barchart(BLT 2.4) barchart(BLT 2.4)
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barchart - Bar chart for plotting X-Y coordinate data.
barchart pathName ?option value?...
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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-byside
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 con-
figure 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-toleft.
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.
AXIS COMPONENTS [Toc] [Back]
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.
CROSSHAIRS COMPONENT [Toc] [Back]
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 tag-
Name. If the first character of command is + then command augments
an existing binding rather than replacing it. If no com-
mand 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 pat-
tern 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 COMPONENT [Toc] [Back]
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.
LEGEND COMPONENT [Toc] [Back]
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 tag-
Name. If the first character of command is + then command augments
an existing binding rather than replacing it. If no com-
mand 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
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