:sourcedir: ../../..

==== PointSymbolizer

The point symbolizer draws a given image at a point position. When given a line or polygon as input the shape will be put at the middle of the line or center of the polygon. 

If no image file is specified a small square is used as the default point image.

For putting symbols along a line or the edge of a polygon the MarkerSymbolizer is usually a better choice.

.PointSymbolizer Attributes
[width="100%",options="header,unbreakable",cols="m,d,d,d"]
|====================
| Attribute          | Type          | Default | Description
| <<pointsymbolizer-file,file>> | file path     | none |
| <<pointsymbolizer-base,base>> | string | none | name of a <FileSource> to find the input file in
| <<pointsymbolizer-allow-overlap,allow-overlap>> | bool          | false | allow to paint over previous symbolizers output
| <<pointsymbolizer-opacity,opacity>> | float         | 1.0 |
| <<pointsymbolizer-placement,placement>> | string | cetroid | Wehter to place on a polygons centroid, which can actually be outside, or its interior
| ignore-placement | bool          | false |  
| <<pointsymbolizer-transform,transform>> | SVG transform | identity |
| comp-op          | Compositing   | src-over |
|====================


[#pointsymbolizer-file]
===== `file` attribute

`file` refers to a SVG or PNG file to include as a symbol at the point position.
The file can be given as a constant string, or as an expression, so files to display can be dynamically chosen from layer data.

By default `file` paths are either absolute or relative to the directory the main style file is in, but different directory paths can be set up using the <<_filesource,`<FileSource>`>> tag and referenced by its `name` using the <<pointsymbolizer-base,`base`>> attribute.

.PointSymbolizer file
====
[source,xml]
-----
include::{sourcedir}/examples/Symbolizer/Point/file.xml[]
-----
image::examples/Symbolizer/Point/file.svg[align="center"]
====


[#pointsymbolizer-opacity]
===== `opacity` attribute

The `opacity` attribute defines how opaque or transparant a point symbol should be rendered. The value range is from `0.0` for completely transparent to `1.0` for completely opaque.

.PointSymbolizer opacity
====
[source,xml]
-----
include::{sourcedir}/examples/Symbolizer/Point/opacity.xml[]
-----
image::examples/Symbolizer/Point/opacity.svg[align="center"]
====


[#pointsymbolizer-base]
===== `base` attribute

The `base` attribute defines which <<_filesource,`<FileSource>`>> should be used as the base directory for a <<pointsymbolizer-file,`file`>> symbol.

NOTE: The `base` attribute only accepts constant strings, no expressions. 
So it can only be chosen dynamically by using <<_rule,`<Rule>`>>/<<_filter,`<Filter>`>> constructs.

.PointSymbolizer base
====
[source,xml]
-----
include::{sourcedir}/examples/Symbolizer/Point/base.xml[]
-----
image::examples/Symbolizer/Point/base.svg[align="center"]
====


[#pointsymbolizer-allow-overlap]
===== `allow-overlap` attribute

The `allow-overlap` defines whether a point symbolizer may be drawn over previous output.

.PointSymbolizer allow-overlap
====
[source,xml]
-----
include::{sourcedir}/examples/Symbolizer/Point/allow-overlap.xml[]
-----
image::examples/Symbolizer/Point/allow-overlap.svg[align="center"]
====


[#pointsymbolizer-placement]
===== `placement` attribute

The `placement` attribute specifies where the point symbol should
be placed on a polygon object. By default it is placed on the `centroid`
of the polygons, but for a non-convex polygon this can actually place the symbol outside of the polygon itself. `interior` makes sure that the symbol is placed within the polygon in all cases.

.PointSymbolizer placement
====
[source,xml]
-----
include::{sourcedir}/examples/Symbolizer/Point/placement.xml[]
-----
image::examples/Symbolizer/Point/placement.svg[align="center"]
====

[#pointsymbolizer-transform]
===== `transform` attribute

TODO: document SVG transformations

.PointSymbolizer scaling 
[#example-pointsymbolizer-scaling]
====
[source,xml]
-----
include::{sourcedir}/examples/Symbolizer/Point/transform-scale.xml[]
-----
image::examples/Symbolizer/Point/transform-scale.svg[align="center"]
====

.PointSymbolizer rotation
[#example-pointsymbolizer-rotation]
====
[source,xml]
-----
include::{sourcedir}/examples/Symbolizer/Point/transform-rotate.xml[]
-----
image::examples/Symbolizer/Point/transform-rotate.svg[align="center"]
====

[#pointsymbolizer-comp-op]
===== `comp-up` attribute

TODO: document SVG compositing

.PointSymbolizer compositing
====
TODO
====