Table of Contents
barchart - Bar chart for plotting X-Y coordinate
data.
barchart pathName ?option value?...
The barchart command
creates a bar chart for plotting two-dimensional data (X-Y coordinates). A
bar chart is a graphic means of comparing numbers by displaying bars of
lengths proportional to the y-coordinates of the points they represented.
The bar chart has many configurable components: coordinate axes, elements,
legend, grid lines, cross hairs, etc. They allow you to customize the look
and feel of the graph.
The barchart command creates a new window
for plotting two-dimensional data (X-Y coordinates), using bars of various
lengths to represent the data points. The bars are drawn in a rectangular
area displayed in the center of the new window. This is the plotting area.
The coordinate axes are drawn in the margins surrounding the plotting
area. By default, the legend is drawn in the right margin. The title is
displayed in top margin.
A barchart widget has several configurable components:
coordinate axes, data elements, legend, grid, cross hairs, pens, postscript,
and annotation markers. Each component can be queried or modified.
- axis
Up to four coordinate axes (two X-coordinate and two Y-coordinate axes)
can be displayed, but you can create and use any number of axes. Axes control
what region of data is displayed and how the data is scaled. Each axis consists
of the axis line, title, major and minor ticks, and tick labels. Tick labels
display the value at each major tick.
- crosshairs
- Cross hairs are used to
position the mouse pointer relative to the X and Y coordinate axes. Two
perpendicular lines, intersecting at the current location of the mouse,
extend across the plotting area to the coordinate axes.
- element
- An element
represents a set of data to be plotted. It contains an x and y vector of
values representing the data points. Each data point is displayed as a
bar where the length of the bar is proportional to the ordinate (Y-coordinate)
of the data point. The appearance of the bar, such as its color, stipple,
or relief is configurable.
A special case exists when two or more data points
have the same abscissa (X-coordinate). By default, the bars are overlayed,
one on top of the other. The bars are drawn in the order of the element
display list. But you can also configure the bars to be displayed in two
other ways. They may be displayed as a stack, where each bar (with the
same abscissa) is stacked on the previous. Or they can be drawn side-by-side
as thin bars. The width of each bar is a function of the number of data
points with the same abscissa.
- grid
- Extends the major and minor ticks of
the X-axis and/or Y-axis across the plotting area.
- legend
- The legend displays
the name and symbol of each data element. The legend can be drawn in any
margin or in the plotting area.
- marker
- Markers are used annotate or highlight
areas of the graph. For example, you could use a text marker to label a
particular data point. Markers come in various forms: text strings, bitmaps,
connected line segments, images, polygons, or embedded widgets.
- pen
- Pens
define attributes for elements. Data elements use pens to specify how they
should be drawn. A data element may use many pens at once. Here the particular
pen used for a data point is determined from each element's weight vector
(see the element's -weight and -style options).
- postscript
- The widget can generate
encapsulated PostScript output. This component has several options to configure
how the PostScript is generated.
barchart pathName ?option value?...
The barchart command creates a new window pathName and makes it into a
barchart widget. At the time this command is invoked, there must not exist
a window named pathName, but pathName's parent must exist. Additional options
may be specified on the command line or in the option database to configure
aspects of the graph such as its colors and font. See the configure operation
below for the exact details about what option and value pairs are valid.
If successful, barchart returns the path name of the widget. It also creates
a new Tcl command by the same name. You can use this command to invoke
various operations that query or modify the graph. The general form is:
pathName operation ?arg?...
Both operation and its arguments determine the exact behavior of the command.
The operations available for the graph are described in the BARCHART
OPERATIONS
section.
The command can also be used to access components of
the graph.
pathName component operation ?arg?...
The operation, now located after the name of the component, is the function
to be performed on that component. Each component has its own set of operations
that manipulate that component. They will be described below in their own
sections.
The barchart command creates a new bar chart.
# Create a new bar chart. Plotting area is black.
barchart .b -plotbackground black
A new Tcl command .b is created. This command can be used to query and modify
the bar chart. For example, to change the title of the graph to "My Plot",
you use the new command and the configure operation.
# Change the title.
.b configure -title "My Plot"
To add data elements, you use the command and the element component.
# Create a new element named "e1"
.b element create e1 \
-xdata { 1 2 3 4 5 6 7 8 9 10 } \
-ydata { 26.18 50.46 72.85 93.31 111.86 128.47 143.14
155.85 166.60 175.38 }
The element's X-Y coordinates are specified using lists of numbers. Alternately,
BLT vectors could be used to hold the X-Y coordinates.
# Create two vectors and add them to the barchart.
vector xVector yVector
xVector set { 1 2 3 4 5 6 7 8 9 10 }
yVector set { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 155.85
166.60 175.38 }
n.b element create e1 -xdata xVector -ydata yVector
The advantage of using vectors is that when you modify one, the graph is
automatically redrawn to reflect the new values.
# Change the y coordinate of the first point.
set yVector(0) 25.18
An element named e1 is now created in .b. It is automatically added to
the display list of elements. You can use this list to control in what
order elements are displayed. To query or reset the element display list,
you use the element's show operation.
# Get the current display list
set elemList [.b element show]
# Remove the first element so it won't be displayed.
.b element show [lrange $elemList 0 end]
The element will be displayed by as many bars as there are data points
(in this case there are ten). The bars will be drawn centered at the x-coordinate
of the data point. All the bars will have the same attributes (colors,
stipple, etc). The width of each bar is by default one unit. You can change
this with using the -barwidth option.
# Change the scale of the x-coordinate data
xVector set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }
# Make sure we change the bar width too.
.b configure -barwidth 0.2
The height of each bar is proportional to the ordinate (Y-coordinate) of
the data point.
If two or more data points have the same abscissa (X-coordinate
value), the bars representing those data points may be drawn in various
ways. The default is to overlay the bars, one on top of the other. The ordering
is determined from the of element display list. If the stacked mode is
selected (using the -barmode configuration option), the bars are stacked,
each bar above the previous.
# Display the elements as stacked.
.b configure -barmode stacked
If the aligned mode is selected, the bars having the same x-coordinates
are displayed side by side. The width of each bar is a fraction of its
normal width, based upon the number of bars with the same x-coordinate.
# Display the elements side-by-side.
.b configure -barmode aligned
By default, the element's label in the legend will be also e1. You can change
the label, or specify no legend entry, again using the element's configure
operation.
# Don't display "e1" in the legend.
.b element configure e1 -label ""
You can configure more than just the element's label. An element has many
attributes such as stipple, foreground and background colors, relief, etc.
.b element configure e1 -fg red -bg pink \
-stipple gray50
Four coordinate axes are automatically created: x, x2, y, and y2. And by
default, elements are mapped onto the axes x and y. This can be changed
with the -mapx and -mapy options.
# Map "e1" on the alternate y axis "y2".
.b element configure e1 -mapy y2
Axes can be configured in many ways too. For example, you change the scale
of the Y-axis from linear to log using the axis component.
# Y-axis is log scale.
.b axis configure y -logscale yes
One important way axes are used is to zoom in on a particular data region.
Zooming is done by simply specifying new axis limits using the -min and
-max configuration options.
.b axis configure x -min 1.0 -max 1.5
.b axis configure y -min 12.0 -max 55.15
To zoom interactively, you link theaxis configure operations with some
user interaction (such as pressing the mouse button), using the bind command.
To convert between screen and graph coordinates, use the invtransform
operation.
# Click the button to set a new minimum
bind .b <ButtonPress-1> {
%W axis configure x -min [%W axis invtransform x %x]
%W axis configure x -min [%W axis invtransform x %y]
}
By default, the limits of the axis are determined from data values. To reset
back to the default limits, set the -min and -max options to the empty value.
# Reset the axes to autoscale again.
.b axis configure x -min {} -max {}
.b axis configure y -min {} -max {}
By default, the legend is drawn in the right margin. You can change this
or any legend configuration options using the legend component.
# Configure the legend font, color, and relief
.b legend configure -position left -relief raised \
-font fixed -fg blue
To prevent the legend from being displayed, turn on the -hide option.
# Don't display the legend.
.b legend configure -hide yes
The barchart has simple drawing procedures called markers. They can be
used to highlight or annotate data in the graph. The types of markers available
are bitmaps, polygons, lines, or windows. Markers can be used, for example,
to mark or brush points. For example there may be a line marker which indicates
some low-water value. Markers are created using the marker operation.
