1Chart(3)              User Contributed Perl Documentation             Chart(3)
2
3
4

NAME

6       Chart - a series of charting modules
7

SYNOPSIS

9           use Chart::type;   (type is one of: Points, Lines, Bars, LinesPoints, Composite,
10           StackedBars, Mountain, Pie, HorizontalBars, Split, ErrorBars, Pareto, Direction)
11
12           $obj = Chart::type->new;
13           $obj = Chart::type->new ( $png_width, $png_height );
14
15           $obj->set ( $key_1, $val_1, ... ,$key_n, $val_n );
16           $obj->set ( $key_1 => $val_1,
17                       ...
18                       $key_n => $val_n );
19           $obj->set ( %hash );
20
21           # GIFgraph.pm-style API to produce png formatted charts
22           @data = ( \@x_tick_labels, \@dataset1, ... , \@dataset_n );
23           $obj->png ( "filename", \@data );
24           $obj->png ( $filehandle, \@data );
25           $obj->png ( FILEHANDLE, \@data );
26           $obj->cgi_png ( \@data );
27
28           # Graph.pm-style API
29           $obj->add_pt ($label, $val_1, ... , $val_n);
30           $obj->add_dataset ($val_1, ... , $val_n);
31           $obj->png ( "filename" );
32           $obj->png ( $filehandle );
33           $obj->png ( FILEHANDLE );
34           $obj->cgi_png ();
35
36           The similar functions are available for j-peg
37
38           # Retrieve image map information
39           $obj->set ( 'imagemap' => 'true' );
40           $imagemap_ref = $obj->imagemap_dump ();
41

