Plotchart -
Simple plotting and charting package
package require Tcl ? 8.3 ?
package require Plotchart ? 0.9 ?
::Plotchart::createXYPlot w xaxis yaxis
::Plotchart::createStripchart w xaxis yaxis
::Plotchart::createPolarPlot w radius_data
::Plotchart::createIsometricPlot w xaxis yaxis stepsize
::Plotchart::create3DPlot w xaxis yaxis zaxis
::Plotchart::createPiechart w
::Plotchart::createBarchart w xlabels yaxis noseries
::Plotchart::createHorizontalBarchart w xlabels yaxis noseries
::Plotchart::createTimechart w time_begin time_end noitems
$anyplot title text
$anyplot saveplot filename
$anyplot xtext text
$anyplot ytext text
$anyplot xconfig -option value ...
$anyplot yconfig -option value ...
$xyplot plot series xcrd ycrd
$polarplot plot series radius angle
$plot3d plotfunc function
$plot3d gridsize nxcells nycells
$plot3d plotdata data
$plot3d colours fill border
$xyplot dataconfig series -option value ...
$pie plot data
$pie colours colour1 colour2 ...
$barchart plot series ydata colour
$barchart plot series xdata colour
$timechart period text time_begin time_end colour
$timechart milestone text time colour
$timechart vertline text time
$isoplot plot rectangle x1 y1 x2 y2 colour
$isoplot plot filled-rectangle x1 y1 x2 y2 colour
$isoplot plot circle xc yc radius colour
$isoplot plot filled-circle xc yc radius colour
::Plotchart::viewPort w pxmin pymin pxmax pymax
::Plotchart::worldCoordinates w xmin ymin xmax ymax
::Plotchart::world3DCoordinates w xmin ymin zmin xmax ymax zmax
::Plotchart::coordsToPixel w x y
::Plotchart::coords3DToPixel w x y z
::Plotchart::polarCoordinates w radmax
::Plotchart::polarToPixel w rad phi
::Plotchart::pixelToCoords w x y
::Plotchart::determineScale xmin xmax
Plotchart is a Tcl-only package that focuses on the easy creation of
xy-plots, barcharts and other common types of graphical presentations.
The emphasis is on ease of use, rather than flexibility. The procedures
that create a plot use the entire canvas window, making the layout
of the plot completely automatic.
This results in the creation of an xy-plot in, say, ten lines of code:
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"
A drawback of the package might be that it does not do any data
management. So if the canvas that holds the plot is to be resized, the
whole plot must be redrawn.
The advantage, though, is that it offers a number of plot and chart
types:
-
XY-plots like the one shown above with any number of data series.
-
Stripcharts, a kind of XY-plots where the horizontal axis is adjusted
automatically. The result is a kind of sliding window on the data
series.
-
Polar plots, where the coordinates are polar instead of cartesian.
-
Isometric plots, where the scale of the coordinates in the two
directions is always the same, i.e. a circle in world coordinates
appears as a circle on the screen.
You can zoom in and out, as well as pan with these plots (Note:
this works best if no axes are drawn, the zooming and panning routines
do not distinguish the axes), using the mouse buttons with the control
key and the arrow keys with the control key.
-
Piecharts, with automatic scaling to indicate the proportions.
-
Barcharts, with either vertical or horizontal bars, stacked bars or
bars side by side.
-
Timecharts, where bars indicate a time period and milestones or other
important moments in time are represented by triangles.
-
3D plots (both for displaying surfaces and 3D bars)
You create the plot or chart with one single command and then fill the
plot with data:
-
::Plotchart::createXYPlot w xaxis yaxis
-
Create a new xy-plot.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
list | xaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the x-axis, in this order.
|
list | yaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.
|
-
::Plotchart::createStripchart w xaxis yaxis
-
Create a new strip chart. The only difference to a regular XY plot is
that the x-axis will be automatically adjusted when the x-coordinate
of a new point exceeds the maximum.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
list | xaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the x-axis, in this order.
|
list | yaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.
|
-
::Plotchart::createPolarPlot w radius_data
-
Create a new polar plot.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
list | radius_data | in |
|
A 2-element list containing maximum radius and stepsize for the radial
axis, in this order.
|
-
::Plotchart::createIsometricPlot w xaxis yaxis stepsize
-
Create a new isometric plot, where the vertical and the horizontal
coordinates are scaled so that a circle will truly appear as a circle.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
list | xaxis | in |
|
A 2-element list containing minimum, and maximum for the x-axis, in this order.
