barchart - Bar chart for plotting X-Y coordinate data.
barchart pathName ?option
value?...
The barchart command creates a bar chart for plotting
two-dimensional data (X-Y coordinates). A bar chart is a graphic means of
comparing numbers by displaying bars of lengths proportional to the
y-coordinates of the points they represented. The bar chart has many
configurable components: coordinate axes, elements, legend, grid lines,
cross hairs, etc. They allow you to customize the look and feel of the
graph.
The barchart command creates a new window for plotting
two-dimensional data (X-Y coordinates), using bars of various lengths to
represent the data points. The bars are drawn in a rectangular area
displayed in the center of the new window. This is the plotting area.
The coordinate axes are drawn in the margins surrounding the plotting area.
By default, the legend is drawn in the right margin. The title is displayed
in top margin.
A barchart widget has several configurable components:
coordinate axes, data elements, legend, grid, cross hairs, pens, postscript,
and annotation markers. Each component can be queried or modified.
- axis
-
Up to four coordinate axes (two X-coordinate and two
Y-coordinate axes) can be displayed, but you can create and use any
number of axes. Axes control what region of data is displayed and how
the data is scaled. Each axis consists of the axis line, title, major
and minor ticks, and tick labels. Tick labels display the value at each
major tick.
- crosshairs
- Cross hairs are used to position the mouse pointer relative to the X and Y
coordinate axes. Two perpendicular lines, intersecting at the current
location of the mouse, extend across the plotting area to the coordinate
axes.
- element
- An element represents a set of data to be plotted. It contains an x and y
vector of values representing the data points. Each data point is
displayed as a bar where the length of the bar is proportional to the
ordinate (Y-coordinate) of the data point. The appearance of the bar, such
as its color, stipple, or relief is configurable.
A special case exists when two or more data points have the
same abscissa (X-coordinate). By default, the bars are overlayed, one on
top of the other. The bars are drawn in the order of the element display
list. But you can also configure the bars to be displayed in two other
ways. They may be displayed as a stack, where each bar (with the same
abscissa) is stacked on the previous. Or they can be drawn side-by-side
as thin bars. The width of each bar is a function of the number of data
points with the same abscissa.
- grid
- Extends the major and minor ticks of the X-axis and/or Y-axis across the
plotting area.
- legend
- The legend displays the name and symbol of each data element. The legend
can be drawn in any margin or in the plotting area.
- marker
- Markers are used annotate or highlight areas of the graph. For example,
you could use a text marker to label a particular data point. Markers come
in various forms: text strings, bitmaps, connected line segments, images,
polygons, or embedded widgets.
- pen
- Pens define attributes for elements. Data elements use pens to specify how
they should be drawn. A data element may use many pens at once. Here the
particular pen used for a data point is determined from each element's
weight vector (see the element's -weight and -style
options).
- postscript
- The widget can generate encapsulated PostScript output. This component has
several options to configure how the PostScript is generated.
barchart pathName ?option value?...
The barchart command creates a new window pathName
and makes it into a barchart widget. At the time this command is
invoked, there must not exist a window named pathName, but
pathName's parent must exist. Additional options may be specified on
the command line or in the option database to configure aspects of the graph
such as its colors and font. See the configure operation below for
the exact details about what option and value pairs are
valid.
If successful, barchart returns the path name of the
widget. It also creates a new Tcl command by the same name. You can use this
command to invoke various operations that query or modify the graph. The
general form is:
pathName operation ?arg?...
Both operation and its arguments determine the exact
behavior of the command. The operations available for the graph are
described in the BARCHART OPERATIONS section.
The command can also be used to access components of the
graph.
pathName component operation ?arg?...
The operation, now located after the name of the component, is the
function to be performed on that component. Each component has its own set
of operations that manipulate that component. They will be described below
in their own sections.
The barchart command creates a new bar chart.
# Create a new bar chart. Plotting area is black.
barchart .b -plotbackground black
A new Tcl command .b is created. This command can be used
to query and modify the bar chart. For example, to change the title of the
graph to "My Plot", you use the new command and the
configure operation.
# Change the title.
.b configure -title "My Plot"
To add data elements, you use the command and the element
component.
# Create a new element named "e1"
.b element create e1 \
-xdata { 1 2 3 4 5 6 7 8 9 10 } \
-ydata { 26.18 50.46 72.85 93.31 111.86 128.47 143.14
155.85 166.60 175.38 }
The element's X-Y coordinates are specified using lists of
numbers. Alternately, BLT vectors could be used to hold the X-Y
coordinates.
# Create two vectors and add them to the barchart.
vector xVector yVector
xVector set { 1 2 3 4 5 6 7 8 9 10 }
yVector set { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 155.85
166.60 175.38 }
n.b element create e1 -xdata xVector -ydata yVector
The advantage of using vectors is that when you modify one, the
graph is automatically redrawn to reflect the new values.
# Change the y coordinate of the first point.
set yVector(0) 25.18
An element named e1 is now created in .b. It is
automatically added to the display list of elements. You can use this list
to control in what order elements are displayed. To query or reset the
element display list, you use the element's show operation.
# Get the current display list
set elemList [.b element show]
# Remove the first element so it won't be displayed.
.b element show [lrange $elemList 0 end]
The element will be displayed by as many bars as there are data
points (in this case there are ten). The bars will be drawn centered at the
x-coordinate of the data point. All the bars will have the same attributes
(colors, stipple, etc). The width of each bar is by default one unit. You
can change this with using the -barwidth option.
