NAME

Plotchart -
Simple plotting and charting package

SYNOPSIS

package require Tcl  ? 8.4 ? 
package require Tk  ? 8.4 ? 
package require Plotchart  ? 1.6 ? 
::Plotchart::createXYPlot w xaxis yaxis
::Plotchart::createStripchart w xaxis yaxis
::Plotchart::createTXPlot w timeaxis xaxis
::Plotchart::createXLogYPlot w xaxis yaxis
::Plotchart::createPolarPlot w radius_data
::Plotchart::createIsometricPlot w xaxis yaxis stepsize
::Plotchart::createHistogram w xaxis yaxis
::Plotchart::create3DPlot w xaxis yaxis zaxis
::Plotchart::createPiechart w
::Plotchart::createRadialchart w names scale style
::Plotchart::createBarchart w xlabels yaxis noseries
::Plotchart::createHorizontalBarchart w ylabels xaxis noseries
::Plotchart::create3DBarchart w yaxis nobars
::Plotchart::create3DRibbonChart w names yaxis zaxis
::Plotchart::createBoxplot w xaxis ylabels
::Plotchart::createTimechart w time_begin time_end args
::Plotchart::createGanttchart w time_begin time_end args
::Plotchart::createRightAxis w yaxis
$anyplot title text
$anyplot saveplot filename args
$anyplot xtext text
$anyplot ytext text
$anyplot xconfig -option value ...
$anyplot yconfig -option value ...
$anyplot background part colour_or_image dir
$anyplot xticklines colour
$anyplot yticklines colour
$anyplot legendconfig -option value ...
$anyplot legend series text
$anyplot balloon x y text dir
$anyplot balloonconfig args
$xyplot plot series xcrd ycrd
$xyplot trend series xcrd ycrd
$xyplot rchart series xcrd ycrd
$xyplot interval series xcrd ymin ymax  ? ycentr ? 
$xyplot box-and-whiskers series xcrd ycrd
$xyplot vector series xcrd ycrd ucmp vcmp
$xyplot vectorconfig series -option value ...
$xyplot dot series xcrd ycrd value
$xyplot dotconfig series -option value ...
$xyplot contourlines xcrd ycrd values  ? classes ? 
$xyplot contourfill xcrd ycrd values  ? classes ? 
$xyplot contourbox xcrd ycrd values  ? classes ? 
$xyplot colorMap colours
$xyplot grid xcrd ycrd
$polarplot plot series radius angle
$plot3d plotfunc function
$plot3d plotfuncont function contours
$plot3d gridsize nxcells nycells
$plot3d plotdata data
$plot3d colours fill border
$xyplot dataconfig series -option value ...
$pie plot data
$pie colours colour1 colour2 ...
$radial plot data colour thickness
$pie colours colour1 colour2 ...
$barchart plot series ydata colour
$barchart plot series xdata colour
$barchart plot label yvalue colour
$barchart config -option value ...
$ribbon line xypairs colour
$ribbon area xypairs colour
$boxplot plot label values
$timechart period text time_begin time_end colour
$timechart milestone text time colour
$timechart vertline text time
$timechart hscroll scrollbar
$timechart vscroll scrollbar
$ganttchart task text time_begin time_end completed
$ganttchart milestone text time colour
$ganttchart vertline text time
$ganttchart connect from to
$ganttchart summary text args
$ganttchart color keyword newcolor
$ganttchart font keyword newfont
$ganttchart hscroll scrollbar
$ganttchart vscroll scrollbar
$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::pixelToIndex w x y
::Plotchart::determineScale xmin xmax inverted
::Plotchart::plotconfig charttype component property value
::Plotchart::plotpack w dir args

DESCRIPTION

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.
• Histograms, for plotting statistical information.
• 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)

With version 1.5 a new command has been introduced: plotconfig, which can be used to configure the plot options for particular types of plots and charts (cf. CONFIGURATION OPTIONS)

PLOT CREATION COMMANDS

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 (configuration type: xyplot).

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. For an inverted axis, where the maximum appears on the left-hand side, use: maximum, minimum and a negative stepsize.
list	yaxis	in
	A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order. For an inverted axis, where the maximum appears at the bottom, use: maximum, minimum and a negative stepsize.

::Plotchart::createStripchart w xaxis yaxis

Create a new strip chart (configuration type: stripchart). 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. Note that an inverted x-axis is not supported for this type of plot.
list	yaxis	in
	A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order. For an inverted axis, where the maximum appears at the bottom, use: maximum, minimum and a negative stepsize.

