Hi,
I have some questions about the SLD stroke-dasharray property support.
Does it exists some reason for stroke-dasharray property only supports
literal expressions ?
After reading some code I come to the conclusion that the only
restriction is defined
by the Stroke interfaces, i.e. org.opengis.style.Stroke and
org.geotools.styling.Stroke.
Basically they define that the stroke-dasharray property can only be an
array of floats
and everyone else just follow that definition.
So, SLD parser for SLD 1.0.0 version do this (SLDParser):
if (res.equalsIgnoreCase("dasharray")
|| res.equalsIgnoreCase("stroke-dasharray")) {
String dashString = null;
if( child.getChildNodes().getLength() == 1 &&
child.getFirstChild().getNodeType() == Node.TEXT_NODE ){
dashString = getFirstChildValue(child);
} else {
Expression definition = parseCssParameter(child);
if( definition instanceof Literal){
dashString = ((Literal)definition).getValue().toString();
}
else {
LOGGER.warning("Only literal stroke-dasharray supported
at this time:"+definition);
}
}
}
And SLD parser for SLD 1.1.0 version do this (SLDStrokeBinding):
float[] dash = null;
if (dashArray != null) {
String[] string = Filters.asString(dashArray).split(" +");
dash = new float[string.length];
for (int i = 0; i < string.length; i++) {
dash[i] = Float.parseFloat(string[i]);
}
}
In the rendering process the getStroke methods retrieve the values from
all the stroke properties
evaluating them except for the dasharray property that is already an
array of floats:
// get the other properties needed for the stroke
float[] dashes = stroke.getDashArray();
float width = evalToFloat(stroke.getWidth(), feature, 1);
float dashOffset = evalToFloat(stroke.getDashOffset(),
feature, 0);
I checked the SLD standard and I haven't found any restriction that
force the dash property to
be represented as an array of floats.
Would it be acceptable to alter the Stroke interface to return and
accept the dashproperty as an Expression
instead of an array of floats ?
If so I can provide a patch for this.
Best regards,
Nuno Oliveira
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