## [OverlayView](https://developers.google.com/maps/documentation/javascript/reference/overlay-view.md.txt#OverlayView) class class `google.maps.OverlayView` extends `MVCObject` library `"maps", "streetView"` You can implement this class if you want to display custom types of overlay objects on the map. Inherit from this class by setting your overlay's prototype: `MyOverlay.prototype = new google.maps.OverlayView();`. The `OverlayView` constructor is guaranteed to be an empty function. You must implement three methods: `onAdd()`, `draw()`, and `onRemove()`. - In the `onAdd()` method, you should create DOM objects and append them as children of the panes. - In the `draw()` method, you should position these elements. - In the `onRemove()` method, you should remove the objects from the DOM. You must call `setMap()` with a valid `Map` object to trigger the call to the `onAdd()` method and `setMap(null)` in order to trigger the `onRemove()` method. The `setMap()` method can be called at the time of construction or at any point afterward when the overlay should be re-shown after removing. The `draw()` method will then be called whenever a map property changes that could change the position of the element, such as zoom, center, or map type.
```javascript const {OverlayView} = await google.maps.importLibrary("maps"); ``` or ```javascript const {OverlayView} = await google.maps.importLibrary("streetView"); ``` | ### Constructor || |---|---| | `OverlayView` | `OverlayView()` **Parameters:** None Creates an `OverlayView`. | | ### Static Methods || |---|---| | `preventMapHitsAndGesturesFrom` | `preventMapHitsAndGesturesFrom(element)` **Parameters:** - `element: Element` **Return Value:** None Stops click, tap, drag, and wheel events on the element from bubbling up to the map. Use this to prevent map dragging and zooming, as well as map "click" events. | | `preventMapHitsFrom` | `preventMapHitsFrom(element)` **Parameters:** - `element: Element` **Return Value:** None Stops click or tap on the element from bubbling up to the map. Use this to prevent the map from triggering "click" events. | | ### Methods || |---|---| | `draw` | `draw()` **Parameters:** None **Return Value:** `void` Implement this method to draw or update the overlay. Use the position from projection.fromLatLngToDivPixel() to correctly position the overlay relative to the MapPanes. This method is called after onAdd(), and is called on change of zoom or center. It is not recommended to do computationally expensive work in this method. | | `getMap` | `getMap()` **Parameters:** None **Return Value:** `Map|StreetViewPanorama|null|undefined` | | `getPanes` | `getPanes()` **Parameters:** None **Return Value:** `MapPanes|null|undefined` Returns the panes in which this OverlayView can be rendered. The panes are not initialized until `onAdd` is called by the API. | | `getProjection` | `getProjection()` **Parameters:** None **Return Value:** `MapCanvasProjection` Returns the `MapCanvasProjection` object associated with this `OverlayView`. The projection is not initialized until `onAdd` is called by the API. | | `onAdd` | `onAdd()` **Parameters:** None **Return Value:** `void` Implement this method to initialize the overlay DOM elements. This method is called once after setMap() is called with a valid map. At this point, panes and projection will have been initialized. | | `onRemove` | `onRemove()` **Parameters:** None **Return Value:** `void` Implement this method to remove your elements from the DOM. This method is called once following a call to setMap(null). | | `setMap` | `setMap(map)` **Parameters:** - `map: Map|StreetViewPanorama optional` The map or panorama. If `null`, the layer will be removed. **Return Value:** None Adds the overlay to the map or panorama. | ## [MapPanes](https://developers.google.com/maps/documentation/javascript/reference/overlay-view.md.txt#MapPanes) interface interface `google.maps.MapPanes` | ### Properties || |---|---| | `floatPane` | **Type:** `Element` This pane contains the info window. It is above all map overlays. (Pane 4). | | `mapPane` | **Type:** `Element` This pane is the lowest pane and is above the tiles. It does not receive DOM events. (Pane 0). | | `markerLayer` | **Type:** `Element` This pane contains markers. It does not receive DOM events. (Pane 2). | | `overlayLayer` | **Type:** `Element` This pane contains polylines, polygons, ground overlays and tile layer overlays. It does not receive DOM events. (Pane 1). | | `overlayMouseTarget` | **Type:** `Element` This pane contains elements that receive DOM events. (Pane 3). | ## [MapCanvasProjection](https://developers.google.com/maps/documentation/javascript/reference/overlay-view.md.txt#MapCanvasProjection) interface interface `google.maps.MapCanvasProjection` This object is made available to the `OverlayView` from within the draw method. It is not guaranteed to be initialized until draw is called. | ### Methods || |---|---| | `fromContainerPixelToLatLng` | `fromContainerPixelToLatLng(pixel[, noClampNoWrap])` **Parameters:** - `pixel: Point optional` - `noClampNoWrap: boolean optional` **Return Value:** `LatLng|null` Computes the geographical coordinates from pixel coordinates in the map's container. | | `fromDivPixelToLatLng` | `fromDivPixelToLatLng(pixel[, noClampNoWrap])` **Parameters:** - `pixel: Point optional` - `noClampNoWrap: boolean optional` **Return Value:** `LatLng|null` Computes the geographical coordinates from pixel coordinates in the div that holds the draggable map. | | `fromLatLngToContainerPixel` | `fromLatLngToContainerPixel(latLng)` **Parameters:** - `latLng: LatLng|LatLngLiteral` **Return Value:** `Point|null` Computes the pixel coordinates of the given geographical location in the map's container element. | | `fromLatLngToDivPixel` | `fromLatLngToDivPixel(latLng)` **Parameters:** - `latLng: LatLng|LatLngLiteral optional` **Return Value:** `Point|null` Computes the pixel coordinates of the given geographical location in the DOM element that holds the draggable map. | | `getVisibleRegion` | `getVisibleRegion()` **Parameters:** None **Return Value:** `VisibleRegion|null` The visible region of the map. Returns `null` if the map has no size. Returns `null` if the OverlayView is on a StreetViewPanorama. | | `getWorldWidth` | `getWorldWidth()` **Parameters:** None **Return Value:** `number` The width of the world in pixels in the current zoom level. For projections with a heading angle of either 90 or 270 degrees, this corresponds to the pixel span in the Y-axis. |