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- Plot is based on the 3-D transformation programs described in the book
- "Graphics Primer for the IBM PC" by Mitchell Waite and Christopher L. Morgan.
- The low-res screen I used doesn't quite match the resolution of the IBM PC
- in hi-res mode (2 colors 640x200) but the plotting is faster and the save-
- picture routine only works in lo-res.
- Plot2 shows the detail available in 640x400 interlace mode. Use Grabbit to
- save screens, if desired.
-
- The menus M*X and M*Y control the aspect ratio and magnification factor of
- the plotting.
- Spin defines the amount of x axis rotation, and tip defines the amount of z
- axis rotation used in displaying the plot.
- When plotting new formulas with 'new plot' and 'new formula' use the green
- cursor to locate the plot on the screen, clicking the left mouse button to
- start plotting.
- Use 'new formula' to enter your own formula. The program as it stands now
- treats parenthesis as blank space. The trig functions translated include
- sine, cosine, tangent and arctangent(atn). The math functions are *,-,/,
- and +. Other trig functions may be added easily by expanding case
- statements in the functions 'translate()' and 'process()'. Other functions
- such as square root, with its dependency on parenthesis will take more
- analysis to include in the formula translation phase.
-
- To reiterate: syntax for an acceptable formula is AS(X)+BS(Y)+CS(Z)...up
- to 30 characters per formula (The dialog box only shows 18).
-
- where A,B and C are optional constants,
- S is an optional trig function (three letters optional, the first letter
- will work).
- X,Y and Z are the variables (X and Y are the only variables understood).
- The '+' could be any of the four math functions.
- Parenthesis is treated as blank space, but useful for titles--
- therefore cos(x)*cos(y) works as well as cx*cy
- but cos(x+y) doesn't work.
- 4x*cos(x)+tan(x) works as well as 4x*cx+tx
- but tan(cos(x*y)) doesn't work.
- Hopefully, I can devise a formula translation routine later that will
- correctly interpret all possibilities, but this is complicated stuff!
- This program is derived from public domain programs, and may not be
- published commercially.
- (The original programs were copyright 1983 by McGraw-Hill, but there is a
- release there to allow them to be typed, stored and executed in any
- computer, so that should include derived works too.)
-
- Any correspondence about this program should be addressed to
-
- Terry W. Gintz
- 4430 Pinecrest Drive
- Eugene, Or 97405
-
-