DESCRIPTION

43       These man-pages give you the most important information about Chart.
44       There is also a complete documentation (Documentation.pdf) within the
45       Chart package. Look at it to get more information.  This module is an
46       attempt to build a general purpose graphing module that is easily
47       modified and expanded.  I borrowed most of the API from Martien
48       Verbruggen's GIFgraph module.  I liked most of GIFgraph, but I thought
49       it was to difficult to modify, and it was missing a few things that I
50       needed, most notably legends.  So I decided to write a new module from
51       scratch, and I've designed it from the bottom up to be easy to modify.
52       Like GIFgraph, Chart uses Lincoln Stein's GD module for all of its
53       graphics primitives calls.
54
55   use-ing Chart
56       Okay, so you caught me.  There's really no Chart::type module.  All of
57       the different chart types (Points, Lines, Bars, LinesPoints, Composite,
58       StackedBars, Pie, Pareto, HorizontalBars, Split, ErrorBars, Direction
59       and Mountain so far) are classes by themselves, each inheriting a bunch
60       of methods from the Chart::Base class.  Simply replace the word type
61       with the type of chart you want and you're on your way.  For example,
62
63         use Chart::Lines;
64
65       would invoke the lines module.
66
67   Getting an object
68       The new method can either be called without arguments, in which case it
69       returns an object with the default image size (400x300 pixels), or you
70       can specify the width and height of the image.  Just remember to
71       replace type with the type of graph you want.  For example,
72
73         $obj = Chart::Bars->new (600,400);
74
75       would return a Chart::Bars object containing a 600x400 pixel image.
76       New also initializes most of the default variables, which you can
77       subsequently change with the set method.
78
79   Setting different options
80       This is where the fun begins.  Set looks for a hash of keys and values.
81       You can pass it a hash that you've already constructed, like
82
83         %hash = ('title' => 'Foo Bar');
84         $obj->set (%hash);
85
86       or you can try just constructing the hash inside the set call, like
87
88         $obj->set ('title' => 'Foo Bar');
89
90       The following are all of the currently supported options:
91
92       'transparent'
93           Makes the background of the image transparent if set to 'true'.
94           Useful for making web page images.  Default is 'false'.
95
96       'png_border'
97           Sets the number of pixels used as a border between the graph and
98           the edges of the png/j-peg.  Defaults to 10.
99
100       'graph_border'
101           Sets the number of pixels used as a border between the title/labels
102           and the actual graph within the png.  Defaults to 10.
103
104       'text_space'
105           Sets the amount of space left on the sides of text, to make it more
106           readable.  Defaults to 2.
107
108       'title'
109           Tells GD graph what to use for the title of the graph.  If empty,
110           no title is drawn.  It recognizes '\n' as a newline, and acts
111           accordingly.  Remember, if you want to use normal quotation marks
112           instead of single quotation marks then you have to quote "\\n".
113           Default is empty.
114
115       'sub_title'
116           Write a sub-title under the title in smaller letters.
117
118       'x_label'
119           Tells Chart what to use for the x-axis label.  If empty, no label
120           is drawn.  Default is empty.
121
122       'y_label', 'y_label2'
123           Tells Chart what to use for the y-axis labels.  If empty, no label
124           is drawn.  Default is empty.
125
126       'legend'
127           Specifies the placement of the legend.  Valid values are 'left',
128           'right', 'top', 'bottom'.  Setting this to 'none' tells chart not
129           to draw a legend.  Default is 'right'.
130
131       'legend_labels'
132           Sets the values for the labels for the different data sets.  Should
133           be assigned a reference to an array of labels.  For example,
134
135             @labels = ('foo', 'bar');
136             $obj->set ('legend_labels' => \@labels);
137
138           Default is empty, in which case 'Dataset 1', 'Dataset 2', etc. are
139           used as the labels.
140
141       'tick_len'
142           Sets the length of the x- and y-ticks in pixels.  Default is 4.
143
144       'x_ticks'
145           Specifies how to draw the x-tick labels.  Valid values are
146           'normal', 'staggered' (staggers the labels vertically), and
147           'vertical' (the labels are draw upwards).  Default is 'normal'.
148
149       'xy_plot'
150           Forces Chart to plot a x-y-graph, which means, that the x-axis is
151           also numeric if set to 'true'. Very useful for mathematical graphs.
152           Works for Lines, Points, LinesPoints and ErrorBars. Split makes
153           always a xy_plot. Defaults to 'false'.
154
155       'min_y_ticks'
156           Sets the minimum number of y_ticks to draw when generating a scale.
157           Default is 6, The minimum is 2.
158
159       'max_y_ticks'
160           Sets the maximum number of y_ticks to draw when generating a scale.
161           Default is 100. This limit is used to avoid plotting an
162           unreasonable large number of ticks if non-round values are used for
163           the min_val and max_val.
164
165           The value for 'max_y_ticks' should be at least 5 times larger than
166           'min_y_ticks'.
167
168       'max_x_ticks', 'min_x_ticks'
169           Work similar as 'max_y_ticks' and 'min_y_ticks'. Of course, only
170           for a xy_plot.
171
172       'integer_ticks_only'
173           Specifies how to draw the x- and y-ticks: as floating point
