DragonFly On-Line Manual Pages
stripchart(n) BLT Built-In Commands stripchart(n)
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NAME
stripchart - 2D strip chart for plotting x and y coordinate data.
SYNOPSIS
stripchart pathName ?option value?...
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DESCRIPTION
The stripchart command creates a strip chart for plotting two-
dimensional data (x,y coordinates). It has many configurable
components: coordinate axes, elements, legend, grid lines, cross hairs,
etc. They allow you to customize the look and feel of the strip chart.
The stripchart is essentially the same as the graph widget. It works
almost exactly the very same way.
The use of a strip chart differs in that the X-axis typically refers to
time points. Data values are added at intervals. The strip chart lets
you automatically maintain a view of the most recent time points. The
axis options -shiftby and -autorange control this. You can specify
different line styles for data points (see the -styles option).
INTRODUCTION
The stripchart command creates a new window for plotting two-
dimensional data (x,y coordinates). Data points are plotted in a box
displayed in the center of the new window. This is the plotting area.
The coordinate axes are displayed in the margins around the plotting
area. By default, the legend is displayed in the right margin. The
title is displayed in top margin.
A strip chart is composed of several components: coordinate axes, data
elements, legend, grid, cross hairs, pens, postscript, and annotation
markers.
axis The stripchart widget can display up to four coordinate axes
(two X-coordinate and two Y-coordinate axes), 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 of each major
tick.
crosshairs
Cross hairs are used to finely position the mouse pointer in
relation to the coordinate axes. Two perpendicular lines are
drawn across the plotting area, intersecting at the current
location of the mouse pointer.
element An element represents a set of data points. Elements can be
plotted with a symbol at each data point and lines connecting
the points. The appearance of the element, such as its
symbol, line width, and color is configurable.
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 polygon marker to fill an area
under a curve, or 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 (both symbol and line style) 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.
SYNTAX
stripchart pathName ?option value?...
The stripchart command creates a new window pathName and makes it into
a stripchart 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 strip 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, stripchart returns the path name of the widget. It also
creates a new Tcl command by the same name. You can use this command
to perform 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 strip chart are described in
the STRIPCHART OPERATIONS section.
The command can also be used to access components of the strip chart.
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.
EXAMPLE
The stripchart command creates a new strip chart.
# Create a new strip chart. Plotting area is black.
stripchart .s -plotbackground black
A new Tcl command .s is also created. This command can be used to
query and modify the strip chart. For example, to change the title of
the strip chart to "My Plot", you use the new command and the widget's
configure operation.
# Change the title.
.s configure -title "My Plot"
A strip chart has several components. To access a particular component
you use the component's name. For example, to add data elements, you
use the new command and the element component.
# Create a new element named "line1"
.s element create line1 \
-xdata { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 } \
-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 and 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 strip chart.
vector xVec yVec
xVec set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }
yVec set { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 155.85
166.60 175.38 }
.s element create line1 -xdata xVec -ydata yVec
The advantage of using vectors is that when you modify one, the graph
is automatically redrawn to display the new values.
# Change the X-Y coordinates of the first point.
set xVec(0) 0.18
set yVec(0) 25.18
An element named line1 is now created in .s. By default, the element's
label in the legend will be also line1. You can change the label, or
specify no legend entry, again using the element's configure operation.
# Don't display "line1" in the legend.
.s element configure line1 -label ""
You can configure more than just the element's label. An element has
many attributes such as symbol type and size, dashed or solid lines,
colors, line width, etc.
.s element configure line1 -symbol square -color red \
-dashes { 2 4 2 } -linewidth 2 -pixels 2c
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 "line1" on the alternate Y-axis "y2".
.s element configure line1 -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 operation.
# Y-axis is log scale.
.s axis configure y -logscale yes
Axis limits are reset by simply specifying new axis limits using the
-min and -max configuration options.
.s axis configure x -min 1.0 -max 1.5
.s axis configure y -min 12.0 -max 55.15
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.
