Plotchart(n) Plotchart Plotchart(n)
NAME
Plotchart - Simple plotting and charting package
SYNOPSIS
package require Tcl ??8.3??
package require Plotchart ??00.9??
::::Plotchart::::createXYPlot w xaxis yaxis
::::Plotchart::::createStripchart w xaxis yaxis
::::Plotchart::::createPolarPlot w radiusdata
::::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 timebegin timeend 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 timebegin timeend 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
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 manage-
ment. 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 num-
ber of plot and chart types:
]o XY-plots like the one shown above with any number of data
series.
]o 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.
]o Polar plots, where the coordinates are polar instead of carte-
sian.
]o Isometric plots, where the scale of the coordinates in the two
directions is always the same, i.e. a circle in world coordi-
nates 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.
]o Piecharts, with automatic scaling to indicate the proportions.
]o Barcharts, with either vertical or horizontal bars, stacked bars
or bars side by side.
]o Timecharts, where bars indicate a time period and milestones or
other important moments in time are represented by triangles.
]o 3D plots (both for displaying surfaces and 3D bars)
PLOT CREATION COMANDS
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.
w widget (in)
Name of the existing canvas widget to hold the plot.
xaxis list (in)
A 3-element list containing minimum, maximum and stepsize
for the x-axis, in this order.
yaxis list (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.
w widget (in)
Name of the existing canvas widget to hold the plot.
xaxis list (in)
A 3-element list containing minimum, maximum and stepsize
for the x-axis, in this order.
yaxis list (in)
A 3-element list containing minimum, maximum and stepsize
for the y-axis, in this order.
::::Plotchart::::createPolarPlot w radiusdata
Create a new polar plot.
w widget (in)
Name of the existing canvas widget to hold the plot.
radiusdata list (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 horizon-
tal coordinates are scaled so that a circle will truly appear as
a circle.
w widget (in)
Name of the existing canvas widget to hold the plot.
xaxis list (in)
A 2-element list containing minimum, and maximum for the
x-axis, in this order.
yaxis list (in)
A 2-element list containing minimum, and maximum for the
y-axis, in this order.
stepsize floatnoaxes (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.
w widget (in)
Name of the existing canvas widget to hold the plot.
xaxis list (in)
A 3-element list containing minimum, maximum and stepsize
for the x-axis, in this order.
yaxis list (in)
A 3-element list containing minimum, maximum and stepsize
for the y-axis, in this order.
zaxis list (in)
A 3-element list containing minimum, maximum and stepsize
for the z-axis, in this order.
::::Plotchart::::createPiechart w
Create a new piechart.
w widget (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.
w widget (in)
Name of the existing canvas widget to hold the plot.
xlabels list (in)
List of labels for the x-axis. Its length also determines
the number of bars that will be plotted per series.
yaxis list (in)
A 3-element list containing minimum, maximum and stepsize
for the y-axis, in this order.
noseries intstacked (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.
w widget (in)
Name of the existing canvas widget to hold the plot.
ylabels list (in)
List of labels for the y-axis. Its length also determines
the number of bars that will be plotted per series.
yaxis list (in)
A 3-element list containing minimum, maximum and stepsize
for the x-axis, in this order.
noseries intstacked (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 timebegin timeend noitems
Create a new timechart. The time axis (= x-axis) goes from
timebegin to timeend, and the vertical spacing is determined
by the number of items to plot.
w widget (in)
Name of the existing canvas widget to hold the plot.
timebegin string (in)
The start time given in a form that is recognised by the
clock scan command (e.g. "1 january 2004").
timeend string (in)
The end time given in a form that is recognised by the
clock scan command (e.g. "1 january 2004").
noitems int (in)
Expected/maximum number of items. This determines the
vertical spacing.
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:
$$anyplot title text
Specify the title of the whole chart.
text string (in)
The text of the title to be drawn.
$$anyplot saveplot filename
Draws the plot into a file, using PostScript.
filename string (in)
Contain the path name of the file to write the plot to.
$$anyplot xtext text
Specify the title of the x-axis, for those plots that have a
straight x-axis.
text string (in)
The text of the x-axis label to be drawn.
$$anyplot ytext text
Specify the title of the y-axis, for those plots that have a
straight y-axis.
text string (in)
The text of the y-axis label to be drawn.
$$anyplot xconfig -option value ...
Set one or more configuration parameters for the x-axis. The
following options are known:
format fmt
The format for the numbers along the axis.
ticklength length
The length of the tickmarks (in pixels).
ticklines boolean
Whether to draw ticklines (true) or not (false).
scale scaledata
New scale data for the axis, i.e. a 3-element list con-
taining minimum, maximum and stepsize for the axis, in
this order.