::Plotchart::createTXPlot w timeaxis xaxis

Create a new time-x-plot (configuration type: txplot). The horizontal axis represents the date/time of the data and the vertical axis the values themselves.

Type	Name	Mode
widget	w	in
	Name of the existing canvas widget to hold the plot.
list	timeaxis	in
	A 3-element list containing the minimum and maximum date/time to be shown and the stepsize (in days) for the time-axis, in this order. Note that an inverted time-axis is not supported.
list	xaxis	in
	A 3-element list containing minimum, maximum and stepsize for the vertical axis, in this order. For an inverted axis, where the maximum appears at the bottom, use: maximum, minimum and a negative stepsize.

::Plotchart::createXLogYPlot w xaxis yaxis

Create a new xy-plot where the y-axis has a logarithmic scale (configuration type: xlogyplot).
The data should be given as for a linear scale, as the logarithmic transformation is taken of internally.

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. For an inverted axis, where the maximum appears on the left-hand side, use: maximum, minimum and a negative stepsize.
list	yaxis	in
	A 2-element list containing minimum and maximum for the y-axis, in this order. Note that an inverted logarithmic axis is not supported.

::Plotchart::createPolarPlot w radius_data

Create a new polar plot (configuration type: polarplot).

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 (configuration type: isometric).

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::createHistogram w xaxis yaxis

Create a new histogram (configuration type: histogram).

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::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 (configuration type: piechart).

Type	Name	Mode
widget	w	in
	Name of the existing canvas widget to hold the plot.

::Plotchart::createRadialchart w names scale style

Create a new radial chart (the data are drawn as a line connecting the spokes of the diagram) (configuration type: radialchart).

Type	Name	Mode
widget	w	in
	Name of the existing canvas widget to hold the plot.
list	names	in
	Names for the spokes.
float	scale	in
	Scale value to determine the position of the data along the spokes.
float	style	in
	Style of the chart (optional). One of: lines - the default: draw the data as independent polylines. cumulative - draw the data as polylines where the data are accumulated. filled - draw the data as filled polygons where the data are accumulated

::Plotchart::createBarchart w xlabels yaxis noseries

Create a new barchart with vertical bars (configuration type: vertbars). 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.
The number of series determines the width of the bars, so that there is space of that number of bars. If you use a floating-point number, like 2.2, instead of an integer, like 2, a small gap between the sets of bars will be drawn - the width depends on the fractional part.

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 ylabels xaxis noseries

Create a new barchart with horizontal bars (configuration type: horizbars). 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	xaxis	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::create3DBarchart w yaxis nobars

Create a new barchart with 3D vertical bars (configuration type: 3dbars). The horizontal axis will display the labels per bar. The number of bars given by nobars determines the position and the width of the bars. The colours can be varied per bar. (This type of chart was inspired by the Wiki page on 3D bars by Richard Suchenwirth.)

Type	Name	Mode
widget	w	in
	Name of the existing canvas widget to hold the plot.
list	yaxis	in
	A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.
int	nobars	in
	The number of bars that will be plotted.

::Plotchart::create3DRibbonChart w names yaxis zaxis

Create a new "ribbon chart" (configuration type: 3dribbon). This is a chart where the data series are represented as ribbons in a three-dimensional axis system. Along the x-axis (which is "into" the screen) the names are plotted, each representing a single series. The first plot command draws the furthest series, the second draws the series in front of that and so on.

Type	Name	Mode
widget	w	in
	Name of the existing canvas widget to hold the plot.
widget	w	in
	Names of the series, plotted as labels along the x-axis
list	yaxis	in
	A 3-element list containing minimum, maximum and stepsize for the y-axis (drawn horizontally!), in this order.
list	zaxis	in
	A 3-element list containing minimum, maximum and stepsize for the z-axis (drawn vertically), in this order.
int	nobars	in
	The number of bars that will be plotted.

::Plotchart::createBoxplot w xaxis ylabels

Create a new boxplot with horizontal boxes (box-and-whiskers). The y-axis is drawn with labels. The boxes are drawn based on the raw data (see the plot subcommand for this type of 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 y-axis, in this order.
list	ylabels	in
	List of labels for the y-axis. Its length also determines the number of boxes that can be plotted. The labels are also used in the plot subcommand.

