Herrick. Installation Ceremony for Endowed Professorships.
  • Sunday, 9 February 2025, 7:30–8:30pm, 3819. Mentor Session.
  • Tuesday, 11 February 2025, 7:00–8:00 p.m., Science 3820. Mentor Session.
  • Tuesday, 18 February 2025. 6:00–7:00 p.m., HSSC A1231. Make a Portfolio Website.

Other good things

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

(none at the moment)

Upcoming work

Q&A

Administrative

Readings

Is the color swatch returned on calling (rgb ) an image, or some other kind of expression? If so, what is it?

It’s a color. Or a representation of a color.

Can we go over self-check 4?

Sure.

For self-check 4, how can we create a procedure that specifies colors by both the colors name and their RGB values?

That’s a great followup question. I believe there’s a color->rgb procedure that converts any form of color to an RGB color. So we could use something like (o rgb-redder rgb-bluer color->rgb).

MP2

Are there problems with outlined-polygon when coordinates are negative?

Yes.

Lab

Please make sure to copy the code from the lab page into DrRacket.

When you submit: If you reference the images in your definitions pane, then you’ll need to upload those, too.

This is a lab in which I’d recommend that you read the rest somewhat carefully. You don’t need to figure out numbers, but you should understand the cuts and such.