NAME¶
stripchart - 2D strip chart for plotting x and y coordinate data.
SYNOPSIS¶
stripchart pathName ?
option value?...
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.
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.
- •
- Try to minimize the number of data points. The more data
points the looked at, the more work the strip 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.
- •
- 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.
- •
- Don't stipple or dash the element. Solid lines are much
faster.
- •
- 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