174           ('false', '0') or as integer numbers ('true', 1). Default: 'false'
175
176       'skip_int_ticks'
177           If 'integer_ticks_only' was set to 'true' the labels and ticks will
178           be drawn every nth tick. Of course in horizontalBars it affects the
179           x-axis. Default to 1, no skipping.
180
181       'precision'
182           Sets the number of numerals after the decimal point. Affects in
183           most cases the y-axis. But also the x-axis if 'xy_plot' was set and
184           also the labels in a pie chart. Defaults to 3.
185
186       'max_val'
187           Sets the maximum y-value on the graph, overriding the normal auto-
188           scaling.  Default is undef.
189
190       'min_val'
191           Sets the minimum y-value on the graph, overriding the normal auto-
192           scaling.  Default is undef.
193
194           Caution should be used when setting 'max_val' and 'min_val' to
195           floating point or non-round numbers. This is because the scale must
196           start & end on a tick, ticks must have round-number intervals, and
197           include round numbers.
198
199           Example: Suppose your data set has a range of 35-114 units. If you
200           specify them as the 'min_val' & 'max_val', the y_axis will be
201           plotted with 80 ticks every 1 unit.. If no 'min_val' & 'max_val',
202           the system will auto scale the range to 30-120 with 10 ticks every
203           10 units.
204
205           If the 'min_val' & 'max_val' are specified to excessive precision,
206           they may be overridden by the system, plotting a maximum
207           'max_y_ticks' ticks.
208
209       'include_zero'
210           If 'true', forces the y-axis to include zero if it is not in the
211           dataset range. Default is 'false'.
212
213           In general, it is better to use this, than to set the 'min_val' if
214           that is all you want to achieve.
215
216       'pt_size'
217           Sets the radius of the points (for Chart::Points, etc.) in pixels.
218           Default is 18.
219
220       'brush_size'
221           Sets the width of the lines (for Chart::Lines, etc.) in pixels.
222           Default is 6.
223
224       'brushStyle'
225           Sets the shape of points for Chart::Points, Chart::LinesPoints.
226           The possibilities are 'FilledCircle', 'circle', 'donut',
227           'OpenCircle', 'fatPlus', 'triangle', 'upsidedownTriangle',
228           'square', 'hollowSquare', 'OpenRectangle', 'FilledDiamond',
229           'OpenDiamond', 'Star', 'OpenStar'.  Default: 'FilledCircle
230
231       'skip_x_ticks'
232           Sets the number of x-ticks and x-tick labels to skip.  (ie.  if
233           'skip_x_ticks' was set to 4, Chart would draw every 4th x-tick and
234           x-tick label).  Default is undef.
235
236       'custom_x_ticks'
237           Used in points, lines, linespoints, errorbars and bars charts, this
238           option allows you to you to specify exactly which x-ticks and
239           x-tick labels should be drawn.  It should be assigned a reference
240           to an array of desired ticks.  Just remember that I'm counting from
241           the 0th element of the array.  (ie., if 'custom_x_ticks' is
242           assigned [0,3,4], then the 0th, 3rd, and 4th x-ticks will be
243           displayed)
244
245       'f_x_tick'
246           Needs a reference to a function which uses the x-tick labels
247           generated by the '@data[0]' as the argument. The result of this
248           function can reformat the labels. For instance
249
250              $obj -> set ('f_x_tick' => \&formatter );
251
252           An example for the function formatter: x labels are seconds since
253           an event.  The referenced function can transform this seconds to
254           hour, minutes and seconds.
255
256       'f_y_tick'
257           The same situation as for 'f_x_tick' but now used for y labels.
258
259       'colors'
260           This option lets you control the colors the chart will use.  It
261           takes a reference to a hash.  The hash should contain keys mapped
262           to references to arrays of rgb values.  For instance,
263
264                   $obj->set('colors' => {'background' => [255,255,255]});
265
266           sets the background color to white (which is the default).  Valid
267           keys for this hash are
268
269                   'background' (background color for the png)
270                   'title' (color of the title)
271                   'text' (all the text in the chart)
272                   'x_label' (color of the x-axis label)
273                   'y_label' (color of the first y axis label)
274                   'y_label2' (color of the second y axis label)
275                   'grid_lines' (color of the grid lines)
276                   'x_grid_lines' (color of the x grid lines - for x axis ticks)
277                   'y_grid_lines' (color of the y grid lines - for to left y axis ticks)
278                   'y2_grid_lines' (color of the y2 grid lines - for right y axis ticks)
279                   'dataset0'..'dataset63' (the different datasets)
280                   'misc' (everything else, ie. ticks, box around the legend)
281
282           NB. For composite charts, there is a limit of 8 datasets per
283           component.  The colors for 'dataset8' through 'dataset15' become
284           the colors for 'dataset0' through 'dataset7' for the second
285           component chart.
286
287       'title_font'
288           This option changes the font of the title. The key has to be a GD
289           font.  eg. GD::Font->Large
290
291       'label_font'
292           This option changes the font of the labels. The key has to be a GD
293           font.
294
295       'legend_font'
296           This option changes the font of the text in the legend.  The key
297           has to be a GD font.
298
299       'tick_label_font'
300           This is the font for the tick labels. It also needs a GD font