::Plotchart::createTimechart w time_begin time_end args

Create a new timechart (configuration type: 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").
arguments	args	in
	The remaining arguments can be: The expected/maximum number of items. This determines the vertical spacing. (If given, it must be the first argument after "time_end" The keyword -barheight and the number of pixels per bar. This is an alternative method to determine the vertical spacing. The keyword -ylabelwidth and the number of pixels to reserve for the labels at the y-axis.

::Plotchart::createGanttchart w time_begin time_end args

Create a new Gantt chart (configuration type: ganttchart). 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. Via the specific commands you can then add tasks and connections between the tasks.

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").
arguments	args	in
	The remaining arguments can be: The expected/maximum number of items. This determines the vertical spacing. (If given this way, it must be the first argument after "time_end") The expected/maximum width of the descriptive text (roughly in characters, for the actual space reserved for the text, it is assumed that a character is about ten pixels wide). Defaults to 20. (If given this way, it must be the second argument after "time_end"). The keyword -barheight and the number of pixels per bar. This is an alternative method to determine the vertical spacing. The keyword -ylabelwidth and the number of pixels to reserve for the labels at the y-axis.

::Plotchart::createRightAxis w yaxis

Create a plot command that will use a right axis instead of the left axis (configuration type: inherited from the existing plot). The widget (w) must already contain an ordinary plot, as the horizontal axis and other properties are reused. To plot data using the right axis, use this new command, to plot data using the left axis, use the original plot command.

Type	Name	Mode
widget	w	in
	Name of the existing canvas widget to hold the plot.
list	yaxis	in
	A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.

PLOT METHODS

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 args

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.
list	args	in
	Optionally you can specify the option -format "some picture format" to store the plot in a different file than a PostScript file. This, however, relies on the Img package to do the actual job. Note: Because the window holding the plot must be fully visible before Img can successfully grab it, it is raised first. On some systems, for instance Linux with KDE, raising a window is not done automatically, but instead you need to click on the window in the task bar. Similar things happen on Windows XP. There seems to be something wrong under some circumstances, so instead of waiting for the visibility of the window, the procedure simply waits two seconds. It is not ideal, but it seems to work better.

$anyplot xtext text

Specify the title of the (horizontal) 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 (horizontal) 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 supported:

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.

$anyplot background part colour_or_image dir

Set the background of a part of the plot

Type	Name	Mode
string	part
	Which part of the plot: "axes" for the axes area and "plot" for the inner part. The interpretation depends on the type of plot. Two further possibilities are: image, in which case a predefined image is loaded into the background of the plot. gradient, in which case the background is coloured in different shades of the given colour. The "dir" argument specifies the direction in which the colour gets whiter.
string	colour_or_image
	Colour for that part or the name of the image if "part" is "image"
string	dir
	The direction of the gradient. One of: top-down, bottom-up, left-right or right-left.

$anyplot xticklines colour

Draw vertical ticklines at each tick location

Type	Name	Mode
string	colour
	Colour of the lines. Specifying an empty colour ("") removes them again. Defaults to "black"

$anyplot yticklines colour

Draw horizontal ticklines at each tick location

Type	Name	Mode
string	colour
	Colour of the lines. Specifying an empty colour ("") removes them again Defaults to "black"

$anyplot legendconfig -option value ...

Set one or more options for the legend. The legend is drawn as a rectangle with text and graphics inside.

background colour

Set the colour of the background (the default colour is white). Set to the empty string for a transparant legend.

border colour

Set the colour of the border (the default colour is white). Set to the empty string if you do not want a border.

canvas c

Draw the legend in a different canvas widget. This gives you the freedom to position the legend outside the actual plot.

position corner

Set the position of the legend. May be one of: top-left, top-right, bottom-left or bottom-right. (Default value is top-right.)

$anyplot legend series text

Add an entry to the legend. The series determines which graphical symbol is to be used. (As a side effect the legend is actually drawn.)

Type	Name	Mode
string	series
	Name of the data series. This determines the colour of the line and the symbol (if any) that will be drawn.
string	text
	Text to be drawn next to the line/symbol.

$anyplot balloon x y text dir

Add balloon text to the plot (except for 3D plots). The arrow will point to the given x- and y-coordinates. For xy-graphs and such, the coordinates are directly related to the axes; for vertical barcharts the x-coordinate is measured as the number of bars minus 1 and similar for horizontal barcharts.

Type	Name	Mode
float	x
	X-coordinate of the point that the arrow of the balloon will point to.
float	y
	Y-coordinate of the point that the arrow of the balloon will point to.
string	text
	Text to be drawn in the balloon.
string	dir
	Direction of the arrow, one of: north, north-east, east, south-east, south, south-west, west or north-west.

