Add expression string to SE_RenderText

[sinkler]

Provide the expression from which a piece of symbolic text is derived to the renderer. This is useful to several autodesk products by allowing tighter editing integration with the display of feature data. One example is click-to-edit funtionality on feature labels.

The stylizer component has this information readily available, and it is relatively simple to pass this information on to the SE_Renderer and derived classes.

[tomfukushima]

Checking performance impact: Is this code that we are adding the changes to executed once per feature drawn, or once per symbol definition used by the layer?

[sinkler]

Replying to tomfukushima:

Checking performance impact: Is this code that we are adding the changes to executed once per feature drawn, or once per symbol definition used by the layer?

The code may be executed more than once per feature if the symbolization contains more than one text primitive. I'll point out that the additional string copy is probably less expensive than the expression evaluation which is happening with the same frequency.

[tomfukushima]

Trunk: r5020