Overview
GMSTileLayer is an abstract class that allows overlaying of custom image tiles on a specified GMSMapView.
It may not be initialized directly, and subclasses must implement the tileForX:y:zoom: method to return tiles.
At zoom level 0 the whole world is a square covered by a single tile, and the coordinates x and y are both 0 for that tile. At zoom level 1, the world is covered by 4 tiles with x and y being 0 or 1, and so on.
Inherited by GMSSyncTileLayer, and GMSURLTileLayer.
Public Member Functions | |
| (void) | - requestTileForX:y:zoom:receiver: |
| requestTileForX:y:zoom:receiver: generates image tiles for GMSTileOverlay. | |
| (void) | - clearTileCache |
| Clears the cache so that all tiles will be requested again. | |
Properties | |
| GMSMapView * | map |
| The map this GMSTileOverlay is displayed on. | |
| int | zIndex |
Higher zIndex value tile layers will be drawn on top of lower zIndex value tile layers and overlays. | |
| NSInteger | tileSize |
| Specifies the number of pixels (not points) that the returned tile images will prefer to display as. | |
| float | opacity |
| Specifies the opacity of the tile layer. | |
| BOOL | fadeIn |
| Specifies whether the tiles should fade in. | |
Member Function Documentation
| - (void) requestTileForX: | (NSUInteger) | x | |
| y: | (NSUInteger) | y | |
| zoom: | (NSUInteger) | zoom | |
| receiver: | (id< GMSTileReceiver >) | receiver | |
requestTileForX:y:zoom:receiver: generates image tiles for GMSTileOverlay.
It must be overridden by subclasses. The tile for the given x, y and zoom _must_ be later passed to receiver.
Specify kGMSTileLayerNoTile if no tile is available for this location; or nil if a transient error occurred and a tile may be available later.
Calls to this method will be made on the main thread. See GMSSyncTileLayer for a base class that implements a blocking tile layer that does not run on your application's main thread.
| - (void) clearTileCache |
Clears the cache so that all tiles will be requested again.
Property Documentation
- (GMSMapView*) map [read, write, assign] |
The map this GMSTileOverlay is displayed on.
Setting this property will add the layer to the map. Setting it to nil removes this layer from the map. A layer may be active on at most one map at any given time.
- (int) zIndex [read, write, assign] |
Higher zIndex value tile layers will be drawn on top of lower zIndex value tile layers and overlays.
Equal values result in undefined draw ordering.
- (NSInteger) tileSize [read, write, assign] |
Specifies the number of pixels (not points) that the returned tile images will prefer to display as.
For best results, this should be the edge length of your custom tiles. Defaults to 256, which is the traditional size of Google Maps tiles.
Values less than the equivalent of 128 points (e.g. 256 pixels on retina devices) may not perform well and are not recommended.
As an example, an application developer may wish to provide retina tiles (512 pixel edge length) on retina devices, to keep the same number of tiles per view as the default value of 256 would give on a non-retina device.
- (float) opacity [read, write, assign] |
Specifies the opacity of the tile layer.
This provides a multiplier for the alpha channel of tile images.
- (BOOL) fadeIn [read, write, assign] |
Specifies whether the tiles should fade in.
Default YES.