Class: ViewModel

H .map.ViewModel

new H.map.ViewModel ()

This class represents a view of the map. It consists of a look-at point which has a position in geo-space and orientation angles (heading, tilt and incline). The view model allows to change the values of this object in order to move or rotate the map or zoom in and out.

Modifying the view of a map is asynchronous as the view model notifies the renderer of a change in its state and triggers the renderer.

A map renderer can choose to ignore or even correct certain values depending on its capabilities. For example a 2D map renderer will ignore tilt values and correct tilt values to be 0 on the view model in order to keep the integrity of the view model.

In order to be notified of changes to the model that originate from the renderer, the view model dispatches a "sync" event whenever the renderer synchronizes the requested changes to the view with its own internal state.

Extends

H.util.EventTarget

Implements

H.map.IControl

Methods

addEventListener (type, handler, opt_capture, opt_scope) inherited

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.

Name	Type	Description
`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

addOnDisposeCallback (callback, opt_scope) inherited

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

Name	Type	Description
`callback`	function	The callback function.
`opt_scope`	Object	optional An optional scope for the callback function

control (moveX, moveY, moveZ, rotateX, rotateY, rotateZ)

To control a look-at-point animation in screen space. Before the look-at-point can be controlled the method H.map.ViewModel#startControl must be invoked once. The animation can be finished via H.map.ViewModel#endControl

Name	Type	Description
`moveX`	number	The movement along the x-axis in pixels per second
`moveY`	number	The movement along the y-axis in pixels per second
`moveZ`	number	The movement along the z-axis in zoom-levels per second
`rotateX`	number	The rotation around the x-axis in degrees per second
`rotateY`	number	The rotation around the y-axis in degrees per second
`rotateZ`	number	The rotation around the z-axis in degrees per second

dispatchEvent (evt) inherited

This method dispatches an event on the EventTarget object.

Name	Type	Description
`evt`	H.util.Event \| string	An object representing the event or a string with the event name

dispose () inherited

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.

endControl (opt_preventKinetics, opt_adjustView)

To finish the control of a look-at-point animation. See also H.map.ViewModel#startControl and H.map.ViewModel#control

Name	Type	Description
`opt_preventKinetics`	boolean	optional Indicates whether a kinetic effect at the end of the controlled animation is prevented.
`opt_adjustView`	function(H.map.ViewModel.ILookAtData)	optional A custom function to adjust the final view. It receives the last requested look-at data from the view model and has to return a possibly modified `H.map.ViewModel.ILookAtData` which is used instead.

Example

//prevent kinetics
viewModel.endControl(true);

//prevent kinetics and set adjusted view
viewModel.endControl(true, function(requested) {
  requested.zoom = Math.round(requested.zoom);
});

getLookAtData ()H.map.ViewModel.ILookAtData

This method retrieves the current rendered look-at data. It returns H.geo.Rect as bounds in case of P2D engine, otherwise bounds is of type H.geo.Polygon.

Returns:

Type	Description
H.map.ViewModel.ILookAtData	The current rendered look-at data

removeEventListener (type, handler, opt_capture, opt_scope) inherited

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

Name	Type	Description
`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 object defining the scope for the handler function

setLookAtData (data, opt_animate, opt_integerZoom)H.map.ViewModel

To set new look-at data for the view model. This method supports any type of geometry. In case of P2D engine type, the bounding box of the geometry is used. In case of other engine types: if the bounds type is H.geo.Polygon, then the exterior of the polygon defines visible area, otherwise the bounding box of the given bounds geometry.

