-
stVectorFieldData
-
Specifies the id of a VectorField data
object. There is no default for this resource; it is the only resource
that must be set in order for the StreamlinePlot object to
draw a plot. You may create a StreamlinePlot object
without setting the stVectorFieldData resource, and auxiliary
annotations such as tick marks and titles may appear as the result of a
draw, but the StreamlinePlot itself will not show up. The
VectorField object can provide either regularly
spaced or irregular rectangular gridded data to the
StreamlinePlot object,
and the VectorField object provides a number of
resources
for controlling the ingestion of the raw data.
Default: <none>
-
stStreamlineDrawOrder
-
This resource of type NhlTDrawOrder
determines when the streamlines are drawn relative to the
drawing of other elements of a composite plot. There are three
choices:
PreDraw
- Draw the streamlines before the standard draw phase; the
arrows will be overlaid by any subsequently drawn elements.
Draw
- Draw the streamlines during the standard draw phase; the arrows will
overlay any elements drawn during the predraw phase, but will
underlie elements drawn during the postdraw phase.
PostDraw
- Draw the streamlines after the standard draw; the arrows will
overlay any elements drawn during the predraw and draw phases.
Default: Draw
-
stMapDirection
-
This resource controls whether the streamline direction is mapped into
the same coordinate space as the location of the vector data grid
point, or whether it is rendered in a locally uniform Cartesian
coordinate space. This resource has an effect whenever a non-uniform
transformation is in effect. These include most of the
MapTransformation transformations and
IrregularTransformation transformations. Also included are
logarithmic transformations provided by the
LogLinTransformation and even linear transformations when
the X and Y unit size is different.
Default: True
-
stStepSizeF
-
This resource specifies, in NDC, the basic step size used to build the
streamlines. Where the flow direction changes rapidly, the step size
is scaled down from the basic step size in order to retain
accuracy. Smaller step sizes produce a more accurate plot at the cost
of a longer drawing time. At initialization or any time
stStepSizeF is given a value less than or equal to 0.0,
StreamlinePlot calculates a value for
stStepSizeF based on the NDC size of an individual grid cell
assuming a linear transformation from data to NDC space. Otherwise,
when stStepSizeF is not set explicitly,
StreamlinePlot makes proportional adjustments to its
value in response to changes in the assumed NDC size of the grid cell
(resulting from changes to the viewport size and/or the number of
elements in the data grid).
Default: <dynamic>
-
stMinLineLengthF
-
THIS RESOURCE IS NOT YET IMPLEMENTED.
Default:
-
stMinLineSpacingF
-
This resource specifies the minimum distance in NDC that a streamline
in progress is allowed to approach existing streamlines before being
terminated. In general, giving this value a larger number increases
the distance between streamlines, and has a tendency to create more,
but shorter streamlines. The spacing is only checked at intervals, so
streamlines can sometimes approach closer than the specified
distance. The stCrossoverCheckCount resource determines the
frequency with with the check is performed. At initialization or any
time stMinLineSpacingF is given a value less than or equal to
0.0, StreamlinePlot calculates a value for
stMinLineSpacingF based on the NDC size of an individual grid
cell assuming a linear transformation from data to NDC space.
Otherwise, when stMinLineSpacingF is not set explicitly,
StreamlinePlot makes proportional adjustments to its
value in response to changes in the assumed NDC size of the grid cell
(resulting from changes to the viewport size and/or the number of
elements in the data grid).
Default: <dynamic>
-
stMinStepFactorF
-
This resource specifies a multiplying factor for the
stStepSizeF resource that determines the minimum amount the
streamline must have grown each time the stream progress is checked in
order not to be terminated. The stream progress is checked each
stLengthCheckCount iterations through the stream-building
loop. Points of convergence or divergence typically cause stream
growth to diminish and the streamline eventually to be terminated.
Default: 2.0
-
stLengthCheckCount
-
This resource specifies the number of iterations through the
streamline-building loop between each check of the streamline
growth. If the distance between the current position of the streamline and
the position saved at the time of the previous check is less than a
minimum amount, defined as stMinStepFactorF times
stStepSizeF, then the current streamline is terminated and a
new one begun if possible.