301           object as an argument.
302
303       'grey_background'
304           Puts a nice soft grey background on the actual data plot when set
305           to 'true'.  Default is 'true'.
306
307       'y_axes'
308           Tells Chart where to place the y-axis. Has no effect on Composite
309           and Pie.  Valid values are 'left', 'right' and 'both'. Defaults to
310           'left'.
311
312       'x_grid_lines'
313           Draws grid lines matching up to x ticks if set to 'true'. Default
314           is false.
315
316       'y_grid_lines'
317           Draws grid lines matching up to y ticks if set to 'true'. Default
318           is false.
319
320       'grid_lines'
321           Draws grid lines matching up to x and y ticks.
322
323       'spaced_bars'
324           Leaves space between the groups of bars at each data point when set
325           to 'true'.  This just makes it easier to read a bar chart.  Default
326           is 'true'.
327
328       'imagemap'
329           Lets Chart know you're going to ask for information about the
330           placement of the data for use in creating an image map from the
331           png.  This information can be retrieved using the imagemap_dump()
332           method.  NB. that the imagemap_dump() method cannot be called until
333           after the Chart has been generated (ie. using the png() or
334           cgi_png() methods).
335
336       'sort'
337           In a xy-plot, the data will be sorted ascending if set to 'true'.
338           (Should be set if the data isn't sorted, especially in Lines, Split
339           and LinesPoints) In a Pareto Chart the data will be sorted
340           descending.  Defaults to 'false'.
341
342       'composite_info'
343           This option is only used for composite charts.  It contains the
344           information about which types to use for the two component charts,
345           and which datasets belong to which component chart. It should be a
346           reference to an array of array references, containing information
347           like the following
348
349                   $obj->set ('composite_info' => [ ['Bars', [1,2]],
350                                                    ['Lines', [3,4] ] ]);
351
352           This example would set the two component charts to be a bar chart
353           and a line chart.  It would use the first two data sets for the bar
354           chart (note that the numbering starts at 1, not zero like most of
355           the other numbered things in Chart), and the second two data sets
356           for the line chart.  The default is undef.
357
358           NB. Chart::Composite can only do two component charts.
359
360       'min_val1', 'min_val2'
361           Only for composite charts, these options specify the minimum
362           y-value for the first and second components respectively.  Both
363           default to undef.
364
365       'max_val1', 'max_val2'
366           Only for composite charts, these options specify the maximum
367           y-value for the first and second components respectively.  Both
368           default to undef.
369
370       'ylabel2'
371           The label for the right y-axis (the second component chart) on a
372           composite chart.  Default is undef.
373
374       'y_ticks1', 'y_ticks2'
375           The number of y ticks to use on the first and second y-axis on a
376           composite chart.  Please note that if you just set the 'y_ticks'
377           option, both axes will use that number of y ticks.  Both default to
378           undef.
379
380       'f_y_ticks1', 'f_y_ticks2'
381           Only for composite charts, needs a reference to a function which
382           has one argument and has to return a string which labels the first
383           resp. second y axis.  Both default to undef.
384
385       'same_y_axes'
386           Forces both component charts in a composite chart to use the same
387           maximum and minimum y-values if set to 'true'.  This helps to keep
388           the composite charts from being too confusing.  Default is undef.
389
390       'no_cache'
391           Adds Pragma: no-cache to the http header.  Be careful with this
392           one, as Netscape 4.5 is unfriendly with POST using this method.
393
394       'legend_example_size'
395           Sets the length of the example line in the legend in pixels.
396           Defaults to 20.
397
398       'same_error'
399           This is a option only for ErrorBars. It tells chart that you want
400           use the same error value of a data point if set to 'true'. Look at
401           the documentation to see how the module ErrorBars works. Default:
402           'false'.
403
404       'skip_y_ticks'
405           Does the same for the y-axis at a HorizontalBars chart as
406           'skip_x_ticks' does for other charts. Defaults to 1.
407
408       'label_values'
409           Tells a pie chart what labels to draw beside the pie. Valid values
410           are 'percent', 'value', 'both' and 'none'. Defaults to 'percent'.
411
412       'legend_label_values'
413           Tells a pie chart what labels to draw in the legend. Valid values
414           are 'percent', 'value', 'both' and 'none'. Defaults to 'value'.
415
416       'start'
417           Required value for a split chart. Sets the start value of the first
418           interval.  If the x coordinate of the first data point is zero, you
419           should 'set' to zero. Default is 'undef'.
420
421       'interval'
422           Also a required value for a split chart. It sets the interval of
423           one line to plot. Defaults 'undef'.
424
425       'interval_ticks'
426           Sets the number of ticks for the x-axis of a Split chart. Defaults
427           to 5.
428
429       'scale'
430           Every y-value of a split chart will be multiplied with that value,
431           but the scale won't change. Which means that split allows one to