# Change the scale of the x-coordinate data
xVector set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }
# Make sure we change the bar width too.
.b configure -barwidth 0.2
The height of each bar is proportional to the ordinate
(Y-coordinate) of the data point.
If two or more data points have the same abscissa (X-coordinate
value), the bars representing those data points may be drawn in various
ways. The default is to overlay the bars, one on top of the other. The
ordering is determined from the of element display list. If the stacked mode
is selected (using the -barmode configuration option), the bars are
stacked, each bar above the previous.
# Display the elements as stacked.
.b configure -barmode stacked
If the aligned mode is selected, the bars having the same
x-coordinates are displayed side by side. The width of each bar is a
fraction of its normal width, based upon the number of bars with the same
x-coordinate.
# Display the elements side-by-side.
.b configure -barmode aligned
By default, the element's label in the legend will be also
e1. You can change the label, or specify no legend entry, again using
the element's configure operation.
# Don't display "e1" in the legend.
.b element configure e1 -label ""
You can configure more than just the element's label. An element
has many attributes such as stipple, foreground and background colors,
relief, etc.
.b element configure e1 -fg red -bg pink \
-stipple gray50
Four coordinate axes are automatically created: x,
x2, y, and y2. And by default, elements are mapped onto
the axes x and y. This can be changed with the -mapx
and -mapy options.
# Map "e1" on the alternate y axis "y2".
.b element configure e1 -mapy y2
Axes can be configured in many ways too. For example, you change
the scale of the Y-axis from linear to log using the axis
component.
# Y-axis is log scale.
.b axis configure y -logscale yes
One important way axes are used is to zoom in on a particular data
region. Zooming is done by simply specifying new axis limits using the
-min and -max configuration options.
.b axis configure x -min 1.0 -max 1.5
.b axis configure y -min 12.0 -max 55.15
To zoom interactively, you link theaxis configure
operations with some user interaction (such as pressing the mouse button),
using the bind command. To convert between screen and graph
coordinates, use the invtransform operation.
# Click the button to set a new minimum
bind .b <ButtonPress-1> {
%W axis configure x -min [%W axis invtransform x %x]
%W axis configure x -min [%W axis invtransform x %y]
}
By default, the limits of the axis are determined from data
values. To reset back to the default limits, set the -min and
-max options to the empty value.
# Reset the axes to autoscale again.
.b axis configure x -min {} -max {}
.b axis configure y -min {} -max {}
By default, the legend is drawn in the right margin. You can
change this or any legend configuration options using the legend
component.
# Configure the legend font, color, and relief
.b legend configure -position left -relief raised \
-font fixed -fg blue
To prevent the legend from being displayed, turn on the
-hide option.
# Don't display the legend.
.b legend configure -hide yes
The barchart has simple drawing procedures called markers.
They can be used to highlight or annotate data in the graph. The types of
markers available are bitmaps, polygons, lines, or windows. Markers can be
used, for example, to mark or brush points. For example there may be a line
marker which indicates some low-water value. Markers are created using the
marker operation.
# Create a line represent the low water mark at 10.0
.b marker create line -name "low_water" \
-coords { -Inf 10.0 Inf 10.0 } \
-dashes { 2 4 2 } -fg red -bg blue
This creates a line marker named low_water. It will display
a horizontal line stretching across the plotting area at the y-coordinate
10.0. The coordinates "-Inf" and "Inf" indicate the
relative minimum and maximum of the axis (in this case the x-axis). By
default, markers are drawn last, on top of the bars. You can change this
with the -under option.
# Draw the marker before elements are drawn.
.b marker configure low_water -under yes
You can add cross hairs or grid lines using the crosshairs
and grid components.
# Display both cross hairs and grid lines.
.b crosshairs configure -hide no -color red
.b grid configure -hide no -dashes { 2 2 }
Finally, to get hardcopy of the graph, use the postscript
component.
# Print the bar chart into file "file.ps"
.b postscript output file.ps -maxpect yes -decorations no
This generates a file file.ps containing the encapsulated
PostScript of the graph. The option -maxpect says to scale the plot
to the size of the page. Turning off the -decorations option denotes
that no borders or color backgrounds should be drawn (i.e. the background of
the margins, legend, and plotting area will be white).
barchart pathName ?option value?...
The barchart command creates a new window pathName
and makes it into a barchart widget. At the time this command is invoked,
there must not exist a window named pathName, but pathName's
parent must exist. Additional options may may be specified on the command
line or in the option database to configure aspects of the bar chart such as
its colors and font. See the configure operation below for the exact
details as to what option and value pairs are valid.
If successful, barchart returns pathName. It also
creates a new Tcl command pathName. This command may be used to
invoke various operations to query or modify the bar chart. It has the
general form:
pathName operation ?arg?...
Both operation and its arguments determine the exact
behavior of the command. The operations available for the bar chart are
described in the following section.
- pathName bar
elemName ?option value?...
- Creates a new barchart element elemName. It's an error if an
element elemName already exists. See the manual for barchart
for details about what option and value pairs are
valid.
- pathName
cget option
- Returns the current value of the configuration option given by
option. Option may be any option described below for the
configure operation.
- pathName
configure ?option value?...
- Queries or modifies the configuration options of the graph. If
option isn't specified, a list describing the current options for
pathName is returned. If option is specified, but not
value, then a list describing option is returned. If one or
more option and value pairs are specified, then for each
pair, the option option is set to value. The following
options are valid.
- -background
color
- Sets the background color. This includes the margins and legend, but not
the plotting area.