.s axis configure x -min {} -max {}
.s axis configure y -min {} -max {}
It's common with strip charts to automatically maintain a view of the
most recent time points. You can do this my setting the -autorange
option.
.s axis configure x -autorange 20.0
If the time points are added in X-coordinates 1.0 unit, only the last
twenty time points will be displayed. As more data is added, the view
will march along.
Sometimes the rate of data is so high that changing the axis limits
with each additional time point is prohibitive. You can use the
-shiftby option to define an increment to shift the view when needed.
.s axis configure x -shiftby 15.0
When the view is shifted, it will allow a range of 15 new time points
to be added until the axis limits are recomputed.
By default, the legend is displayed in the right margin. You can
change this or any other legend configuration options using the legend
component.
# Configure the legend font, color, and relief
.s 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.
.s legend configure -hide yes
The stripchart widget has simple drawing procedures called markers.
They can be used to highlight or annotate data in the strip chart. The
types of markers available are bitmaps, images, polygons, lines, or
windows. Markers can be used, for example, to mark or brush points.
Here is a text marker which labels the data first point. Markers are
created using the marker operation.
# Create a label for the first data point of "line1".
.s marker create text -name first_marker -coords { 0.2 26.18 } \
-text "start" -anchor se -xoffset -10 -yoffset -10
This creates a text marker named first_marker. It will display the
text "start" near the coordinates of the first data point. The
-anchor, -xoffset, and -yoffset options are used to display the marker
above and to the left of the data point, so that the actual data point
isn't covered by the marker. By default, markers are drawn last, on
top of data. You can change this with the -under option.
# Draw the label before elements are drawn.
.s marker configure first_marker -under yes
You can add cross hairs or grid lines using the crosshairs and grid
operations.
# Display both cross hairs and grid lines.
.s crosshairs configure -hide no -color red
.s grid configure -hide no -dashes { 2 2 }
Finally, to get hardcopy of the strip chart, use the postscript
operation.
# Print the strip chart into file "file.ps"
.s postscript output file.ps -maxpect yes -decorations no
This generates a file file.ps containing the encapsulated PostScript of
the strip chart. The option -maxpect says to scale the plot to the
size of the page. Turning off the -decorations option indicates that
no borders or color backgrounds should be displayed (i.e. the
background of the margins, legend, and plotting area will be white).
STRIPCHART OPERATIONS
pathName axis operation ?arg?...
See the AXIS COMPONENTS 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 stripchart 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 strip
chart. If option isn't specified, a list describing all of 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 stripchart option option is set to
value. The following options are valid for the stripchart.
-background color
Sets the background color. This includes the margins and
legend, but not the plotting area.
-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 to draw elements into a pixmap before
displaying them on the screen. The advantage of
buffering elements is when markers are used heavily.
Markers can be moved and redrawn without requiring every
element to be redrawn again. The disadvantage is that it
takes slightly longer to draw the graph. If boolean is
true, data elements are drawn to an internal pixmap. The
option should be turned off if the plot is updated
frequently. See the SPEED TIPS section. The default is
1.
-buffergraph boolean
Indicates whether to draw the graph into a pixmap first.
If boolean is true, the entire graph is drawn into a
pixmap and then copied onto the screen. This reduces
flashing. If false, the graph is drawn directly into the
window. Especially under Windows, turning off the option
can be helpful when the stripchart is updated frequently.
Turning off this option also turns -bufferelements off.
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 title font. 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
indicates how the interior of the plotting area should
appear relative to rest of the strip chart; for example,
raised means the plot should appear to protrude from the
strip chart, relative to the surface of the strip chart.
The default is sunken.
-relief relief
Specifies the 3-D effect for the widget. Relief
indicates how the strip chart should appear relative to
widget it is packed into; for example, raised means the
strip chart 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
displayed 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. 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 strip chart. 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 graph coordinates.
pathName legend operation ?arg?...
See the LEGEND COMPONENT section.
pathName line elemName ?option value?...
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 stripchart. 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 strip chart 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.