432           overdraw certain rows! Only useful if you want to give prominence
433           to the maximal amplitudes of the data. Defaults to 1.
434
435       'point'
436           Indicates to draw points in a direction chart. 'true' or 'false'
437           possible.  Defaults to 'true'.
438
439       'line'
440           If you turn this option to 'true', then direction will connect the
441           points with lines. Defaults to 'false'.
442
443       'arrow'
444           This is also an option for the direction module. If set to 'true',
445           chart will draw a arrow from the center to the point. Defaults to
446           'false'.
447
448       'angle_interval'
449           This option tells direction, how many angle lines should be drawn.
450           The default value is 30, which means that a line will be drawn
451           every 30 degrees. Valid Values are: 0, 5, 10, 15, 20, 30, 45 and
452           60. If you choose 0, direction will draw no line.
453
454       'min_circles'
455           Sets the minimum number of circles when generating a scale for
456           direction.  Default is 4, minimum is 2.
457
458       'max_circles'
459           Sets the maximum number of circles when generating a scale for
460           direction.  Default is 100. This limit is used to avoid plotting
461           an unreasonable large number of ticks if non-round values are used
462           for the min_val and max_val.
463
464       'pairs'
465           Only used for direction how to handle more datasets.
466                          If 'pairs' is set to 'true',
467                          Chart uses the first dataset as a set of degrees and
468                          the second dataset as a set of values.
469                          Then, the third set is a set of degrees and the
470           fourth a set of values \dots. \\
471                          If 'pairs' is set to 'false',
472                          Chart uses the first dataset as a set of angels
473                          and all following datasets as sets of values.
474                          Defaults to 'false'.
475
476           Sets the maximum number of circles when generating a scale for
477           direction.  Default is 100. This limit is used to avoid plotting
478           an unreasonable large number of ticks if non-round values are used
479           for the min_val and max_val.
480
481   GIFgraph.pm-style API
482       Sending the image to a file
483           Invoking the png method causes the graph to be plotted and saved to
484           a file.  It takes the name of the output file and a reference to
485           the data as arguments.  For example,
486
487             $obj->png ("foo.png", \@data);
488
489           would plot the data in @data, and the save the image to foo.png.
490           Of course, this then beggars the question "What should @data look
491           like?".  Well, just like GIFgraph, @data should contain references
492           to arrays of data, with the first array reference pointing to an
493           array of x-tick labels.  For example,
494
495             @data = ( [ 'foo', 'bar', 'junk' ],
496                       [ 30.2,  23.5,  92.1   ] );
497
498           would set up a graph with one dataset, and three data points in
499           that set.  In general, the @data array should look something like
500
501             @data = ( \@x_tick_labels, \@dataset1, ... , \@dataset_n );
502
503           And no worries, I make my own internal copy of the data, so that it
504           doesn't mess with yours.
505
506       CGI and Chart
507           Okay, so you're probably thinking, "Do I always have to save these
508           images to disk?  What if I want to use Chart to create dynamic
509           images for my web site?"  Well, here's the answer to that.
510
511             $obj->cgi_png ( \@data );
512
513           The cgi_png method will print the chart, along with the appropriate
514           http header, to stdout, allowing you to call chart-generating
515           scripts directly from your html pages (ie. with a <lt>img
516           src=image.pl<gt> HTML tag).  The @data array should be set up the
517           same way as for the normal png method.
518
519   Graph.pm-style API
520       You might ask, "But what if I just want to add a few points to the
521       graph, and then display it, without all those references to
522       references?".  Well, friend, the solution is simple.  Borrowing the
523       add_pt idea from Matt Kruse's Graph module, you simply make a few calls
524       to the add_pt method, like so:
525
526           $obj->add_pt ('foo', 30, 25);
527           $obj->add_pt ('bar', 16, 32);
528
529       Or, if you want to be able to add entire datasets, simply use the
530       add_dataset method:
531
532           $obj->add_dataset ('foo', 'bar');
533           $obj->add_dataset (30, 16);
534           $obj->add_dataset (25, 32);
535
536       These methods check to make sure that the points and datasets you are
537       adding are the same size as the ones already there.  So, if you have
538       two datasets currently stored, and try to add a data point with three
539       different values, it will carp (per the Carp module) an error message.
540       Similarly, if you try to add a dataset with 4 data points, and all the
541       other datasets have 3 data points, it will carp an error message.
542
543       Don't forget, when using this API, that I treat the first dataset as a
544       series of x-tick labels.  So, in the above examples, the graph would
545       have two x-ticks, labeled 'foo' and 'bar', each with two data points.
546       Pie and ErrorBars handle it different, look at the documentation to see
547       how it works.
548
549       Adding a datafile
550           You can also add a complete datafile to a chart object. Just use
551           the add_datafile() method.
552
553                   $obj->add_datafile('file', 'set' or 'pt');
554
