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forgejo/web_src/js/markup/mermaid.js
silverwind 9ce5e092f3
Fix scroll over mermaid frame (#21925)
When starting a scroll while the mouse is over a mermaid diagram, the
scroll sometimes propagates to the iframe, preventing the parent page
from scrolling. Fix this by disabling scroll inside the iframe. This is
not a problem because those frames are never meant to scroll. Bug seems
to affect Firefox only.


![scroll](https://user-images.githubusercontent.com/115237/203847578-6831e3c8-9df4-4577-8501-822fb9ea1278.gif)
2022-11-24 20:56:57 +00:00

67 lines
2.3 KiB
JavaScript

import {isDarkTheme} from '../utils.js';
const {mermaidMaxSourceCharacters} = window.config;
const iframeCss = `
:root {color-scheme: normal}
body {margin: 0; padding: 0; overflow: hidden}
#mermaid {display: block; margin: 0 auto}
`;
function displayError(el, err) {
el.closest('pre').classList.remove('is-loading');
const errorNode = document.createElement('div');
errorNode.setAttribute('class', 'ui message error markup-block-error mono');
errorNode.textContent = err.str || err.message || String(err);
el.closest('pre').before(errorNode);
}
export async function renderMermaid() {
const els = document.querySelectorAll('.markup code.language-mermaid');
if (!els.length) return;
const {default: mermaid} = await import(/* webpackChunkName: "mermaid" */'mermaid');
mermaid.initialize({
startOnLoad: false,
theme: isDarkTheme() ? 'dark' : 'neutral',
securityLevel: 'strict',
});
for (const el of els) {
const source = el.textContent;
if (mermaidMaxSourceCharacters >= 0 && source.length > mermaidMaxSourceCharacters) {
displayError(el, new Error(`Mermaid source of ${source.length} characters exceeds the maximum allowed length of ${mermaidMaxSourceCharacters}.`));
continue;
}
let valid;
try {
valid = mermaid.parse(source);
} catch (err) {
displayError(el, err);
}
if (!valid) {
el.closest('pre').classList.remove('is-loading');
continue;
}
try {
// can't use bindFunctions here because we can't cross the iframe boundary. This
// means js-based interactions won't work but they aren't intended to work either
mermaid.mermaidAPI.render('mermaid', source, (svgStr) => {
const heightStr = (svgStr.match(/viewBox="(.+?)"/) || ['', ''])[1].split(/\s+/)[3];
if (!heightStr) return displayError(el, new Error('Could not determine chart height'));
const iframe = document.createElement('iframe');
iframe.classList.add('markup-render');
iframe.sandbox = 'allow-scripts';
iframe.style.height = `${Math.ceil(parseFloat(heightStr))}px`;
iframe.srcdoc = `<html><head><style>${iframeCss}</style></head><body>${svgStr}</body></html>`;
el.closest('pre').replaceWith(iframe);
});
} catch (err) {
displayError(el, err);
}
}
}