# Class 44: Time to Work on Projects

Back to Association Lists. On to Higher-Order Procedures, Revisited.

This outline is also available in PDF.

Held: Friday, April 23, 2010

Summary: Some class time for you to work on your projects.

Related Pages:

Notes:

• Reading for Monday: Higher-Order Procedures.
• Although you would not know it from the way I speak, it's Talk Like Shakespeare",/a> day in Chicago.
• EC for CS table today: Alumnus Josh More '??, who graduated from Grinnell with a degree in Physics but is now in computing (he calls himself an "Entropologist", one who deals with chaos in systems). You can learn more about Josh at his Web site, `http://www.starmind.org/`.
• EC for cultural evening Friday sponsored by ISO.
• EC for Chamber Concert Saturday at 3:15 in S-L.
• EC for Tennis on Saturday and Sunday.
• EC for Field day a week from Saturday.

Overview:

• Project Tips.
• Project Time.

## A Few Project Ideas

• You can draw curved lines with
`(image-draw-curve image start end control)`
• Line from start to end
• Curves in the direction of control
• All three positions are created with `(position-new col row)`
• You can also create positions with `(cons col row)`
• You can draw more complex curves with
`(image-curve-the-dots image list-of-positions curviness)`
• The line goes through all the positions
• The curviness expresses how much to curve as it makes the path
• You'll probably want to experiment with it
• You can compute pixels in the selected region with
`(selection-compute-pixels! image position-to-color)`.
• If you want to compute the color of pixels along a line, you're best off selecting the line (that is, a polygonal shape close to the line) and using `selection-compute-pixels!`.
• You can get stuff from one image to another with
`(image-copy-selection IMAGE)` and
`(image-paste! IMAGE)`

## Time to Work on Projects

Use the remaining time to work on projects and to get ideas and advice from other folks.

Back to Association Lists. On to Higher-Order Procedures, Revisited.

Disclaimer: I usually create these pages on the fly, which means that I rarely proofread them and they may contain bad grammar and incorrect details. It also means that I tend to update them regularly (see the history for more details). Feel free to contact me with any suggestions for changes.

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Samuel A. Rebelsky, rebelsky@grinnell.edu

Copyright © 2007-10 Janet Davis, Matthew Kluber, Samuel A. Rebelsky, and Jerod Weinman. (Selected materials copyright by John David Stone and Henry Walker and used by permission.) This material is based upon work partially supported by the National Science Foundation under Grant No. CCLI-0633090. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This work is licensed under a Creative Commons Attribution-NonCommercial 2.5 License. To view a copy of this license, visit `http://creativecommons.org/licenses/by-nc/2.5/` or send a letter to Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 94105, USA.