# Create a line represent the low water mark at 10.0
.b marker create line -name "low_water" \
-coords { -Inf 10.0 Inf 10.0 } \
-dashes { 2 4 2 } -fg red -bg blue
This creates a line marker named low_water. It will display a horizontal
line stretching across the plotting area at the y-coordinate 10.0. The coordinates
"-Inf" and "Inf" indicate the relative minimum and maximum of the axis (in
this case the x-axis). By default, markers are drawn last, on top of the
bars. You can change this with the -under option.
# Draw the marker before elements are drawn.
.b marker configure low_water -under yes
You can add cross hairs or grid lines using the crosshairs and grid components.
# Display both cross hairs and grid lines.
.b crosshairs configure -hide no -color red
.b grid configure -hide no -dashes { 2 2 }
Finally, to get hardcopy of the graph, use the postscript component.
# Print the bar chart into file "file.ps"
.b postscript output file.ps -maxpect yes -decorations no
This generates a file file.ps containing the encapsulated PostScript of
the graph. The option -maxpect says to scale the plot to the size of the
page. Turning off the -decorations option denotes that no borders or color
backgrounds should be drawn (i.e. the background of the margins, legend,
and plotting area will be white).
barchart pathName ?option value?...
The barchart command creates a new window pathName and makes it into a
barchart widget. At the time this command is invoked, there must not exist
a window named pathName, but pathName's parent must exist. Additional options
may may be specified on the command line or in the option database to configure
aspects of the bar chart such as its colors and font. See the configure
operation below for the exact details as to what option and value pairs
are valid.
If successful, barchart returns pathName. It also creates a new
Tcl command pathName. This command may be used to invoke various operations
to query or modify the bar chart. It has the general form:
pathName operation ?arg?...
Both operation and its arguments determine the exact behavior of the command.
The operations available for the bar chart are described in the following
section.
- pathName bar elemName ?option value?...
- Creates
a new barchart element elemName. It's an error if an element elemName already
exists. See the manual for barchart for details about what option and
value pairs are valid.
- pathName cget option
- Returns the current value of
the configuration option given by option. Option may be any option described
below for the configure operation.
- pathName configure ?option value?...
- Queries
or modifies the configuration options of the graph. If option isn't specified,
a list describing the current options for pathName is returned. If option
is specified, but not value, then a list describing option is returned.
If one or more option and value pairs are specified, then for each pair,
the option option is set to value. The following options are valid.
- -background
color
- Sets the background color. This includes the margins and legend, but
not the plotting area.
- -barmode mode
- Indicates how related bar elements
will be drawn. Related elements have data points with the same abscissas
(X-coordinates). Mode indicates how those segments should be drawn. Mode can
be infront, aligned, overlap, or stacked. The default mode is infront.
- infront
- Each successive segment is drawn in front of the previous.
- stacked
- Each
successive segment is stacked vertically on top of the previous.
- aligned
- Segments is displayed aligned from right-to-left.
- overlap
- Like aligned but
segments slightly overlap each other.
- -barwidth value
- Specifies the width
of the bars. This value can be overrided by the individual elements using
their -barwidth configuration option. Value is the width in terms of graph
coordinates. The default width is 1.0.
- -borderwidth pixels
- Sets the width
of the 3-D border around the outside edge of the widget. The -relief option
determines if the border is to be drawn. The default is 2.
- -bottommargin
pixels
- Specifies the size of the margin below the X-coordinate axis. If
pixels is 0, the size of the margin is selected automatically. The default
is 0.
- -bufferelements boolean
- Indicates whether an internal pixmap to buffer
the display of data elements should be used. If boolean is true, data elements
are drawn to an internal pixmap. This option is especially useful when
the graph is redrawn frequently while the remains data unchanged (for example,
moving a marker across the plot). See the SPEED TIPS
section. The default
is 1.
- -cursor cursor
- Specifies the widget's cursor. The default cursor is
crosshair.
- -font fontName
- Specifies the font of the graph title. The default
is *-Helvetica-Bold-R-Normal-*-18-180-*.
- -halo pixels
- Specifies a maximum distance
to consider when searching for the closest data point (see the element's
closest operation below). Data points further than pixels away are ignored.
The default is 0.5i.
- -height pixels
- Specifies the requested height of widget.
The default is 4i.
- -invertxy boolean
- Indicates whether the placement X-axis
and Y-axis should be inverted. If boolean is true, the X and Y axes are
swapped. The default is 0.
- -justify justify
- Specifies how the title should
be justified. This matters only when the title contains more than one line
of text. Justify must be left, right, or center. The default is center.
- -leftmargin
pixels
- Sets the size of the margin from the left edge of the window to
the Y-coordinate axis. If pixels is 0, the size is calculated automatically.
The default is 0.
- -plotbackground color
- Specifies the background color of
the plotting area. The default is white.
- -plotborderwidth pixels
- Sets the
width of the 3-D border around the plotting area. The -plotrelief option
determines if a border is drawn. The default is 2.
- -plotpadx pad
- Sets the
amount of padding to be added to the left and right sides of the plotting
area. Pad can be a list of one or two screen distances. If pad has two
elements, the left side of the plotting area entry is padded by the first
distance and the right side by the second. If pad is just one distance,
both the left and right sides are padded evenly. The default is 8.
- -plotpady
pad
- Sets the amount of padding to be added to the top and bottom of the
plotting area. Pad can be a list of one or two screen distances. If pad
has two elements, the top of the plotting area is padded by the first distance
and the bottom by the second. If pad is just one distance, both the top
and bottom are padded evenly. The default is 8.
- -plotrelief relief
- Specifies
the 3-D effect for the plotting area. Relief specifies how the interior
of the plotting area should appear relative to rest of the graph; for example,
raised means the plot should appear to protrude from the graph, relative
to the surface of the graph. The default is sunken.
- -relief relief
- Specifies
the 3-D effect for the barchart widget. Relief specifies how the graph should
appear relative to widget it is packed into; for example, raised means
the graph should appear to protrude. The default is flat.
- -rightmargin pixels
- Sets the size of margin from the plotting area to the right edge of the
window. By default, the legend is drawn in this margin. If pixels is than
1, the margin size is selected automatically.
- -takefocus focus
- Provides
information used when moving the focus from window to window via keyboard
traversal (e.g., Tab and Shift-Tab). If focus is 0, this means that this window
should be skipped entirely during keyboard traversal. 1 means that the
this window should always receive the input focus. An empty value means
that the traversal scripts make the decision whether to focus on the window.
The default is "".
- -tile image
- Specifies a tiled background for the widget.
If image isn't "", the background is tiled using image. Otherwise, the normal
background color is drawn (see the -background option). Image must be an
image created using the Tk image command. The default is "".
- -title text
- Sets the title to text. If text is "", no title will be displayed.
- -topmargin
pixels
- Specifies the size of the margin above the x2 axis. If pixels is
0, the margin size is calculated automatically.
- -width pixels
- Specifies the
requested width of the widget. The default is 5i.
- pathName crosshairs operation
?arg?
- See the CROSSHAIRS COMPONENT
section.
- pathName element operation
?arg?...
- See the ELEMENT COMPONENTS
section.
- pathName extents item
- Returns
the size of a particular item in the graph. Item must be either leftmargin,
rightmargin, topmargin, bottommargin, plotwidth, or plotheight.
- pathName
grid operation ?arg?...
- See the GRID COMPONENT
section.
- pathName invtransform
winX winY
- Performs an inverse coordinate transformation, mapping window
coordinates back to graph coordinates, using the standard X-axis and Y-axis.
Returns a list of containing the X-Y graph coordinates.
- pathName inside x
y
- Returns 1 is the designated screen coordinate (x and y) is inside the
plotting area and 0 otherwise.
- pathName legend operation ?arg?...
- See the
LEGEND COMPONENT
section.
- pathName line operation arg...
- The operation is
the same as element.
- pathName marker operation ?arg?...
- See the MARKER COMPONENTS
section.
- pathName metafile ?fileName?
- This operation is for Window platforms
only. Creates a Windows enhanced metafile of the barchart. If present,
fileName is the file name of the new metafile. Otherwise, the metafile is
automatically added to the clipboard.
- pathName postscript operation ?arg?...
- See the POSTSCRIPT COMPONENT
section.
- pathName snap photoName
- Takes a
snapshot of the graph and stores the contents in the photo image photoName.
PhotoName is the name of a Tk photo image that must already exist.