$anyplot balloonconfig args

Configure the balloon text for the plot. The new settings will be used for the next balloon text.

font fontname

Font to be used for the text

justify left|center|right

Way to justify multiline text

textcolour colour

Colour for the text (synonym: textcolor)

background colour

Background colour for the balloon

outline colour

Colour of the outline of the balloon

margin value

Margin around the text (in pixels)

rimwidth value

Width of the outline of the balloon (in pixels)

arrowsize value

Length factor for the arrow (in pixels)

Note: The commands xconfig and yconfig are currently implemented only for XY-plots and only the option -format has any effect.

For xy plots, stripcharts, histograms and time-x-plots:

$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. (For time-x plots this must be valid date/time that can be read with the clock scan command).
float	ycrd	in
	Y-coordinate of the new point.

Note on histograms:

For histograms the x-coordinate that is given is interpreted to be the x-coordinate of the right side of the bar. The first bar starts at the y-axis on the left. To completely fill the range of the x-axis, you should draw a bar at the maximum x-coordinate.

For xy plots:

$xyplot trend series xcrd ycrd

Draw or update a trend line using the data given sofar.

Type	Name	Mode
string	series	in
	Name of the data series the trend line belongs to.
float	xcrd	in
	X-coordinate of the new data point
float	ycrd	in
	Y-coordinate of the new data point

$xyplot rchart series xcrd ycrd

Draw data in the same way as the plot method, but with two lines added that indicate the expected range (+/- 3*standard deviation) of the data.

Type	Name	Mode
string	series	in
	Name of the data series the data point belongs to.
float	xcrd	in
	X-coordinate of the new data point
float	ycrd	in
	Y-coordinate of the new data point

$xyplot interval series xcrd ymin ymax ? ycentr ?

Add a vertical error interval to the plot. The interval is drawn from ymin to ymax. If the ycentr argument is given, a symbol is drawn at that position.

Type	Name	Mode
string	series	in
	Name of the data series the interval belongs to.
float	xcrd	in
	X-coordinate of the interval
float	ymin	in
	Minimum y-coordinate of the interval.
float	ymax	in
	Maximum y-coordinate of the interval.
float	ycentr	in
	Y-coordinate to draw the symbol at (optional)

$xyplot box-and-whiskers series xcrd ycrd

Draw a box and whiskers in the plot. If the argument xcrd is a list of several values and the argument ycrd is a single value, a horizontal box is drawn with the quartiles determined from the list of values contained in xcrd.
If, instead, the argument ycrd contains a list of several values and the argument xcrd a single value, then a vertical box is drawn and the quartiles are determined from ycrd. (There must be exactly one list of several values. Otherwise an error is reported.)
The option -boxwidth (default: 10 pixels) determines the width (or height) of the box.

Type	Name	Mode
string	series	in
	Name of the data series the box-and-whiskers belongs to.
float	xcrd	in
	X-coordinate of the box or a list of values.
float	ymin	in
	Y-coordinate of the box or a list of values.

$xyplot vector series xcrd ycrd ucmp vcmp

Draw a vector in the plot. The vector can be given as either cartesian coordinates or as length/angle, where the angle is in degrees and is interpreted according to the mathematical convention or the nautical. (See the vectorconfig subcommand)

Type	Name	Mode
string	series	in
	Name of the series the vector belongs to. Determines the appearance and interpretation.
float	xcrd	in
	X-coordinate of the point where the arrow appears
float	ycrd	in
	Y-coordinate of the point where the arrow appears
float	ucmp	in
	X-component or the length of the vector
float	ycentr	in
	Y-component or the angle of the vector

$xyplot vectorconfig series -option value ...

] Set the vector drawing options for a particular series

Type	Name	Mode
string	series	in
	Name of the series the vector belongs to.

The options can be one of the following:

colour

The colour of the arrow (default: black; synonym: color)

scale value

The scale factor used to convert the length of the arrow into a number of pixels (default: 1.0)

centred onoff

Logical value indicating that the xy-coordinates are to be used as the start of the arrow or as the centre (default: 0; synonym: centered)

type keyword

Interpretation of the vector components. Can be "cartesian" (default), in which case the x- and y-components are expected, "polar" (the angle 0 coincides with the positive x-axis, 90 coincides with the positive y-axis) or "nautical" (0 is "north" and 90 is "east").

