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Maps API for JavaScript

China specific
Maps API for JavaScript Developer's Guide

H.map.render.RenderEngine

Class Summary

Extends: H.util.EventTarget

This is an abstract class representing a render engine. Render engines are used to render the geographical position from a view model on the screen (viewport element). The rendered result may be different for different engines, because every engine uses its own capabilities and specific implementation to present the current view model data in best possible way. For example, 2D engines create a two-dimensional flat map composed of tiles, while 3D engines can generate panoramas displaying the same coordinates as a 'street view'.

[ For full details, see the Class Details ]

Method Summary

Table 1. Methods
Methods

addEventListener (type, handler, opt_capture, opt_scope)

This method adds a listener for a specific event.

removeEventListener (type, handler, opt_capture, opt_scope)

This method removes a previously added listener from the EventTarget instance.

dispatchEvent (evt)

This method dispatches an event on the EventTarget object.

dispose ()

This method removes listeners from the given object. Classes that extend EventTarget may need to override this method in order to remove references to DOM Elements and additional listeners.

addOnDisposeCallback (callback, opt_scope)

This method adds a callback which is triggered when the EventTarget object is being disposed.

Events Summary

Table 2. Events
Events

render : {H.util.Event}

Fired when one of the layers or the engine (all layers) has been rendered completely. The event target references either the completed layer or the render engine itself

Class Description

This is an abstract class representing a render engine. Render engines are used to render the geographical position from a view model on the screen (viewport element). The rendered result may be different for different engines, because every engine uses its own capabilities and specific implementation to present the current view model data in best possible way. For example, 2D engines create a two-dimensional flat map composed of tiles, while 3D engines can generate panoramas displaying the same coordinates as a 'street view'.

A RenderEngine is responsible for managing the rendering loop as well as for synchronizing rendered data with the view model and the data model. It manages what is rendered inside the current viewport and how.

Constructor Details

H.map.render.RenderEngine(viewPort, viewModel, dataModel, options)

Parameters:
 
viewPort:
{H.map.ViewPort}
 
An object representing the map viewport
viewModel:
{H.map.ViewModel}
 
An object representing a view of the map
dataModel:
{H.map.DataModel}
 
An object encapsulating the data to be rendered on the map (layers and objects)
options:
{H.map.render.RenderEngine.Options}
 
An object containing the render engine initialization options

Method Details

addEventListener (type, handler, opt_capture, opt_scope)

This method adds a listener for a specific event.

Note that to prevent potential memory leaks, you must either call removeEventListener or dispose on the given object when you no longer need it.

Parameters:
 
type:
{string}
 
The name of the event
handler:
{!Function}
 
An event handler function
opt_capture:
{boolean=} [optional]
 
true indicates that the method should listen in the capture phase (bubble otherwise)
opt_scope:
{Object=} [optional]
 
An object defining the scope for the handler function

removeEventListener (type, handler, opt_capture, opt_scope)

This method removes a previously added listener from the EventTarget instance.

Parameters:
 
type:
{string}
 
The name of the event
handler:
{!Function}
 
A previously added event handler
opt_capture:
{boolean=} [optional]
 
true indicates that the method should listen in the capture phase (bubble otherwise)
opt_scope:
{Object=} [optional]
 
An oject defining the scope for the handler function

dispatchEvent (evt)

This method dispatches an event on the EventTarget object.

Parameters:
 
evt:
{(H.util.Event | string)}
 
An object representing the event or a string with the event name

dispose ()

This method removes listeners from the given object. Classes that extend EventTarget may need to override this method in order to remove references to DOM Elements and additional listeners.

addOnDisposeCallback (callback, opt_scope)

This method adds a callback which is triggered when the EventTarget object is being disposed.

Parameters:
 
callback:
{!Function}
 
The callback function.
opt_scope:
{Object=} [optional]
 
An optional scope for the callback function

Event Details

render: {H.util.Event}

Fired when one of the layers or the engine (all layers) has been rendered completely. The event target references either the completed layer or the render engine itself