- pathName
transform x y
- Performs a coordinate transformation, mapping graph coordinates
to window coordinates, using the standard X-axis and Y-axis. Returns a list
containing the X-Y screen coordinates.
- pathName xaxis operation ?arg?...
- pathName
x2axis operation ?arg?...
- pathName yaxis operation ?arg?...
- pathName y2axis
operation ?arg?...
- See the AXIS COMPONENTS
section.
A
graph is composed of several components: coordinate axes, data elements,
legend, grid, cross hairs, postscript, and annotation markers. Instead of
one big set of configuration options and operations, the graph is partitioned,
where each component has its own configuration options and operations that
specifically control that aspect or part of the graph.
Four
coordinate axes are automatically created: two X-coordinate axes (x and
x2) and two Y-coordinate axes (y, and y2). By default, the axis x is located
in the bottom margin, y in the left margin, x2 in the top margin, and y2
in the right margin.
An axis consists of the axis line, title, major and
minor ticks, and tick labels. Major ticks are drawn at uniform intervals
along the axis. Each tick is labeled with its coordinate value. Minor ticks
are drawn at uniform intervals within major ticks.
The range of the axis
controls what region of data is plotted. Data points outside the minimum
and maximum limits of the axis are not plotted. By default, the minimum
and maximum limits are determined from the data, but you can reset either
limit.
You can create and use several axes. To create an axis, invoke the
axis component and its create operation.
# Create a new axis called "temperature"
.b axis create temperature
You map data elements to an axis using the element's -mapy and -mapx configuration
options. They specify the coordinate axes an element is mapped onto.
# Now map the temperature data to this axis.
.b element create "temp" -xdata $x -ydata $tempData \
-mapy temperature
While you can have many axes, only four axes can be displayed simultaneously.
They are drawn in each of the margins surrounding the plotting area. The
axes x and y are drawn in the bottom and left margins. The axes x2 and y2
are drawn in top and right margins. Only x and y are shown by default. Note
that the axes can have different scales.
To display a different axis, you
invoke one of the following components: xaxis, yaxis, x2axis, and y2axis.
The use operation designates the axis to be drawn in the corresponding
margin: xaxis in the bottom, yaxis in the left, x2axis in the top, and
y2axis in the right.
# Display the axis temperature in the left margin.
.b yaxis use temperature
You can configure axes in many ways. The axis scale can be linear or logarithmic.
The values along the axis can either monotonically increase or decrease.
If you need custom tick labels, you can specify a Tcl procedure to format
the label any way you wish. You can control how ticks are drawn, by changing
the major tick interval or the number of minor ticks. You can define non-uniform
tick intervals, such as for time-series plots.
- pathName axis cget axisName
option
- Returns the current value of the option given by option for axisName.
Option may be any option described below for the axis configure operation.
- pathName axis configure axisName ?axisName?... ?option value?...
- Queries or modifies
the configuration options of axisName. Several axes can be changed. If option
isn't specified, a list describing all the current options for axisName
is returned. If option is specified, but not value, then a list describing
option is returned. If one or more option and value pairs are specified,
then for each pair, the axis option option is set to value. The following
options are valid for axes.
- -autorange range
- Sets the range of values for
the axis to range. The axis limits are automatically reset to display the
most recent data points in this range. If range is 0.0, the range is determined
from the limits of the data. If -min or -max are specified, they override
this option. The default is 0.0.
- -color color
- Sets the color of the axis and
tick labels. The default is black.
- -command prefix
- Specifies a Tcl command
to be invoked when formatting the axis tick labels. Prefix is a string containing
the name of a Tcl proc and any extra arguments for the procedure. This
command is invoked for each major tick on the axis. Two additional arguments
are passed to the procedure: the pathname of the widget and the current
the numeric value of the tick. The procedure returns the formatted tick
label. If "" is returned, no label will appear next to the tick. You can
get the standard tick labels again by setting prefix to "". The default
is "".
Please note that this procedure is invoked while the bar chart is
redrawn. You may query the widget's configuration options. But do not reset
options, because this can have unexpected results.
- -descending boolean
- Indicates
whether the values along the axis are monotonically increasing or decreasing.
If boolean is true, the axis values will be decreasing. The default is
0.
- -hide boolean
- Indicates whether the axis is displayed.
- -justify justify
- Specifies how the axis title should be justified. This matters only when
the axis title contains more than one line of text. Justify must be left,
right, or center. The default is center.
- -limits formatStr
- Specifies a printf-like
description to format the minimum and maximum limits of the axis. The limits
are displayed at the top/bottom or left/right sides of the plotting area.
FormatStr is a list of one or two format descriptions. If one description
is supplied, both the minimum and maximum limits are formatted in the same
way. If two, the first designates the format for the minimum limit, the
second for the maximum. If "" is given as either description, then the
that limit will not be displayed. The default is "".
- -linewidth pixels
- Sets
the width of the axis and tick lines. The default is 1 pixel.
- -logscale boolean
- Indicates whether the scale of the axis is logarithmic or linear. If boolean
is true, the axis is logarithmic. The default scale is linear.
- -loose boolean
- Indicates whether the limits of the axis should fit the data points tightly,
at the outermost data points, or loosely, at the outer tick intervals. This
is relevant only when the axis limit is automatically calculated. If boolean
is true, the axis range is "loose". The default is 0.
- -majorticks majorList
- Specifies where to display major axis ticks. You can use this option to
display ticks at non-uniform intervals. MajorList is a list of axis coordinates
designating the location of major ticks. No minor ticks are drawn. If majorList
is "", major ticks will be automatically computed. The default is "".
- -max
value
- Sets the maximum limit of axisName. Any data point greater than
value is not displayed. If value is "", the maximum limit is calculated
using the largest data value. The default is "".
- -min value
- Sets the minimum
limit of axisName. Any data point less than value is not displayed. If
value is "", the minimum limit is calculated using the smallest data value.
The default is "".
- -minorticks minorList
- Specifies where to display minor
axis ticks. You can use this option to display minor ticks at non-uniform
intervals. MinorList is a list of real values, ranging from 0.0 to 1.0, designating
the placement of a minor tick. No minor ticks are drawn if the -majortick
option is also set. If minorList is "", minor ticks will be automatically
computed. The default is "".
- -rotate theta
- Specifies the how many degrees
to rotate the axis tick labels. Theta is a real value representing the number
of degrees to rotate the tick labels. The default is 0.0 degrees.
- -shiftby
value
- Specifies how much to automatically shift the range of the axis. When
the new data exceeds the current axis maximum, the maximum is increased
in increments of value. You can use this option to prevent the axis limits
from being recomputed at each new time point. If value is 0.0, then no automatic
shifting is down. The default is 0.0.
- -showticks boolean
- Indicates whether
axis ticks should be drawn. If boolean is true, ticks are drawn. If false,
only the axis line is drawn. The default is 1.
- -stepsize value
- Specifies the
interval between major axis ticks. If value isn't a valid interval (must
be less than the axis range), the request is ignored and the step size
is automatically calculated.
- -subdivisions number
- Indicates how many minor
axis ticks are to be drawn. For example, if number is two, only one minor
tick is drawn. If number is one, no minor ticks are displayed. The default
is 2.
- -tickfont fontName
- Specifies the font for axis tick labels. The default
is *-Courier-Bold-R-Normal-*-100-*.
- -ticklength pixels
- Sets the length of major
and minor ticks (minor ticks are half the length of major ticks). If pixels
is less than zero, the axis will be inverted with ticks drawn pointing
towards the plot. The default is 0.1i.
- -title text
- Sets the title of the axis.
If text is "", no axis title will be displayed.
- -titlecolor color
- Sets
the color of the axis title. The default is black.
- -titlefont fontName
- Specifies
the font for axis title. The default is *-Helvetica-Bold-R-Normal-*-14-140-*.
Axis
configuration options may be also be set by the option command. The resource
class is Axis. The resource names are the names of the axes (such as x
or x2).
option add *Barchart.Axis.Color blue
option add *Barchart.x.LogScale true
option add *Barchart.x2.LogScale false
pathName axis create axisName ?option value?...
Creates a new axis by the
name axisName. No axis by the same name can already exist. Option and value
are described in above in the axis configure operation.
pathName axis delete
?axisName?...
Deletes the named axes. An axis is not really deleted until it
is not longer in use, so it's safe to delete axes mapped to elements.
pathName
axis invtransform axisName value
Performs the inverse transformation, changing
the screen coordinate value to a graph coordinate, mapping the value mapped
to axisName. Returns the graph coordinate.
pathName axis limits axisName
Returns a list of the minimum and maximum limits for axisName. The order
of the list is min max.
pathName axis names ?pattern?...
