ANNOUNCE: Plotchart 2.0 (alpha)

[arjenmarkus]

PLOTCHART 2.0
-------------

* Note *
This is an alpha release of Plotchart 2.0 - see below.
I release this version now, so that you can experiment with it.

Get it from the CVS repository at http://tcllib.sf.net

Arjen
* End note *


Plotchart is a Tcl-only package for producing xy-plots, barcharts
and other popular types of graphical presentations. It aims at
being easy to use and therefore mainly provides high-level commands
to create an empty plot and commands to add the data you want to
present.

Here is a simple but typical example of how to create a plot
and fill it with data:

package require Plotchart

canvas .c -background white -width 400 -height 200
pack .c -fill both

#
# Create the plot with its x- and y-axes
#
set s [::Plotchart::createXYPlot .c {0.0 100.0 10.0} {0.0 100.0 20.0}]

foreach {x y} {0.0 32.0 10.0 50.0 25.0 60.0 78.0 11.0 } {
$s plot series1 $x $y
}

$s title "Data series"

Before version 2.0 all plots and charts were created on a dedicated
canvas. The dimensions of the area for the axes of an xy-plot were
derived from the entire size of the canvas, similarly for barcharts,
piecharts and all other types. One of the innovations in version 2.0
is that you can combine various plots and charts in one canvas.
Another one is that you now have the possibility to define styles
for the plots and charts to create a consistent look.

Version 2.0 also defines several new plot and chart types, among
others a "table" chart that allows you to present the data in a
combined textual and graphical way.

Plotchart 2.0 was developed by Arjen Markus and Torsten Berg
with contributions from various people.

What's new?
-----------
New commands:

createTableChart:
Create a so-called table chart. With a table chart you can
combine tabular information with graphics

createSpiralPie:
A variant on an ordinary piechart, where the radius is used
to show the size of an entry, rather than the angle.

clearcanvas:
Remove all data from a given canvas but leave the axes and
other elements intact.

plotstyle:
Define or load a style for the plots to be created. A style
consists of specific values for the various options used to
create a plot or chart.

plotmethod:
Add a new subcommand for a given plot/chart type. This
subcommand is implemented via a user-defined procedure.


New subcommands:

$anyplot removefromcanvas:
Remove an entry from the legend.

$xyplot plotlist
Plot a large series of data in one go, rather than each
data point individually.

$xyplot object (or drawobject)
$piechart object
$barchart object
$stripchart object
$boxplot
Plot an object (rectangle, circle, ...) in an xy-plot,
a barchart or a piechart using the plot's/chart's coordinate system.

$xyplot legendisolines
$xyplot legendshades
Add the class values for an isoline or contour plot to
the legend.

$xyplot getplotarea
Return the area (in pixels) reserved for the data.

$piechart colours
Set the colours to be used in a piechart (independent
from the style).

$histogram plotcumulative
Plot the data on top of the previous series.


New options:

For boxplots:
-whisher, -whiskerwidth, -mediancolour, -medianwidth (appearance of
the "whisker")
An optional argument for specifying the orientation

For symbols:
-radius (size of all symbols)

For histograms:
-style (style for drawing the data)

For right axes:
-ylabels (what labels to use along the axis)

For legends:
-type rectangle (meant for objects)
An optional argument to the "legend" subcommand: the distance
between entries

For the saveplot subcommand:
-plotregion (save what is visible or the entire canvas)

For gridlines:
The dash pattern of the lines as an optional argument

For several plot and chart types:
-box Defines the part of the canvas that is reserved for
the plot/chart
-axesbox Defines this part using the coordinate system of an
existing plot
-unit Defines the size of a piechart's pie
-reference Defines the position of a piechart wrt an existing plot

For piecharts and spiral charts:
Options for the circle segments: -outlinewidth, -outline,
Options for the data: -shownumbers, -placement, -sorted, -shownumbers,
-format, -formatright

For dots in an xy-plot:
3D effect enabled via "$p dotconfig -3deffect 1"

For the text and labels along axes:
The render option for the plotting style of a plot/chart with numerical
axes can be set to "text", in which case superscript and subscript are
possible.


Improvements and bugfixes:

- Method coordsToPixel now automatically handles the various coordinate
systems

- Vertical text along the axis can be configured properly

- Proper configuration for logarithmic axes (no new command required)

- Improved colour computation for isolines and shades


Incompatibilities:

- The default colour for the gridlines in polar plots has been changed
to grey instead
of black, as the black lines were too conspicuous


Known bugs and quirks:

- Some geometric computations concerning the margins for the plot area are
off by one pixel. This is noticeable in the "demographic.tcl" example.

- The titles for individual plots are positioned with respect to the
first plot.

- Not all plot and chart types support yet the -box and -axesbox or
similar options.

- The documentation is not complete yet.