Files
openlayers/src/ol/source/VectorTile.js
2021-05-30 21:22:03 +02:00

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17 KiB
JavaScript

/**
* @module ol/source/VectorTile
*/
import EventType from '../events/EventType.js';
import Tile from '../VectorTile.js';
import TileCache from '../TileCache.js';
import TileState from '../TileState.js';
import UrlTile from './UrlTile.js';
import VectorRenderTile from '../VectorRenderTile.js';
import {
buffer as bufferExtent,
getIntersection,
intersects,
} from '../extent.js';
import {
createForProjection,
createXYZ,
extentFromProjection,
} from '../tilegrid.js';
import {fromKey, getKeyZXY} from '../tilecoord.js';
import {isEmpty} from '../obj.js';
import {loadFeaturesXhr} from '../featureloader.js';
import {toSize} from '../size.js';
/**
* @typedef {Object} Options
* @property {import("./Source.js").AttributionLike} [attributions] Attributions.
* @property {boolean} [attributionsCollapsible=true] Attributions are collapsible.
* @property {number} [cacheSize] Initial tile cache size. Will auto-grow to hold at least twice the number of tiles in the viewport.
* @property {import("../extent.js").Extent} [extent] Extent.
* @property {import("../format/Feature.js").default} [format] Feature format for tiles. Used and required by the default.
* @property {boolean} [overlaps=true] This source may have overlapping geometries. Setting this
* to `false` (e.g. for sources with polygons that represent administrative
* boundaries or TopoJSON sources) allows the renderer to optimise fill and
* stroke operations.
* @property {import("../proj.js").ProjectionLike} [projection='EPSG:3857'] Projection of the tile grid.
* @property {import("./State.js").default} [state] Source state.
* @property {typeof import("../VectorTile.js").default} [tileClass] Class used to instantiate image tiles.
* Default is {@link module:ol/VectorTile}.
* @property {number} [maxZoom=22] Optional max zoom level. Not used if `tileGrid` is provided.
* @property {number} [minZoom] Optional min zoom level. Not used if `tileGrid` is provided.
* @property {number|import("../size.js").Size} [tileSize=512] Optional tile size. Not used if `tileGrid` is provided.
* @property {number} [maxResolution] Optional tile grid resolution at level zero. Not used if `tileGrid` is provided.
* @property {import("../tilegrid/TileGrid.js").default} [tileGrid] Tile grid.
* @property {import("../Tile.js").LoadFunction} [tileLoadFunction]
* Optional function to load a tile given a URL. Could look like this for pbf tiles:
* ```js
* function(tile, url) {
* tile.setLoader(function(extent, resolution, projection) {
* fetch(url).then(function(response) {
* response.arrayBuffer().then(function(data) {
* const format = tile.getFormat() // ol/format/MVT configured as source format
* const features = format.readFeatures(data, {
* extent: extent,
* featureProjection: projection
* });
* tile.setFeatures(features);
* });
* });
* });
* }
* ```
* If you do not need extent, resolution and projection to get the features for a tile (e.g.
* for GeoJSON tiles), your `tileLoadFunction` does not need a `setLoader()` call. Only make sure
* to call `setFeatures()` on the tile:
* ```js
* const format = new GeoJSON({featureProjection: map.getView().getProjection()});
* async function tileLoadFunction(tile, url) {
* const response = await fetch(url);
* const data = await response.json();
* tile.setFeatures(format.readFeatures(data));
* }
* ```
* @property {import("../Tile.js").UrlFunction} [tileUrlFunction] Optional function to get tile URL given a tile coordinate and the projection.
* @property {string} [url] URL template. Must include `{x}`, `{y}` or `{-y}`, and `{z}` placeholders.
* A `{?-?}` template pattern, for example `subdomain{a-f}.domain.com`, may be
* used instead of defining each one separately in the `urls` option.
* @property {number} [transition] A duration for tile opacity
* transitions in milliseconds. A duration of 0 disables the opacity transition.
* @property {Array<string>} [urls] An array of URL templates.
* @property {boolean} [wrapX=true] Whether to wrap the world horizontally.
* When set to `false`, only one world
* will be rendered. When set to `true`, tiles will be wrapped horizontally to
* render multiple worlds.