Returns a list of
axes matching zero or more patterns. If no pattern argument is give, the
names of all axes are returned.
pathName axis transform axisName value
Transforms
the coordinate value to a screen coordinate by mapping the it to axisName.
Returns the transformed screen coordinate.
Only four axes can be displayed
simultaneously. By default, they are x, y, x2, and y2. You can swap in
a different axis with use operation of the special axis components: xaxis,
x2axis, yaxis, and y2axis.
.g create axis temp
.g create axis time
...
.g xaxis use temp
.g yaxis use time
Only the axes specified for use are displayed on the screen.
The xaxis,
x2axis, yaxis, and y2axis components operate on an axis location rather
than a specific axis like the more general axis component does. The xaxis
component manages the X-axis located in the bottom margin (whatever axis
that happens to be). Likewise, yaxis uses the Y-axis in the left margin,
x2axis the top X-axis, and y2axis the right Y-axis.
They implicitly control
the axis that is currently using to that location. By default, xaxis uses
the x axis, yaxis uses y, x2axis uses x2, and y2axis uses y2. These components
can be more convenient to use than always determining what axes are current
being displayed by the graph.
The following operations are available for
axes. They mirror exactly the operations of the axis component. The axis
argument must be xaxis, x2axis, yaxis, or y2axis.
- pathName axis cget option
- pathName axis configure ?option value?...
- pathName axis invtransform value
- pathName axis limits
- pathName axis transform value
- pathName axis use ?axisName?
- Designates the axis axisName is to be displayed at this location. AxisName
can not be already in use at another location. This command returns the
name of the axis currently using this location.
Cross
hairs consist of two intersecting lines (one vertical and one horizontal)
drawn completely across the plotting area. They are used to position the
mouse in relation to the coordinate axes. Cross hairs differ from line
markers in that they are implemented using XOR drawing primitives. This
means that they can be quickly drawn and erased without redrawing the entire
widget.
The following operations are available for cross hairs:
- pathName
crosshairs cget option
- Returns the current value of the cross hairs configuration
option given by option. Option may be any option described below for the
cross hairs configure operation.
- pathName crosshairs configure ?option value?...
- Queries or modifies the configuration options of the cross hairs. If
option isn't specified, a list describing all the current options for the
cross hairs is returned. If option is specified, but not value, then a
list describing option is returned. If one or more option and value pairs
are specified, then for each pair, the cross hairs option option is set
to value. The following options are available for cross hairs.
- -color color
- Sets the color of the cross hairs. The default is black.
- -dashes dashList
- Sets the dash style of the cross hairs. DashList is a list of up to 11 numbers
that alternately represent the lengths of the dashes and gaps on the cross
hair lines. Each number must be between 1 and 255. If dashList is "", the
cross hairs will be solid lines.
- -hide boolean
- Indicates whether cross hairs
are drawn. If boolean is true, cross hairs are not drawn. The default is
yes.
- -linewidth pixels
- Set the width of the cross hair lines. The default
is 1.
- -position pos
- Specifies the screen position where the cross hairs
intersect. Pos must be in the form "@x,y", where x and y are the window
coordinates of the intersection.
Cross hairs configuration options may be
also be set by the option command. The resource name and class are crosshairs
and Crosshairs respectively.
option add *Barchart.Crosshairs.LineWidth 2
option add *Barchart.Crosshairs.Color red
pathName crosshairs off
Turns off the cross hairs.
pathName crosshairs
on
Turns on the display of the cross hairs.
pathName crosshairs toggle
Toggles the current state of the cross hairs, alternately mapping and unmapping
the cross hairs.
A data element represents a set of data. It contains
x and y vectors which are the coordinates of the data points. Elements
are displayed as bars where the length of the bar is proportional to the
ordinate of the data point. Elements also control the appearance of the
data, such as the color, stipple, relief, etc.
When new data elements are
created, they are automatically added to a list of displayed elements.
The display list controls what elements are drawn and in what order.
The following operations are available for elements.
- pathName element activate
elemName ?index?...
- Specifies the data points of element elemName to be drawn
using active foreground and background colors. ElemName is the name of
the element and index is a number representing the index of the data point.
If no indices are present then all data points become active.
- pathName element
bind tagName ?sequence? ?command?
- Associates command with tagName such
that whenever the event sequence given by sequence occurs for an element
with this tag, command will be invoked. The syntax is similar to the bind
command except that it operates on graph elements, rather than widgets.
See the bind manual entry for complete details on sequence and the substitutions
performed on command before invoking it.
If all arguments are specified
then a new binding is created, replacing any existing binding for the
same sequence and tagName. If the first character of command is + then command
augments an existing binding rather than replacing it. If no command argument
is provided then the command currently associated with tagName and sequence
(it's an error occurs if there's no such binding) is returned. If both command
and sequence are missing then a list of all the event sequences for which
bindings have been defined for tagName.
- pathName element cget elemName
option
- Returns the current value of the element configuration option given
by option. Option may be any of the options described below for the element
configure operation.
- pathName element closest x y ?option value?... ?elemName?...
- Finds the data point representing the bar closest to the window coordinates
x and y in the element elemName. ElemName is the name of an element, which
must be displayed. If no elements are specified, then all displayed elements
are searched. It returns a list containing the name of the closest element,
the index of its closest point, and the graph coordinates of the point.
If no data point within the threshold distance can be found, "" is returned.
The following option-value pairs are available.
- -halo pixels
- Specifies a
threshold distance where selected data points are ignored. Pixels is a valid
screen distance, such as 2 or 1.2i. If this option isn't specified, then it
defaults to the value of the barchart's -halo option.
- pathName element configure
elemName ?elemName... ?option value?...
- Queries or modifies the configuration
options for elements. Several elements can be modified at the same time.
If option isn't specified, a list describing all the current options for
elemName is returned. If option is specified, but not value, then a list
describing the option option is returned. If one or more option and value
pairs are specified, then for each pair, the element option option is set
to value. The following options are valid for elements.
- -activepen penName
- Specifies pen to use to draw active element. If penName is "", no active
elements will be drawn. The default is activeLine.
- -bindtags tagList
- Specifies
the binding tags for the element. TagList is a list of binding tag names.
The tags and their order will determine how events for elements. Each
tag in the list matching the current event sequence will have its Tcl command
executed. Implicitly the name of the element is always the first tag in
the list. The default value is all.
- -background color
- Sets the the color
of the border around each bar. The default is white.
- -barwidth value
- Specifies
the width the bars drawn for the element. Value is the width in X-coordinates.
If this option isn't specified, the width of each bar is the value of the
widget's -barwidth option.
- -baseline value
- Specifies the baseline of the bar
segments. This affects how bars are drawn since bars are drawn from their
respective y-coordinate the baseline. By default the baseline is 0.0.
- -borderwidth
pixels
- Sets the border width of the 3-D border drawn around the outside
of each bar. The -relief option determines if such a border is drawn. Pixels
must be a valid screen distance like 2 or 0.25i. The default is 2.
- -data coordList
- Specifies the X-Y coordinates of the data. CoordList is a list of numeric
expressions representing the X-Y coordinate pairs of each data point.
- -foreground
color
- Sets the color of the interior of the bars.
- -hide boolean
- Indicates
whether the element is displayed. The default is no.
- -label text
- Sets the
element's label in the legend. If text is "", the element will have no entry
in the legend. The default label is the element's name.
- -mapx xAxis
- Selects
the X-axis to map the element's X-coordinates onto. XAxis must be the name
of an axis. The default is x.
- -mapy yAxis
- Selects the Y-axis to map the element's
Y-coordinates onto. YAxis must be the name of an axis. The default is y.
- -relief
string
- Specifies the 3-D effect desired for bars. Relief indicates how the
interior of the bar should appear relative to the surface of the chart;
for example, raised means the bar should appear to protrude from the surface
of the plotting area. The default is raised.
- -stipple bitmap
- Specifies a
stipple pattern with which to draw the bars. If bitmap is "", then the
bar is drawn in a solid fashion.
- -xdata xVector
- Specifies the x-coordinate
vector of the data. XVector is the name of a BLT vector or a list of numeric
expressions.
- -ydata yVector
- Specifies the y-coordinate vector of the data.
YVector is the name of a BLT vector or a list of numeric expressions.
