Displaying Feature with Text or changing feature extent

GarySchneir — Fri, 16 Apr 2010 22:43:45 GMT

I am trying to display some text with features and I have created a new C++ class that implements the IFeatureRenderer to do this. In the Draw method, I access additional fields from the features found by the FeatureCursor and I explicitly call display->DrawText to display up to 6 text strings where I want and with the necessary size and color. Because I am using an inMemoryWorkspaceFactory, I cannot use the standard annotation features. Other text approaches that I have taken, don't seem to work well, including dynamic display layers.

My problem is that when I call IScreen->Invalidate() to force ArcEngine to redisplay specific areas, the spatialQuery that is used to find the features that need to be refreshed, don't always find the features associated with the text that I am drawing. Therefore the screen is left blank where some of the text is normally drawn.

I have thought about extending the IFeatureClass with IFeatureClassExtensions but I don't think that will solve the problem since the spatial query is using the shape stored in the feature class.

I could try to change the geometry stored in the feature class to be a simple rectangle that contains the bounding box of my text but the text is drawn at a constant size, so the geometry will grow or shrink based on the zoom level. That would mean that on every zoom, I would need to recalculate each feature's bounding box which seems very inefficient.

topic Displaying Feature with Text or changing feature extent in ArcObjects SDK Questions

Displaying Feature with Text or changing feature extent