Introduction
This chapter explores from the basics, the most important and common controls that OpenLayers offers us as developers. Controls allow us to navigate through the map, play with layers, zoom in or out, perform actions such as editing features, measuring distances, and the like. In essence, controls allow us to interact.
The
OpenLayers.Control class is the base class for all the controls and contains the common properties and methods that a control can have. We can summarize this as follows:
A control is attached to a map
A control can trigger events
A control can be activated or deactivated
A control can have a visual representation (such as a button) or have no visual representation (such as the drag action)
Controls are closely related to the
handlers. While controls are designed to contain the logic of the action, they delegate to the handlers the low-level tasks, such as to know about the mouse or keyboard events. For example, the OpenLayers.Control.DragPan control is responsible...