|
list | yaxis | in |
|
A 2-element list containing minimum, and maximum for the y-axis, in this order.
|
float|noaxes
| stepsize | in |
|
Either the stepsize used by both axes or the keyword noaxes to
signal the plot that it should use the full area of the widget, to not
draw any of the axes.
|
-
::Plotchart::create3DPlot w xaxis yaxis zaxis
-
Create a new 3D plot.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
list | xaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the x-axis, in this order.
|
list | yaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.
|
list | zaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the z-axis, in this order.
|
-
::Plotchart::createPiechart w
-
Create a new piechart.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
-
::Plotchart::createBarchart w xlabels yaxis noseries
-
Create a new barchart with vertical bars. The horizontal axis will
display the labels contained in the argument xlabels. The number
of series given by noseries determines both the width of the
bars, and the way the series will be drawn.
If the keyword stacked was specified the series will be drawn
stacked on top of each other. Otherwise each series that is drawn will
be drawn shifted to the right.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
list | xlabels | in |
|
List of labels for the x-axis. Its length also determines the number of
bars that will be plotted per series.
|
list | yaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.
|
int|stacked
| noseries | in |
|
The number of data series that will be plotted. This has to be an
integer number greater than zero (if stacked is not used).
|
-
::Plotchart::createHorizontalBarchart w xlabels yaxis noseries
-
Create a new barchart with horizontal bars. The vertical axis will
display the labels contained in the argument ylabels. The number
of series given by noseries determines both the width of the
bars, and the way the series will be drawn.
If the keyword stacked was specified the series will be drawn
stacked from left to right. Otherwise each series that is drawn will
be drawn shifted upward.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
list | ylabels | in |
|
List of labels for the y-axis. Its length also determines the number of
bars that will be plotted per series.
|
list | yaxis | in |
|
A 3-element list containing minimum, maximum and stepsize for the x-axis, in this order.
|
int|stacked
| noseries | in |
|
The number of data series that will be plotted. This has to be an
integer number greater than zero (if stacked is not used).
|
-
::Plotchart::createTimechart w time_begin time_end noitems
-
Create a new timechart.
The time axis (= x-axis) goes from time_begin to time_end,
and the vertical spacing is determined by the number of items to plot.
Type | Name | Mode |
widget | w | in |
|
Name of the existing canvas widget to hold the plot.
|
string | time_begin | in |
|
The start time given in a form that is recognised by the clock scan
command (e.g. "1 january 2004").
|
string | time_end | in |
|
The end time given in a form that is recognised by the clock scan
command (e.g. "1 january 2004").
|
int | noitems | in |
|
Expected/maximum number of items. This determines the vertical
spacing.
|
Each of the creation commands explained in the last section returns
the name of a new object command that can be used to manipulate the
plot or chart. The subcommands available to a chart command depend on
the type of the chart.
General subcommands for all types of charts. $anyplot is the command
returned by the creation command:
-
$anyplot title text
-
Specify the title of the whole chart.
Type | Name | Mode |
string | text | in |
|
The text of the title to be drawn.
|
-
$anyplot saveplot filename
-
Draws the plot into a file, using PostScript.
Type | Name | Mode |
string | filename | in |
|
Contain the path name of the file to write the plot to.
|
-
$anyplot xtext text
-
Specify the title of the x-axis, for those plots that have a straight
x-axis.
Type | Name | Mode |
string | text | in |
|
The text of the x-axis label to be drawn.
|
-
$anyplot ytext text
-
Specify the title of the y-axis, for those plots that have a straight
y-axis.
Type | Name | Mode |
string | text | in |
|
The text of the y-axis label to be drawn.
|
-
$anyplot xconfig -option value ...
-
Set one or more configuration parameters for the x-axis.
The following options are known:
-
format fmt
-
The format for the numbers along the axis.
-
ticklength length
-
The length of the tickmarks (in pixels).
-
ticklines boolean
-
Whether to draw ticklines (true) or not (false).
-
scale scale_data
-
New scale data for the axis, i.e. a 3-element list containing minimum,
maximum and stepsize for the axis, in this order.
Beware: Setting this option will clear all data from the plot.
-
$anyplot yconfig -option value ...
-
Set one or more configuration parameters for the y-axis. This method
accepts the same options and values as the method xconfig.
Note: The commands xconfig and yconfig are
currently implemented only for XY-plots
and only the option -format has any effect.
For xy plots and stripcharts:
-
$xyplot plot series xcrd ycrd
-
Add a data point to the plot.