Default: 35
-
stCrossoverCheckCount
-
This resource specifies the number of iterations through the
streamline-building loop between checks for streamline crossover, that
is, one streamline growing closer than stMinLineSpacingF to
previously created streamlines. A negative value causes
Streamlines to check for crossover only when a new data grid box is
entered. At each crossover check, the current streamline position is
compared with a sampling of previous streamline positions retained in
an internal circular list. This list is currently fixed to a length of
750. Since up to this number of comparisons are performed at each
crossover check, the frequency with which these checks are performed
can have a noticeable impact on the drawing time.
Default: -1
-
stLineStartStride
-
StreamlinePlot can start only one streamline within
each data grid box. This resource allows you to define a sparser
streamline plot by allowing only certain grid boxes to be eligible for
starting a streamline. If stLineStartStride is set to 3, for
instance, only every third grid box (along each axis direction) will
be eligible for starting a streamline. A streamline will actually be
started within an eligible grid box only if no previously drawn
streamline passes through the grid box.
Default: 2
-
stArrowStartStride
-
StreamlinePlot draws directional arrows based on the
data grid location. No more than one directional arrow can be drawn
within each grid box. This resource allows you to draw fewer
directional arrows by skipping grid boxes. If
stArrowStartStride is set to 3, for instance, only every
third grid box (along each axis direction) will be eligible for a
directional arrow. Of course, the arrow will appear only if
a streamline is actually drawn within the area of the grid box.
Default: 2
-
stArrowLengthF
-
This resource specifies, in units of NDC, the length of the lines used
to draw the directional arrows that appear periodically along the length
of the streamlines. At initialization or any
time stArrowLengthF is given a value less than or equal to
0.0, StreamlinePlot calculates a value for
stArrowLengthF based on the NDC size of an individual grid
cell assuming a linear transformation from data to NDC space.
Otherwise, when stArrowLengthF is not set explicitly,
StreamlinePlot makes proportional adjustments to its
value in response to changes in the assumed NDC size of the grid cell
(resulting from changes to the viewport size and/or the number of
elements in the data grid).
Default: <dynamic>
-
stMinArrowSpacingF
-
This resource specifies an NDC minimum distance for adjacent
directional arrowheads along a single streamline. If the data grid is
transformed in such a way that adjacent grid cells become very close
in NDC space, as for instance in many map projections near the poles,
you can use this resource to help reduce the otherwise cluttered
appearance of these regions of the plot. If
stMinArrowSpacingF is less than or equal to 0.0, then no
arrowheads are eliminated. When stMinArrowSpacingF is not set
explcitly, StreamlinePlot adjusts its value in
proportion to changes to vpWidthF.
Default: 0.0
-
stLineThicknessF
-
This resource sets the thickness of the lines used to draw the
streamlines and also the directional arrows. The value acts as a
multiplier of a (device-dependent) unit thickness.
Default: 1.0
-
stLineColor
-
This resource of type NhlTColorIndex
sets the color index used to draw the streamlines.
Default: Foreground
-
stNoDataLabelOn
-
This boolean resource, when set True, causes a label to appear when
StreamlinePlot is drawn without any data having been
provided. Except for the label string, all attributes of this label,
including its position, are set using resources belonging to the
zero field label. When set False, no such label appears.
Default: True
-
stNoDataLabelString
-
This resource contains the string that appears in the 'No Data' label
if you draw a StreamlinePlot object without providing
any data. No substitution substrings are allowed in this label, since
all the substitutions depend on data being available. Except for the
boolean switch that turns it on and off, all attributes of this label,
including its position, are set using resources belonging to the
zero field label.
Default: "NO STREAMLINE DATA"
-
stZeroFLabelOn
-
The StreamlinePlot object draws a zero field label
annotation only when stZeroFLabelOn is set True and
the ScalarField data are determined to consist entirely
of zero magnitude vectors within the limits of the available
precision.
Default: True
-
stZeroFLabelString
-
Specifies the string to use when drawing a zero field label. The
string may contain function codes.
Default: "ZERO FIELD"
-
stZeroFLabelTextDirection
-
This resource of type NhlTTextDirection specifies
the direction of the text in the zero field label. There are two
choices:
Down
- Each character is placed below the previous character in the text string.