- -barmode
mode
- Indicates how related bar elements will be drawn. Related elements have
data points with the same abscissas (X-coordinates). Mode indicates
how those segments should be drawn. Mode can be infront,
aligned, overlap, or stacked. The default mode is
infront.
- infront
- Each successive segment is drawn in front of the previous.
- stacked
- Each successive segment is stacked vertically on top of the previous.
- aligned
- Segments is displayed aligned from right-to-left.
- overlap
- Like aligned but segments slightly overlap each other.
- -barwidth
value
- Specifies the width of the bars. This value can be overrided by the
individual elements using their -barwidth configuration option.
Value is the width in terms of graph coordinates. The default width
is 1.0.
- -borderwidth
pixels
- Sets the width of the 3-D border around the outside edge of the widget.
The -relief option determines if the border is to be drawn. The
default is 2.
- -bottommargin
pixels
- Specifies the size of the margin below the X-coordinate axis. If
pixels is 0, the size of the margin is selected
automatically. The default is 0.
- -bufferelements
boolean
- Indicates whether an internal pixmap to buffer the display of data
elements should be used. If boolean is true, data elements are
drawn to an internal pixmap. This option is especially useful when the
graph is redrawn frequently while the remains data unchanged (for example,
moving a marker across the plot). See the SPEED TIPS
section. The default is 1.
- -cursor
cursor
- Specifies the widget's cursor. The default cursor is
crosshair.
- -font
fontName
- Specifies the font of the graph title. The default is
*-Helvetica-Bold-R-Normal-*-18-180-*.
- -halo
pixels
- Specifies a maximum distance to consider when searching for the closest
data point (see the element's closest operation below). Data points
further than pixels away are ignored. The default is
0.5i.
- -height
pixels
- Specifies the requested height of widget. The default is 4i.
- -invertxy
boolean
- Indicates whether the placement X-axis and Y-axis should be inverted. If
boolean is true, the X and Y axes are swapped. The default is
0.
- -justify
justify
- Specifies how the title should be justified. This matters only when the
title contains more than one line of text. Justify must be
left, right, or center. The default is
center.
- -leftmargin
pixels
- Sets the size of the margin from the left edge of the window to the
Y-coordinate axis. If pixels is 0, the size is calculated
automatically. The default is 0.
- -plotbackground
color
- Specifies the background color of the plotting area. The default is
white.
- -plotborderwidth
pixels
- Sets the width of the 3-D border around the plotting area. The
-plotrelief option determines if a border is drawn. The default is
2.
- -plotpadx
pad
- Sets the amount of padding to be added to the left and right sides of the
plotting area. Pad can be a list of one or two screen distances. If
pad has two elements, the left side of the plotting area entry is
padded by the first distance and the right side by the second. If
pad is just one distance, both the left and right sides are padded
evenly. The default is 8.
- -plotpady
pad
- Sets the amount of padding to be added to the top and bottom of the
plotting area. Pad can be a list of one or two screen distances. If
pad has two elements, the top of the plotting area is padded by the
first distance and the bottom by the second. If pad is just one
distance, both the top and bottom are padded evenly. The default is
8.
- -plotrelief
relief
- Specifies the 3-D effect for the plotting area. Relief specifies
how the interior of the plotting area should appear relative to rest of
the graph; for example, raised means the plot should appear to
protrude from the graph, relative to the surface of the graph. The default
is sunken.
- -relief
relief
- Specifies the 3-D effect for the barchart widget. Relief specifies
how the graph should appear relative to widget it is packed into; for
example, raised means the graph should appear to protrude. The
default is flat.
- -rightmargin
pixels
- Sets the size of margin from the plotting area to the right edge of the
window. By default, the legend is drawn in this margin. If pixels
is than 1, the margin size is selected automatically.
- -takefocus
focus
- Provides information used when moving the focus from window to window via
keyboard traversal (e.g., Tab and Shift-Tab). If focus is 0,
this means that this window should be skipped entirely during keyboard
traversal. 1 means that the this window should always receive the
input focus. An empty value means that the traversal scripts make the
decision whether to focus on the window. The default is
"".
- -tile
image
- Specifies a tiled background for the widget. If image isn't
"", the background is tiled using image.
Otherwise, the normal background color is drawn (see the
-background option). Image must be an image created using
the Tk image command. The default is "".
- -title
text
- Sets the title to text. If text is "", no
title will be displayed.
- -topmargin
pixels
- Specifies the size of the margin above the x2 axis. If pixels is
0, the margin size is calculated automatically.
- -width
pixels
- Specifies the requested width of the widget. The default is
5i.
- pathName
crosshairs operation ?arg?
- See the CROSSHAIRS COMPONENT section.
- pathName
element operation ?arg?...
- See the ELEMENT COMPONENTS section.
- pathName
extents item
- Returns the size of a particular item in the graph. Item must be
either leftmargin, rightmargin, topmargin,
bottommargin, plotwidth, or plotheight.
- pathName
grid operation ?arg?...
- See the GRID COMPONENT section.
- pathName
invtransform winX winY
- Performs an inverse coordinate transformation, mapping window coordinates
back to graph coordinates, using the standard X-axis and Y-axis. Returns a
list of containing the X-Y graph coordinates.
- pathName
inside x y
- Returns 1 is the designated screen coordinate (x and
y) is inside the plotting area and 0 otherwise.
- pathName
legend operation ?arg?...
- See the LEGEND COMPONENT section.
- pathName
line operation arg...
- The operation is the same as element.
- pathName
marker operation ?arg?...
- See the MARKER COMPONENTS section.
- pathName
metafile ?fileName?