Beware: Setting this option will clear all data from the
plot.
$$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 xcon-
fig.
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:
$$xyplot plot series xcrd ycrd
Add a data point to the plot.
series string (in)
Name of the data series the new point belongs to.
xcrd float (in)
X-coordinate of the new point.
ycrd float (in)
Y-coordinate of the new point.
For polar plots:
$$polarplot plot series radius angle
Add a data point to the polar plot.
series string (in)
Name of the data series the new point belongs to.
radius float (in)
Radial coordinate of the new point.
angle float (in)
Angular coordinate of the new point (in degrees).
For 3D plots:
$$plot3d plotfunc function
Plot a function defined over two variables x and y. The resolu-
tion is determined by the set grid sizes (see the method grid-
size for more information).
function string (in)
Name of the procedure that calculates the z-value for the
given x and y coordinates. The procedure has to accept
two float arguments (x is first argument, y is second)
and return a floating-point value.
$$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.
nxcells int (in)
Number of grid cells in x direction. Has to be an integer
number greater than zero.
nycells int (in)
Number of grid cells in y direction. Has to be an integer
number greater than zero.
$$plot3d plotdata data
Plot a matrix of data.
data list (in)
The data to be plotted. The data has to be provided as a
nested list with 2 levels. The outer list contains rows,
drawn in y-direction, and each row is a list whose ele-
ments are drawn in x-direction, for the columns. Example:
set data {
{1.0 2.0 3.0}
{4.0 5.0 6.0}
}
$$plot3d colours fill border
Configure the colours to use for polygon borders and inner area.
fill color (in)
The colour to use for filling the polygons.
border color (in)
The colour to use for the border of the polygons.
For xy plots, stripcharts and polar plots:
$$xyplot dataconfig series -option value ...
Set the value for one or more options regarding the drawing of
data of a specific series.
series string (in)
Name of the data series whose configuration we are chang-
ing.
The following option are known:
colour c
color c
The colour to be used when drawing the data series.
type enum
The drawing mode chosen for the series. This can be one
of line, symbol, or both.
symbol enum
What kind of symbol to draw. The value of this option is
ignored when the drawing mode line was chosen. This can
be one of plus, cross, circle, up (triangle pointing up),
down (triangle pointing down), dot (filled circle),
upfilled or downfilled (filled triangles).
For piecharts:
$$pie plot data
Fill a piechart.
data list (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.
$$pie colours colour1 colour2 ...
Set the colours to be used.
colour1 color (in)
The first colour.
colour2 color (in)
The second colour, and so on.
For vertical barcharts:
$$barchart plot series ydata colour
Add a data series to a barchart.
series string (in)
Name of the series the values belong to.
ydata list (in)
A list of values, one for each x-axis label.
colour color (in)
The colour of the bars.
For horizontal barcharts:
$$barchart plot series xdata colour
Add a data series to a barchart.
series string (in)
Name of the series the values belong to.
xdata list (in)
A list of values, one for each y-axis label.
colour color (in)
The colour of the bars.
For timecharts:
$$timechart period text timebegin timeend colour
Add a time period to the chart.
text string (in)
The text describing the period.
timebegin string (in)
Start time of the period.
timeend string (in)
Stop time of the period.
colour color (in)
The colour of the bar (defaults to black).
$$timechart milestone text time colour
Add a milestone (represented as an point-down triangle) to the
chart.
text string (in)
The text describing the milestone.
time string (in)
Time at which the milestone must be positioned.
colour color (in)
The colour of the triangle (defaults to black).
$$timechart vertline text time
Add a vertical line (to indicate the start of the month for
instance) to the chart.
text string (in)
The text appearing at the top (an abbreviation of the
date/time for instance).
time string (in)
Time at which the line must be positioned.
For isometric plots (to be extended):
$$isoplot plot rectangle x1 y1 x2 y2 colour
Plot the outlines of a rectangle.
x1 float (in)
Minimum x coordinate of the rectangle to be drawn.
y1 float (in)
Minimum y coordinate of the rectangle.
x2 float (in)
Maximum x coordinate of the rectangle to be drawn.
y2 float (in)
Maximum y coordinate of the rectangle.
colour color (in)
The colour of the rectangle.
$$isoplot plot filled-rectangle x1 y1 x2 y2 colour
Plot a rectangle filled with the given colour.
x1 float (in)
Minimum x coordinate of the rectangle to be drawn.
y1 float (in)
Minimum y coordinate of the rectangle.
x2 float (in)
Maximum x coordinate of the rectangle to be drawn.
y2 float (in)
Maximum y coordinate of the rectangle.
colour color (in)
The colour of the rectangle.
$$isoplot plot circle xc yc radius colour
Plot the outline of a circle.
xc float (in)
X coordinate of the circle's centre.
yc float (in)
Y coordinate of the circle's centre.
colour color (in)
The colour of the circle.
$$isoplot plot filled-circle xc yc radius colour
Plot a circle filled with the given colour.
xc float (in)
X coordinate of the circle's centre.
yc float (in)
Y coordinate of the circle's centre.
colour color (in)
The colour of the circle.
