Category : Printer + Display Graphics
Archive   : GRAPHIT2.ZIP
Filename : GRAPHIT3.HLP

 
Output of file : GRAPHIT3.HLP contained in archive : GRAPHIT2.ZIP
THE DEFAULT SETTINGS

When you run GraphIt! without any command-line arguments,
the following settings are in effect:
Start of range: (-12.0, -8.14*) End of range: (19.5, 8.14*)
Fineness: 1.0 ** Step rate: 0.0625 (1/16)
Legends: ON Warnings: OFF
Printer: OFF AutoRedraw: ON

This provides a basic rectangular grid of decent size with the origin
centered, a square aspect ratio (a 1x1 square on the grid really LOOKS
square), and a good resolution graph.

* on VGA + or - 8.48 because its 30 text rows allow more of the vertical
pixels to be used for the graph than the 25 rows of CGA/EGA.
** 0.5 on CGA systems to speed up graphs with reduced resolution.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
VIEWING THE SETTINGS

The current settings are almost always displayed whenever you change one
of them. Every item under Options (unless aborted) will bring up the settings
screen. You can also look at them manually by selecting Settings in the
Options menu. Press PgDn for help on Scale.
CHANGING THE SCALE

The scale function allows you to change the scale of the graph you have
on-screen while keeping the center of the display the same (the origin may
move but if (2,2) is at the middle of the screen, it will stay there). The
scale is totally relative to the size of the grid that is presently on the
screen, so you need not make any comparison with an absolute scale of 1. To
rescale the grid, select "Scale" from the options menu. Then respond to the
prompt according to the following guidelines:

Enter a positive number to zoom in, or a negative number to pan out. The
number of units across the screen will be divided or multiplied by that number
accordingly. Numbers between -1 and 1, inclusive, are invalid because they
produce meaningless values. Decimals greater than 1 or less than -1 are valid
though.

If you enter an invalid number, you will be asked again to enter the
scale. To abort rescaling, just press enter on a blank line.

To scale the default range, use the "/S" option on the command line (see
Appendix A of GRAPHIT.DOC).

Press PgDn for help on Range.
ADJUSTING THE RANGE

The ability to adjust the grid by inputting the beginning and end of the
desired range is one of the most powerful and flexible features GraphIt!
offers. It can rescale the grid to either be a perfect fit for the function
you are graphing so that as much of it is visible as possible or to render the
most accurate image possible on even the lowest resolution CGA screen. Both of
these features can be accomplished by selecting Range in the Options menu.

To create a grid such as the first, graph an equation on the standard
grid, and from that graph determine the top-, bottom-, left- and rightmost
extremities of the graph, and respond with the proper values to the 4 Range
prompts. The new grid may be somewhat expanded or compressed depending on the
aspect ratio, but it will show the same amount of graph in much greater
detail.
To create a more accurate representation like the second grid, have some
idea in your mind as to the left, right, and top of the grid. Enter these 3
numbers in the first 3 range prompts, and on the fourth one just press enter.
Voil…. The bottom of the grid will be AutoScaled to the exact y to x ratio
needed to get a square aspect ratio...if it isn't, you'd better check the
vertical size knob on your monitor! To set the range from the command line,
use the /X1:, /X2:, /Y1:, /Y2:, and /Y2 options [described in Appendix A].

Press PgDn for help on Fineness.
ADJUSTING THE FINENESS
The fineness factor determines how high the resolution of the graph will
be, and in effect, also the amount of time it takes to complete the graph. The
default fineness factor of 1 is quite adequate in most circumstances. With the
addition of SmartFineness automatic fineness adjustment in the graph-drawing
loop, the manual fineness adjustment has become almost obsolete, but I left it
in to accomodate the need for especially sharp graphs or for especially quick
renderings. SmartFineness automatically decreases the fineness when the point
being graphed is not on the screen to speed up blank areas, then recovers
automatically and backtracks to the spot where the graph comes on-screen
again. It also varies the fineness with the slope of the equation being
graphed, so steep graphs are tracked more effectively. As the fineness is
increased, more of the curve will be smoothed out, but remember that if you
increase the fineness factor to 5, the computer will be slowed down to 1/5 its
normal graphing speed under the load of all the extra calculations.
If you have CGA adapter, GraphIt! assumes you are using an 8088 non-turbo
PC and reduces the fineness to 0.5 to speed up graphing; the difference in
resolution is usually not very noticeable on the CGA screen, but the
difference in speed is.
To change the fineness factor, select Fineness from the Options menu. Any
value greater than zero is valid; however I would recommend not going below
0.25, as the image quality suffers.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄEnd of Options help. Press ESC to return to menu.ÄÄÄÄÄÄÄÄÄÄÄÄÄÄ


  3 Responses to “Category : Printer + Display Graphics
Archive   : GRAPHIT2.ZIP
Filename : GRAPHIT3.HLP

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