- This operation is for Window platforms only. Creates a Windows
enhanced metafile of the barchart. If present, fileName is the file
name of the new metafile. Otherwise, the metafile is automatically added
to the clipboard.
- pathName
postscript operation ?arg?...
- See the POSTSCRIPT COMPONENT section.
- pathName
snap photoName
- Takes a snapshot of the graph and stores the contents in the photo image
photoName. PhotoName is the name of a Tk photo image that
must already exist.
- pathName
transform x y
- Performs a coordinate transformation, mapping graph coordinates to window
coordinates, using the standard X-axis and Y-axis. Returns a list
containing the X-Y screen coordinates.
- pathName
xaxis operation ?arg?...
- pathName
x2axis operation ?arg?...
- pathName
yaxis operation ?arg?...
- pathName
y2axis operation ?arg?...
- See the AXIS COMPONENTS section.
A graph is composed of several components: coordinate axes, data
elements, legend, grid, cross hairs, postscript, and annotation markers.
Instead of one big set of configuration options and operations, the graph is
partitioned, where each component has its own configuration options and
operations that specifically control that aspect or part of the graph.
Four coordinate axes are automatically created: two X-coordinate
axes (x and x2) and two Y-coordinate axes (y, and
y2). By default, the axis x is located in the bottom margin,
y in the left margin, x2 in the top margin, and y2 in
the right margin.
An axis consists of the axis line, title, major and minor ticks,
and tick labels. Major ticks are drawn at uniform intervals along the axis.
Each tick is labeled with its coordinate value. Minor ticks are drawn at
uniform intervals within major ticks.
The range of the axis controls what region of data is plotted.
Data points outside the minimum and maximum limits of the axis are not
plotted. By default, the minimum and maximum limits are determined from the
data, but you can reset either limit.
You can create and use several axes. To create an axis, invoke the
axis component and its create operation.
# Create a new axis called "temperature"
.b axis create temperature
You map data elements to an axis using the element's -mapy and
-mapx configuration options. They specify the coordinate axes an element is
mapped onto.
# Now map the temperature data to this axis.
.b element create "temp" -xdata $x -ydata $tempData \
-mapy temperature
While you can have many axes, only four axes can be displayed
simultaneously. They are drawn in each of the margins surrounding the
plotting area. The axes x and y are drawn in the bottom and
left margins. The axes x2 and y2 are drawn in top and right
margins. Only x and y are shown by default. Note that the axes
can have different scales.
To display a different axis, you invoke one of the following
components: xaxis, yaxis, x2axis, and y2axis.
The use operation designates the axis to be drawn in the
corresponding margin: xaxis in the bottom, yaxis in the left,
x2axis in the top, and y2axis in the right.
# Display the axis temperature in the left margin.
.b yaxis use temperature
You can configure axes in many ways. The axis scale can be linear
or logarithmic. The values along the axis can either monotonically increase
or decrease. If you need custom tick labels, you can specify a Tcl procedure
to format the label any way you wish. You can control how ticks are drawn,
by changing the major tick interval or the number of minor ticks. You can
define non-uniform tick intervals, such as for time-series plots.
- pathName
axis cget axisName option
- Returns the current value of the option given by option for
axisName. Option may be any option described below for the
axis configure operation.
- pathName
axis configure axisName ?axisName?...
?option value?...
- Queries or modifies the configuration options of axisName. Several
axes can be changed. If option isn't specified, a list describing
all the current options for axisName is returned. If option
is specified, but not value, then a list describing option
is returned. If one or more option and value pairs are
specified, then for each pair, the axis option option is set to
value. The following options are valid for axes.
- -autorange
range
- Sets the range of values for the axis to range. The axis limits are
automatically reset to display the most recent data points in this range.
If range is 0.0, the range is determined from the limits of the
data. If -min or -max are specified, they override this
option. The default is 0.0.
- -color
color
- Sets the color of the axis and tick labels. The default is
black.
- -command
prefix
- Specifies a Tcl command to be invoked when formatting the axis tick
labels. Prefix is a string containing the name of a Tcl proc and
any extra arguments for the procedure. This command is invoked for each
major tick on the axis. Two additional arguments are passed to the
procedure: the pathname of the widget and the current the numeric value of
the tick. The procedure returns the formatted tick label. If
"" is returned, no label will appear next to the tick.
You can get the standard tick labels again by setting prefix to
"". The default is "".
Please note that this procedure is invoked while the bar chart
is redrawn. You may query the widget's configuration options. But do not
reset options, because this can have unexpected results.
- -descending
boolean
- Indicates whether the values along the axis are monotonically increasing
or decreasing. If boolean is true, the axis values will be
decreasing. The default is 0.
- -hide
boolean
- Indicates whether the axis is displayed.
- -justify
justify
- Specifies how the axis title should be justified. This matters only when
the axis title contains more than one line of text. Justify must be
left, right, or center. The default is
center.
- -limits
formatStr
- Specifies a printf-like description to format the minimum and maximum
limits of the axis. The limits are displayed at the top/bottom or
left/right sides of the plotting area. FormatStr is a list of one
or two format descriptions. If one description is supplied, both the
minimum and maximum limits are formatted in the same way. If two, the
first designates the format for the minimum limit, the second for the
maximum. If "" is given as either description, then the
that limit will not be displayed. The default is "".
- -linewidth
pixels
- Sets the width of the axis and tick lines. The default is 1
pixel.
- -logscale
boolean
- Indicates whether the scale of the axis is logarithmic or linear. If
boolean is true, the axis is logarithmic. The default scale is
linear.
