## Meta Layers Allows you to create additional layers of meta information and add them to the map. {toc} ### DG.Meta.layer Inherits from DG.Layer. #### Creation

Factory	Usage	Description
`DG.Meta.layer( <String> source, <DG.Meta.layer options> options? )`	`DG.Meta.layer(…)`	Creates additional layer with meta-information. Takes the source URL as a parameter with which the tiles of an additional layer are available.

#### Options

Option	Type	Default	Description
`tileSize`	`Number`	`256`	The tile size (width and height in pixels, it is assumed that the tile is square).
`minZoom`	`Number`	`0`	The minimum zoom level.
`maxZoom`	`Number`	`18`	The maximum zoom level.
`zoomOffset`	`Number`	`0`	Value which will shift the zoom level in the tile's address.
`eventBubbling`	`String`	`'transparent'\|\|'layer'`	The way in which meta-layer handles events. Accepts values layer or transparent (default): transparent — meta-layer receives all of the events and carry them to the map layer — meta-layer receives all of the events and stops them after processing

#### Events You can subscribe to the following events using these methods.

Event	Data	Description
`mouseover`	`MetaEvent`	Called when you hover the mouse over the additional layer object.
`mouseout`	`MetaEvent`	Called when the mouse cursor leaves the bounds of an additional layer object.
`mousemove`	`MetaEvent`	Called when the mouse cursor moves over an additional layer object.
`click`	`MetaEvent`	Called when the mouse click in the additional layer.
`dblclick`	`MetaEvent`	Called when the mouse double-click in the additional layer.
`mousedown`	`MetaEvent`	Called when the mouse button is pressed while the cursor is over the additional layer.
`contextmenu`	`MetaEvent`	Called when you click the right mouse button in the additional layer.

#### Methods

Method	Returns	Description
`getOrigin()`	`Object`	Returns origin-instance of additional layer.

### DG.Meta.origin Works with the meta data of a layer, inherits from DG.Class. #### Creation

Factory	Usage	Description
`DG.Meta.origin( <String> source, <DG.Meta.layer options> options? )`	`DG.Meta.origin(…)`	Creates an instance for work with the meta layer data. Takes the source URL as a parameter with which the tiles of an additional layer are available.

#### Options

Option	Type	Default	Description
`subdomains`	`String` или `String[]`	`'0123'`	Tile service subdomains. Can be sent as one string (where each letter — is a subdomain name) or as an array of strings.
`dataFilter`	`Function`	`null`	Optional parameter, which takes a function to filter or convert the meta data received from the server.

#### Methods

Method	Returns	Description
`getTileData( <Object> coord)`	`Object`	Returns the metadata of the meta layer for the specified tile.
`setTileData( <String>/<Object> coord, <Object> data)`	`this`	Assigns data for the tile with the coord key.
`flush()`	`this`	Clear cached data for all tiles.
`setURL( <String> url, <Boolean> flush?)`	`this`	Sets the url used to get the meta data. If the parameter flush=true, the cached data will be cleared.
`getTileKey( <Object> coord)`	`String`	Returns the key of the tile as a string.