我正在尝试在网络工作者中运行此打字稿代码:
async BuildImage(): Promise<void> {
let data1 = `<svg xmlns='http://www.w3.org/2000/svg' width='50' height='50'>
<foreignObject width='100%' height='100%' style="background:blue">
<div xmlns='http://www.w3.org/1999/xhtml' style='font-size:12px'>
<ellipse cx="23" cy="23" rx="25" ry="25" style="fill:yellow;stroke:purple;stroke-width:2" />
</div>
</foreignObject>
</svg>`;
let svg = new Blob([data1], { type: "image/svg+xml;charset=utf-8" });
var image = await createImageBitmap(svg);
}
但是用"The source image could not be decoded."
抛出"InvalidStateError"
我也尝试过此代码:
async BuildImage(): Promise<void> {
let data1 = `<svg xmlns='http://www.w3.org/2000/svg' width='50' height='50'>
<foreignObject width='100%' height='100%' style="background:blue">
<div xmlns='http://www.w3.org/1999/xhtml' style='font-size:12px'>
<ellipse cx="23" cy="23" rx="25" ry="25" style="fill:yellow;stroke:purple;stroke-width:2" />
</div>
</foreignObject>
</svg>`;
let svg = new Blob([data1], { type: "image/svg+xml;charset=utf-8" });
let url = URL.createObjectURL(svg);
var loadImageAsync = new Promise<HTMLImageElement>(resolve => {
let img = new Image();
img.onload = () => resolve(img);
img.onerror = () => resolve(img);
img.src = url;
});
this.image = await loadImageAsync;}
但是现在的问题是new Image()
对象没有在Web工作者中定义,因为它无权访问DOM。但是,这最后一种方法在非网络工作者的情况下可用,但是createImageBitmap在任何地方都无法使用。
任何人都知道如何在Web-Worker中使用SVG进行构建和映像,或针对这种情况的任何解决方法?
谢谢
由于他们尚未执行该规范,
目前一种可能的解决方法是从主线程中的svg字符串生成图像,然后将生成的图像位图发布回给工作人员。
所以在您的主线程代码中
// Loads the SVG image asynchronously
function loadSVGAsync(svgString)
return new Promise(resolve => {
const img = new Image();
img.onload = function () {
resolve(this);
};
img.src = 'data:image/svg+xml;charset=utf8,' + encodeURIComponent(svgString);
});
}
const worker = new Worker('...');
worker.addEventListener('message', async ev => {
const YourSvgString = '...';
const img = await loadSVGAsync(YourSvgString);
// Pass over the image Bit map to your worker
worker.postMessage({svg: await createImageBitMap(img)});
});
在你的工人中
self.addEventListener('message', (ev) => {
// Do whatever you need with the image
const svgImage = ev.data.svg;
});