- -loose
boolean
- Indicates whether the limits of the axis should fit the data points
tightly, at the outermost data points, or loosely, at the outer tick
intervals. This is relevant only when the axis limit is automatically
calculated. If boolean is true, the axis range is
"loose". The default is 0.
- -majorticks
majorList
- Specifies where to display major axis ticks. You can use this option to
display ticks at non-uniform intervals. MajorList is a list of axis
coordinates designating the location of major ticks. No minor ticks are
drawn. If majorList is "", major ticks will be
automatically computed. The default is "".
- -max
value
- Sets the maximum limit of axisName. Any data point greater than
value is not displayed. If value is "", the
maximum limit is calculated using the largest data value. The default is
"".
- -min
value
- Sets the minimum limit of axisName. Any data point less than
value is not displayed. If value is "", the
minimum limit is calculated using the smallest data value. The default is
"".
- -minorticks
minorList
- Specifies where to display minor axis ticks. You can use this option to
display minor ticks at non-uniform intervals. MinorList is a list
of real values, ranging from 0.0 to 1.0, designating the placement of a
minor tick. No minor ticks are drawn if the -majortick option is
also set. If minorList is "", minor ticks will be
automatically computed. The default is "".
- -rotate
theta
- Specifies the how many degrees to rotate the axis tick labels.
Theta is a real value representing the number of degrees to rotate
the tick labels. The default is 0.0 degrees.
- -shiftby
value
- Specifies how much to automatically shift the range of the axis. When the
new data exceeds the current axis maximum, the maximum is increased in
increments of value. You can use this option to prevent the axis
limits from being recomputed at each new time point. If value is
0.0, then no automatic shifting is down. The default is 0.0.
- -showticks
boolean
- Indicates whether axis ticks should be drawn. If boolean is true,
ticks are drawn. If false, only the axis line is drawn. The default is
1.
- -stepsize
value
- Specifies the interval between major axis ticks. If value isn't a
valid interval (must be less than the axis range), the request is ignored
and the step size is automatically calculated.
- -subdivisions
number
- Indicates how many minor axis ticks are to be drawn. For example, if
number is two, only one minor tick is drawn. If number is
one, no minor ticks are displayed. The default is 2.
- -tickfont
fontName
- Specifies the font for axis tick labels. The default is
*-Courier-Bold-R-Normal-*-100-*.
- -ticklength
pixels
- Sets the length of major and minor ticks (minor ticks are half the length
of major ticks). If pixels is less than zero, the axis will be
inverted with ticks drawn pointing towards the plot. The default is
0.1i.
- -title
text
- Sets the title of the axis. If text is "", no axis
title will be displayed.
- -titlecolor
color
- Sets the color of the axis title. The default is black.
- -titlefont
fontName
- Specifies the font for axis title. The default is
*-Helvetica-Bold-R-Normal-*-14-140-*.
Axis configuration options may be also be set by the option
command. The resource class is Axis. The resource names are the names
of the axes (such as x or x2).
option add *Barchart.Axis.Color blue
option add *Barchart.x.LogScale true
option add *Barchart.x2.LogScale false
- pathName
axis create axisName ?option
value?...
- Creates a new axis by the name axisName. No axis by the same name
can already exist. Option and value are described in above
in the axis configure operation.
- pathName
axis delete ?axisName?...
- Deletes the named axes. An axis is not really deleted until it is not
longer in use, so it's safe to delete axes mapped to elements.
- pathName
axis invtransform axisName value
- Performs the inverse transformation, changing the screen coordinate
value to a graph coordinate, mapping the value mapped to
axisName. Returns the graph coordinate.
- pathName
axis limits axisName
- Returns a list of the minimum and maximum limits for axisName. The
order of the list is min max.
- pathName
axis names ?pattern?...
- Returns a list of axes matching zero or more patterns. If no
pattern argument is give, the names of all axes are returned.
- pathName
axis transform axisName value
- Transforms the coordinate value to a screen coordinate by mapping
the it to axisName. Returns the transformed screen coordinate.
Only four axes can be displayed simultaneously. By default, they
are x, y, x2, and y2. You can swap in a
different axis with use operation of the special axis components:
xaxis, x2axis, yaxis, and y2axis.
.g create axis temp
.g create axis time
...
.g xaxis use temp
.g yaxis use time
Only the axes specified for use are displayed on the screen.
The xaxis, x2axis, yaxis, and y2axis
components operate on an axis location rather than a specific axis like the
more general axis component does. The xaxis component manages
the X-axis located in the bottom margin (whatever axis that happens to be).
Likewise, yaxis uses the Y-axis in the left margin, x2axis the
top X-axis, and y2axis the right Y-axis.
They implicitly control the axis that is currently using to that
location. By default, xaxis uses the x axis, yaxis uses
y, x2axis uses x2, and y2axis uses y2.
These components can be more convenient to use than always determining what
axes are current being displayed by the graph.
The following operations are available for axes. They mirror
exactly the operations of the axis component. The axis
argument must be xaxis, x2axis, yaxis, or
y2axis.
- pathName
axis cget option
- pathName
axis configure ?option value?...
- pathName
axis invtransform value
- pathName
axis limits
- pathName
axis transform value
- pathName
axis use ?axisName?
- Designates the axis axisName is to be displayed at this location.
AxisName can not be already in use at another location. This
command returns the name of the axis currently using this location.
Cross hairs consist of two intersecting lines (one vertical and
one horizontal) drawn completely across the plotting area. They are used to
position the mouse in relation to the coordinate axes. Cross hairs differ
from line markers in that they are implemented using XOR drawing primitives.
This means that they can be quickly drawn and erased without redrawing the
entire widget.