Element configuration options may also be set by the option command. The
resource names in the option database are prefixed by elem.
option add *Barchart.Element.background blue
pathName element create elemName ?option value?...
Creates a new element elemName.
Element names must be unique, so an element elemName may not already exist.
If additional arguments are present, they specify any of the element options
valid for element configure operation.
pathName element deactivate pattern...
Deactivates all the elements matching pattern for the graph. Elements
whose names match any of the patterns given are redrawn using their normal
colors.
pathName element delete ?pattern?...
Deletes all the elements matching
pattern for the graph. Elements whose names match any of the patterns
given are deleted. The graph will be redrawn without the deleted elements.
pathName element exists elemName
Returns 1 if an element elemName currently
exists and 0 otherwise.
pathName element names ?pattern?...
Returns the elements
matching one or more pattern. If no pattern is given, the names of all
elements is returned.
pathName element show ?nameList?
Queries or modifies
the element display list. The element display list designates the elements
drawn and in what order. NameList is a list of elements to be displayed
in the order they are named. If there is no nameList argument, the current
display list is returned.
pathName element type elemName
Returns the type
of elemName. If the element is a bar element, the commands returns the
string "bar", otherwise it returns "line".
Grid lines extend
from the major and minor ticks of each axis horizontally or vertically
across the plotting area. The following operations are available for grid
lines.
- pathName grid cget option
- Returns the current value of the grid line
configuration option given by option. Option may be any option described
below for the grid configure operation.
- pathName grid configure ?option
value?...
- Queries or modifies the configuration options for grid lines. If
option isn't specified, a list describing all the current grid options for
pathName is returned. If option is specified, but not value, then a list
describing option is returned. If one or more option and value pairs are
specified, then for each pair, the grid line option option is set to value.
The following options are valid for grid lines.
- -color color
- Sets the color
of the grid lines. The default is black.
- -dashes dashList
- Sets the dash style
of the grid lines. DashList is a list of up to 11 numbers that alternately
represent the lengths of the dashes and gaps on the grid lines. Each number
must be between 1 and 255. If dashList is "", the grid will be solid lines.
- -hide boolean
- Indicates whether the grid should be drawn. If boolean is true,
grid lines are not shown. The default is yes.
- -linewidth pixels
- Sets the width
of grid lines. The default width is 1.
- -mapx xAxis
- Specifies the X-axis to
display grid lines. XAxis must be the name of an axis or "" for no grid
lines. The default is "".
- -mapy yAxis
- Specifies the Y-axis to display grid
lines. YAxis must be the name of an axis or "" for no grid lines. The default
is y.
- -minor boolean
- Indicates whether the grid lines should be drawn for
minor ticks. If boolean is true, the lines will appear at minor tick intervals.
The default is 1.
Grid configuration options may also be set by the option
command. The resource name and class are grid and Grid respectively.
option add *Barchart.grid.LineWidth 2
option add *Barchart.Grid.Color black
pathName grid off
Turns off the display the grid lines.
pathName grid on
Turns on the display the grid lines.
pathName grid toggle
Toggles the display
of the grid.
The legend displays a list of the data elements.
Each entry consists of the element's symbol and label. The legend can appear
in any margin (the default location is in the right margin). It can also
be positioned anywhere within the plotting area.
The following operations
are valid for the legend.
- pathName legend activate pattern...
- Selects legend
entries to be drawn using the active legend colors and relief. All entries
whose element names match pattern are selected. To be selected, the element
name must match only one pattern.
- pathName legend bind tagName ?sequence?
?command?
- Associates command with tagName such that whenever the event
sequence given by sequence occurs for a legend entry with this tag, command
will be invoked. Implicitly the element names in the entry are tags. The
syntax is similar to the bind command except that it operates on legend
entries, rather than widgets. See the bind manual entry for complete details
on sequence and the substitutions performed on command before invoking
it.
If all arguments are specified then a new binding is created, replacing
any existing binding for the same sequence and tagName. If the first character
of command is + then command augments an existing binding rather than
replacing it. If no command argument is provided then the command currently
associated with tagName and sequence (it's an error occurs if there's no
such binding) is returned. If both command and sequence are missing then
a list of all the event sequences for which bindings have been defined
for tagName.
- pathName legend cget option
- Returns the current value of a
legend configuration option. Option may be any option described below in
the legend configure operation.
- pathName legend configure ?option value?...
- Queries or modifies the configuration options for the legend. If option
isn't specified, a list describing the current legend options for pathName
is returned. If option is specified, but not value, then a list describing
option is returned. If one or more option and value pairs are specified,
then for each pair, the legend option option is set to value. The following
options are valid for the legend.
- -activebackground color
- Sets the background
color for active legend entries. All legend entries marked active (see
the legend activate operation) are drawn using this background color.
- -activeborderwidth
pixels
- Sets the width of the 3-D border around the outside edge of the active
legend entries. The default is 2.
- -activeforeground color
- Sets the foreground
color for active legend entries. All legend entries marked as active (see
the legend activate operation) are drawn using this foreground color.
- -activerelief
relief
- Specifies the 3-D effect desired for active legend entries. Relief
denotes how the interior of the entry should appear relative to the legend;
for example, raised means the entry should appear to protrude from the
legend, relative to the surface of the legend. The default is flat.
- -anchor
anchor
- Tells how to position the legend relative to the positioning point
for the legend. This is dependent on the value of the -position option.
The default is center.
- left or right
- The anchor describes how to position
the legend vertically.
- top or bottom
- The anchor describes how to position
the legend horizontally.
- @x,y
- The anchor specifies how to position the
legend relative to the positioning point. For example, if anchor is center
then the legend is centered on the point; if anchor is n then the legend
will be drawn such that the top center point of the rectangular region
occupied by the legend will be at the positioning point.
- plotarea
- The anchor
specifies how to position the legend relative to the plotting area. For
example, if anchor is center then the legend is centered in the plotting
area; if anchor is ne then the legend will be drawn such that occupies
the upper right corner of the plotting area.
- -background color
- Sets the background
color of the legend. If color is "", the legend background with be transparent.
- -bindtags tagList
- Specifies the binding tags for legend entries. TagList
is a list of binding tag names. The tags and their order will determine
how events for legend entries. Each tag in the list matching the current
event sequence will have its Tcl command executed. The default value is
all.
- -borderwidth pixels
- Sets the width of the 3-D border around the outside
edge of the legend (if such border is being drawn; the relief option determines
this). The default is 2 pixels.
- -font fontName
- FontName specifies a font
to use when drawing the labels of each element into the legend. The default
is *-Helvetica-Bold-R-Normal-*-12-120-*.
- -foreground color
- Sets the foreground color
of the text drawn for the element's label. The default is black.
- -hide boolean
- Indicates whether the legend should be displayed. If boolean is true, the
legend will not be draw. The default is no.
- -ipadx pad
- Sets the amount of
internal padding to be added to the width of each legend entry. Pad can
be a list of one or two screen distances. If pad has two elements, the
left side of the legend entry is padded by the first distance and the right
side by the second. If pad is just one distance, both the left and right
sides are padded evenly. The default is 2.
- -ipady pad
- Sets an amount of internal
padding to be added to the height of each legend entry. Pad can be a list
of one or two screen distances. If pad has two elements, the top of the
entry is padded by the first distance and the bottom by the second. If
pad is just one distance, both the top and bottom of the entry are padded
evenly. The default is 2.
- -padx pad
- Sets the padding to the left and right
exteriors of the legend. Pad can be a list of one or two screen distances.
If pad has two elements, the left side of the legend is padded by the
first distance and the right side by the second. If pad has just one distance,
both the left and right sides are padded evenly. The default is 4.
- -pady
pad
- Sets the padding above and below the legend. Pad can be a list of one
or two screen distances. If pad has two elements, the area above the legend
is padded by the first distance and the area below by the second. If pad
is just one distance, both the top and bottom areas are padded evenly.
The default is 0.
- -position pos
- Specifies where the legend is drawn. The -anchor
option also affects where the legend is positioned. If pos is left, left,
top, or bottom, the legend is drawn in the specified margin. If pos is
plotarea, then the legend is drawn inside the plotting area at a particular
anchor. If pos is in the form "@x,y", where x and y are the window coordinates,
the legend is drawn in the plotting area at the specified coordinates.
The default is right.
- -raised boolean
- Indicates whether the legend is above
or below the data elements. This matters only if the legend is in the plotting
area. If boolean is true, the legend will be drawn on top of any elements
that may overlap it. The default is no.
