[bug] remote icons do not load in rasterized .png images

[nberlette]

Describe the Bug

The custom iconUrl parameter appears to be broken. In actuality, it functions fine when rendering an .svg, but displays nothing when requesting the same image as a .png. This is a major problem is PNG is by far the most popular file type.

There's a high likelihood of this being a problem with resvg_wasm rendering foreign objects / external image URLs. Maybe we can bypass this by encoding the image as a base64 datauri?

PR's welcome.

Expected Behavior

Instead of using the standard icon parameter, which is limited to the Iconify syntax of {collection-name}:{icon-identifier}, users are supposed to be able to provide a fully-resolved URL with the iconUrl parameter, overriding the former to display their custom icon instead.

Reproduction

These are the same exact image URL's, except for the extensions - .svg and .png. Notice the .svg renders fine, with the Apple Emoji T-Rex icon displaying as intended.

SVG: https://migo.deno.dev/image.svg?title=deno911%E2%81%84+kit&subtitle=deno+module+starter+template&titleFontFamily=serif&titleFontSize=72&titleFontWeight=900&titleTextAnchor=left&titleX=160&titleY=110&subtitleFontSize=36&subtitleFontWeight=900&subtitleFontFamily=monospace&subtitleTextAnchor=left&subtitleX=40&subtitleY=250&pxRatio=1.5&width=1000&height=300&bgColor=111827&titleColor=fff&subtitleColor=ddd&iconW=100&iconH=100&iconX=40&iconY=30&borderRadius=10&iconUrl=https://emoji.aranja.com/static/emoji-data/img-apple-160/1f996.png

The png, however.... no dice.

PNG: https://migo.deno.dev/image.png?title=deno911%E2%81%84+kit&subtitle=deno+module+starter+template&titleFontFamily=serif&titleFontSize=72&titleFontWeight=900&titleTextAnchor=left&titleX=160&titleY=110&subtitleFontSize=36&subtitleFontWeight=900&subtitleFontFamily=monospace&subtitleTextAnchor=left&subtitleX=40&subtitleY=250&pxRatio=1.5&width=1000&height=300&bgColor=111827&titleColor=fff&subtitleColor=ddd&iconW=100&iconH=100&iconX=40&iconY=30&borderRadius=10&iconUrl=https://emoji.aranja.com/static/emoji-data/img-apple-160/1f996.png

Screenshots

SVG

PNG