将 svg 显示为来自外部 url 的图像

Question

I have a Firebase storage bucket with svg files in it. The urls for each file are stored in Firestore. I am fetching the urls from firestore so I can display the svgs as images in html. I am using vanilla HTML, CSS, and JS and using UIKit for layout.

What I mean by "display the svgs as images" is:

• I want the user to be able to right click, and click "Save image as".
• I do NOT want my CSS to affect the svgs in any way.
• I do not need to manipulate the SVGs programmatically.

I am using UIKit and have tried both of their documented methods of displaying svgs:

Method 1: as an inline svg image

var source = logo.imageURL;

var div = document.createElement("div");
var img = document.createElement("img");
img.width = 160;
img.src = source;
img.setAttribute("uk-svg", "");
div.appendChild(img)
parent.appendChild(div);

This results in the ability to see the svgs on the page, but:

• You can't right click them to save them
• UIKit's CSS is affecting the colors (all fills are gray).

Method 2: lazy loading using Image component

var source = logo.imageURL;

var div = document.createElement("div");
var img = document.createElement("img");
img.width = 160;
img.src = source;
img.setAttribute("uk-img", "data-src:" + source);
img.setAttribute("uk-svg", "");
div.appendChild(img)
parent.appendChild(div);

This results in the svgs showing up as blank white squares.

Other tests I have done:

I grabbed one of the svg files and added it to my frontend /images folder and hardcoded the source variable to use the local file. The SVGs showed up fine, and met all my criteria above, so I assume there's nothing wrong with the file itself.

Any help or advice with this would be great.

Answer 1

With vanilla HTML5, if your want CSS isolation you need to place it in shadowDOM (supported in all modern browsers)

Either attach shadowDOM to your own <span> element;

Or take it one step further and create your own re-usable HTML Element <shadow-svg> (or any name you want)

Note: the SVG being an IMG src should be enough to not be affected by global CSS; so shadowDOM not strictly required. It ensures the IMG can not be styled by global CSS in this example.

 <span id=SVG></span> <shadow-svg src="https://svgshare.com/i/U7z.svg"></shadow-svg> <shadow-svg src="https://svgshare.com/i/U7o.svg"></shadow-svg> <shadow-svg src="https://svgshare.com/i/U7p.svg"></shadow-svg> <style> #SVG { height: 130px; background: pink } </style> <script> SVG.attachShadow({ mode: "open" }).innerHTML = `<style>:host{display:inline-block}img{height:130px;width:130px}</style>` + `<img src="https://svgshare.com/i/U7L.svg">`; // OR customElements.define("shadow-svg", class extends HTMLElement { constructor() { super().attachShadow({ mode: "open" }).innerHTML = `<style>:host{display:inline-block}img{height:130px;width:130px}</style>` + `<img src="${this.getAttribute("src")}">`; } }); </script>