|
import LRU from '../../core/LRU';
|
import { platformApi } from '../../core/platform';
|
import { ImageLike } from '../../core/types';
|
|
const globalImageCache = new LRU<CachedImageObj>(50);
|
|
type PendingWrap = {
|
hostEl: {dirty: () => void}
|
cb: (image: ImageLike, payload: any) => void
|
cbPayload: any
|
}
|
|
type CachedImageObj = {
|
image: ImageLike
|
pending: PendingWrap[]
|
}
|
|
export function findExistImage(newImageOrSrc: string | ImageLike): ImageLike {
|
if (typeof newImageOrSrc === 'string') {
|
const cachedImgObj = globalImageCache.get(newImageOrSrc);
|
return cachedImgObj && cachedImgObj.image;
|
}
|
else {
|
return newImageOrSrc;
|
}
|
}
|
|
/**
|
* Caution: User should cache loaded images, but not just count on LRU.
|
* Consider if required images more than LRU size, will dead loop occur?
|
*
|
* @param newImageOrSrc
|
* @param image Existent image.
|
* @param hostEl For calling `dirty`.
|
* @param onload params: (image, cbPayload)
|
* @param cbPayload Payload on cb calling.
|
* @return image
|
*/
|
export function createOrUpdateImage<T>(
|
newImageOrSrc: string | ImageLike,
|
image: ImageLike,
|
hostEl: { dirty: () => void },
|
onload?: (image: ImageLike, payload: T) => void,
|
cbPayload?: T
|
) {
|
if (!newImageOrSrc) {
|
return image;
|
}
|
else if (typeof newImageOrSrc === 'string') {
|
|
// Image should not be loaded repeatly.
|
if ((image && (image as any).__zrImageSrc === newImageOrSrc) || !hostEl) {
|
return image;
|
}
|
|
// Only when there is no existent image or existent image src
|
// is different, this method is responsible for load.
|
const cachedImgObj = globalImageCache.get(newImageOrSrc);
|
|
const 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 as any).__zrImageSrc = newImageOrSrc;
|
|
globalImageCache.put(
|
newImageOrSrc,
|
(image as any).__cachedImgObj = {
|
image: image,
|
pending: [pendingWrap]
|
}
|
);
|
}
|
|
return image;
|
}
|
// newImageOrSrc is an HTMLImageElement or HTMLCanvasElement or Canvas
|
else {
|
return newImageOrSrc;
|
}
|
}
|
|
function imageOnLoad(this: any) {
|
const cachedImgObj = this.__cachedImgObj;
|
this.onload = this.onerror = this.__cachedImgObj = null;
|
|
for (let i = 0; i < cachedImgObj.pending.length; i++) {
|
const pendingWrap = cachedImgObj.pending[i];
|
const cb = pendingWrap.cb;
|
cb && cb(this, pendingWrap.cbPayload);
|
pendingWrap.hostEl.dirty();
|
}
|
cachedImgObj.pending.length = 0;
|
}
|
|
export function isImageReady(image: ImageLike) {
|
return image && image.width && image.height;
|
}
|
