heli-agri/lib/source/DataTile.js

HeliAgri is a high-performance, feature-packed library for creating interactive maps on the web. It can display map tiles, vector data and markers loaded from any source on any web page. OpenLayers has been developed to further the use of geographic infor

/**
 * @module ol/source/DataTile
 */
import DataTile from '../DataTile.js';
import EventType from '../events/EventType.js';
import ReprojDataTile from '../reproj/DataTile.js';
import TileCache from '../TileCache.js';
import TileEventType from './TileEventType.js';
import TileSource, {TileSourceEvent} from './Tile.js';
import TileState from '../TileState.js';
import {
  createXYZ,
  extentFromProjection,
  getForProjection as getTileGridForProjection,
} from '../tilegrid.js';
import {equivalent, get as getProjection} from '../proj.js';
import {getKeyZXY} from '../tilecoord.js';
import {getUid} from '../util.js';
import {toPromise} from '../functions.js';
import {toSize} from '../size.js';

/**
 * Data tile loading function.  The function is called with z, x, and y tile coordinates and
 * returns {@link import("../DataTile.js").Data data} for a tile or a promise for the same.
 * @typedef {function(number, number, number) : (import("../DataTile.js").Data|Promise<import("../DataTile.js").Data>)} Loader
 */

/**
 * @typedef {Object} Options
 * @property {Loader} [loader] Data loader.  Called with z, x, and y tile coordinates.
 * Returns {@link import("../DataTile.js").Data data} for a tile or a promise for the same.
 * For loaders that generate images, the promise should not resolve until the image is loaded.
 * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
 * @property {boolean} [attributionsCollapsible=true] Attributions are collapsible.
 * @property {number} [maxZoom=42] Optional max zoom level. Not used if `tileGrid` is provided.
 * @property {number} [minZoom=0] Optional min zoom level. Not used if `tileGrid` is provided.
 * @property {number|import("../size.js").Size} [tileSize=[256, 256]] The pixel width and height of the source tiles.
 * This may be different than the rendered pixel size if a `tileGrid` is provided.
 * @property {number} [gutter=0] The size in pixels of the gutter around data tiles to ignore.
 * This allows artifacts of rendering at tile edges to be ignored.
 * Supported data should be wider and taller than the tile size by a value of `2 x gutter`.
 * @property {number} [maxResolution] Optional tile grid resolution at level zero. Not used if `tileGrid` is provided.
 * @property {import("../proj.js").ProjectionLike} [projection='EPSG:3857'] Tile projection.
 * @property {import("../tilegrid/TileGrid.js").default} [tileGrid] Tile grid.
 * @property {boolean} [opaque=false] Whether the layer is opaque.
 * @property {import("./Source.js").State} [state] The source state.
 * @property {boolean} [wrapX=false] Render tiles beyond the antimeridian.
 * @property {number} [transition] Transition time when fading in new tiles (in milliseconds).
 * @property {number} [bandCount=4] Number of bands represented in the data.
 * @property {boolean} [interpolate=false] Use interpolated values when resampling.  By default,
 * the nearest neighbor is used when resampling.
 */

/**
 * @classdesc
 * A source for typed array data tiles.
 *
 * @fires import("./Tile.js").TileSourceEvent
 * @api
 */
class DataTileSource extends TileSource {
  /**
   * @param {Options} options DataTile source options.
   */
  constructor(options) {
    const projection =
      options.projection === undefined ? 'EPSG:3857' : options.projection;

    let tileGrid = options.tileGrid;
    if (tileGrid === undefined && projection) {
      tileGrid = createXYZ({
        extent: extentFromProjection(projection),
        maxResolution: options.maxResolution,
        maxZoom: options.maxZoom,
        minZoom: options.minZoom,
        tileSize: options.tileSize,
      });
    }

    super({
      cacheSize: 0.1, // don't cache on the source
      attributions: options.attributions,
      attributionsCollapsible: options.attributionsCollapsible,
      projection: projection,
      tileGrid: tileGrid,
      opaque: options.opaque,
      state: options.state,
      wrapX: options.wrapX,
      transition: options.transition,
      interpolate: options.interpolate,
    });

    /**
     * @private
     * @type {number}
     */
    this.gutter_ = options.gutter !== undefined ? options.gutter : 0;

    /**
     * @private
     * @type {import('../size.js').Size|null}
     */
    this.tileSize_ = options.tileSize ? toSize(options.tileSize) : null;