- -relief relief
- Specifies the 3-D effect
for the border around the legend. Relief specifies how the interior of the
legend should appear relative to the bar chart; for example, raised means
the legend should appear to protrude from the bar chart, relative to the
surface of the bar chart. The default is sunken.
Legend configuration options
may also be set by the option command. The resource name and class are
legend and Legend respectively.
option add *Barchart.legend.Foreground blue
option add *Barchart.Legend.Relief raised
pathName legend deactivate pattern...
Selects legend entries to be drawn using
the normal legend colors and relief. All entries whose element names match
pattern are selected. To be selected, the element name must match only
one pattern.
pathName legend get pos
Returns the name of the element whose
entry is at the screen position pos in the legend. Pos must be in the form
"@x,y", where x and y are window coordinates. If the given coordinates
do not lie over a legend entry, "" is returned.
Pens define
attributes for elements. Pens mirror the configuration options of data elements
that pertain to how symbols and lines are drawn. Data elements use pens
to determine how they are drawn. A data element may use several pens at
once. In this case, the pen used for a particular data point is determined
from each element's weight vector (see the element's -weight and -style options).
One pen, called activeBar, is automatically created. It's used as the default
active pen for elements. So you can change the active attributes for all
elements by simply reconfiguring this pen.
.g pen configure "activeBar" -fg green -bg green4
You can create and use several pens. To create a pen, invoke the pen component
and its create operation.
.g pen create myPen
You map pens to a data element using either the element's -pen or -activepen
options.
.g element create "e1" -xdata $x -ydata $tempData \
-pen myPen
An element can use several pens at once. This is done by specifying the
name of the pen in the element's style list (see the -styles option).
.g element configure "e1" -styles { myPen 2.0 3.0 }
This says that any data point with a weight between 2.0 and 3.0 is to be
drawn using the pen myPen. All other points are drawn with the element's
default attributes.
The following operations are available for pen components.
- pathName pen cget penName option
- Returns the current value of the option
given by option for penName. Option may be any option described below for
the pen configure operation.
- pathName pen configure penName ?penName... ?option
value?...
- Queries or modifies the configuration options of penName. Several
pens can be modified at once. If option isn't specified, a list describing
the current options for penName is returned. If option is specified, but
not value, then a list describing option is returned. If one or more option
and value pairs are specified, then for each pair, the pen option option
is set to value. The following options are valid for pens.
- -background color
- Sets the the color of the border around each bar. The default is white.
- -borderwidth pixels
- Sets the border width of the 3-D border drawn around
the outside of each bar. The -relief option determines if such a border
is drawn. Pixels must be a valid screen distance like 2 or 0.25i. The default
is 2.
- -foreground color
- Sets the color of the interior of the bars.
- -relief
string
- Specifies the 3-D effect desired for bars. Relief indicates how the
interior of the bar should appear relative to the surface of the chart;
for example, raised means the bar should appear to protrude from the bar
chart, relative to the surface of the plotting area. The default is raised.
- -stipple bitmap
- Specifies a stipple pattern with which to draw the bars.
If bitmap is "", then the bar is drawn in a solid fashion.
- -type elemType
- Specifies the type of element the pen is to be used with. This option should
only be employed when creating the pen. This is for those that wish to
mix different types of elements (bars and lines) on the same graph. The
default type is "bar".
Pen configuration options may be also be set by the
option command. The resource class is Pen. The resource names are the names
of the pens.
option add *Barchart.Pen.Foreground blue
option add *Barchart.activeBar.foreground green
pathName pen create penName ?option value?...
Creates a new pen by the name
penName. No pen by the same name can already exist. Option and value are
described in above in the pen configure operation.
pathName pen delete
?penName?...
Deletes the named pens. A pen is not really deleted until it is
not longer in use, so it's safe to delete pens mapped to elements.
pathName
pen names ?pattern?...
Returns a list of pens matching zero or more patterns.
If no pattern argument is give, the names of all pens are returned.
The barchart can generate encapsulated PostScript output. There
are several configuration options you can specify to control how the plot
will be generated. You can change the page dimensions and borders. The
plot itself can be scaled, centered, or rotated to landscape. The PostScript
output can be written directly to a file or returned through the interpreter.
The following postscript operations are available.
- pathName postscript cget
option
- Returns the current value of the postscript option given by option.
Option may be any option described below for the postscript configure
operation.
- pathName postscript configure ?option value?...
- Queries or modifies
the configuration options for PostScript generation. If option isn't specified,
a list describing the current postscript options for pathName is returned.
If option is specified, but not value, then a list describing option is
returned. If one or more option and value pairs are specified, then for
each pair, the postscript option option is set to value. The following
postscript options are available.
- -center boolean
- Indicates whether the plot
should be centered on the PostScript page. If boolean is false, the plot
will be placed in the upper left corner of the page. The default is 1.
- -colormap
varName
- VarName must be the name of a global array variable that specifies
a color mapping from the X color name to PostScript. Each element of varName
must consist of PostScript code to set a particular color value (e.g. ``1.0
1.0 0.0 setrgbcolor''). When generating color information in PostScript, the
array variable varName is checked if an element of the name as the color
exists. If so, it uses its value as the PostScript command to set the color.
If this option hasn't been specified, or if there isn't an entry in varName
for a given color, then it uses the red, green, and blue intensities from
the X color.
- -colormode mode
- Specifies how to output color information. Mode
must be either color (for full color output), gray (convert all colors
to their gray-scale equivalents) or mono (convert foreground colors to black
and background colors to white). The default mode is color.
- -fontmap varName
- VarName must be the name of a global array variable that specifies a font
mapping from the X font name to PostScript. Each element of varName must
consist of a Tcl list with one or two elements; the name and point size
of a PostScript font. When outputting PostScript commands for a particular
font, the array variable varName is checked to see if an element by the
specified font exists. If there is such an element, then the font information
contained in that element is used in the PostScript output. (If the point
size is omitted from the list, the point size of the X font is used). Otherwise
the X font is examined in an attempt to guess what PostScript font to use.
This works only for fonts whose foundry property is Adobe (such as Times,
Helvetica, Courier, etc.). If all of this fails then the font defaults to
Helvetica-Bold.
- -decorations boolean
- Indicates whether PostScript commands
to generate color backgrounds and 3-D borders will be output. If boolean
is false, the graph will background will be white and no 3-D borders will
be generated. The default is 1.
- -height pixels
- Sets the height of the plot.
This lets you print the bar chart with a height different from the one
drawn on the screen. If pixels is 0, the height is the same as the widget's
height. The default is 0.
- -landscape boolean
- If boolean is true, this specifies
the printed area is to be rotated 90 degrees. In non-rotated output the
X-axis of the printed area runs along the short dimension of the page (``portrait''
orientation); in rotated output the X-axis runs along the long dimension
of the page (``landscape'' orientation). Defaults to 0.
- -maxpect boolean
- Indicates
to scale the plot so that it fills the PostScript page. The aspect ratio
of the barchart is still retained. The default is 0.
- -padx pad
- Sets the horizontal
padding for the left and right page borders. The borders are exterior to
the plot. Pad can be a list of one or two screen distances. If pad has
two elements, the left border is padded by the first distance and the right
border by the second. If pad has just one distance, both the left and right
borders are padded evenly. The default is 1i.
- -pady pad
- Sets the vertical
padding for the top and bottom page borders. The borders are exterior to
the plot. Pad can be a list of one or two screen distances. If pad has
two elements, the top border is padded by the first distance and the bottom
border by the second. If pad has just one distance, both the top and bottom
borders are padded evenly. The default is 1i.
- -paperheight pixels
- Sets the
height of the postscript page. This can be used to select between different
page sizes (letter, A4, etc). The default height is 11.0i.
- -paperwidth pixels
- Sets the width of the postscript page. This can be used to select between
different page sizes (letter, A4, etc). The default width is 8.5i.
- -width
pixels
- Sets the width of the plot. This lets you generate a plot of a width
different from that of the widget. If pixels is 0, the width is the same
as the widget's width. The default is 0.
Postscript configuration options
may be also be set by the option command. The resource name and class are
postscript and Postscript respectively.
option add *Barchart.postscript.Decorations false
option add *Barchart.Postscript.Landscape true
pathName postscript output ?fileName? ?option value?...
