464 lines
13 KiB
JavaScript
464 lines
13 KiB
JavaScript
/**
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* @module ol/control/ScaleLine
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*/
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import {getChangeEventType} from '../Object.js';
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import {assert} from '../asserts.js';
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import Control from './Control.js';
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import {CLASS_UNSELECTABLE} from '../css.js';
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import {getPointResolution, METERS_PER_UNIT} from '../proj.js';
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import ProjUnits from '../proj/Units.js';
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/**
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* @type {string}
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*/
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const UNITS_PROP = 'units';
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/**
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* Units for the scale line. Supported values are `'degrees'`, `'imperial'`,
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* `'nautical'`, `'metric'`, `'us'`.
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* @enum {string}
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*/
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export const Units = {
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DEGREES: 'degrees',
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IMPERIAL: 'imperial',
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NAUTICAL: 'nautical',
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METRIC: 'metric',
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US: 'us'
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};
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/**
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* @const
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* @type {Array<number>}
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*/
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const LEADING_DIGITS = [1, 2, 5];
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/**
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* @const
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* @type {number}
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*/
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const DEFAULT_DPI = 25.4 / 0.28;
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/**
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* @typedef {Object} Options
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* @property {string} [className='ol-scale-line'] CSS Class name.
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* @property {number} [minWidth=64] Minimum width in pixels at the OGC default dpi. The width will be
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* adjusted to match the dpi used.
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* @property {function(import("../MapEvent.js").default)} [render] Function called when the control
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* should be re-rendered. This is called in a `requestAnimationFrame` callback.
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* @property {HTMLElement|string} [target] Specify a target if you want the control
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* to be rendered outside of the map's viewport.
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* @property {Units|string} [units='metric'] Units.
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* @property {boolean} [bar=false] Render scalebars instead of a line.
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* @property {number} [steps=4] Number of steps the scalebar should use. Use even numbers
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* for best results. Only applies when `bar` is `true`.
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* @property {boolean} [text=false] Render the text scale above of the scalebar. Only applies
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* when `bar` is `true`.
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* @property {number|undefined} [dpi=undefined] dpi of output device such as printer. Only applies
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* when `bar` is `true`. If undefined the OGC default screen pixel size of 0.28mm will be assumed.
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*/
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/**
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* @classdesc
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* A control displaying rough y-axis distances, calculated for the center of the
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* viewport. For conformal projections (e.g. EPSG:3857, the default view
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* projection in OpenLayers), the scale is valid for all directions.
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* No scale line will be shown when the y-axis distance of a pixel at the
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* viewport center cannot be calculated in the view projection.
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* By default the scale line will show in the bottom left portion of the map,
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* but this can be changed by using the css selector `.ol-scale-line`.
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* When specifying `bar` as `true`, a scalebar will be rendered instead
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* of a scaleline.
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*
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* @api
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*/
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class ScaleLine extends Control {
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/**
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* @param {Options=} opt_options Scale line options.
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*/
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constructor(opt_options) {
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const options = opt_options ? opt_options : {};
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const className = options.className !== undefined ? options.className :
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options.bar ? 'ol-scale-bar' : 'ol-scale-line';
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super({
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element: document.createElement('div'),
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render: options.render || render,
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target: options.target
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});
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/**
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* @private
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* @type {HTMLElement}
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*/
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this.innerElement_ = document.createElement('div');
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this.innerElement_.className = className + '-inner';
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this.element.className = className + ' ' + CLASS_UNSELECTABLE;
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this.element.appendChild(this.innerElement_);
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/**
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* @private
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* @type {?import("../View.js").State}
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*/
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this.viewState_ = null;
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/**
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* @private
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* @type {number}
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*/
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this.minWidth_ = options.minWidth !== undefined ? options.minWidth : 64;
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/**
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* @private
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* @type {boolean}
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*/
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this.renderedVisible_ = false;
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/**
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* @private
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* @type {number|undefined}
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*/
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this.renderedWidth_ = undefined;
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/**
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* @private
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* @type {string}
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*/
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this.renderedHTML_ = '';
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this.addEventListener(getChangeEventType(UNITS_PROP), this.handleUnitsChanged_);
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this.setUnits(options.units || Units.METRIC);
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/**
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* @private
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* @type {boolean}
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*/
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this.scaleBar_ = options.bar || false;
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/**
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* @private
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* @type {number}
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*/
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this.scaleBarSteps_ = options.steps || 4;
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/**
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* @private
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* @type {boolean}
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*/
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this.scaleBarText_ = options.text || false;
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/**
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* @private
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* @type {number|undefined}
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*/
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this.dpi_ = options.dpi || undefined;
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}
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/**
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* Return the units to use in the scale line.