* @property {number} [zDirection=1] Indicate which resolution should be used
* by a renderer if the view resolution does not match any resolution of the tile source.
* If 0, the nearest resolution will be used. If 1, the nearest lower resolution
* will be used. If -1, the nearest higher resolution will be used.
*/
/**
* @classdesc
* Class for layer sources providing vector data divided into a tile grid, to be
* used with {@link module:ol/layer/VectorTile~VectorTile}. Although this source receives tiles
* with vector features from the server, it is not meant for feature editing.
* Features are optimized for rendering, their geometries are clipped at or near
* tile boundaries and simplified for a view resolution. See
* {@link module:ol/source/Vector} for vector sources that are suitable for feature
* editing.
*
* @fires import("./Tile.js").TileSourceEvent
* @api
*/
class VectorTile extends UrlTile {
/**
* @param {!Options} options Vector tile options.
*/
constructor(options) {
const projection = options.projection || 'EPSG:3857';
const extent = options.extent || extentFromProjection(projection);
const tileGrid =
options.tileGrid ||
createXYZ({
extent: extent,
maxResolution: options.maxResolution,
maxZoom: options.maxZoom !== undefined ? options.maxZoom : 22,
minZoom: options.minZoom,
tileSize: options.tileSize || 512,
});
super({
attributions: options.attributions,
attributionsCollapsible: options.attributionsCollapsible,
cacheSize: options.cacheSize,
opaque: false,
projection: projection,
state: options.state,
tileGrid: tileGrid,
tileLoadFunction: options.tileLoadFunction
? options.tileLoadFunction
: defaultLoadFunction,
tileUrlFunction: options.tileUrlFunction,
url: options.url,
urls: options.urls,
wrapX: options.wrapX === undefined ? true : options.wrapX,
transition: options.transition,
zDirection: options.zDirection === undefined ? 1 : options.zDirection,
});
/**
* @private
* @type {import("../format/Feature.js").default}
*/
this.format_ = options.format ? options.format : null;
/**
* @private
* @type {TileCache}
*/
this.sourceTileCache = new TileCache(this.tileCache.highWaterMark);
/**
* @private
* @type {boolean}
*/
this.overlaps_ = options.overlaps == undefined ? true : options.overlaps;
/**
* @protected
* @type {typeof import("../VectorTile.js").default}
*/
this.tileClass = options.tileClass ? options.tileClass : Tile;
/**
* @private
* @type {Object<string, import("../tilegrid/TileGrid.js").default>}
*/
this.tileGrids_ = {};
}
/**
* Get features whose bounding box intersects the provided extent. Only features for cached
* tiles for the last rendered zoom level are available in the source. So this method is only
* suitable for requesting tiles for extents that are currently rendered.
*
* Features are returned in random tile order and as they are included in the tiles. This means
* they can be clipped, duplicated across tiles, and simplified to the render resolution.
*
* @param {import("../extent.js").Extent} extent Extent.
* @return {Array<import("../Feature.js").FeatureLike>} Features.
* @api
*/
getFeaturesInExtent(extent) {
const features = [];
const tileCache = this.tileCache;
if (tileCache.getCount() === 0) {
return features;
}
const z = fromKey(tileCache.peekFirstKey())[0];
const tileGrid = this.tileGrid;
tileCache.forEach(function (tile) {
if (tile.tileCoord[0] !== z || tile.getState() !== TileState.LOADED) {
return;
}
const sourceTiles = tile.getSourceTiles();
for (let i = 0, ii = sourceTiles.length; i < ii; ++i) {
const sourceTile = sourceTiles[i];
const tileCoord = sourceTile.tileCoord;
if (intersects(extent, tileGrid.getTileCoordExtent(tileCoord))) {
const tileFeatures = sourceTile.getFeatures();
if (tileFeatures) {
for (let j = 0, jj = tileFeatures.length; j < jj; ++j) {
const candidate = tileFeatures[j];
const geometry = candidate.getGeometry();
if (intersects(extent, geometry.getExtent())) {
features.push(candidate);
}
}
}
}
}
});
return features;
}
/**
* @return {boolean} The source can have overlapping geometries.