There are a number of public procedures that may be useful in specific
situations: Pro memorie.
CORDINATE 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 coor-
dinates 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.
w widget (in)
Name of the window (canvas widget) in question.
pxmin float (in)
Left-most pixel coordinate.
pymin float (in)
Top-most pixel coordinate (remember: the vertical pixel
coordinate starts with 0 at the top!).
pxmax float (in)
Right-most pixel coordinate.
pymax float (in)
Bottom-most pixel coordinate.
::::Plotchart::::worldCoordinates w xmin ymin xmax ymax
Set the extreme world coordinates for window w. The world coor-
dinates need not be in ascending order (i.e. xmin can be larger
than xmax, so that a reversal of the x-axis is achieved).
w widget (in)
Name of the window (canvas widget) in question.
xmin float (in)
X-coordinate to be mapped to left side of viewport.
ymin float (in)
Y-coordinate to be mapped to bottom of viewport.
xmax float (in)
X-coordinate to be mapped to right side of viewport.
ymax float (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).
w widget (in)
Name of the window (canvas widget) in question.
xmin float (in)
X-coordinate to be mapped to front side of the 3D view-
port.
ymin float (in)
Y-coordinate to be mapped to left side of the viewport.
zmin float (in)
Z-coordinate to be mapped to bottom of viewport.
xmax float (in)
X-coordinate to be mapped to back side of viewport.
ymax float (in)
Y-coordinate to be mapped to right side of viewport.
zmax float (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.
w widget (in)
Name of the window (canvas widget) in question.
x float (in)
X-coordinate to be mapped.
y float (in)
Y-coordinate to be mapped.
::::Plotchart::::coords3DToPixel w x y z
Return a list of pixel coordinates valid for the given window.
w widget (in)
Name of the window (canvas widget) in question.
x float (in)
X-coordinate to be mapped.
y float (in)
Y-coordinate to be mapped.
y float (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.
w widget (in)
Name of the window (canvas widget) in question.
radmax float (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. Con-
verts polar coordinates to pixel coordinates. Note: To be use-
ful it should be accompanied by a matching ::::Plotchart::::worldCo-
ordinates procedure. This is automatically taken care of in the
creation routine for polar plots.
w widget (in)
Name of the window (canvas widget) in question.
rad float (in)
Radius of the point.
phi float (in)
Angle to the positive x-axis.
::::Plotchart::::pixelToCoords w x y
Return a list of world coordinates valid for the given window.
w widget (in)
Name of the window (canvas widget) in question.
x float (in)
X-pixel to be mapped.
y float (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.
xmin float (in)
Rough minimum value for the scaling
xmax float (in)
Rough maximum value for the scaling.
OTHER OUTPUT FORMATS
Besides output to the canvas on screen, the module is capable, via can-
vas 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 exam-
ining 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 ele-
ments 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 simu-
late 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 cur-
rently 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:
]o Emulate the create subcommand to create all the items in the
correct format
]o Emulate the cget subcommand for the options -width and -height
to allow the correct calculation of the rectangle's position and
size
]o Solve the problem of raising and lowering the items so that they
are properly clipped, for instance by redefining the routine
DrawMask.
]o Take care of the currently fixed text size properties
ROM FOR IMPROVEMENT
In this version there are a lot of things that still need to be imple-
mented:
]o General options like legends and text to the axes.
]o More robust handling of incorrect calls (right now the proce-
dures may fail when called incorrectly):
]o The axis drawing routines can not handle inverse axes
right now.
]o If the user provides an invalid date/time string, the
routines simply throw an error.
TODO - SOME PRIVATE NOTES
I have the following wishlist:
]o Isometric plots - allow new items to be implemented easily.
]o Add support for histograms where the independent axis is numeri-
cal.
]o A general 3D viewer - emphasis on geometry, not a ray-tracer.
KEYWORDS
3D bars, 3D surfaces, bar charts, charts, coordinate transformations,
coordinates, graphical presentation, isometric plots, pie charts, plot-
ting, polar plots, strip charts, time charts, xy-plots
COPYRIGHT
Copyright (c) 2004 Arjen Markus
plotchart 0.9 Plotchart(n)
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