Live: https://jeegurda.github.io/TexMetrix/
Measures font size as it's rendered in current browser using TextMetrics interface inside a canvas.
The size on the left of each line is (W px/F px) where W is the exact width of the inline element with the specifed text and F is its height. Note that changing line height does not affect inline element height. Also note that specified width is not the same as font actual bounding box width.
$ npm i
$ npm run build
$ npx serve build/ # 'serve' not included, just as an example$ npm i
$ npm run serve # runs at http://localhost:8000