15 LineSymbolizer

Jez Nicholson edited this page 2018-01-23 12:53:12 +00:00

Table of Contents

• Configuration Options
• Examples
• Default
• XML
• Python
• C++

Symbolizer that specifies rendering of a "stroke" along a linear geometry.

Configuration Options

parameter	value	description	unit	default	accepts expressions
stroke	CSS colour	A Color value such as 'green' or #A3D979	-	"black"	mapnik >= 3.0
stroke-width	0.0 - n	Width of line	pixels	1.0	mapnik >= 3.0
stroke-opacity	0.0 - 1.0	1 is fully opaque while zero is fully transparent and .5 would be 50% transparent	transparency	1.0	mapnik >= 3.0
stroke-linejoin	miter, round, bevel	See SVG stroke-linejoin for an example for each value	-	miter	no
stroke-linecap	round, butt, square	See SVG stroke-linecap for an example for each value	-	butt	no
stroke-dasharray	0.0 - n,0.0 - n	A pair of length values [a,b], where (a) is the dash length and (b) is the gap length respectively. More than two values are supported as well (e.g. to start the line not with a stroke, but with a gap).	pixels	none	no
comp-op		Compositing		none	no
smooth	0.0 - 1.0	1 means completely smoothed lines, 0 means no change	-	0.0

Examples

Default

<LineSymbolizer />

XML

<LineSymbolizer stroke="#0000ff" stroke-width="4" />

Python

l = LineSymbolizer(Color('green'),0.1)

To work directly with the stroke object:

l = LineSymbolizer()
s = Stroke(Color('green'),0.1)
s.add_dash(.1,.1)
s.opacity = .5
l.stroke = s

Fetch all the possible methods like:

>>> from mapnik import LineSymbolizer
>>> dir(LineSymbolizer().stroke)

C++

rule_type rule;
stroke ls;         // This is the line symbolizer
ls.set_color(color(255, 255, 255));
ls.set_width(4);   // width of the line in pixels
ls.set_line_join(mapnik::ROUND_JOIN);
ls.set_line_cap(mapnik::ROUND_CAP);
ls.add_dash(2.5, 1.0);
ls.set_opacity(0.5);
rule.append(ls);