STRIPCHART COMPONENTS
A strip chart 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 strip chart is partitioned, where each component has
its own configuration options and operations that specifically control
that aspect or part of the strip chart.
AXIS COMPONENTS
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"
.s 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.
.s 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.
.s 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 as 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 ?option value?...
Queries or modifies the configuration options of axisName. 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
strip chart is redrawn. You may query the configuration
options. But do not reset them, 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 done. 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 *Stripchart.Axis.Color blue
option add *Stripchart.x.LogScale true
option add *Stripchart.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
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 strip chart.
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 *Stripchart.Crosshairs.LineWidth 2
option add *Stripchart.Crosshairs.Color red
pathName crosshairs off
Turns of 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.
ELEMENT COMPONENTS
A data element represents a set of data. It contains x and y vectors
containing the coordinates of the data points. Elements can be
displayed with a symbol at each data point and lines connecting the
points. Elements also control the appearance of the data, such as the
symbol type, line width, color 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 cget elemName option
Returns the current value of the element configuration option
given by option. Option may be any option described below for
the element configure operation.
pathName element closest x y varName ?option value?... ?elemName?...
Finds the data point closest to the window coordinates x and y
in the element elemName. ElemName is the name of an element,
that must not be hidden. If no elements are specified, then all
visible elements are searched. It returns via the array
variable varName the name of the closest element, the index of
its closest point, and the graph coordinates of the point.
Returns 0, if no data point within the threshold distance can be
found, otherwise 1 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 stripchart's -halo option.
-interpolate boolean
Indicates that both the data points and interpolated
points along the line segment formed should be
considered. If boolean is true, the closest line segment
will be selected instead of the closest point. If this
option isn't specified, boolean defaults to 0.
pathName element configure elemName ?option value?...
Queries or modifies the configuration options for elements. 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.
-color color
Sets the color of the traces connecting the data points.
-dashes dashList
Sets the dash style of element line. DashList is a list
of up to 11 numbers that alternately represent the
lengths of the dashes and gaps on the element line. Each
number must be between 1 and 255. If dashList is "", the
lines will be solid.
-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.
-fill color
Sets the interior color of symbols. If color is "", then
the interior of the symbol is transparent. If color is
defcolor, then the color will be the same as the -color
option. The default is defcolor.
-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.
-linewidth pixels
Sets the width of the connecting lines between data
points. If pixels is 0, no connecting lines will be
drawn between symbols. The default is 0.
-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.
-offdash color
Sets the color of the stripes when traces are dashed (see
the -dashes option). If color is "", then the "off"
pixels will represent gaps instead of stripes. If color
is defcolor, then the color will be the same as the
-color option. The default is defcolor.
-outline color
Sets the color or the outline around each symbol. If
color is "", then no outline is drawn. If color is
defcolor, then the color will be the same as the -color
option. The default is defcolor.
-outlinewidth pixels
Sets the width of the outline bordering each symbol. If
pixels is 0, no outline will be drawn. The default is 1.
-pixels pixels
Sets the size of symbols. If pixels is 0, no symbols
will be drawn. The default is 0.125i.
-scalesymbols boolean
If boolean is true, the size of the symbols drawn for
elemName will change with scale of the X-axis and Y-axis.
At the time this option is set, the current ranges of the
axes are saved as the normalized scales (i.e scale factor
is 1.0) and the element is drawn at its designated size
(see the -pixels option). As the scale of the axes
change, the symbol will be scaled according to the
smaller of the X-axis and Y-axis scales. If boolean is
false, the element's symbols are drawn at the designated
size, regardless of axis scales. The default is 0.
-smooth smooth
Specifies how connecting line segments are drawn between
data points. Smooth can be either linear, step, natural,
or quadratic. If smooth is linear, a single line segment
is drawn, connecting both data points. When smooth is
step, two line segments are drawn. The first is a
horizontal line segment which steps the next x-
coordinate. The second is a vertical line, moving to the
next y-coordinate. Both natural and quadratic generate
multiple segments between data points. If natural, the
segments are generated using a cubic spline. If
quadratic, a quadratic spline is used. The default is
linear.