Across
- Each character is placed to the right of the previous character in
the text string.
These descriptions apply before rotation due to stZeroFieldAngleF.
Default: Across
-
-
stZeroFLabelFontHeightF
-
This resource controls the height in NDC of characters used
in the text of the zero field label. The character width scales
proportionally, unless you also modify the aspect ratio using the
stZeroFLabelFontAspectF resource. The zero label text height
scales with changes to the viewport width, unless you explicitly set
stZeroFLabelFontHeightF during the same call.
Default: <dynamic>
-
stZeroFLabelFont
-
This resource of type NhlTFont
specifies the font used to render the zero field label.
Default: 0
-
stZeroFLabelFontColor
-
This resource specifies the HLU color index used to render
zero field label text.
Default: True
-
stZeroFLabelFontAspectF
-
This resource determines the shape of the zero field label
characters. Values increasing from 1.0 result in
characters that appear thinner. Values decreasing from 1.0 make the characters
appear wider. Values less than or equal to 0.0 result in a WARNING message
and a restoration of the default value.
Default: 1.3125
-
stZeroFLabelFontThicknessF
-
Sets the thickness of the line used to draw zero field label
text. The value acts as a multiplier of a (device-dependent) unit
thickness. This resource is ignored when the stZeroFLabelFont
specifies a filled font (font indexes 21-22, 25-26, 29-30, and 33-37).
Default: 1.0
-
stZeroFLabelFontQuality
-
This resource of type NhlTFontQuality
determines the quality of the font used to draw the
StreamlinePlot zero field label.
Default: High
-
stZeroFLabelConstantSpacingF
-
Normally when stZeroFFontQuality is set to
High,
the StreamlinePlot object writes zero field label text with
proportional spacing. Setting the stZeroFLabelConstantSpacingF
to a value greater than 0.0 overrides this behavior. Instead, the
distance from the start of one character to the next is computed by
multiplying a single standard character width by the value of
stZeroFConstantSpacingF. When
stZeroFConstantSpacingF has a value between 0.0 and 1.0,
characters will overlap. A value of 1.0 implies, on average, no space
between characters, while values increasing from 1.0 cause the space
between characters to grow. This parameter is ignored when
stZeroFLabelFontQuality is not High. Values less
than 0.0 result in an error and are replaced with the default value.
Default: 0.0
-
stZeroFLabelAngleF
-
This resource specifies the angle, in degrees, of the zero field
label text and its surrounding box.
Default: 0.0
-
stZeroFLabelFuncCode
-
This resource of type NhlTCharacter sets the
function code character that the low level utilities will use when
parsing the zero field label string.
Default: :
-
stZeroFLabelBackgroundColor
-
This resource sets the background color used to fill the box surrounding
the zero field label. If you do not want the box to be filled at all, set
stZeroFLabelBackgroundColor to
Transparent (-1).
Default: Background
-
stZeroFLabelPerimOn
-
stZeroFLabelPerimOn is a boolean resource that determines
whether StreamlinePlot will draw an outline around the
perimeter of the box surrounding the zero field label. If set
False, no outline will be drawn.
Default: True
-
stZeroFLabelPerimSpaceF
-
stZeroFLabelPerimSpaceF determines the spacing or margin
between the text of the zero field label and the edge of the
zero field label box as a fraction of the current label text
height.
Default: 0.33
-
stZeroFLabelPerimColor
-
This resource sets the HLU color index used to draw the perimeter of
the zero field label box.
Default: Foreground
-
stZeroFLabelPerimThicknessF
-
This resource determines the thickness of the perimeter line around
the zero field label box. The value acts as a multiplier of a
(device-dependent) unit thickness.
Default: 1.0
-
stZeroFLabelZone
-
StreamlinePlot implements the zero field label as an
embedded annotation. stZeroFLabelZone specifies the
PlotManager zone assigned to the zero field
annotation. The PlotManager
Location Control Model requires this resource to allow control of
the zero field label consistent with other annotations. If
stZeroFLabelZone is set to 0, the positional origin is the
center of the plot viewport; otherwise it is on or outside one of the
sides of the viewport.
