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 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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