The following
syntax is the complete syntax for the LINEATTRS= option:
LINEATTRS = style-element | style-element (line-options) | (line-options)
By default, a
style-element is used for the LINEATTRS= setting.
For the REFERENCELINE and DROPLINE statements, the default style element
is the GraphReference element. What exactly does this mean?
If we look up the GraphReference
element in the DEFAULT style (
see Graph Style Elements for GTL for a complete
list of all elements and attributes and their defaults), we find the
following:
style GraphReference /
linethickness = 1px
linestyle = 1
contrastcolor = GraphColors('greferencelines');
This definition
is ODS style syntax for an attribute bundle. The following table shows
how this definition's style attributes map to GTL options.
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dimension, most often
pixels
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dimension, most often
pixels
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numeric; 1 to 46, 1
being a solid line
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either 1 to 46 or a
pattern name, such as SOLID, DASH, DOT ( see Values for Line Patterns for examples
of available line patterns)
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The default specification
for REFERENCELINE and DROPLINE statements is
LINEATTRS=GraphReference, which is a shortcut meaning "initialize the three GTL line properties
with the corresponding attributes that are defined in a style element."
This can be explicitly expressed in GTL as follows:
LINEATTRS=( PATTERN = GraphReference:LineStyle
THICKNESS= GraphReference:LineThickness
COLOR = GraphReference:ContrastColor )
In GTL, a style reference
is a construct of the form
style-element :
style-attribute. This
convention is the way to refer to a specific style attribute of a
specific style element.
First, we will look
at what it means to use a different style element for the LINEATTRS=
option.
When selecting a different
style element, you should make sure that the style element does set
line properties (graph style elements do not necessarily define all
possible attributes). Some reasonable choices might be GraphDataDefault,
GraphAxisLines, GraphGridLines. and GraphBorderLines. You might choose
GraphGridLines to force a reference line to match the properties of
grid lines (if displayed). When you make this type of assignment,
you really do not know what actual line properties will be used because
they might change, depending on how a given style is defined. What
you should be confident of is that the grid lines and reference lines
are identical in terms of line properties.
Now we will assume that
you want reference lines to be somewhat like a style element, but
nevertheless different. This involves an override. Here are some examples:
1) LINEATTRS=GraphGridLines(THICKNESS=2px)
2) LINEATTRS=GraphAxisLines(PATTERN=DASH)
3) LINEATTRS=GraphReference(COLOR=GraphAxisLines:ContrastColor)
4) LINEATTRS=(COLOR=GraphAxisLines:ContrastColor)
5) LINEATTRS=(COLOR=BLUE)
In example 1, the reference
line looks like a grid line (color and pattern), but be thicker (assuming
most styles define grid lines as 1px).
In example 2, the reference
line looks like an axis line (color and thickness), but it uses the
DASH pattern.
In example 3, the reference
line looks like a reference line (pattern and thickness), but it
has the color of axis lines.
Example 4 is a short
form for example 3. Any time you do not supply a style element or
do not override all the suboptions, the suboptions not overridden
come from the default style references.
Example 5 shows how
you can hardcode visual properties. This technique is a straightforward
way of getting what you want. The results might look good when the
DEFAULT or LISTING styles are in effect, but might not look good when
the ANALYSIS style is in effect because ANALYSIS does not use any
blues in its color scheme.
When specifying the
attributes for a line, the available
line-options can be any one or more of the following settings. The options must
be enclosed in parentheses, and each option is specified as a
name =
value pair. In all cases, the value can be a
style-reference in the form
style-element:
style-attribute (see Example
3).
COLOR=
style-reference |
color
specifies the line
color. If you use a style-reference, the style-attribute should
be a valid attribute, such as COLOR, CONTRASTCOLOR, STARTCOLOR, NEUTRAL,
or ENDCOLOR. The convention is to use CONTRASTCOLOR for lines.
PATTERN=
style-reference |
line-pattern-name |
line-pattern-number
specifies the line
pattern. If you use a
style-reference, the
style-attribute should
be LINESTYLE. Line patterns can be specified as a pattern name or
pattern number.
See Values for Marker Symbols and Line Patterns for a list
of all possible line patterns.
THICKNESS=
style-reference |
dimension
specifies the line
thickness. If you use a style-reference, the style-attribute should
be LINETHICKNESS.