$xyplot dot series xcrd ycrd value

Draw a dot in the plot. The size and colour is determined by the value and by the options set for the series it belongs to. (See the dotconfig subcommand)

Type	Name	Mode
string	series	in
	Name of the series the dot belongs to. Determines size and colour
float	xcrd	in
	X-coordinate of the point where the arrow appears
float	ycrd	in
	Y-coordinate of the point where the arrow appears
float	value	in
	Value determining size and colour

$xyplot dotconfig series -option value ...

] Set the dot drawing options for a particular series

Type	Name	Mode
string	series	in
	Name of the series the dot belongs to.

The options can be one of the following:

colour

The colour of the dot if no scaling is used or the value exceeds the last limit of the classes.

scale value

The scale factor used to convert the value into the radius of the dot in pixels (default: 1.0)

radius value

The default radius of the dots, used if there is no scaling by value (in pixels; default: 3)

scalebyvalue onoff

Determines whether the dots all have the same size or a size depending on the given value (default: on).

outline onoff

Draw a black circle around the dot or not (default: on)

classes list

Set the limits and the corresponding colours. For instance:

    $xyplot series1 -classes {0 blue 1 green} -colour red

will cause a blue dot to be drawn for values smaller than 0, a green dot for values larger/equal 0 but lower than 1 and a red dot for values larger/equal 1.
If there is no list of classes for the particular series, the dots are scaled by the value.
You can combine the colouring by value and the scaling by value by setting a list of classes and setting the scalebyvalue option on.

$xyplot contourlines xcrd ycrd values ? classes ?

Draw contour lines for the values given on the grid. The grid is defined by the xcrd and ycrd arguments (they give the x- and y-coordinates of the grid cell corners). The values are given at these corners. The classes determine which contour lines are drawn. If a value on one of the corners is missing, the contour lines in that cell will not be drawn.

Type	Name	Mode
list	xcrd	in
	List of lists, each value is an x-coordinate for a grid cell corner
list	ycrd	in
	List of lists, each value is an y-coordinate for a grid cell corner
list	values	in
	List of lists, each value is the value at a grid cell corner
list	classes	in
	List of class values or a list of lists of two elements (each inner list the class value and the colour to be used). If empty or missing, the classes are determined automatically. Note: The class values must enclose the whole range of values.

$xyplot contourfill xcrd ycrd values ? classes ?

Draw filled contours for the values given on the grid. (The use of this method is identical to the "contourlines" method).

$xyplot contourbox xcrd ycrd values ? classes ?

Draw the cells as filled quadrangles. The colour is determined from the average of the values on all four corners.

$xyplot colorMap colours

Set the colours to be used with the contour methods. The argument is either a predefined colourmap (grey/gray, jet, hot or cool) or a list of colours. When selecting the colours for actually drawing the contours, the given colours will be interpolated (based on the HLS scheme).

Type	Name	Mode
list	colours	in
	List of colour names or colour values or one of the predefined maps: grey or gray: gray colours from dark to light jet: rainbow colours hot: colours from yellow via red to darkred cool: colours from cyan via blue to magenta

$xyplot grid xcrd ycrd

Draw the grid cells as lines connecting the (valid) grid points.

Type	Name	Mode
list	xcrd	in
	List of lists, each value is an x-coordinate for a grid cell corner
list	ycrd	in
	List of lists, each value is an y-coordinate for a grid cell corner

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 plotfuncont function contours

Plot a function defined over two variables x and y using the contour levels in contours to colour the surface. 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.
list	contours	in
	List of values in ascending order that represent the contour levels (the boundaries between the colours in the contour map).

$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 options are allowed:

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).

filled enum

Whether to fill the area above or below the data line or not. Can be one of: no, up or down (SPECIAL EFFECTS)

fillcolour colour

Colour to use when filling the area associated with the data line.

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 radial charts:

$radial plot data colour thickness

Draw a new line in the radial chart

Type	Name	Mode
list	data	in
	A list of data (one for each spoke). The values determine the distance from the centre of the line connecting the spokes.
color	colour	in
	The colour for the line.
int	thickness	in
	An optional argument for the thickness of the line.

$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 3D barcharts:

$barchart plot label yvalue colour

Add the next bar to the barchart.

Type	Name	Mode
string	label	in
	The label to be shown below the column.
float	yvalue	in
	The value that determines the height of the column
color	colour	in
	The colour of the column.

$barchart config -option value ...