Outputs a file of
encapsulated PostScript. If a fileName argument isn't present, the command
returns the PostScript. If any option-value pairs are present, they set configuration
options controlling how the PostScript is generated. Option and value can
be anything accepted by the postscript configure operation above.
Markers are simple drawing procedures used to annotate or highlight
areas of the graph. Markers have various types: text strings, bitmaps,
images, connected lines, windows, or polygons. They can be associated with
a particular element, so that when the element is hidden or un-hidden, so
is the marker. By default, markers are the last items drawn, so that data
elements will appear in behind them. You can change this by configuring
the -under option.
Markers, in contrast to elements, don't affect the scaling
of the coordinate axes. They can also have elastic coordinates (specified
by -Inf and Inf respectively) that translate into the minimum or maximum
limit of the axis. For example, you can place a marker so it always remains
in the lower left corner of the plotting area, by using the coordinates
-Inf,-Inf.
The following operations are available for markers.
- pathName marker
after markerId ?afterId?
- Changes the order of the markers, drawing the
first marker after the second. If no second afterId argument is specified,
the marker is placed at the end of the display list. This command can be
used to control how markers are displayed since markers are drawn in the
order of this display list.
- pathName marker before markerId ?beforeId?
- Changes
the order of the markers, drawing the first marker before the second. If
no second beforeId argument is specified, the marker is placed at the beginning
of the display list. This command can be used to control how markers are
displayed since markers are drawn in the order of this display list.
- pathName
marker bind tagName ?sequence? ?command?
- Associates command with tagName
such that whenever the event sequence given by sequence occurs for a marker
with this tag, command will be invoked. The syntax is similar to the bind
command except that it operates on graph markers, rather than widgets.
See the bind manual entry for complete details on sequence and the substitutions
performed on command before invoking it.
If all arguments are specified
then a new binding is created, replacing any existing binding for the
same sequence and tagName. If the first character of command is + then command
augments an existing binding rather than replacing it. If no command argument
is provided then the command currently associated with tagName and sequence
(it's an error occurs if there's no such binding) is returned. If both command
and sequence are missing then a list of all the event sequences for which
bindings have been defined for tagName.
- pathName marker cget option
- Returns
the current value of the marker configuration option given by option. Option
may be any option described below in the configure operation.
- pathName marker
configure markerId ?option value?...
- Queries or modifies the configuration
options for markers. If option isn't specified, a list describing the current
options for markerId is returned. If option is specified, but not value,
then a list describing option is returned. If one or more option and value
pairs are specified, then for each pair, the marker option option is set
to value.
The following options are valid for all markers. Each type of marker
also has its own type-specific options. They are described in the sections
below.
- -bindtags tagList
- Specifies the binding tags for the marker. TagList
is a list of binding tag names. The tags and their order will determine
how events for markers are handled. Each tag in the list matching the
current event sequence will have its Tcl command executed. Implicitly
the name of the marker is always the first tag in the list. The default
value is all.
- -coords coordList
- Specifies the coordinates of the marker.
CoordList is a list of graph coordinates. The number of coordinates required
is dependent on the type of marker. Text, image, and window markers need
only two coordinates (an X-Y coordinate). Bitmap markers can take either
two or four coordinates (if four, they represent the corners of the bitmap).
Line markers need at least four coordinates, polygons at least six. If coordList
is "", the marker will not be displayed. The default is "".
- -element elemName
- Links the marker with the element elemName. The marker is drawn only if
the element is also currently displayed (see the element's show operation).
If elemName is "", the marker is always drawn. The default is "".
- -hide
boolean
- Indicates whether the marker is drawn. If boolean is true, the
marker is not drawn. The default is no.
- -mapx xAxis
- Specifies the X-axis
to map the marker's X-coordinates onto. XAxis must the name of an axis. The
default is x.
- -mapy yAxis
- Specifies the Y-axis to map the marker's Y-coordinates
onto. YAxis must the name of an axis. The default is y.
- -name markerId
- Changes
the identifier for the marker. The identifier markerId can not already
be used by another marker. If this option isn't specified, the marker's name
is uniquely generated.
- -under boolean
- Indicates whether the marker is drawn
below/above data elements. If boolean is true, the marker is be drawn underneath
the data elements. Otherwise, the marker is drawn on top of the element.
The default is 0.
- -xoffset pixels
- Specifies a screen distance to offset
the marker horizontally. Pixels is a valid screen distance, such as 2 or
1.2i. The default is 0.
- -yoffset pixels
- Specifies a screen distance to offset
the markers vertically. Pixels is a valid screen distance, such as 2 or
1.2i. The default is 0.
Marker configuration options may also be set by the
option command. The resource class is either BitmapMarker, ImageMarker,
LineMarker, PolygonMarker, TextMarker, or WindowMarker, depending on the
type of marker. The resource name is the name of the marker.
option add *Barchart.TextMarker.Foreground white
option add *Barchart.BitmapMarker.Foreground white
option add *Barchart.m1.Background blue
pathName marker create type ?option value?...
Creates a marker of the selected
type. Type may be either text, line, bitmap, image, polygon, or window.
This command returns the marker identifier, used as the markerId argument
in the other marker-related commands. If the -name option is used, this overrides
the normal marker identifier. If the name provided is already used for
another marker, the new marker will replace the old.
pathName marker delete
?name?...
Removes one of more markers. The graph will automatically be redrawn
without the marker..
pathName marker exists markerId
Returns 1 if the
marker markerId exists and 0 otherwise.
pathName marker names ?pattern?
Returns the names of all the markers that currently exist. If pattern
is supplied, only those markers whose names match it will be returned.
pathName
marker type markerId
Returns the type of the marker given by markerId,
such as line or text. If markerId is not a valid a marker identifier, ""
is returned.
A bitmap marker displays a bitmap. The size of
the bitmap is controlled by the number of coordinates specified. If two
coordinates, they specify the position of the top-left corner of the bitmap.
The bitmap retains its normal width and height. If four coordinates, the
first and second pairs of coordinates represent the corners of the bitmap.
The bitmap will be stretched or reduced as necessary to fit into the bounding
rectangle.
Bitmap markers are created with the marker's create operation
in the form:
pathName marker create bitmap ?option value?...
There may be many option-value pairs, each sets a configuration options
for the marker. These same option-value pairs may be used with the marker's
configure operation.
The following options are specific to bitmap markers:
- -background color
- Same as the -fill option.
- -bitmap bitmap
- Specifies the bitmap
to be displayed. If bitmap is "", the marker will not be displayed. The
default is "".
- -fill color
- Sets the background color of the bitmap. If color
is the empty string, no background will be transparent. The default background
color is "".
- -foreground color
- Same as the -outline option.
- -mask mask
- Specifies
a mask for the bitmap to be displayed. This mask is a bitmap itself, denoting
the pixels that are transparent. If mask is "", all pixels of the bitmap
will be drawn. The default is "".
- -outline color
- Sets the foreground color
of the bitmap. The default value is black.
- -rotate theta
- Sets the rotation
of the bitmap. Theta is a real number representing the angle of rotation
in degrees. The marker is first rotated and then placed according to its
anchor position. The default rotation is 0.0.
A image marker
displays an image. Image markers are created with the marker's create operation
in the form:
pathName marker create image ?option value?...
There may be many option-value pairs, each sets a configuration option for
the marker. These same option-value pairs may be used with the marker's configure
operation.
The following options are specific to image markers:
- -anchor anchor
- Anchor tells how to position the image relative to the positioning point
for the image. For example, if anchor is center then the image is centered
on the point; if anchor is n then the image will be drawn such that the
top center point of the rectangular region occupied by the image will be
at the positioning point. This option defaults to center.
- -image image
- Specifies
the image to be drawn. If image is "", the marker will not be drawn. The
default is "".
A line marker displays one or more connected
line segments. Line markers are created with marker's create operation in
the form:
pathName marker create line ?option value?...
There may be many option-value pairs, each sets a configuration option for
the marker. These same option-value pairs may be used with the marker's configure
operation.
The following options are specific to line markers:
- -dashes dashList
- Sets the dash style of the line. DashList is a list of up to 11 numbers
that alternately represent the lengths of the dashes and gaps on the line.
Each number must be between 1 and 255. If dashList is "", the marker line
will be solid.
- -fill color
- Sets the background color of the line. This color
is used with striped lines (see the -fdashesR option). If color is the empty
string, no background color is drawn (the line will be dashed, not striped).
The default background color is "".
- -linewidth pixels
- Sets the width of
the lines. The default width is 0.
