- ...Language
- This problem set was developed by Hal
Abelson, based upon work by Peter Henderson (``Functional Geometry,''
in Proc. ACM Conference on Lisp and Functional Programming,
1982). The image display code was designed and implemented by Daniel
Coore.
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- ...assignment.
- Section
2.2.4 does not depend very strongly on section 2.2.3, so you can start
working on this problem set without reading 2.2.3. Be sure, however,
to read all of section 2.2 before lecture on February 24.
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- ....
- This way of constructing a
painter is a lot like the procedure->picture procedure you used
in problem set 1. The difference is that here the x and y
arguments range between 0 and 1, rather than from 0 to 127.
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- ...painter.
- The images are kept in
the directory specified by the variable 6001-image-directory.
These images are accessible in a shared directory in the lab, and they
are loaded as part of the PS3 problem set code if you are using your
own computer. Use the Edwin command M-x list-directory to see
the entire contents of the image directory. Each image is
, stored in ``pgm'' format.
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- ...interesting.
- Painting a primitive image
like rogers won't look any different at high resolution, because
the original picture is only . But as you start
stretching and shrinking the image, you will see differences at higher
resolution.
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- ...paint.
- You
may have already learned how to print graphics when you did problem
set 1. If not, consult the ``Don't Panic'' manual.
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- ...painters.
- If setup (or painting) does not work, there
are several things that could be wrong. Your data abstraction
definitions might be incorrect. Or the system might not be able to
locate the image files or the compiled code files need for this
problem set. Whatever the problem is fix it now,
getting help if necessary, before going on.
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- ...frame.
- This isn't interesting if both painters are images that fill the
entire frame-you'll just see painter2-but it becomes
interesting if the second painter is a line drawing.
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