逐步完成前后端服务器

frontend/node_modules/zrender/lib/graphic/helper/image.js

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+import LRU from '../../core/LRU.js';
+import { platformApi } from '../../core/platform.js';
+var globalImageCache = new LRU(50);
+export function findExistImage(newImageOrSrc) {
+    if (typeof newImageOrSrc === 'string') {
+        var cachedImgObj = globalImageCache.get(newImageOrSrc);
+        return cachedImgObj && cachedImgObj.image;
+    }
+    else {
+        return newImageOrSrc;
+    }
+}
+export function createOrUpdateImage(newImageOrSrc, image, hostEl, onload, cbPayload) {
+    if (!newImageOrSrc) {
+        return image;
+    }
+    else if (typeof newImageOrSrc === 'string') {
+        if ((image && image.__zrImageSrc === newImageOrSrc) || !hostEl) {
+            return image;
+        }
+        var cachedImgObj = globalImageCache.get(newImageOrSrc);
+        var pendingWrap = { hostEl: hostEl, cb: onload, cbPayload: cbPayload };
+        if (cachedImgObj) {
+            image = cachedImgObj.image;
+            !isImageReady(image) && cachedImgObj.pending.push(pendingWrap);
+        }
+        else {
+            image = platformApi.loadImage(newImageOrSrc, imageOnLoad, imageOnLoad);
+            image.__zrImageSrc = newImageOrSrc;
+            globalImageCache.put(newImageOrSrc, image.__cachedImgObj = {
+                image: image,
+                pending: [pendingWrap]
+            });
+        }
+        return image;
+    }
+    else {
+        return newImageOrSrc;
+    }
+}
+function imageOnLoad() {
+    var cachedImgObj = this.__cachedImgObj;
+    this.onload = this.onerror = this.__cachedImgObj = null;
+    for (var i = 0; i < cachedImgObj.pending.length; i++) {
+        var pendingWrap = cachedImgObj.pending[i];
+        var cb = pendingWrap.cb;
+        cb && cb(this, pendingWrap.cbPayload);
+        pendingWrap.hostEl.dirty();
+    }
+    cachedImgObj.pending.length = 0;
+}
+export function isImageReady(image) {
+    return image && image.width && image.height;
+}