    /**
     * @private
     * @type {Array<import('../size.js').Size>|null}
     */
    this.tileSizes_ = null;

    /**
     * @private
     * @type {!Object<string, boolean>}
     */
    this.tileLoadingKeys_ = {};

    /**
     * @private
     */
    this.loader_ = options.loader;

    this.handleTileChange_ = this.handleTileChange_.bind(this);

    /**
     * @type {number}
     */
    this.bandCount = options.bandCount === undefined ? 4 : options.bandCount; // assume RGBA if undefined

    /**
     * @private
     * @type {!Object<string, import("../tilegrid/TileGrid.js").default>}
     */
    this.tileGridForProjection_ = {};

    /**
     * @private
     * @type {!Object<string, import("../TileCache.js").default>}
     */
    this.tileCacheForProjection_ = {};
  }

  /**
   * Set the source tile sizes.  The length of the array is expected to match the number of
   * levels in the tile grid.
   * @protected
   * @param {Array<import('../size.js').Size>} tileSizes An array of tile sizes.
   */
  setTileSizes(tileSizes) {
    this.tileSizes_ = tileSizes;
  }

  /**
   * Get the source tile size at the given zoom level.  This may be different than the rendered tile
   * size.
   * @protected
   * @param {number} z Tile zoom level.
   * @return {import('../size.js').Size} The source tile size.
   */
  getTileSize(z) {
    if (this.tileSizes_) {
      return this.tileSizes_[z];
    }
    if (this.tileSize_) {
      return this.tileSize_;
    }
    const tileGrid = this.getTileGrid();
    return tileGrid ? toSize(tileGrid.getTileSize(z)) : [256, 256];
  }

  /**
   * @param {import("../proj/Projection.js").default} projection Projection.
   * @return {number} Gutter.
   */
  getGutterForProjection(projection) {
    const thisProj = this.getProjection();
    if (!thisProj || equivalent(thisProj, projection)) {
      return this.gutter_;
    }

    return 0;
  }

  /**
   * @param {Loader} loader The data loader.
   * @protected
   */
  setLoader(loader) {
    this.loader_ = loader;
  }

  /**
   * @param {number} z Tile coordinate z.
   * @param {number} x Tile coordinate x.
   * @param {number} y Tile coordinate y.
   * @param {import("../proj/Projection.js").default} targetProj The output projection.
   * @param {import("../proj/Projection.js").default} sourceProj The input projection.
   * @return {!DataTile} Tile.
   */
  getReprojTile_(z, x, y, targetProj, sourceProj) {
    const cache = this.getTileCacheForProjection(targetProj);
    const tileCoordKey = getKeyZXY(z, x, y);
    if (cache.containsKey(tileCoordKey)) {
      const tile = cache.get(tileCoordKey);
      if (tile && tile.key == this.getKey()) {
        return tile;
      }
    }

    const tileGrid = this.getTileGrid();
    const reprojTilePixelRatio = Math.max.apply(
      null,
      tileGrid.getResolutions().map((r, z) => {
        const tileSize = toSize(tileGrid.getTileSize(z));
        const textureSize = this.getTileSize(z);
        return Math.max(
          textureSize[0] / tileSize[0],
          textureSize[1] / tileSize[1]
        );
      })
    );

    const sourceTileGrid = this.getTileGridForProjection(sourceProj);
    const targetTileGrid = this.getTileGridForProjection(targetProj);
    const tileCoord = [z, x, y];
    const wrappedTileCoord = this.getTileCoordForTileUrlFunction(
      tileCoord,
      targetProj
    );

    const options = Object.assign(
      {
        sourceProj,
        sourceTileGrid,
        targetProj,
        targetTileGrid,
        tileCoord,
        wrappedTileCoord,
        pixelRatio: reprojTilePixelRatio,
        gutter: this.getGutterForProjection(sourceProj),
        getTileFunction: (z, x, y, pixelRatio) =>
          this.getTile(z, x, y, pixelRatio, sourceProj),
      },
      this.tileOptions
    );
    const newTile = new ReprojDataTile(options);
    newTile.key = this.getKey();
    return newTile;
  }