-styles styleList
Specifies what pen to use based upon the range of weights
given. StyleList is a list of style specifications. Each
style specification, in turn, is a list consisting of a
pen name, and optionally a minimum and maximum range.
Data points whose weight (see the -weight option) falls
in this range, are drawn with this pen. If no range is
specified it defaults to the number of the pen in the
list.
-symbol symbol
Specifies the symbol for data points. Symbol can be
either square, circle, diamond, plus, cross, splus,
scross, triangle, "" (where no symbol is drawn), or a
bitmap. Bitmaps are specified as "source ?mask?", where
source is the name of the bitmap, and mask is the
bitmap's optional mask. The default is circle.
-weights wVec
Specifies the weights of the individual data points.
This, in conjunction with the list pen styles (see the
-styles option) controls how data points are drawn. WVec
is the name of a BLT vector or a list of numeric
expressions representing the weights for each data point.
-xdata xVec
Specifies the x-coordinates of the data. XVec is the
name of a BLT vector or a list of numeric expressions.
-ydata yVec
Specifies the y-coordinates of the data. YVec 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 class is Element. The resource name is
the name of the element.
option add *Stripchart.Element.symbol line
option add *Stripchart.e1.symbol line
pathName element create elemName ?option value?...
Creates a new element elemName. It's an error is an element
elemName already exists. If additional arguments are present,
they specify options valid for element configure operation.
pathName element deactivate elemName ?elemName?...
Deactivates all the elements matching pattern. Elements whose
names match any of the patterns given are redrawn using their
normal colors.
pathName element delete ?elemName?...
Deletes all the named elements. The graph is automatically
redrawn.
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 COMPONENT
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. The default is x.
-mapy yAxis
Specifies the Y-axis to display grid lines. YAxis must
be the name of an axis. 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 *Stripchart.grid.LineWidth 2
option add *Stripchart.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
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 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.
-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 strip chart; for example,
raised means the legend should appear to protrude from
the strip chart, relative to the surface of the strip
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 *Stripchart.legend.Foreground blue
option add *Stripchart.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.
PEN COMPONENTS
Pens define attributes (both symbol and line style) 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 activeLine, 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.
.s pen configure "activeLine" -color green
You can create and use any number of pens. To create a pen, invoke the
pen component and its create operation.
.s pen create myPen
You map pens to a data element using either the element's -pen or
-activepen options.
.s element create "line1" -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).
.s element configure "line1" -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 ?option value?...
Queries or modifies the configuration options of penName. 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.
-color color
Sets the color of the traces connecting the data points.
-dashes dashList
Sets the dash style of element line. DashList is a list
of up to 11 numbers that alternately represent the
lengths of the dashes and gaps on the element line. Each
number must be between 1 and 255. If dashList is "", the
lines will be solid.
-fill color
Sets the interior color of symbols. If color is "", then
the interior of the symbol is transparent. If color is
defcolor, then the color will be the same as the -color
option. The default is defcolor.
-linewidth pixels
Sets the width of the connecting lines between data
points. If pixels is 0, no connecting lines will be
drawn between symbols. The default is 0.
-offdash color
Sets the color of the stripes when traces are dashed (see
the -dashes option). If color is "", then the "off"
pixels will represent gaps instead of stripes. If color
is defcolor, then the color will be the same as the
-color option. The default is defcolor.
-outline color
Sets the color or the outline around each symbol. If
color is "", then no outline is drawn. If color is
defcolor, then the color will be the same as the -color
option. The default is defcolor.
-outlinewidth pixels
Sets the width of the outline bordering each symbol. If
pixels is 0, no outline will be drawn. The default is 1.
-pixels pixels
Sets the size of symbols. If pixels is 0, no symbols
will be drawn. The default is 0.125i.