Set one or more configuration parameters. The following options are supported:

usebackground boolean

Whether to draw walls to the left and to the back of the columns or not

useticklines boolean

Whether to draw ticklines on the walls or not

showvalues boolean

Whether to show the values or not

labelfont newfont

Name of the font to use for labels

labelcolour colour

Colour for the labels

valuefont newfont

Name of the font to use for the values

valuecolour colour

Colour for the values

For 3D ribbon charts:

$ribbon line xypairs colour

Plot the given xy-pairs as a ribbon in the chart

Type	Name	Mode
list	xypairs	in
	The pairs of x/y values to be drawn (the series is drawn as a whole)
color	colour	in
	The colour of the ribbon.

$ribbon area xypairs colour

Plot the given xy-pairs as a ribbon with a filled area in front. The effect is that of a box with the data as its upper surface.

Type	Name	Mode
list	xypairs	in
	The pairs of x/y values to be drawn (the series is drawn as a whole)
color	colour	in
	The colour of the ribbon/area.

For boxplots:

$boxplot plot label values

Add a box-and-whisker to the plot.

Type	Name	Mode
string	label	in
	The label along the y-axis to which the data belong
list	values	in
	List of raw values, the extent of the box and the whiskers will be determined from this list.

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.

$timechart hscroll scrollbar

Connect a horizontal scrollbar to the chart. See also the section on scrolling.

Type	Name	Mode
widget	scrollbar	in
	The horizontal scrollbar that is to be connected to the chart

$timechart vscroll scrollbar

Connect a vertical scrollbar to the chart. See also the section on scrolling.

Type	Name	Mode
widget	scrollbar	in
	The vertical scrollbar that is to be connected to the chart

For Gantt charts:

$ganttchart task text time_begin time_end completed

Add a task with its period and level of completion to the chart. Returns a list of canvas items that can be used for further manipulations, like connecting two tasks.

Type	Name	Mode
string	text	in
	The text describing the task.
string	time_begin	in
	Start time of the task.
string	time_end	in
	Stop time of the task.
float	completed	in
	The percentage of the task that is completed.

$ganttchart 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).

$ganttchart 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.

$ganttchart connect from to

Add an arrow that connects the from task with the to task.

Type	Name	Mode
list	from	in
	The list of items returned by the "task" command that represents the task from which the arrow starts.
string	text	in
	The text summarising the tasks
list	args	in
	One or more tasks (the lists returned by the "task" command). They are shifted down to make room for the summary.
list	to	in
	The list of items returned by the "task" command that represents the task at which the arrow ends.

$ganttchart summary text args

Add a summary item that spans all the tasks listed. The graphical representation is a thick bar running from the leftmost task to the rightmost.
Use this command before connecting the tasks, as the arrow would not be shifted down!

Type	Name	Mode
string	text	in
	The text summarising the tasks
list	args	in
	One or more tasks (the lists returned by the "task" command). They are shifted down to make room for the summary.

$ganttchart color keyword newcolor

Set the colour of a part of the Gantt chart. These colours hold for all items of that type.

Type	Name	Mode
string	keyword	in
	The keyword indicates which part of the Gantt chart to change: description - the colour of the descriptive text completed - the colour of the filled bar representing the completed part of a task left - the colour for the part that is not yet completed odd - the background colour for the odd entries even - the background colour for the even entries summary - the colour for the summary text summarybar - the colour for the bar for a summary
string	newcolor	in
	The new colour for the chosen items.

$ganttchart font keyword newfont

Set the font of a part of the Gantt chart. These fonts hold for all items of that type.

Type	Name	Mode
string	keyword	in
	The keyword indicates which part of the Gantt chart to change: description - the font used for descriptive text summary - the font used for summaries scale - the font used for the time scale
string	newfont	in
	The new font for the chosen items.

$ganttchart hscroll scrollbar

Connect a horizontal scrollbar to the chart. See also the section on scrolling.

Type	Name	Mode
widget	scrollbar	in
	The horizontal scrollbar that is to be connected to the chart

$ganttchart vscroll scrollbar

Connect a vertical scrollbar to the chart. See also the section on scrolling.

Type	Name	Mode
widget	scrollbar	in
	The vertical scrollbar that is to be connected to the chart

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.

COORDINATE TRANSFORMATIONS

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.