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* @return {Units} The units
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* to use in the scale line.
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* @observable
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* @api
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*/
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getUnits() {
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return this.get(UNITS_PROP);
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}
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/**
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* @private
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*/
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handleUnitsChanged_() {
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this.updateElement_();
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}
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/**
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* Set the units to use in the scale line.
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* @param {Units} units The units to use in the scale line.
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* @observable
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* @api
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*/
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setUnits(units) {
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this.set(UNITS_PROP, units);
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}
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/**
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* Specify the dpi of output device such as printer.
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* @param {number|undefined} dpi The dpi of output device.
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* @api
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*/
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setDpi(dpi) {
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this.dpi_ = dpi;
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}
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/**
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* @private
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*/
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updateElement_() {
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const viewState = this.viewState_;
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if (!viewState) {
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if (this.renderedVisible_) {
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this.element.style.display = 'none';
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this.renderedVisible_ = false;
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}
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return;
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}
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const center = viewState.center;
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const projection = viewState.projection;
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const units = this.getUnits();
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const pointResolutionUnits = units == Units.DEGREES ?
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ProjUnits.DEGREES :
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ProjUnits.METERS;
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let pointResolution =
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getPointResolution(projection, viewState.resolution, center, pointResolutionUnits);
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const minWidth = this.minWidth_ * (this.dpi_ || DEFAULT_DPI) / DEFAULT_DPI;
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let nominalCount = minWidth * pointResolution;
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let suffix = '';
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if (units == Units.DEGREES) {
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const metersPerDegree = METERS_PER_UNIT[ProjUnits.DEGREES];
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nominalCount *= metersPerDegree;
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if (nominalCount < metersPerDegree / 60) {
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suffix = '\u2033'; // seconds
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pointResolution *= 3600;
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} else if (nominalCount < metersPerDegree) {
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suffix = '\u2032'; // minutes
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pointResolution *= 60;
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} else {
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suffix = '\u00b0'; // degrees
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}
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} else if (units == Units.IMPERIAL) {
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if (nominalCount < 0.9144) {
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suffix = 'in';
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pointResolution /= 0.0254;
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} else if (nominalCount < 1609.344) {
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suffix = 'ft';
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pointResolution /= 0.3048;
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} else {
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suffix = 'mi';
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pointResolution /= 1609.344;
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}
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} else if (units == Units.NAUTICAL) {
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pointResolution /= 1852;
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suffix = 'nm';
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} else if (units == Units.METRIC) {
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if (nominalCount < 0.001) {
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suffix = 'μm';
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pointResolution *= 1000000;
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} else if (nominalCount < 1) {
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suffix = 'mm';
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pointResolution *= 1000;
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} else if (nominalCount < 1000) {
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suffix = 'm';
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} else {
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suffix = 'km';
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pointResolution /= 1000;
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}
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} else if (units == Units.US) {
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if (nominalCount < 0.9144) {
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suffix = 'in';
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pointResolution *= 39.37;
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} else if (nominalCount < 1609.344) {
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suffix = 'ft';
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pointResolution /= 0.30480061;
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} else {
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suffix = 'mi';
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pointResolution /= 1609.3472;
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}
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} else {
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assert(false, 33); // Invalid units
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}
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let i = 3 * Math.floor(
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Math.log(minWidth * pointResolution) / Math.log(10));
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let count, width, decimalCount;
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while (true) {
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decimalCount = Math.floor(i / 3);
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const decimal = Math.pow(10, decimalCount);
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count = LEADING_DIGITS[((i % 3) + 3) % 3] * decimal;
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width = Math.round(count / pointResolution);
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if (isNaN(width)) {
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this.element.style.display = 'none';
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this.renderedVisible_ = false;
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return;
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} else if (width >= minWidth) {
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break;
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}
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++i;
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}
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let html;
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if (this.scaleBar_) {
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html = this.createScaleBar(width, count, suffix);
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} else {
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html = count.toFixed(decimalCount < 0 ? -decimalCount : 0) + ' ' + suffix;
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}
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if (this.renderedHTML_ != html) {
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this.innerElement_.innerHTML = html;
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this.renderedHTML_ = html;
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}
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if (this.renderedWidth_ != width) {
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this.innerElement_.style.width = width + 'px';
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this.renderedWidth_ = width;
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}
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if (!this.renderedVisible_) {
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this.element.style.display = '';
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this.renderedVisible_ = true;
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}
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}
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/**
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* @private
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* @param {number} width The current width of the scalebar.