-symbol symbol
Specifies the symbol for data points. Symbol can be
either square, circle, diamond, plus, cross, splus,
scross, triangle, "" (where no symbol is drawn), or a
bitmap. Bitmaps are specified as "source ?mask?", where
source is the name of the bitmap, and mask is the
bitmap's optional mask. The default is circle.
-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 "line".
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 *Stripchart.Pen.Color blue
option add *Stripchart.activeLine.color 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.
POSTSCRIPT COMPONENT
The strip chart can generate encapsulated PostScript output. There are
several configuration options you can specify to control how the plot
is 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 outputting color
information in PostScript, the array variable varName is
checked to see if an element of the name of the color
exists. If so, it uses the value of the element 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, which are 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 an element of 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 if PostScript commands to generate color
backgrounds and 3-D borders should be output. If boolean
is false, the 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 plot the
stripchart with a height different from the one displayed
on the screen. If pixels is 0, the height is the same as
the displayed 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 the plot so that it fills the
PostScript page. The aspect ratio of the strip chart 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 plot the strip
chart with a width different from the one drawn on the
screen. 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 *Stripchart.postscript.Decorations false
option add *Stripchart.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.
MARKER COMPONENTS
Markers are simple drawing procedures used to annotate or highlight
areas of the strip chart. 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 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.
-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 element symbols and lines.
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 *Stripchart.TextMarker.Foreground white
option add *Stripchart.BitmapMarker.Foreground white
option add *Stripchart.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.
BITMAP MARKERS
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
Sets the background color of the bitmap. If color is "", the
background color will be transparent. The default background
color is white.
-bitmap bitmap
Specifies the bitmap to be displayed. If bitmap is "", the
marker will not be displayed. The default is "".
-foreground color
Sets the foreground color of the bitmap. The default foreground
color is black.
-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 "".
-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.
IMAGE MARKERS
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 "".
LINE MARKERS
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:
-background color
Sets the background color of the line. The option is affects
the line color only when the -stipple option is set. If this
option isn't specified then it defaults to white.
-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.
-foreground color
Sets the foreground color. The default foreground color is
black.
-linewidth pixels
Sets the width of the lines. The default width is 0.
-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 "".
POLYGON MARKERS
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 "".
TEXT MARKERS
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 strip chart. 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
Sets the background color of the text string. If color is "",
the background will be transparent. The default is white.
-font fontName
Specifies the font of the text. The default is *-Helvetica-
Bold-R-Normal-*-120-*.
-foreground color
Sets the foreground color of the text. The default is black.
-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.
-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.
WINDOW MARKERS
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. PathName must be a child of
the stripchart widget.
GRAPH COMPONENT BINDINGS
Specific stripchart 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 -bindtagsfor 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.
C LANGUAGE API
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 and y data coordinates of an element as vectors and
manipulate the vector from C. The strip chart will be redrawn
automatically after the vectors are updated.
From Tcl, create the vectors and configure the element to use them.
vector X Y
.s 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
strip chart 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.
SPEED TIPS
There may be cases where the strip 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.
o Try to minimize the number of data points. The more data points the
looked at, the more work the strip chart must do.
o 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.
o Data elements without symbols are drawn faster than with symbols.
Set the data element's -symbol option to none. If you need to draw
symbols, try using the simple symbols such as splus and scross.
o Don't stipple or dash the element. Solid lines are much faster.
o If you update data elements frequently, try turning off the widget's
-bufferelements option. When the strip chart is first displayed, it
draws data elements into an internal pixmap. The pixmap acts as a
cache, so that when the strip 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 strip chart.
But if the strip chart is updated frequently, changing either the
element data or coordinate axes, the buffering becomes redundant.
LIMITATIONS
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.
FUTURE INCOMPATIBILITY
The -mapped options are obsoleted and will be removed. You can achieve
the same results using the -hide option instead.
# Works for now.
.s legend configure -mapped no
# Instead use this.
.s legend configure -hide yes
KEYWORDS
stripchart, graph, widget
BLT 2.5 stripchart(n)