Type | Name | Mode |
string | series | in |
|
Name of the data series the new point belongs to.
|
float | xcrd | in |
|
X-coordinate of the new point.
|
float | ycrd | in |
|
Y-coordinate of the new point.
|
For polar plots:
-
$polarplot plot series radius angle
-
Add a data point to the polar plot.
Type | Name | Mode |
string | series | in |
|
Name of the data series the new point belongs to.
|
float | radius | in |
|
Radial coordinate of the new point.
|
float | angle | in |
|
Angular coordinate of the new point (in degrees).
|
For 3D plots:
-
$plot3d plotfunc function
-
Plot a function defined over two variables x and y.
The resolution is determined by the set grid sizes (see the method
gridsize for more information).
Type | Name | Mode |
string | function | in |
|
Name of the procedure that calculates the z-value for the given x and
y coordinates. The procedure has to accept two float arguments (x is
first argument, y is second) and return a floating-point value.
|
-
$plot3d gridsize nxcells nycells
-
Set the grid size in the two directions. Together they determine how
many polygons will be drawn for a function plot.
Type | Name | Mode |
int | nxcells | in |
|
Number of grid cells in x direction. Has to be an integer number
greater than zero.
|
int | nycells | in |
|
Number of grid cells in y direction. Has to be an integer number
greater than zero.
|
-
$plot3d plotdata data
-
Plot a matrix of data.
Type | Name | Mode |
list | data | in |
|
The data to be plotted. The data has to be provided as a nested list
with 2 levels. The outer list contains rows, drawn in y-direction, and
each row is a list whose elements are drawn in x-direction, for the
columns. Example:
|
set data {
{1.0 2.0 3.0}
{4.0 5.0 6.0}
}
-
$plot3d colours fill border
-
Configure the colours to use for polygon borders and inner area.
Type | Name | Mode |
color | fill | in |
|
The colour to use for filling the polygons.
|
color | border | in |
|
The colour to use for the border of the polygons.
|
For xy plots, stripcharts and polar plots:
-
$xyplot dataconfig series -option value ...
-
Set the value for one or more options regarding the drawing of data of
a specific series.
Type | Name | Mode |
string | series | in |
|
Name of the data series whose configuration we are changing.
|
The following option are known:
-
colour c
-
-
color c
-
The colour to be used when drawing the data series.
-
type enum
-
The drawing mode chosen for the series.
This can be one of line, symbol, or both.
-
symbol enum
-
What kind of symbol to draw. The value of this option is ignored when
the drawing mode line was chosen. This can be one of
plus, cross, circle, up (triangle
pointing up), down (triangle pointing down), dot
(filled circle), upfilled or downfilled (filled
triangles).
For piecharts:
-
$pie plot data
-
Fill a piechart.
Type | Name | Mode |
list | data | in |
|
A list of pairs (labels and values). The values determine the relative
size of the circle segments. The labels are drawn beside the circle.
|
-
$pie colours colour1 colour2 ...
-
Set the colours to be used.
Type | Name | Mode |
color | colour1 | in |
|
The first colour.
|
color | colour2 | in |
|
The second colour, and so on.
|
For vertical barcharts:
-
$barchart plot series ydata colour
-
Add a data series to a barchart.
Type | Name | Mode |
string | series | in |
|
Name of the series the values belong to.
|
list | ydata | in |
|
A list of values, one for each x-axis label.
|
color | colour | in |
|
The colour of the bars.
|
For horizontal barcharts:
-
$barchart plot series xdata colour
-
Add a data series to a barchart.
Type | Name | Mode |
string | series | in |
|
Name of the series the values belong to.
|
list | xdata | in |
|
A list of values, one for each y-axis label.
|
color | colour | in |
|
The colour of the bars.
|
For timecharts:
-
$timechart period text time_begin time_end colour
-
Add a time period to the chart.
Type | Name | Mode |
string | text | in |
|
The text describing the period.
|
string | time_begin | in |
|
Start time of the period.
|
string | time_end | in |
|
Stop time of the period.
|
color | colour | in |
|
The colour of the bar (defaults to black).
|
-
$timechart milestone text time colour
-
Add a milestone (represented as an point-down triangle) to the
chart.
Type | Name | Mode |
string | text | in |
|
The text describing the milestone.
|
string | time | in |
|
Time at which the milestone must be positioned.
|
color | colour | in |
|
The colour of the triangle (defaults to black).
|
-
$timechart vertline text time
-
Add a vertical line (to indicate the start of the month for instance)
to the chart.