The following operations are available for cross hairs:
- pathName
crosshairs cget option
- Returns the current value of the cross hairs configuration option given by
option. Option may be any option described below for the
cross hairs configure operation.
- pathName
crosshairs configure ?option value?...
- Queries or modifies the configuration options of the cross hairs. If
option isn't specified, a list describing all the current options
for the cross hairs is returned. If option is specified, but not
value, then a list describing option is returned. If one or
more option and value pairs are specified, then for each
pair, the cross hairs option option is set to value. The
following options are available for cross hairs.
- -color
color
- Sets the color of the cross hairs. The default is black.
- -dashes
dashList
- Sets the dash style of the cross hairs. DashList is a list of up to
11 numbers that alternately represent the lengths of the dashes and gaps
on the cross hair lines. Each number must be between 1 and 255. If
dashList is "", the cross hairs will be solid
lines.
- -hide
boolean
- Indicates whether cross hairs are drawn. If boolean is true, cross
hairs are not drawn. The default is yes.
- -linewidth
pixels
- Set the width of the cross hair lines. The default is 1.
- -position
pos
- Specifies the screen position where the cross hairs intersect. Pos
must be in the form "@x,y", where x and y
are the window coordinates of the intersection.
Cross hairs configuration options may be also be set by the
option command. The resource name and class are crosshairs and
Crosshairs respectively.
option add *Barchart.Crosshairs.LineWidth 2
option add *Barchart.Crosshairs.Color red
- pathName
crosshairs off
- Turns off the cross hairs.
- pathName
crosshairs on
- Turns on the display of the cross hairs.
- pathName
crosshairs toggle
- Toggles the current state of the cross hairs, alternately mapping and
unmapping the cross hairs.
A data element represents a set of data. It contains x and y
vectors which are the coordinates of the data points. Elements are displayed
as bars where the length of the bar is proportional to the ordinate of the
data point. Elements also control the appearance of the data, such as the
color, stipple, relief, etc.
When new data elements are created, they are automatically added
to a list of displayed elements. The display list controls what elements are
drawn and in what order.
The following operations are available for elements.
- pathName
element activate elemName ?index?...
- Specifies the data points of element elemName to be drawn using
active foreground and background colors. ElemName is the name of
the element and index is a number representing the index of the
data point. If no indices are present then all data points become
active.
- pathName
element bind tagName ?sequence?
?command?
- Associates command with tagName such that whenever the event
sequence given by sequence occurs for an element with this tag,
command will be invoked. The syntax is similar to the bind
command except that it operates on graph elements, rather than widgets.
See the bind manual entry for complete details on sequence
and the substitutions performed on command before invoking it.
If all arguments are specified then a new binding is created,
replacing any existing binding for the same sequence and
tagName. If the first character of command is +
then command augments an existing binding rather than replacing
it. If no command argument is provided then the command currently
associated with tagName and sequence (it's an error occurs
if there's no such binding) is returned. If both command and
sequence are missing then a list of all the event sequences for
which bindings have been defined for tagName.
- pathName
element cget elemName option
- Returns the current value of the element configuration option given by
option. Option may be any of the options described below for
the element configure operation.
- pathName
element closest x y ?option value?...
?elemName?...
- Finds the data point representing the bar closest to the window
coordinates x and y in the element elemName.
ElemName is the name of an element, which must be displayed. If no
elements are specified, then all displayed elements are searched. It
returns a list containing the name of the closest element, the index of
its closest point, and the graph coordinates of the point. If no data
point within the threshold distance can be found, "" is
returned. The following option-value pairs are
available.
- -halo
pixels
- Specifies a threshold distance where selected data points are ignored.
Pixels is a valid screen distance, such as 2 or 1.2i.
If this option isn't specified, then it defaults to the value of the
barchart's -halo option.
- pathName
element configure elemName ?elemName... ?option
value?...
- Queries or modifies the configuration options for elements. Several
elements can be modified at the same time. If option isn't
specified, a list describing all the current options for elemName
is returned. If option is specified, but not value, then a
list describing the option option is returned. If one or more
option and value pairs are specified, then for each pair,
the element option option is set to value. The following
options are valid for elements.
- -activepen
penName
- Specifies pen to use to draw active element. If penName is
"", no active elements will be drawn. The default is
activeLine.
- -bindtags
tagList
- Specifies the binding tags for the element. TagList is a list of
binding tag names. The tags and their order will determine how events for
elements. Each tag in the list matching the current event sequence will
have its Tcl command executed. Implicitly the name of the element is
always the first tag in the list. The default value is all.
- -background
color
- Sets the the color of the border around each bar. The default is
white.
- -barwidth
value
- Specifies the width the bars drawn for the element. Value is the
width in X-coordinates. If this option isn't specified, the width of each
bar is the value of the widget's -barwidth option.
- -baseline
value
- Specifies the baseline of the bar segments. This affects how bars are
drawn since bars are drawn from their respective y-coordinate the
baseline. By default the baseline is 0.0.
- -borderwidth
pixels
- Sets the border width of the 3-D border drawn around the outside of each
bar. The -relief option determines if such a border is drawn.
Pixels must be a valid screen distance like 2 or
0.25i. The default is 2.
- -data
coordList
- Specifies the X-Y coordinates of the data. CoordList is a list of
numeric expressions representing the X-Y coordinate pairs of each data
point.
- -foreground
color
- Sets the color of the interior of the bars.
- -hide
boolean
- Indicates whether the element is displayed. The default is no.
- -label
text
- Sets the element's label in the legend. If text is
"", the element will have no entry in the legend. The
default label is the element's name.
