sij/mapnik
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Created Text Rendering Overview (markdown)

herm 2012-01-24 05:31:32 -08:00
parent 00bdc8243f
commit 5767c489d5
1 changed files with 22 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
Text-Rendering-Overview.md Normal file

@ -0,0 +1,22 @@
## Abstract
This page aims to give an explanation of how all the parts in rendering a TextSymbolizer play together. (For textplacement branch)
# TextSymbolizer
As it's only property contains a pointer to a ```text_placements``` object.
# text_placements
This object handles the management of all TextSymbolizer properties. It can be used as a base class for own objects which implement new processing semantics.
## Functions
* ```get_all_expressions```: Get a list of all expressions used in any placement. This function is used to collect attributes.
* ```get_placement_info```: _(Abstract function)_ Get a text_ placement_info object to use in rendering. The returned object creates a list of settings which is used to try to find a placement and stores all information that is generated by the placement finder.
This function usually is implemented as
```text_placement_info_ptr text_placements_XXX::get_placement_info() const
{
return text_placement_info_ptr(new text_placement_info_XXX(this));
}
```
## Properties
All properties are grouped into a class ```text_symbolizer_properties``` accessible via public member ```properties```. They are used by subclasses as their defaults.