::Plotchart::pixelToIndex w x y

Return the index of the pie segment containing the pixel coordinates (x,y)

Type	Name	Mode
widget	w	in
	Name of the window (canvas widget) in question, holding a piechart.
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 inverted

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.
boolean	inverted	in
	Optional argument: if 1, then the returned list produces an inverted axis. Defaults to 0 (the axis will be from minimum to maximum)

MISSING VALUES

Often data that need to be plotted contain gaps - in a series of measurement data, they can occur because the equipment failed, a sample was not collected correctly or for many other reasons. The Plotchart handles these gaps by assuming that one or both coordinates of such data points are an empty string:

    #
    # 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 {} 25.0 60.0 78.0 11.0 } {
        $s plot series1 $x $y
    }

The effect varies according to the type of plot:

• For xy-plots, radial plots and strip charts the missing data point causes a gap in the line through the points.
• For barchats, missing values are treated as if a value of zero was given.
• For time charts and Gantt charts missing values cause errors - there is no use for them there.

OTHER OUTPUT FORMATS

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

SPECIAL EFFECTS

As an example of some special effects you can achieve, here is the code for a plot where the area below the data line varies in colour:

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

set s [::Plotchart::createXYPlot .c {0.0 100.0 10.0} {0.0 100.0 20.0}]

$s background gradient green top-down

$s dataconfig series1 -filled up -fillcolour white

$s plot series1  0.0 20.0
$s plot series1 10.0 20.0
$s plot series1 30.0 50.0
$s plot series1 35.0 45.0
$s plot series1 45.0 25.0
$s plot series1 75.0 55.0
$s plot series1 100.0 55.0

$s plaintext 30.0 60.0 "Peak" south

The trick is to fill the background with a colour that changes from green at the top to white at the bottom. Then the area above the data line is filled with a white polygon. Thus the green shading varies with the height of the line.

ROOM FOR IMPROVEMENT

In this version there are a lot of things that still need to be implemented:

• 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.

RESIZING

Plotchart has not been designed to create plots and charts that keep track of the data that are put in. This means that if an application needs to allow the user to resize the window holding the plot or chart, it must take care to redraw the complete plot.

The code below is a simple example of how to do that:

package require Plotchart

grid [canvas .c -background white] -sticky news
grid columnconfigure . 0 -weight 1
grid rowconfigure . 0 -weight 1

bind .c <Configure> {doResize}

proc doPlot {} {
    #
    # Clean up the contents (see also the note below!)
    #
    .c delete all

    #
    # (Re)draw the bar chart
    #
    set p [::Plotchart::createBarchart .c {x y z} {0 100 10} 3]
    $p plot R {10 30 40} red
    $p plot G {30 40 60} green
}

proc doResize {} {
    global redo

    #
    # To avoid redrawing the plot many times during resizing,
    # cancel the callback, until the last one is left.
    #
    if { [info exists redo] } {
        after cancel $redo
    }

    set redo [after 50 doPlot]
}

Please note: The code above will work fine for barcharts and many other types of plots, but as Plotchart keeps some private information for xy plots, more is needed in these cases. This actually requires a command "destroyPlot" to take care of such details. A next version of Plotchart will have that.

ZOOMING IN

As the Plotchart package does not keep track of the data itself, rescaling an existing plot - for instance when zooming in - would have to be done by redefining the plot and redrawing the data. However, the canvas widget offers a way out by scaling and moving items, so that zooming in becomes a bit simpler.

Whether zooming is indeed useful, depends on the type of plot. Currently it is defined for XY-plots only. The method is called "rescale" and simply redraws the axes and scales and moves the data items so that they conform to the new axes. The drawback is that any symbols are scaled by the same amount. The rescale method works best for plots that only have lines, not symbols.

The method works very simply:

   $p rescale {newxmin newxmax newxstep} {newymin newymax newystep}

CONFIGURATION OPTIONS

The command plotconfig can be used to set all manner of options. The syntax is:

::Plotchart::plotconfig charttype component property value

Set a new value for the property of a component in a particular chart or plot type or query its current value. Each argument is optional.

Type	Name	Mode
string	charttype	in
	The type of chart or plot (see the configuration type that is mentioned for each create command). If not given or empty, a list of chart types is returned. If it is given, the properties for that particular type are used.
string	component	in
	The component of the plot/chart: leftaxis, rightaxis, background, margin and so on. If not given or empty, a list of components is returned. If it is given, the properties for that particular component will be set for that particular type of chart.
string	property	in
	The property of the component of the plot/chart: textcolor, thickness of the axis line, etc. If not given or empty, a list of properties is returned. If it is given, that particular property for that particular component will be set for that particular type of chart.
string	value	in
	The new value for the property. If empty, the current value is returned. If the value is "default", the default value will be restored. Note, that in some cases an empty value is useful. Use "none" in this case - it can be useful for colours and for formats.