- -mapx
xAxis
- Selects the X-axis to map the element's X-coordinates onto. XAxis
must be the name of an axis. The default is x.
- -mapy
yAxis
- Selects the Y-axis to map the element's Y-coordinates onto. YAxis
must be the name of an axis. The default is y.
- -relief
string
- Specifies the 3-D effect desired for bars. Relief indicates how the
interior of the bar should appear relative to the surface of the chart;
for example, raised means the bar should appear to protrude from
the surface of the plotting area. The default is raised.
- -stipple
bitmap
- Specifies a stipple pattern with which to draw the bars. If bitmap
is "", then the bar is drawn in a solid fashion.
- -xdata
xVector
- Specifies the x-coordinate vector of the data. XVector is the name
of a BLT vector or a list of numeric expressions.
- -ydata
yVector
- Specifies the y-coordinate vector of the data. YVector is the name
of a BLT vector or a list of numeric expressions.
Element configuration options may also be set by the option
command. The resource names in the option database are prefixed by
elem.
option add *Barchart.Element.background blue
- pathName
element create elemName ?option value?...
- Creates a new element elemName. Element names must be unique, so an
element elemName may not already exist. If additional arguments are
present, they specify any of the element options valid for element
configure operation.
- pathName
element deactivate pattern...
- Deactivates all the elements matching pattern for the graph.
Elements whose names match any of the patterns given are redrawn using
their normal colors.
- pathName
element delete ?pattern?...
- Deletes all the elements matching pattern for the graph. Elements
whose names match any of the patterns given are deleted. The graph will be
redrawn without the deleted elements.
- pathName
element exists elemName
- Returns 1 if an element elemName currently exists and
0 otherwise.
- pathName
element names ?pattern?...
- Returns the elements matching one or more pattern. If no pattern is
given, the names of all elements is returned.
- pathName
element show ?nameList?
- Queries or modifies the element display list. The element display list
designates the elements drawn and in what order. NameList is a list
of elements to be displayed in the order they are named. If there is no
nameList argument, the current display list is returned.
- pathName
element type elemName
- Returns the type of elemName. If the element is a bar element, the
commands returns the string "bar", otherwise it returns
"line".
Grid lines extend from the major and minor ticks of each axis
horizontally or vertically across the plotting area. The following
operations are available for grid lines.
- pathName
grid cget option
- Returns the current value of the grid line configuration option given by
option. Option may be any option described below for the
grid configure operation.
- pathName
grid configure ?option value?...
- Queries or modifies the configuration options for grid lines. If
option isn't specified, a list describing all the current grid
options for pathName is returned. If option is specified,
but not value, then a list describing option is returned. If
one or more option and value pairs are specified, then for
each pair, the grid line option option is set to value. The
following options are valid for grid lines.
- -color
color
- Sets the color of the grid lines. The default is black.
- -dashes
dashList
- Sets the dash style of the grid lines. DashList is a list of up to
11 numbers that alternately represent the lengths of the dashes and gaps
on the grid lines. Each number must be between 1 and 255. If
dashList is "", the grid will be solid lines.
- -hide
boolean
- Indicates whether the grid should be drawn. If boolean is true,
grid lines are not shown. The default is yes.
- -linewidth
pixels
- Sets the width of grid lines. The default width is 1.
- -mapx
xAxis
- Specifies the X-axis to display grid lines. XAxis must be the name
of an axis or "" for no grid lines. The default is
"".
- -mapy
yAxis
- Specifies the Y-axis to display grid lines. YAxis must be the name
of an axis or "" for no grid lines. The default is
y.
- -minor
boolean
- Indicates whether the grid lines should be drawn for minor ticks. If
boolean is true, the lines will appear at minor tick intervals. The
default is 1.
Grid configuration options may also be set by the option
command. The resource name and class are grid and Grid
respectively.
option add *Barchart.grid.LineWidth 2
option add *Barchart.Grid.Color black
- pathName
grid off
- Turns off the display the grid lines.
- pathName
grid on
- Turns on the display the grid lines.
- pathName
grid toggle
- Toggles the display of the grid.
The legend displays a list of the data elements. Each entry
consists of the element's symbol and label. The legend can appear in any
margin (the default location is in the right margin). It can also be
positioned anywhere within the plotting area.
The following operations are valid for the legend.
- pathName
legend activate pattern...
- Selects legend entries to be drawn using the active legend colors and
relief. All entries whose element names match pattern are selected.
To be selected, the element name must match only one pattern.
- pathName
legend bind tagName ?sequence?
?command?
- Associates command with tagName such that whenever the event
sequence given by sequence occurs for a legend entry with this tag,
command will be invoked. Implicitly the element names in the entry
are tags. The syntax is similar to the bind command except that it
operates on legend entries, rather than widgets. See the bind
manual entry for complete details on sequence and the substitutions
performed on command before invoking it.
If all arguments are specified then a new binding is created,
replacing any existing binding for the same sequence and
tagName. If the first character of command is +
then command augments an existing binding rather than replacing
it. If no command argument is provided then the command currently
associated with tagName and sequence (it's an error occurs
if there's no such binding) is returned. If both command and
sequence are missing then a list of all the event sequences for
which bindings have been defined for tagName.
- pathName
legend cget option
- Returns the current value of a legend configuration option. Option
may be any option described below in the legend configure
operation.
- pathName
legend configure ?option value?...
- Queries or modifies the configuration options for the legend. If
option isn't specified, a list describing the current legend
options for pathName is returned. If option is specified,
but not value, then a list describing option is returned. If
one or more option and value pairs are specified, then for
each pair, the legend option option is set to value. The
following options are valid for the legend.
