heli-agri/dist/style/IconImageCache.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/style/IconImageCache
 */
import { asString } from '../color.js';
/**
 * @classdesc
 * Singleton class. Available through {@link module:ol/style/IconImageCache.shared}.
 */
class IconImageCache {
    constructor() {
        /**
         * @type {!Object<string, import("./IconImage.js").default>}
         * @private
         */
        this.cache_ = {};
        /**
         * @type {number}
         * @private
         */
        this.cacheSize_ = 0;
        /**
         * @type {number}
         * @private
         */
        this.maxCacheSize_ = 32;
    }
    /**
     * FIXME empty description for jsdoc
     */
    clear() {
        this.cache_ = {};
        this.cacheSize_ = 0;
    }
    /**
     * @return {boolean} Can expire cache.
     */
    canExpireCache() {
        return this.cacheSize_ > this.maxCacheSize_;
    }
    /**
     * FIXME empty description for jsdoc
     */
    expire() {
        if (this.canExpireCache()) {
            let i = 0;
            for (const key in this.cache_) {
                const iconImage = this.cache_[key];
                if ((i++ & 3) === 0 && !iconImage.hasListener()) {
                    delete this.cache_[key];
                    --this.cacheSize_;
                }
            }
        }
    }
    /**
     * @param {string} src Src.
     * @param {?string} crossOrigin Cross origin.
     * @param {import("../color.js").Color} color Color.
     * @return {import("./IconImage.js").default} Icon image.
     */
    get(src, crossOrigin, color) {
        const key = getKey(src, crossOrigin, color);
        return key in this.cache_ ? this.cache_[key] : null;
    }
    /**
     * @param {string} src Src.
     * @param {?string} crossOrigin Cross origin.
     * @param {import("../color.js").Color} color Color.
     * @param {import("./IconImage.js").default} iconImage Icon image.
     */
    set(src, crossOrigin, color, iconImage) {
        const key = getKey(src, crossOrigin, color);
        this.cache_[key] = iconImage;
        ++this.cacheSize_;
    }
    /**
     * Set the cache size of the icon cache. Default is `32`. Change this value when
     * your map uses more than 32 different icon images and you are not caching icon
     * styles on the application level.
     * @param {number} maxCacheSize Cache max size.
     * @api
     */
    setSize(maxCacheSize) {
        this.maxCacheSize_ = maxCacheSize;
        this.expire();
    }
}
/**
 * @param {string} src Src.
 * @param {?string} crossOrigin Cross origin.
 * @param {import("../color.js").Color} color Color.
 * @return {string} Cache key.
 */
function getKey(src, crossOrigin, color) {
    const colorString = color ? asString(color) : 'null';
    return crossOrigin + ':' + src + ':' + colorString;
}
export default IconImageCache;
/**
 * The {@link module:ol/style/IconImageCache~IconImageCache} for
 * {@link module:ol/style/Icon~Icon} images.
 * @api
 */
export const shared = new IconImageCache();