Jason Peasgood presents a utility for pie
charts, bar graphs and line graphs for simple home use. The program
is suitable for the 1029 printer but we have added a routine for
Epson compatibles
Many Atari owners use their computers
for some sort of business or record keeping so here is a simple
utility to give all those dry figures a bit of sparkle. Graph Maker
is not a super sophisticated program like the commercial B/Graph but
it will produce neat graphs of various figures, percentages etc.
which can be dumped out on a 1029, Epson or fully Epson compatible
printer.
The program gives you a choice of
either a Pie Chart, usually chosen for showing percentages of a base
number, a Bar Chart for showing comparative values of different
objects or a Line Graph, used for showing different values over a
period of time.
The main listing for Graph Maker will
print out graphs on a 1029 printer, but owners of Epson or Epson
compatible printers can omit lines 30000 to 30150 from Listing 1 and
use Listing 2  instead. Just leave Listing 1 in memory and carry on
typing Listing 2. Listing 2 can also be used as a stand alone
routine for a Graphics 8 screen dump on an Epson or compatible
printer:
PREPARING YOUR GRAPHS
The program has many easy to
understand prompts throughout but details of each type of graph are
given here for reference.
PIE CHART: This option allows
you to show percentages of any number neatly in an accurately
segmented circle. After the initial circle has been drawn you will
be asked to input the base number. This is the total that the
segments of the pie chart will be percentages of. You will then be
asked for the number of fields you require which is the number of
segments that the total will be divided into, so if you wanted 5
segments you would type 5.
The name and size of each field is
then requested. The size should not be input as a percentage, but as
the actual number it represents. Each segment is then calculated and
drawn, and the name is printed next to it. After all the segments
have been named and drawn you are asked for the title of the chart.
You will finally be given the option of either dumping the screen to
a printer, or creating another graph.
BAR CHART: You can use this
option to create graphs with up to 36 bars across (the xaxis), and
a wide range of scales are available on the yaxis.
After choosing the number of bars you
want you are asked for the smallest number you want on the yaxis,
which can be any number from 049. Next you are asked for the
maximum, which can be any number from 150, as long as it is larger
than the minimum number, but the difference between the two cannot
be more than 18. The numbers on the yaxis are then plotted, with
the scale calculated automatically thus using as
much of the screen as possible.
The height of each bar is then
requested. You must calculate the figures according to the scale
selected and you can only enter whole numbers up to the maximum
chosen. After the bar chart is drawn you are asked if you want to
create another graph or print the current one. If you choose to
print it you will be asked for individual names for each bar, and
labels for both axes.
LINE GRAPH: This can be used
to create a line graph, similar to the sort you see on a manager's
office wall referring to sales over an amount of time, but the
figures could represent anything such as the increase in a baby's
weight over a given period of time for example.
You will first be asked for the
number of points you want plotted, up to a maximum of 36. You are
then asked for the yaxis scale and the value of the points on the
xaxis, with the same rules applying as for the bar chart. The
points are then plotted, according to the numbers that were entered,
and joined up. When this is complete you are again asked if you want
to dump this graph to a printer, or create another graph. If you
choose to print it you will be asked for axis labels but you have a
choice whether you want individual labels for each point or if the
xaxis label is the general name. For example the xaxis could be
called 'November' or each point on the xaxis could be a separate
day/date.
ROUTINES INCLUDED
General routines included in the
program are a short program for printing text quickly onto a
Graphics 8 screen and a routine for drawing an accurate circle. The
printer dump routine is a Graphics 8 screen dump for the 1029 and
starts at line 30000. Remember, if you have an Epson printer, use
Listing 2 instead.
FINALLY ...
This program may not be as
sophisticated as commercial products like Mini Office II or B/Graph,
but it is a cheap and effective way to produce simple graphs and
charts which should cope well for small every day needs like who
pays what percentage of the telephone bill!



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