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Pushing the boundary of browser typography rendering!

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Statistics on underlineJS

Number of watchers on Github 1954
Number of open issues 22
Average time to close an issue 5 days
Main language JavaScript
Average time to merge a PR about 1 hour
Open pull requests 3+
Closed pull requests 0+
Last commit over 4 years ago
Repo Created about 5 years ago
Repo Last Updated almost 2 years ago
Size 9.12 MB
Homepage http://underlinej...
Organization / Authorwentin
Page Updated
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A javascript library that sets out to do one simple job: draw and animate the most perfect and playful text underline


The project is currently under development.

If you have 8 minutes and want to know what is the story behind creating underline.js, you can hear all about it in this NY Tech Meetup presentation video


Underline.js has following features:

  1. It doesn't have ghost pixels. It is not just pixel perfect, but also pixel perfect on half pixel level for retina display pixel-perfect
  2. It has an optimized thin stroke-width. It is always 1/6 of width of the period mark. optimal-stroke-width
  3. It sits on the optimal Y position between the baseline and descender line, that optimal Y positon is the golden ratio point. golden-ratio
  4. It has holes around descenders. Completely respect the type's shape. If you ask, the size of the holes are also optimized to the perfection. descender-holes

CSS4 Proposal to W3C

Underline.js is not designed to be the most useful javascript library. It is more exploratory, and it is trying to push the boundary of web typography. I want to propose these new css rules to W3C for css4 edition:

text-underline-color: #000000;
// auto means the same color as the text color, or hex value

text-underline-position: auto;
// could be ratio or px or auto

text-underline-skip: true;
// true to set holes around descenders, false to turn it off

text-underline-width: auto;
// could be auto or px or ratio

text-underline-animation: true
// true or false, this one is only for underline.js


Marcin Wichary's article on crafting's underline

Mentions (thank you!)

Tweets article

codrops collective Note: underline.js doesn't have dependency on jquery Parsons Alumni news us8


underlineJS open issues Ask a question     (View All Issues)
  • about 4 years Status of project
  • over 4 years Instructions?
  • over 4 years Line flickering and disappearing on Chrome 43 (Windows and MacOS)
  • about 5 years Demo doesn't recalculate on window.resize events, looks janky
  • about 5 years text-underline-width
  • about 5 years Bower?
  • about 5 years Bad rendering in firefox 35.0.1
  • about 5 years a library to return ascender line, descender line and baseline posY
  • about 5 years display:block element filltext position y offset issue
  • about 5 years golden radio on the optimized distance
  • about 5 years investigate html2canvas
  • about 5 years explore SVG as an option
  • about 5 years data viz option
  • about 5 years find a way to calculate accurately of baseline, ascender/descender line's posy
  • about 5 years roll back to default if browser not support
  • about 5 years refresh the canvas when layout changes
  • about 5 years When using "Qeicigndis" at h1
  • about 5 years half pixel, retina display support
underlineJS open pull requests (View All Pulls)
  • Fix baselineRatio calculation when break-word word-wrap
  • Update
  • accept ele color as underline color
underlineJS list of languages used
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