[OpenLayers-Dev] feature label enhancement

"Dominik Gärner" domi-g at gmx.at
Wed Feb 10 05:29:48 EST 2010

Hi everyone,

I'd like to do some label enhancement for vector features. I want the label to follow the feature shape (e.g. see http://www.svgbasics.com/text2.html )
It shouldn't be that hard by using SVG & VML. However, since this means some changes in the Renderers - and I'm not so familiar with the whole existing implementations - I need some ideas & help for creating a concept:

- using SVG, a textpath needs a <path> element. In SVG i could link the text to the path element (using the xlink:href attribute), but currently only Polygon and Curve geometries are using <path> node types. And I'm not sure if VML allows links. 
The better way will be to create a separate path element for the text/label, using the feature's geometry (--> this means changes to the drawText methods in the Renderers)

- maybe some additional style attributes for the label have to be added.

- Who knows something about Canvas? Is it possible to implement curved text like in SVG & VML?
  Where or which component decides what to use (besides of IE->VML, Firefox->SVG)
- Rotating labels comes for free by rotating the vector feature. Does it make sense to create an extra Label/Text class for placing just labels (e.g. if I want to place just a text, not a feature with a label attribute)

- Did I forget something essential? Sees anyone bigger blockades for the programming of this?

Any ideas and suggestions are welcome!

Best regards
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