- -activebackground
color
- Sets the background color for active legend entries. All legend entries
marked active (see the legend activate operation) are drawn using
this background color.
- -activeborderwidth
pixels
- Sets the width of the 3-D border around the outside edge of the active
legend entries. The default is 2.
- -activeforeground
color
- Sets the foreground color for active legend entries. All legend entries
marked as active (see the legend activate operation) are drawn
using this foreground color.
- -activerelief
relief
- Specifies the 3-D effect desired for active legend entries. Relief
denotes how the interior of the entry should appear relative to the
legend; for example, raised means the entry should appear to
protrude from the legend, relative to the surface of the legend. The
default is flat.
- -anchor
anchor
- Tells how to position the legend relative to the positioning point for the
legend. This is dependent on the value of the -position option. The
default is center.
- left or
right
- The anchor describes how to position the legend vertically.
- top or
bottom
- The anchor describes how to position the legend horizontally.
- @x,y
- The anchor specifies how to position the legend relative to the
positioning point. For example, if anchor is center then the
legend is centered on the point; if anchor is n then the
legend will be drawn such that the top center point of the rectangular
region occupied by the legend will be at the positioning point.
- plotarea
- The anchor specifies how to position the legend relative to the plotting
area. For example, if anchor is center then the legend is
centered in the plotting area; if anchor is ne then the
legend will be drawn such that occupies the upper right corner of the
plotting area.
- -background
color
- Sets the background color of the legend. If color is
"", the legend background with be transparent.
- -bindtags
tagList
- Specifies the binding tags for legend entries. TagList is a list of
binding tag names. The tags and their order will determine how events for
legend entries. Each tag in the list matching the current event sequence
will have its Tcl command executed. The default value is all.
- -borderwidth
pixels
- Sets the width of the 3-D border around the outside edge of the legend (if
such border is being drawn; the relief option determines this). The
default is 2 pixels.
- -font
fontName
- FontName specifies a font to use when drawing the labels of each
element into the legend. The default is
*-Helvetica-Bold-R-Normal-*-12-120-*.
- -foreground
color
- Sets the foreground color of the text drawn for the element's label. The
default is black.
- -hide
boolean
- Indicates whether the legend should be displayed. If boolean is
true, the legend will not be draw. The default is no.
- -ipadx
pad
- Sets the amount of internal padding to be added to the width of each
legend entry. Pad can be a list of one or two screen distances. If
pad has two elements, the left side of the legend entry is padded
by the first distance and the right side by the second. If pad is
just one distance, both the left and right sides are padded evenly. The
default is 2.
- -ipady
pad
- Sets an amount of internal padding to be added to the height of each
legend entry. Pad can be a list of one or two screen distances. If
pad has two elements, the top of the entry is padded by the first
distance and the bottom by the second. If pad is just one distance,
both the top and bottom of the entry are padded evenly. The default is
2.
- -padx
pad
- Sets the padding to the left and right exteriors of the legend. Pad
can be a list of one or two screen distances. If pad has two
elements, the left side of the legend is padded by the first distance and
the right side by the second. If pad has just one distance, both
the left and right sides are padded evenly. The default is 4.
- -pady
pad
- Sets the padding above and below the legend. Pad can be a list of
one or two screen distances. If pad has two elements, the area
above the legend is padded by the first distance and the area below by the
second. If pad is just one distance, both the top and bottom areas
are padded evenly. The default is 0.
- -position
pos
- Specifies where the legend is drawn. The -anchor option also
affects where the legend is positioned. If pos is left,
left, top, or bottom, the legend is drawn in the
specified margin. If pos is plotarea, then the legend is
drawn inside the plotting area at a particular anchor. If pos is in
the form "@x,y", where x and y are the
window coordinates, the legend is drawn in the plotting area at the
specified coordinates. The default is right.
- -raised
boolean
- Indicates whether the legend is above or below the data elements. This
matters only if the legend is in the plotting area. If boolean is
true, the legend will be drawn on top of any elements that may overlap it.
The default is no.
- -relief
relief
- Specifies the 3-D effect for the border around the legend. Relief
specifies how the interior of the legend should appear relative to the bar
chart; for example, raised means the legend should appear to
protrude from the bar chart, relative to the surface of the bar chart. The
default is sunken.
Legend configuration options may also be set by the option
command. The resource name and class are legend and Legend
respectively.
option add *Barchart.legend.Foreground blue
option add *Barchart.Legend.Relief raised
- pathName
legend deactivate pattern...
- Selects legend entries to be drawn using the normal legend colors and
relief. All entries whose element names match pattern are selected.
To be selected, the element name must match only one pattern.
- pathName
legend get pos
- Returns the name of the element whose entry is at the screen position
pos in the legend. Pos must be in the form
"@x,y", where x and y are window
coordinates. If the given coordinates do not lie over a legend entry,
"" is returned.
Pens define attributes for elements. Pens mirror the configuration
options of data elements that pertain to how symbols and lines are drawn.
Data elements use pens to determine how they are drawn. A data element may
use several pens at once. In this case, the pen used for a particular data
point is determined from each element's weight vector (see the element's
-weight and -style options).
One pen, called activeBar, is automatically created. It's
used as the default active pen for elements. So you can change the active
attributes for all elements by simply reconfiguring this pen.
.g pen configure "activeBar" -fg green -bg green4
You can create and use several pens. To create a pen, invoke the
pen component and its create operation.
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 -fdashes 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.