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* @param {number} scale The current scale.
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* @param {string} suffix The suffix to append to the scale text.
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* @returns {string} The stringified HTML of the scalebar.
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*/
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createScaleBar(width, scale, suffix) {
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const mapScale = '1 : ' + Math.round(this.getScaleForResolution()).toLocaleString();
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const scaleSteps = [];
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const stepWidth = width / this.scaleBarSteps_;
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let backgroundColor = '#ffffff';
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for (let i = 0; i < this.scaleBarSteps_; i++) {
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if (i === 0) {
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// create the first marker at position 0
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scaleSteps.push(this.createMarker('absolute', i));
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}
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scaleSteps.push(
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'<div>' +
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'<div ' +
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'class="ol-scale-singlebar" ' +
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'style=' +
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'"width: ' + stepWidth + 'px;' +
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'background-color: ' + backgroundColor + ';"' +
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'>' +
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'</div>' +
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this.createMarker('relative', i) +
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/*render text every second step, except when only 2 steps */
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(i % 2 === 0 || this.scaleBarSteps_ === 2 ?
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this.createStepText(i, width, false, scale, suffix) :
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''
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) +
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'</div>'
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);
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if (i === this.scaleBarSteps_ - 1) {
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{/*render text at the end */}
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scaleSteps.push(this.createStepText(i + 1, width, true, scale, suffix));
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}
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// switch colors of steps between black and white
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if (backgroundColor === '#ffffff') {
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backgroundColor = '#000000';
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} else {
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backgroundColor = '#ffffff';
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}
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}
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let scaleBarText;
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if (this.scaleBarText_) {
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scaleBarText = '<div ' +
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'class="ol-scale-text" ' +
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'style="width: ' + width + 'px;">' +
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mapScale +
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'</div>';
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} else {
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scaleBarText = '';
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}
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const container = '<div ' +
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'style="display: flex;">' +
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scaleBarText +
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scaleSteps.join('') +
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'</div>';
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return container;
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}
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/**
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* Creates a marker at given position
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* @param {string} position - The position, absolute or relative
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* @param {number} i - The iterator
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* @returns {string} The stringified div containing the marker
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*/
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createMarker(position, i) {
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const top = position === 'absolute' ? 3 : -10;
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return '<div ' +
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'class="ol-scale-step-marker" ' +
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'style="position: ' + position + ';' +
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'top: ' + top + 'px;"' +
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'></div>';
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}
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/**
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* Creates the label for a marker marker at given position
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* @param {number} i - The iterator
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* @param {number} width - The width the scalebar will currently use
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* @param {boolean} isLast - Flag indicating if we add the last step text
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* @param {number} scale - The current scale for the whole scalebar
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* @param {string} suffix - The suffix for the scale
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* @returns {string} The stringified div containing the step text
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*/
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createStepText(i, width, isLast, scale, suffix) {
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const length = i === 0 ? 0 : Math.round((scale / this.scaleBarSteps_ * i) * 100) / 100;
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const lengthString = length + (i === 0 ? '' : ' ' + suffix);
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const margin = i === 0 ? -3 : width / this.scaleBarSteps_ * -1;
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const minWidth = i === 0 ? 0 : width / this.scaleBarSteps_ * 2;
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return '<div ' +
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'class="ol-scale-step-text" ' +
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'style="' +
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'margin-left: ' + margin + 'px;' +
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'text-align: ' + (i === 0 ? 'left' : 'center') + '; ' +
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'min-width: ' + minWidth + 'px;' +
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'left: ' + (isLast ? width + 'px' : 'unset') + ';"' +
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'>' +
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lengthString +
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'</div>';
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}
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/**
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* Returns the appropriate scale for the given resolution and units.
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* @return {number} The appropriate scale.
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*/
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getScaleForResolution() {
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const resolution = getPointResolution(
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this.viewState_.projection,
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this.viewState_.resolution,
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this.viewState_.center
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);
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const dpi = this.dpi_ || DEFAULT_DPI;
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const mpu = this.viewState_.projection.getMetersPerUnit();
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const inchesPerMeter = 39.37;
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return parseFloat(resolution.toString()) * mpu * inchesPerMeter * dpi;
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}
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}
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/**
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* Update the scale line element.
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* @param {import("../MapEvent.js").default} mapEvent Map event.
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* @this {ScaleLine}
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*/
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export function render(mapEvent) {
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const frameState = mapEvent.frameState;
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if (!frameState) {
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this.viewState_ = null;
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} else {
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this.viewState_ = frameState.viewState;
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}
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this.updateElement_();
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}
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export default ScaleLine;
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