If you create a StreamlinePlot object without an
active PlotManager by setting tfPlotManagerOn
False, then StreamlinePlot manages the zero field
annotation by itself. In this case, the stZeroFLabelZone
resource is not as meaningful.
Default: 0
-
stZeroFLabelSide
-
This resource of type NhlTPosition
determines where to place the zero field
annotation in relation to the sides of the plot
object. The PlotManager Location
Control Model requires this resource to allow control of the
zero field label consistent with other annotations. Its value
determines a coordinate system origin and the direction of the
positional resources, stZeroFLabelParallelPosF and
stZeroFLabelOrthogonalPosF. It also constrains the value of
the stZeroFLabelJust appropriately. There are four settings,
which behave as follows, unless stZeroFLabelZone is set to
one of the special zones (0 or 1):
Top
- The PlotManager locates the zero field label
annotation relative to a line paralleling the top viewport boundary.
stZeroFLabelOrthogonalPosF increases in the direction of
increasing NDC Y-Axis values and is constrained to positive values.
stZeroFLabelParallelPosF increases in the direction of
increasing NDC X-Axis values. stZeroFLabelJust is
constrained to
BottomRight, BottomCenter, or
BottomLeft.
Bottom
- The PlotManager locates the zero field label
annotation relative to a line paralleling the bottom viewport
boundary. stZeroFLabelOrthogonalPosF increases in the
direction of decreasing NDC Y-Axis values and is constrained to
positive values. stZeroFLabelParallelPosF increases in the
direction of increasing NDC X-Axis values. stZeroFLabelJust
is constrained to
TopRight, TopCenter, or
TopLeft.
Right
- The PlotManager locates the zero field label
annotation relative to a line paralleling the right viewport
boundary. stZeroFLabelOrthogonalPosF increases in the
direction of increasing NDC X-Axis values and is constrained to
positive values. stZeroFLabelParallelPosF increases in the
direction of increasing NDC Y-Axis values. stZeroFLabelJust
is constrained to
TopLeft, CenterLeft, or
BottomLeft.
Left
- The PlotManager locates the zero field label
annotation relative to a line paralleling the left viewport boundary.
stZeroFLabelOrthogonalPosF increases in the direction of
decreasing NDC X-Axis values and is constrained to positive values.
stZeroFLabelParallelPosF increases in the direction of
increasing NDC Y-Axis values. stZeroFLabelJust is
constrained to
TopRight, CenterRight, or
BottomRight.
If stZeroFLabelZone is set to 0, The
PlotManager locates the zero field label
annotation relative to the viewport center. If
stZeroFLabelZone is 1, the direction of the
stZeroFLabelOrthogonalPosF is opposite to the specification
given above. Also if the stZeroFLabelZone is either
0 or 1, stZeroFLabelJust is not constrained, and
stZeroFLabelOrthogonalPosF may take on negative values.
Default: Bottom
-
stZeroFLabelParallelPosF
-
stZeroFLabelParallelPosF specifies the coordinate of the
base location of the zero field label annotation
parallel to the current stZeroFLabelSide and directed
toward increasing NDC values. The PlotManager Location
Control Model requires this resource to allow control of the
zero field label consistent with other annotations.
Default: 0.0
-
stZeroFLabelOrthogonalPosF
-
stZeroFLabelOrthogonalPosF sets the coordinate of the base
location of the zero field label annotation
orthogonal to the current stZeroFLabelSide and directed away
from the center of the viewport. The PlotManager Location
Control Model requires this resource to allow control of the
zero field label consistent with other annotations.
Default: 0.0
-
stZeroFLabelJust
-
This resource of type NhlTJustification, after
constraint to an appropriate value based on
stZeroFLabelSide, sets the justification of the zero
field label annotation with respect to its base location. The
PlotManager Location
Control Model requires this resource to allow control of the
zero field label consistent with other annotations.
Default: CenterCenter
Reference Manual Control Panel
NG4.1 Home, Index, Examples, Glossary, Feedback, Ref Contents, Ref WhereAmI?
$Revision: 1.9 $ $Date: 1998/08/19 01:09:20 $