Mouse Events

The main mouse events (mouse down, mouse up, mouse move) are overriden in CanvasMap which then calls the view, which calls the Scene, which then calls the layers:

1. CanvasMap overrides the mouse events with MouseDown, MouseUp, and MouseMove functions.
   1. If the event is not used by CanvasMap (i.e. the user is not dragging the contents of the map) then the View's mouse event function of the same name is called.
2. The View converts the coordinates of the mouse cursor to reference units (map units) and then call's the Scene's mouse event function of the same name with this coordinate.
3. The Scene calls all the layers mouse event function until one of the layers returns value of "true" for "Used" (i.e. the layer has used the mouse event and other layers should not use it).
4. The layers typically check if the mouse event was inside one of their features. If so, the layer takes apprpriate action like putting up an information window and returns "true" to keep other layers from using the event. Otherwise, the layer returns "false".

The Reference, Function Reference, and Design Details pages contain additional information on the design.