Type | Name | Mode |
string | text | in |
|
The text appearing at the top (an abbreviation of the
date/time for instance).
|
string | time | in |
|
Time at which the line must be positioned.
|
For isometric plots (to be extended):
-
$isoplot plot rectangle x1 y1 x2 y2 colour
-
Plot the outlines of a rectangle.
Type | Name | Mode |
float | x1 | in |
|
Minimum x coordinate of the rectangle to be drawn.
|
float | y1 | in |
|
Minimum y coordinate of the rectangle.
|
float | x2 | in |
|
Maximum x coordinate of the rectangle to be drawn.
|
float | y2 | in |
|
Maximum y coordinate of the rectangle.
|
color | colour | in |
|
The colour of the rectangle.
|
-
$isoplot plot filled-rectangle x1 y1 x2 y2 colour
-
Plot a rectangle filled with the given colour.
Type | Name | Mode |
float | x1 | in |
|
Minimum x coordinate of the rectangle to be drawn.
|
float | y1 | in |
|
Minimum y coordinate of the rectangle.
|
float | x2 | in |
|
Maximum x coordinate of the rectangle to be drawn.
|
float | y2 | in |
|
Maximum y coordinate of the rectangle.
|
color | colour | in |
|
The colour of the rectangle.
|
-
$isoplot plot circle xc yc radius colour
-
Plot the outline of a circle.
Type | Name | Mode |
float | xc | in |
|
X coordinate of the circle's centre.
|
float | yc | in |
|
Y coordinate of the circle's centre.
|
color | colour | in |
|
The colour of the circle.
|
-
$isoplot plot filled-circle xc yc radius colour
-
Plot a circle filled with the given colour.
Type | Name | Mode |
float | xc | in |
|
X coordinate of the circle's centre.
|
float | yc | in |
|
Y coordinate of the circle's centre.
|
color | colour | in |
|
The colour of the circle.
|
There are a number of public procedures that may be useful in specific
situations: Pro memorie.
Besides the commands that deal with the plots and charts directly,
there are a number of commands that can be used to convert world
coordinates to pixels and vice versa.
These include:
-
::Plotchart::viewPort w pxmin pymin pxmax pymax
-
Set the viewport for window w. Should be used in cooperation
with ::Plotchart::worldCoordinates.
Type | Name | Mode |
widget | w | in |
|
Name of the window (canvas widget) in question.
|
float | pxmin | in |
|
Left-most pixel coordinate.
|
float | pymin | in |
|
Top-most pixel coordinate (remember: the vertical pixel coordinate
starts with 0 at the top!).
|
float | pxmax | in |
|
Right-most pixel coordinate.
|
float | pymax | in |
|
Bottom-most pixel coordinate.
|
-
::Plotchart::worldCoordinates w xmin ymin xmax ymax
-
Set the extreme world coordinates for window w. The world
coordinates need not be in ascending order (i.e. xmin can be larger
than xmax, so that a reversal of the x-axis is achieved).
Type | Name | Mode |
widget | w | in |
|
Name of the window (canvas widget) in question.
|
float | xmin | in |
|
X-coordinate to be mapped to left side of viewport.
|
float | ymin | in |
|
Y-coordinate to be mapped to bottom of viewport.
|
float | xmax | in |
|
X-coordinate to be mapped to right side of viewport.
|
float | ymax | in |
|
Y-coordinate to be mapped to top side of viewport.
|
-
::Plotchart::world3DCoordinates w xmin ymin zmin xmax ymax zmax
-
Set the extreme three-dimensional world coordinates for window
w. The world coordinates need not be in ascending order (i.e. xmin
can be larger than xmax, so that a reversal of the x-axis is
achieved).
Type | Name | Mode |
widget | w | in |
|
Name of the window (canvas widget) in question.
|
float | xmin | in |
|
X-coordinate to be mapped to front side of the 3D viewport.
|
float | ymin | in |
|
Y-coordinate to be mapped to left side of the viewport.
|
float | zmin | in |
|
Z-coordinate to be mapped to bottom of viewport.
|
float | xmax | in |
|
X-coordinate to be mapped to back side of viewport.
|
float | ymax | in |
|
Y-coordinate to be mapped to right side of viewport.
|
float | zmax | in |
|
Z-coordinate to be mapped to top side of viewport.
|
-
::Plotchart::coordsToPixel w x y
-
Return a list of pixel coordinates valid for the given window.
Type | Name | Mode |
widget | w | in |
|
Name of the window (canvas widget) in question.
|
float | x | in |
|
X-coordinate to be mapped.
|
float | y | in |
|
Y-coordinate to be mapped.
|
-
::Plotchart::coords3DToPixel w x y z
-
Return a list of pixel coordinates valid for the given window.