  /**
   * @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 {!DataTile} Tile.
   */
  getTile(z, x, y, pixelRatio, projection) {
    const sourceProjection = this.getProjection();
    if (
      sourceProjection &&
      projection &&
      !equivalent(sourceProjection, projection)
    ) {
      return this.getReprojTile_(z, x, y, projection, sourceProjection);
    }

    const size = this.getTileSize(z);
    const tileCoordKey = getKeyZXY(z, x, y);
    if (this.tileCache.containsKey(tileCoordKey)) {
      return this.tileCache.get(tileCoordKey);
    }

    const sourceLoader = this.loader_;

    function loader() {
      return toPromise(function () {
        return sourceLoader(z, x, y);
      });
    }

    const options = Object.assign(
      {
        tileCoord: [z, x, y],
        loader: loader,
        size: size,
      },
      this.tileOptions
    );

    const tile = new DataTile(options);
    tile.key = this.getKey();
    tile.addEventListener(EventType.CHANGE, this.handleTileChange_);

    this.tileCache.set(tileCoordKey, tile);
    return tile;
  }

  /**
   * Handle tile change events.
   * @param {import("../events/Event.js").default} event Event.
   */
  handleTileChange_(event) {
    const tile = /** @type {import("../Tile.js").default} */ (event.target);
    const uid = getUid(tile);
    const tileState = tile.getState();
    let type;
    if (tileState == TileState.LOADING) {
      this.tileLoadingKeys_[uid] = true;
      type = TileEventType.TILELOADSTART;
    } else if (uid in this.tileLoadingKeys_) {
      delete this.tileLoadingKeys_[uid];
      type =
        tileState == TileState.ERROR
          ? TileEventType.TILELOADERROR
          : tileState == TileState.LOADED
          ? TileEventType.TILELOADEND
          : undefined;
    }
    if (type) {
      this.dispatchEvent(new TileSourceEvent(type, tile));
    }
  }

  /**
   * @param {import("../proj/Projection.js").default} projection Projection.
   * @return {!import("../tilegrid/TileGrid.js").default} Tile grid.
   */
  getTileGridForProjection(projection) {
    const thisProj = this.getProjection();
    if (this.tileGrid && (!thisProj || equivalent(thisProj, projection))) {
      return this.tileGrid;
    }

    const projKey = getUid(projection);
    if (!(projKey in this.tileGridForProjection_)) {
      this.tileGridForProjection_[projKey] =
        getTileGridForProjection(projection);
    }
    return this.tileGridForProjection_[projKey];
  }

  /**
   * Sets the tile grid to use when reprojecting the tiles to the given
   * projection instead of the default tile grid for the projection.
   *
   * This can be useful when the default tile grid cannot be created
   * (e.g. projection has no extent defined) or
   * for optimization reasons (custom tile size, resolutions, ...).
   *
   * @param {import("../proj.js").ProjectionLike} projection Projection.
   * @param {import("../tilegrid/TileGrid.js").default} tilegrid Tile grid to use for the projection.
   * @api
   */
  setTileGridForProjection(projection, tilegrid) {
    const proj = getProjection(projection);
    if (proj) {
      const projKey = getUid(proj);
      if (!(projKey in this.tileGridForProjection_)) {
        this.tileGridForProjection_[projKey] = tilegrid;
      }
    }
  }

  /**
   * @param {import("../proj/Projection.js").default} projection Projection.
   * @return {import("../TileCache.js").default} Tile cache.
   */
  getTileCacheForProjection(projection) {
    const thisProj = this.getProjection();
    if (!thisProj || equivalent(thisProj, projection)) {
      return this.tileCache;
    }

    const projKey = getUid(projection);
    if (!(projKey in this.tileCacheForProjection_)) {
      this.tileCacheForProjection_[projKey] = new TileCache(0.1); // don't cache
    }
    return this.tileCacheForProjection_[projKey];
  }

  /**
   * @param {import("../proj/Projection.js").default} projection Projection.
   * @param {!Object<string, boolean>} usedTiles Used tiles.
   */
  expireCache(projection, usedTiles) {
    const usedTileCache = this.getTileCacheForProjection(projection);

    this.tileCache.expireCache(
      this.tileCache == usedTileCache ? usedTiles : {}
    );
    for (const id in this.tileCacheForProjection_) {
      const tileCache = this.tileCacheForProjection_[id];
      tileCache.expireCache(tileCache == usedTileCache ? usedTiles : {});
    }
  }

  clear() {
    super.clear();
    for (const id in this.tileCacheForProjection_) {
      this.tileCacheForProjection_[id].clear();
    }
  }
}

export default DataTileSource;