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171 lines
5.8 KiB
171 lines
5.8 KiB
/**
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* @module ol/tilegrid
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*/
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import TileGrid from './tilegrid/TileGrid.js';
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import {DEFAULT_MAX_ZOOM, DEFAULT_TILE_SIZE} from './tilegrid/common.js';
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import {METERS_PER_UNIT, get as getProjection} from './proj.js';
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import {
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containsCoordinate,
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createOrUpdate,
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getCorner,
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getHeight,
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getWidth,
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} from './extent.js';
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import {toSize} from './size.js';
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/**
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* @param {import("./proj/Projection.js").default} projection Projection.
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* @return {!TileGrid} Default tile grid for the
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* passed projection.
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*/
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export function getForProjection(projection) {
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let tileGrid = projection.getDefaultTileGrid();
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if (!tileGrid) {
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tileGrid = createForProjection(projection);
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projection.setDefaultTileGrid(tileGrid);
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}
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return tileGrid;
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}
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/**
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* @param {TileGrid} tileGrid Tile grid.
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* @param {import("./tilecoord.js").TileCoord} tileCoord Tile coordinate.
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* @param {import("./proj/Projection.js").default} projection Projection.
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* @return {import("./tilecoord.js").TileCoord} Tile coordinate.
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*/
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export function wrapX(tileGrid, tileCoord, projection) {
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const z = tileCoord[0];
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const center = tileGrid.getTileCoordCenter(tileCoord);
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const projectionExtent = extentFromProjection(projection);
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if (!containsCoordinate(projectionExtent, center)) {
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const worldWidth = getWidth(projectionExtent);
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const worldsAway = Math.ceil(
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(projectionExtent[0] - center[0]) / worldWidth
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);
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center[0] += worldWidth * worldsAway;
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return tileGrid.getTileCoordForCoordAndZ(center, z);
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} else {
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return tileCoord;
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}
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}
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/**
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* @param {import("./extent.js").Extent} extent Extent.
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* @param {number} [maxZoom] Maximum zoom level (default is
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* DEFAULT_MAX_ZOOM).
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* @param {number|import("./size.js").Size} [tileSize] Tile size (default uses
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* DEFAULT_TILE_SIZE).
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* @param {import("./extent.js").Corner} [corner] Extent corner (default is `'top-left'`).
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* @return {!TileGrid} TileGrid instance.
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*/
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export function createForExtent(extent, maxZoom, tileSize, corner) {
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corner = corner !== undefined ? corner : 'top-left';
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const resolutions = resolutionsFromExtent(extent, maxZoom, tileSize);
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return new TileGrid({
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extent: extent,
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origin: getCorner(extent, corner),
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resolutions: resolutions,
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tileSize: tileSize,
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});
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}
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/**
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* @typedef {Object} XYZOptions
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* @property {import("./extent.js").Extent} [extent] Extent for the tile grid. The origin for an XYZ tile grid is the
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* top-left corner of the extent. If `maxResolution` is not provided the zero level of the grid is defined by the resolution
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* at which one tile fits in the provided extent. If not provided, the extent of the EPSG:3857 projection is used.
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* @property {number} [maxResolution] Resolution at level zero.
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* @property {number} [maxZoom] Maximum zoom. The default is `42`. This determines the number of levels
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* in the grid set. For example, a `maxZoom` of 21 means there are 22 levels in the grid set.
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* @property {number} [minZoom=0] Minimum zoom.
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* @property {number|import("./size.js").Size} [tileSize=[256, 256]] Tile size in pixels.
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*/
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/**
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* Creates a tile grid with a standard XYZ tiling scheme.
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* @param {XYZOptions} [options] Tile grid options.
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* @return {!TileGrid} Tile grid instance.
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* @api
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*/
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export function createXYZ(options) {
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const xyzOptions = options || {};
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const extent = xyzOptions.extent || getProjection('EPSG:3857').getExtent();
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const gridOptions = {
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extent: extent,
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minZoom: xyzOptions.minZoom,
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tileSize: xyzOptions.tileSize,
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resolutions: resolutionsFromExtent(
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extent,
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xyzOptions.maxZoom,
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xyzOptions.tileSize,
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xyzOptions.maxResolution
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),
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};
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return new TileGrid(gridOptions);
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}
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/**
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* Create a resolutions array from an extent. A zoom factor of 2 is assumed.
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* @param {import("./extent.js").Extent} extent Extent.
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* @param {number} [maxZoom] Maximum zoom level (default is
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* DEFAULT_MAX_ZOOM).
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* @param {number|import("./size.js").Size} [tileSize] Tile size (default uses
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* DEFAULT_TILE_SIZE).
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* @param {number} [maxResolution] Resolution at level zero.
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* @return {!Array<number>} Resolutions array.
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*/
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function resolutionsFromExtent(extent, maxZoom, tileSize, maxResolution) {
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maxZoom = maxZoom !== undefined ? maxZoom : DEFAULT_MAX_ZOOM;
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tileSize = toSize(tileSize !== undefined ? tileSize : DEFAULT_TILE_SIZE);
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const height = getHeight(extent);
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const width = getWidth(extent);
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maxResolution =
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maxResolution > 0
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? maxResolution
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: Math.max(width / tileSize[0], height / tileSize[1]);
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const length = maxZoom + 1;
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const resolutions = new Array(length);
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for (let z = 0; z < length; ++z) {
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resolutions[z] = maxResolution / Math.pow(2, z);
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}
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return resolutions;
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}
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/**
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* @param {import("./proj.js").ProjectionLike} projection Projection.
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* @param {number} [maxZoom] Maximum zoom level (default is
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* DEFAULT_MAX_ZOOM).
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* @param {number|import("./size.js").Size} [tileSize] Tile size (default uses
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* DEFAULT_TILE_SIZE).
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* @param {import("./extent.js").Corner} [corner] Extent corner (default is `'top-left'`).
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* @return {!TileGrid} TileGrid instance.
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*/
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export function createForProjection(projection, maxZoom, tileSize, corner) {
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const extent = extentFromProjection(projection);
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return createForExtent(extent, maxZoom, tileSize, corner);
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}
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/**
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* Generate a tile grid extent from a projection. If the projection has an
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* extent, it is used. If not, a global extent is assumed.
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* @param {import("./proj.js").ProjectionLike} projection Projection.
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* @return {import("./extent.js").Extent} Extent.
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*/
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export function extentFromProjection(projection) {
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projection = getProjection(projection);
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let extent = projection.getExtent();
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if (!extent) {
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const half =
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(180 * METERS_PER_UNIT.degrees) / projection.getMetersPerUnit();
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extent = createOrUpdate(-half, -half, half, half);
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}
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return extent;
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}
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