*/
getOverlaps() {
return this.overlaps_;
}
/**
* clear {@link module:ol/TileCache~TileCache} and delete all source tiles
* @api
*/
clear() {
this.tileCache.clear();
this.sourceTileCache.clear();
}
/**
* @param {import("../proj/Projection.js").default} projection Projection.
* @param {!Object<string, boolean>} usedTiles Used tiles.
*/
expireCache(projection, usedTiles) {
super.expireCache(projection, usedTiles);
this.sourceTileCache.expireCache({});
}
/**
* @param {number} pixelRatio Pixel ratio.
* @param {import("../proj/Projection").default} projection Projection.
* @param {VectorRenderTile} tile Vector image tile.
* @return {Array<import("../VectorTile").default>} Tile keys.
*/
getSourceTiles(pixelRatio, projection, tile) {
if (tile.getState() === TileState.IDLE) {
tile.setState(TileState.LOADING);
const urlTileCoord = tile.wrappedTileCoord;
const tileGrid = this.getTileGridForProjection(projection);
const extent = tileGrid.getTileCoordExtent(urlTileCoord);
const z = urlTileCoord[0];
const resolution = tileGrid.getResolution(z);
// make extent 1 pixel smaller so we don't load tiles for < 0.5 pixel render space
bufferExtent(extent, -resolution, extent);
const sourceTileGrid = this.tileGrid;
const sourceExtent = sourceTileGrid.getExtent();
if (sourceExtent) {
getIntersection(extent, sourceExtent, extent);
}
const sourceZ = sourceTileGrid.getZForResolution(resolution, 1);
sourceTileGrid.forEachTileCoord(extent, sourceZ, (sourceTileCoord) => {
const tileUrl = this.tileUrlFunction(
sourceTileCoord,
pixelRatio,
projection
);
const sourceTile = this.sourceTileCache.containsKey(tileUrl)
? this.sourceTileCache.get(tileUrl)
: new this.tileClass(
sourceTileCoord,
tileUrl ? TileState.IDLE : TileState.EMPTY,
tileUrl,
this.format_,
this.tileLoadFunction
);
tile.sourceTiles.push(sourceTile);
const sourceTileState = sourceTile.getState();
if (sourceTileState === TileState.IDLE) {
sourceTile.extent = sourceTileGrid.getTileCoordExtent(
sourceTileCoord
);
sourceTile.projection = projection;
sourceTile.resolution = sourceTileGrid.getResolution(
sourceTileCoord[0]
);
this.sourceTileCache.set(tileUrl, sourceTile);
const listenChange = (event) => {
this.handleTileChange(event);
const state = sourceTile.getState();
if (state === TileState.LOADED || state === TileState.ERROR) {
const sourceTileKey = sourceTile.getKey();
if (sourceTileKey in tile.errorTileKeys) {
if (sourceTile.getState() === TileState.LOADED) {
delete tile.errorTileKeys[sourceTileKey];
}
} else {
tile.loadingSourceTiles--;
}
if (state === TileState.ERROR) {
tile.errorTileKeys[sourceTileKey] = true;
} else {
sourceTile.removeEventListener(EventType.CHANGE, listenChange);
}
if (tile.loadingSourceTiles === 0) {
tile.setState(
isEmpty(tile.errorTileKeys)
? TileState.LOADED
: TileState.ERROR
);
}
}
};
sourceTile.addEventListener(EventType.CHANGE, listenChange);
tile.loadingSourceTiles++;
sourceTile.load();
}
});
if (!tile.loadingSourceTiles) {
tile.setState(
tile.sourceTiles.some(
(sourceTile) => sourceTile.getState() === TileState.ERROR
)
? TileState.ERROR
: TileState.LOADED
);
}
}
return tile.sourceTiles;
}
/**
* @param {number} z Tile coordinate z.
* @param {number} x Tile coordinate x.
* @param {number} y Tile coordinate y.
* @param {number} pixelRatio Pixel ratio.
* @param {import("../proj/Projection.js").default} projection Projection.
* @return {!VectorRenderTile} Tile.