555           file can be the name of the data file or a filehandle.  'set' or
556           'pt is the type of the datafile.  If the parameter is 'set' then
557           each line in the data file has to be a complete data set. The value
558           of the set has to be separated by white spaces. For example the
559           file looks like this:
560
561                   'foo'  'bar'
562                   30     16
563                   25     32
564
565           If the parameter is 'pt', one line has to include all values of one
566           data point separated by white spaces. For example:
567
568                   'foo'  30  25
569                   'bar'  16  32
570
571       Clearing the data
572           A simple call to the clear_data method empties any values that may
573           have been entered.
574
575               $obj->clear_data ();
576
577       Getting a copy of the data
578           If you want a copy of the data that has been added so far, make a
579           call to the get_data method like so:
580
581                   $dataref = $obj->get_data;
582
583           It returns (you guessed it!) a reference to an array of references
584           to datasets.  So the x-tick labels would be stored as
585
586                   @x_labels = @{$dataref->[0]};
587
588       Sending the image to a file
589           If you just want to print this chart to a file, all you have to do
590           is pass the name of the file to the png() method.
591
592                   $obj->png ("foo.png");
593
594       Sending the image to a filehandle
595           If you want to do something else with the image, you can also pass
596           a filehandle (either a typeglob or a FileHandle object) to png, and
597           it will print directly to that.
598
599                   $obj->png ($filehandle);
600                   $obj->png (FILEHANDLE);
601
602       CGI and Chart
603           Okay, so you're probably thinking (again), "Do I always have to
604           save these images to disk?  What if I want to use Chart to create
605           dynamic images for my web site?"  Well, here's the answer to that.
606
607                   $obj->cgi_png ();
608
609           The cgi_png method will print the chart, along with the appropriate
610           http header, to stdout, allowing you to call chart-generating
611           scripts directly from your html pages (ie. with a <lt>img
612           src=image.pl<gt> HTML tag).
613
614       Produce a png image as a scalar
615           Like scalar_jpeg() the image is produced as a scalar so that the
616           programmer-user can do whatever the heck s/he wants to with it:
617
618                   $obj-scalar_png($dataref)
619
620       Produce a jpeg image as a scalar
621           Like scalar_png() the image is produced as a scalar so that the
622           programmer-user can do whatever the heck s/he wants to with it:
623
624                   $obj-scalar_jpeg($dataref)
625
626   Imagemap Support
627       Chart can also return the pixel positioning information so that you can
628       create image maps from the pngs Chart generates.  Simply set the
629       'imagemap' option to 'true' before you generate the png, then call the
630       imagemap_dump() method afterwards to retrieve the information.  You
631       will be returned a data structure almost identical to the @data array
632       described above to pass the data into Chart.
633
634               $imagemap_data = $obj->imagemap_dump ();
635
636       Instead of single data values, you will be passed references to arrays
637       of pixel information.  For Bars, HorizontalBars and StackedBars charts,
638       the arrays will contain two x-y pairs (specifying the upper left and
639       lower right corner of the bar), like so
640
641               ( $x1, $y1, $x2, $y2 ) = @{ $imagemap_data->[$dataset][$datapoint] };
642
643       For Lines, Points, ErrorBars, Split and LinesPoints, the arrays will
644       contain a single x-y pair (specifying the center of the point), like so
645
646               ( $x, $y ) = @{ $imagemap_data->[$dataset][$datapoint] };
647
648       A few caveats apply here.  First of all, GD treats the upper-left
649       corner of the png as the (0,0) point, so positive y values are measured
650       from the top of the png, not the bottom.  Second, these values will
651       most likely contain long decimal values.  GD, of course, has to
652       truncate these to single pixel values.  Since I don't know how GD does
653       it, I can't truncate it the same way he does.  In a worst-case
654       scenario, this will result in an error of one pixel on your imagemap.
655       If this is really an issue, your only option is to either experiment
656       with it, or to contact Lincoln Stein and ask him.  Third, please
657       remember that the 0th dataset will be empty, since that's the place in
658       the @data array for the data point labels.
659

TO DO

661       ยท   Add some 3-D graphs.  Include True Type Fonts
662

BUGS

664       Probably quite a few, since it's been completely rewritten.  As usual,
665       please mail me with any bugs, patches, suggestions, comments, flames,
666       death threats, etc.
667

AUTHOR

669       David Bonner (dbonner@cs.bu.edu)
670

MAINTAINER

672       Chart Group (Chart@fs.wettzell.de)
673
675       Copyright(c) 1997-1998 by David Bonner, 1999 by Peter Clark, 2001 by
676       the Chart group at BKG-Wettzell.  All rights reserved.  This program is
677       free software; you can redistribute it and/or modify it under the same
678       terms as Perl itself.
679

POD ERRORS

681       Hey! The above document had some coding errors, which are explained
682       below:
683
684       Around line 694:
685           '=item' outside of any '=over'
686
687       Around line 706:
688           '=item' outside of any '=over'
689
690
691
692perl v5.32.0                      2020-07-28                          Chart(3)
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