Below is a more detailed list of the components and properties:

• Axes come in a wide variety:
  • leftaxis, rightaxis, topaxis, bottomaxis for the plots with a rectangular shape.
  • xaxis, yaxis and zaxis are used for the 3D plots
  • axis, this represents the radial and tangential axes of a polar plot
  All axes have the following properties:
  • color - the colour of the line and the tickmarks
  • thickness - the width of the line of the axis itself, not the tickmarks
  • ticklength - the length of the tickmarks in pixels. A positive value is outward, a negative value is inward.
  • font - the font for the labels and the text at the axis
  • format - the format for rendering the (numerical) labels. For the time axis it is the format for a date and time.
  • textcolor - the colour for the labels and the text.
• The margin is important for the layout. Currently only the rectangular plots allow the margins to be set: left, right, top and bottom. The values are in pixels.
• The text component is meant for any text appearing via the plaintext subcommand. The properties are: textcolor, font and anchor (positioning of the text relative to the given coordinates).
• The background has two properties: outercolor, the colour outside of the actual plot, and innercolor, the colour inside the plot. (Note: only "outercolor" has now been implemented).
• The legend has three properties: background, border and position. See the legend subcommand for the meaning.

See the examples in plotdemos7.tcl for it use.

SCROLLING FOR TIMECHARTS AND GANTT CHARTS

For two types of plots automatic scrolling management has been implemented: timecharts and Gantt charts. The subcommands hscroll and vscroll associate (existing) scrollbars to the plot, in much the same way as for text and canvas widgets.

Once the association is made, the scrollbars are automatically updated if:

• You add an item with a period wider than the current one.
• You add a vertical line for a time beyond the current bounds.
• You add an extra item beyond the number that was used to create the chart.

For instance:

package require Plotchart

canvas .c -width 400 -height 200
scrollbar .y -orient vertical
scrollbar .x -orient horizontal

grid .c .y -sticky news
grid .x    -sticky news

source plotchart.tcl

set s [::Plotchart::createTimechart .c "1 january 2004"  "31 december 2004" 4]

$s period "Spring" "1 march 2004" "1 june 2004" green
$s period "Summer" "1 june 2004" "1 september 2004" yellow
$s vertline "1 jan" "1 january 2004"
$s vertline "1 apr" "1 april 2004"
$s vertline "1 jul" "1 july 2004"
$s vertline "1 oct" "1 october 2004"
$s vertline "1 jan" "1 january 2005"
$s vertline "1 apr" "1 april 2005"
$s vertline "1 jul" "1 july 2005"
$s milestone "Longest day" "21 july 2004"
$s milestone "Longest day 2" "21 july 2004"
$s milestone "Longest day 3" "21 july 2004"
$s milestone "Longest day 4" "21 july 2004"
$s milestone "Longest day 5" "21 july 2004"
$s milestone "Longest day 6" "21 july 2004"
$s title "Seasons (northern hemisphere)"

$s vscroll .y
$s hscroll .x

The original extent of the chart is from 1 january 2004 to 31 december 2004. But because of the addition of vertical lines in 2005 and more items than was specified at the creation of the chart, both the horizontal and the vertical scrollbar will be enabled.

ARRANGING MULTIPLE PLOTS IN A CANVAS

The command plotpack allows you to copy the contents of a plot into another canvas widget. This canvas widget does not act as a composite plot, but it can be saved as a PostScript file for instance: Note: the command simply takes a snapshot of the plots/charts as they are at that moment.

::Plotchart::plotpack w dir args

Copy the contents of the plots/charts into another widget, in a manner similar to the pack geometry manager.

Type	Name	Mode
widget	w	in
	The name of the canvas widget to copy the plots/charts into
string	dir	in
	The direction of the arrangement - top, left, bottom or right
list	args	in
	List of plots/charts to be copied.

For example:

    set p1 [createXYPlot ...]
    set p2 [createBarchart ...]

    ... fill the plots ...

    toplevel .t
    pack [canvas .t.c2 -width ...]

    #
    # Copy the two plots above each other in the new canvas
    #
    plotpack .t.c2 top $p1 $p2

NOTES ON TAGS

P.M.

TODO - SOME PRIVATE NOTES

I have the following wishlist:

• Isometric plots - allow new items to be implemented easily.
• A general 3D viewer - emphasis on geometry, not a ray-tracer.
• Several improvements for boxplots:
  • Height of the box scales with the logarithm of the number of points
  • Marker line to indicate a "current" value
  • Box drawn from quantiles

KEYWORDS

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