*/
getTile(z, x, y, pixelRatio, projection) {
const coordKey = getKeyZXY(z, x, y);
const key = this.getKey();
let tile;
if (this.tileCache.containsKey(coordKey)) {
tile = this.tileCache.get(coordKey);
if (tile.key === key) {
return tile;
}
}
const tileCoord = [z, x, y];
let urlTileCoord = this.getTileCoordForTileUrlFunction(
tileCoord,
projection
);
const sourceExtent = this.getTileGrid().getExtent();
const tileGrid = this.getTileGridForProjection(projection);
if (urlTileCoord && sourceExtent) {
const tileExtent = tileGrid.getTileCoordExtent(urlTileCoord);
// make extent 1 pixel smaller so we don't load tiles for < 0.5 pixel render space
bufferExtent(tileExtent, -tileGrid.getResolution(z), tileExtent);
if (!intersects(sourceExtent, tileExtent)) {
urlTileCoord = null;
}
}
let empty = true;
if (urlTileCoord !== null) {
const sourceTileGrid = this.tileGrid;
const resolution = tileGrid.getResolution(z);
const sourceZ = sourceTileGrid.getZForResolution(resolution, 1);
// make extent 1 pixel smaller so we don't load tiles for < 0.5 pixel render space
const extent = tileGrid.getTileCoordExtent(urlTileCoord);
bufferExtent(extent, -resolution, extent);
sourceTileGrid.forEachTileCoord(
extent,
sourceZ,
function (sourceTileCoord) {
empty =
empty &&
!this.tileUrlFunction(sourceTileCoord, pixelRatio, projection);
}.bind(this)
);
}
const newTile = new VectorRenderTile(
tileCoord,
empty ? TileState.EMPTY : TileState.IDLE,
urlTileCoord,
this.getSourceTiles.bind(this, pixelRatio, projection)
);
newTile.key = key;
if (tile) {
newTile.interimTile = tile;
newTile.refreshInterimChain();
this.tileCache.replace(coordKey, newTile);
} else {
this.tileCache.set(coordKey, newTile);
}
return newTile;
}
/**
* @param {import("../proj/Projection.js").default} projection Projection.
* @return {!import("../tilegrid/TileGrid.js").default} Tile grid.
*/
getTileGridForProjection(projection) {
const code = projection.getCode();
let tileGrid = this.tileGrids_[code];
if (!tileGrid) {
// A tile grid that matches the tile size of the source tile grid is more
// likely to have 1:1 relationships between source tiles and rendered tiles.
const sourceTileGrid = this.tileGrid;
tileGrid = createForProjection(
projection,
undefined,
sourceTileGrid
? sourceTileGrid.getTileSize(sourceTileGrid.getMinZoom())
: undefined
);
this.tileGrids_[code] = tileGrid;
}
return tileGrid;
}
/**
* Get the tile pixel ratio for this source.
* @param {number} pixelRatio Pixel ratio.
* @return {number} Tile pixel ratio.
*/
getTilePixelRatio(pixelRatio) {
return pixelRatio;
}
/**
* @param {number} z Z.
* @param {number} pixelRatio Pixel ratio.
* @param {import("../proj/Projection.js").default} projection Projection.
* @return {import("../size.js").Size} Tile size.
*/
getTilePixelSize(z, pixelRatio, projection) {
const tileGrid = this.getTileGridForProjection(projection);
const tileSize = toSize(tileGrid.getTileSize(z), this.tmpSize);
return [
Math.round(tileSize[0] * pixelRatio),
Math.round(tileSize[1] * pixelRatio),
];
}
/**
* Increases the cache size if needed
* @param {number} tileCount Minimum number of tiles needed.
* @param {import("../proj/Projection.js").default} projection Projection.
*/
updateCacheSize(tileCount, projection) {
super.updateCacheSize(tileCount * 2, projection);
}
}
export default VectorTile;
/**
* Sets the loader for a tile.
* @param {import("../VectorTile.js").default} tile Vector tile.
* @param {string} url URL.
*/
export function defaultLoadFunction(tile, url) {
tile.setLoader(
/**
* @param {import("../extent.js").Extent} extent Extent.
* @param {number} resolution Resolution.
* @param {import("../proj/Projection.js").default} projection Projection.
*/
function (extent, resolution, projection) {
loadFeaturesXhr(
url,
tile.getFormat(),
extent,
resolution,
projection,
tile.onLoad.bind(tile),
tile.onError.bind(tile)
);
}
);
}