Type | Name | Mode |
widget | w | in |
|
Name of the window (canvas widget) in question.
|
float | x | in |
|
X-coordinate to be mapped.
|
float | y | in |
|
Y-coordinate to be mapped.
|
float | y | in |
|
Z-coordinate to be mapped.
|
-
::Plotchart::polarCoordinates w radmax
-
Set the extreme polar coordinates for window w. The angle always
runs from 0 to 360 degrees and the radius starts at 0. Hence you only
need to give the maximum radius.
Note: If the viewport is not square, this procedure will not
adjust the extremes, so that would result in an elliptical plot. The
creation routine for a polar plot always determines a square viewport.
Type | Name | Mode |
widget | w | in |
|
Name of the window (canvas widget) in question.
|
float | radmax | in |
|
Maximum radius.
|
-
::Plotchart::polarToPixel w rad phi
-
Wrapper for a call to ::Plotchart::coordsToPixel, which assumes
the world coordinates and viewport are set appropriately. Converts
polar coordinates to pixel coordinates.
Note: To be useful it should be accompanied by a matching
::Plotchart::worldCoordinates procedure. This is automatically
taken care of in the creation routine for polar plots.
Type | Name | Mode |
widget | w | in |
|
Name of the window (canvas widget) in question.
|
float | rad | in |
|
Radius of the point.
|
float | phi | in |
|
Angle to the positive x-axis.
|
-
::Plotchart::pixelToCoords w x y
-
Return a list of world coordinates valid for the given window.
Type | Name | Mode |
widget | w | in |
|
Name of the window (canvas widget) in question.
|
float | x | in |
|
X-pixel to be mapped.
|
float | y | in |
|
Y-pixel to be mapped.
|
Furthermore there is a routine to determine "pretty" numbers for use
with an axis:
-
::Plotchart::determineScale xmin xmax
-
Determine "pretty" numbers from the given range and return a list
containing the minimum, maximum and stepsize that can be used for a
(linear) axis.
Type | Name | Mode |
float | xmin | in |
|
Rough minimum value for the scaling
|
float | xmax | in |
|
Rough maximum value for the scaling.
|
Besides output to the canvas on screen, the module is capable, via
canvas postscript, of producing PostScript files. One may wonder
whether it is possible to extend this set of output formats and the
answer is "yes". This section tries to sum up the aspects of using this
module for another sort of output.
One way you can create output files in a different format, is by
examining the contents of the canvas after everything has been drawn and
render that contents in the right form. This is probably the easiest
way, as it involves nothing more than the re-creation of all the
elements in the plot that are already there.
The drawback of that method is that you need to have a display, which is
not always the case if you run a CGI server or something like that.
An alternative is to emulate the canvas command. For this to work, you
need to know which canvas subcommands are used and what for. Obviously,
the create subcommand is used to create the lines, texts and
other items. But also the raise and lower subcommands are
used, because with these the module can influence the drawing order -
important to simulate a clipping rectangle around the axes. (The routine
DrawMask is responsible for this - if the output format supports proper
clipping areas, then a redefinition of this routine might just solve
this).
Furthermore, the module uses the cget subcommand to find out the
sizes of the canvas. A more mundane aspect of this is that the module
currently assumes that the text is 14 pixels high and that 80 pixels in
width suffice for the axis' labels. No "hook" is provided to customise
this.
In summary:
-
Emulate the create subcommand to create all the items in the
correct format
-
Emulate the cget subcommand for the options -width and -height to
allow the correct calculation of the rectangle's position and size
-
Solve the problem of raising and lowering the items so
that they are properly clipped, for instance by redefining the
routine DrawMask.
-
Take care of the currently fixed text size properties
In this version there are a lot of things that still need to
be implemented:
-
General options like legends and text to the axes.
-
More robust handling of incorrect calls (right now the procedures may
fail when called incorrectly):
-
The axis drawing routines can not handle inverse axes right now.
-
If the user provides an invalid date/time string, the routines simply
throw an error.
I have the following wishlist:
-
Isometric plots - allow new items to be implemented easily.
-
Add support for histograms where the independent axis is numerical.
-
A general 3D viewer - emphasis on geometry, not a ray-tracer.
graphical presentation, plotting, charts, xy-plots, bar charts, strip charts, polar plots, isometric plots, pie charts, time charts, 3D surfaces, 3D bars, coordinates, coordinate transformations