Name Type Description

Name	Type	Description
`data`	H.map.ViewModel.ILookAtData	The values to be modified. Here are some of the main possibilities to reposition the camera at a given look-at point: `position` - use existing (default) zoom and change map center `zoom` - use existing (default) map center and change zoom `position` & `zoom` - use specified position as map center and zoom `bounds` - set center of the bounds as a new map center and calculate zoom such that bounds are visible `bounds` & `position` - set specified position as map center and calculate zoom such that bounds are visible `bounds` & `zoom` - set center of the bounds as a new map center and set specified zoom `bounds` & `position` & `zoom` - ignore bounds and use specified position and zoom `tilt`, `heading`, `incline` - set look-at angles
`opt_animate`	boolean \| number	optional A boolean indicating if an animated transition should be applied. Alternatively, a positive number representing a speed factor that's multiplied to the default animation speed computed by the rendering engine. Valid for vector engines only. Examples: 1.1 means 10% faster than the default animation speed. 0.5 means 50% slower. Default is `false`.
`opt_integerZoom`	boolean	optional Indicates if the resulting zoom level should be rounded down. It is only applied in case that the LookAtData's zoom level is not specified but bounds are. This can be used to prevent blurry raster tile maps when set the "look at" to specified bounds. Default is `false`.

data

H.map.ViewModel.ILookAtData

The values to be modified. Here are some of the main possibilities to reposition the camera at a given look-at point:

position - use existing (default) zoom and change map center
zoom - use existing (default) map center and change zoom
position & zoom - use specified position as map center and zoom
bounds - set center of the bounds as a new map center and calculate zoom such that bounds are visible
bounds & position - set specified position as map center and calculate zoom such that bounds are visible
bounds & zoom - set center of the bounds as a new map center and set specified zoom
bounds & position & zoom - ignore bounds and use specified position and zoom
tilt, heading, incline - set look-at angles

opt_animate

boolean | number

optional

A boolean indicating if an animated transition should be applied. Alternatively, a positive number representing a speed factor that's multiplied to the default animation speed computed by the rendering engine. Valid for vector engines only. Examples:

1.1 means 10% faster than the default animation speed.
0.5 means 50% slower.

Default is false.

opt_integerZoom

boolean

optional

Indicates if the resulting zoom level should be rounded down. It is only applied in case that the LookAtData's zoom level is not specified but bounds are. This can be used to prevent blurry raster tile maps when set the "look at" to specified bounds.

Default is false.

Fires:

H.map.ViewModel#event:update

Returns:

Type	Description
H.map.ViewModel	this view model object

startControl (opt_kinetics, opt_atX, opt_atY)

To start the controlling of the look-at-point animation. After this method was invoked, the look-at-point animation can be controlled by several calls of H.map.ViewModel#control and finished by a call of H.map.ViewModel#endControl

Name	Type	Description
`opt_kinetics`	H.util.kinetics.IKinetics	optional Kinetics settings
`opt_atX`	number	optional The x screen coordinate at which control starts
`opt_atY`	number	optional The y screen coordinate at which control starts

Type Definitions

H.map.ViewModel.ILookAtData Object

An Interface to describe a look-at data set.

Properties:

Name	Type	Argument	Description
`position`	H.geo.IPoint	<optional>	This property represents the look-at position in geographical space.
`zoom`	number	<optional>	This property represents the zoom level. The maximum and minimum zoom levels of the current base layer are defined during its creation and might differ depending on the map layer and its specific configuration.
`bounds`	H.geo.AbstractGeometry	<optional>	This property represents the visible area.
`heading`	number	<optional>	This property represents the rotation angle relative to North. A positive angle increases southward. The range is from 0 to 360 but it can be restricted by the render engine capabilities. 0 - looks from the North; 90 - looks from the East; 180 - looks from the South; 270 - looks from the West.
`incline`	number	<optional>	This property represents the angle between the look-at vector and normal to the surface along x-axis. The range is from -180 to +180, but it can be restricted by the render engine capabilities. 0 - no incline, 90 - left incline, -90 - right incline.
`tilt`	number	<optional>	This property represents the angle between the look-at vector and normal to the surface along z-axis. The range is from 0 to 90, but it can be restricted by the render engine capabilities. 0 - looks down; 90 - looks straight.