- -outline color
- Sets the foreground color
of the line. The default value is black.
- -stipple bitmap
- Specifies a stipple
pattern used to draw the line, rather than a solid line. Bitmap specifies
a bitmap to use as the stipple pattern. If bitmap is "", then the line
is drawn in a solid fashion. The default is "".
A polygon
marker displays a closed region described as two or more connected line
segments. It is assumed the first and last points are connected. Polygon
markers are created using the marker create operation in the form:
pathName marker create polygon ?option value?...
There may be many option-value pairs, each sets a configuration option for
the marker. These same option-value pairs may be used with the marker configure
command to change the marker's configuration. The following options are supported
for polygon markers:
- -dashes dashList
- Sets the dash style of the outline
of the polygon. DashList is a list of up to 11 numbers that alternately
represent the lengths of the dashes and gaps on the outline. Each number
must be between 1 and 255. If dashList is "", the outline will be a solid
line.
- -fill color
- Sets the fill color of the polygon. If color is "", then
the interior of the polygon is transparent. The default is white.
- -linewidth
pixels
- Sets the width of the outline of the polygon. If pixels is zero,
no outline is drawn. The default is 0.
- -outline color
- Sets the color of the
outline of the polygon. If the polygon is stippled (see the -stipple option),
then this represents the foreground color of the stipple. The default is
black.
- -stipple bitmap
- Specifies that the polygon should be drawn with a
stippled pattern rather than a solid color. Bitmap specifies a bitmap to
use as the stipple pattern. If bitmap is "", then the polygon is filled
with a solid color (if the -fill option is set). The default is "".
A text marker displays a string of characters on one or more lines
of text. Embedded newlines cause line breaks. They may be used to annotate
regions of the graph. Text markers are created with the create operation
in the form:
pathName marker create text ?option value?...
There may be many option-value pairs, each sets a configuration option
for the text marker. These same option-value pairs may be used with the
marker's configure operation.
The following options are specific to text
markers:
- -anchor anchor
- Anchor tells how to position the text relative to
the positioning point for the text. For example, if anchor is center then
the text is centered on the point; if anchor is n then the text will be
drawn such that the top center point of the rectangular region occupied
by the text will be at the positioning point. This default is center.
- -background
color
- Same as the -fill option.
- -font fontName
- Specifies the font of the text.
The default is *-Helvetica-Bold-R-Normal-*-120-*.
- -fill color
- Sets the background
color of the text. If color is the empty string, no background will be
transparent. The default background color is "".
- -foreground color
- Same as
the -outline option.
- -justify justify
- Specifies how the text should be justified.
This matters only when the marker contains more than one line of text.
Justify must be left, right, or center. The default is center.
- -outline color
- Sets the color of the text. The default value is black.
- -padx pad
- Sets the
padding to the left and right exteriors of the text. Pad can be a list of
one or two screen distances. If pad has two elements, the left side of
the text is padded by the first distance and the right side by the second.
If pad has just one distance, both the left and right sides are padded
evenly. The default is 4.
- -pady pad
- Sets the padding above and below the
text. Pad can be a list of one or two screen distances. If pad has two
elements, the area above the text is padded by the first distance and the
area below by the second. If pad is just one distance, both the top and
bottom areas are padded evenly. The default is 4.
- -rotate theta
- Specifies
the number of degrees to rotate the text. Theta is a real number representing
the angle of rotation. The marker is first rotated along its center and
is then drawn according to its anchor position. The default is 0.0.
- -text text
- Specifies the text of the marker. The exact way the text is displayed may
be affected by other options such as -anchor or -rotate.
A window
marker displays a widget at a given position. Window markers are created
with the marker's create operation in the form:
pathName marker create window ?option value?...
There may be many option-value pairs, each sets a configuration option for
the marker. These same option-value pairs may be used with the marker's configure
command.
The following options are specific to window markers:
- -anchor anchor
- Anchor tells how to position the widget relative to the positioning point
for the widget. For example, if anchor is center then the widget is centered
on the point; if anchor is n then the widget will be displayed such that
the top center point of the rectangular region occupied by the widget will
be at the positioning point. This option defaults to center.
- -height pixels
- Specifies the height to assign to the marker's window. If this option isn't
specified, or if it is specified as "", then the window is given whatever
height the widget requests internally.
- -width pixels
- Specifies the width
to assign to the marker's window. If this option isn't specified, or if it
is specified as "", then the window is given whatever width the widget
requests internally.
- -window pathName
- Specifies the widget to be managed
by the barchart. PathName must be a child of the barchart widget.
Specific barchart components, such as elements, markers
and legend entries, can have a command trigger when event occurs in them,
much like canvas items in Tk's canvas widget. Not all event sequences are
valid. The only binding events that may be specified are those related
to the mouse and keyboard (such as Enter, Leave, ButtonPress, Motion, and
KeyPress).
Only one element or marker can be picked during an event. This
means, that if the mouse is directly over both an element and a marker,
only the uppermost component is selected. This isn't true for legend entries.
Both a legend entry and an element (or marker) binding commands will
be invoked if both items are picked.
It is possible for multiple bindings
to match a particular event. This could occur, for example, if one binding
is associated with the element name and another is associated with one
of the element's tags (see the -bindtags option). When this occurs, all of
the matching bindings are invoked. A binding associated with the element
name is invoked first, followed by one binding for each of the element's
bindtags. If there are multiple matching bindings for a single tag, then
only the most specific binding is invoked. A continue command in a binding
script terminates that script, and a break command terminates that script
and skips any remaining scripts for the event, just as for the bind command.
The -bindtags option for these components controls addition tag names which
can be matched. Implicitly elements and markers always have tags matching
their names. Setting the value of the -bindtags option doesn't change this.
You can manipulate data elements from the C language. There
may be situations where it is too expensive to translate the data values
from ASCII strings. Or you might want to read data in a special file format.
Data can manipulated from the C language using BLT vectors. You specify
the X-Y data coordinates of an element as vectors and manipulate the vector
from C. The barchart will be redrawn automatically after the vectors are
updated.
From Tcl, create the vectors and configure the element to use them.
vector X Y
.g element configure line1 -xdata X -ydata Y
To set data points from C, you pass the values as arrays of doubles using
the Blt_ResetVector call. The vector is reset with the new data and at
the next idle point (when Tk re-enters its event loop), the graph will be
redrawn automatically.
#include <tcl.h>
#include <blt.h>
register int i;
Blt_Vector *xVec, *yVec;
double x[50], y[50];
/* Get the BLT vectors "X" and "Y" (created above from Tcl) */
if ((Blt_GetVector(interp, "X", 50, &xVec) != TCL_OK) ||
(Blt_GetVector(interp, "Y", 50, &yVec) != TCL_OK)) {
return TCL_ERROR;
}
for (i = 0; i < 50; i++) {
x[i] = i * 0.02;
y[i] = sin(x[i]);
}
/* Put the data into BLT vectors */
if ((Blt_ResetVector(xVec, x, 50, 50, TCL_VOLATILE) != TCL_OK) ||
(Blt_ResetVector(yVec, y, 50, 50, TCL_VOLATILE) != TCL_OK)) {
return TCL_ERROR;
}
See the vector manual page for more details.
There may be cases
where the bar chart needs to be drawn and updated as quickly as possible.
If drawing speed becomes a big problem, here are a few tips to speed up
displays.
·- Try to minimize the number of data points. The more data points
looked at, the more work the bar chart must do.
·- If your data is generated
as floating point values, the time required to convert the data values
to and from ASCII strings can be significant, especially when there any
many data points. You can avoid the redundant string-to-decimal conversions
using the C API to BLT vectors.
·- Don't stipple or dash the element. Solid
bars are much faster.
·- If you update data elements frequently, try turning
off the widget's -bufferelements option. When the bar chart is first displayed,
it draws data elements into an internal pixmap. The pixmap acts as a cache,
so that when the bar chart needs to be redrawn again, and the data elements
or coordinate axes haven't changed, the pixmap is simply copied to the screen.
This is especially useful when you are using markers to highlight points
and regions on the bar chart. But if the bar chart is updated frequently,
changing either the element data or coordinate axes, the buffering becomes
redundant.
Auto-scale routines do not use requested min/max limits
as boundaries when the axis is logarithmically scaled.
The PostScript
output generated for polygons with more than 1500 points may exceed the
limits of some printers (See PostScript Language Reference Manual, page
568). The work-around is to break the polygon into separate pieces.
bar
chart, widget
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