Skip to content

fix(Shuffle): clip wrapper is shorter than the glyph, cutting descenders - #1051

Open
Baltsar wants to merge 1 commit into
DavidHDev:mainfrom
Baltsar:fix/shuffle-mask-clips-descenders
Open

fix(Shuffle): clip wrapper is shorter than the glyph, cutting descenders#1051
Baltsar wants to merge 1 commit into
DavidHDev:mainfrom
Baltsar:fix/shuffle-mask-clips-descenders

Conversation

@Baltsar

@Baltsar Baltsar commented Aug 22, 2026

Copy link
Copy Markdown

The problem

Shuffle.jsx sizes the clip wrapper from the character box:

const h = ch.getBoundingClientRect().height;
// ...
height: shuffleDirection === 'up' || shuffleDirection === 'down' ? h + 'px' : 'auto',

and Shuffle.css pins that box with .shuffle-char { line-height: 1 }.

Every typeface has a content area taller than 1em, so the overflow: hidden wrapper ends up shorter than the glyph it is meant to mask, and the bottom of g j p q y is cut off.

Measured in the browser at font-size: 64px, wrapper clientHeight vs scrollHeight:

Font Clip box Content Cut off
Outfit 64px 72px 8px
Playfair Display 64px 75px 11px
Poppins 64px 77px 13px

It does not show up in the demo because the default face is Press Start 2P with text-transform: uppercase, and uppercase Latin has no descenders. It appears as soon as someone changes the font or drops the uppercase — which is the normal thing to do with a copy-paste component.

The fix

Give the character its own line-height: normal, which resolves to the font's ascent + descent, so the wrapper is sized correctly per face. Line spacing stays where it was, on .shuffle-parent.

  • content/ and ts-default/: .shuffle-char { line-height: normal }
  • tailwind/ and ts-tailwind/: those variants ship no stylesheet, so the char inherits leading-none from the parent. Added leading-normal to charsClass instead.

After, same measurement:

Font Clip box Content Cut off
Outfit 81px 81px 0
Playfair Display 85px 85px 0
Poppins 96px 96px 0

Trade-off you should weigh

This makes the boxes taller. At 64px, Outfit goes 64 → 81px and Poppins 64 → 96px. line-height: normal includes the font's line gap, so it is a little more generous than strictly required. That changes the vertical rhythm for anyone already using the component, which is a real cost even though the current rendering is wrong.

If you would rather keep the tight rhythm, the exact alternative is to size the wrapper from the real metrics instead of the char box:

const m = ctx.measureText(ch.textContent);
const h = m.fontBoundingBoxAscent + m.fontBoundingBoxDescent;

That gives the minimum correct height with no line-gap slack, at the cost of a canvas measurement per face. Happy to switch this PR to that version if you prefer it — or to close it if you would rather solve it your own way.

I did not touch public/r/*.json, since those are jsrepo build output.

How this was found, honestly

This is an AI-assisted contribution. I was building something similar — a masked text-animation generator — and hit exactly this class of bug in my own code: the mask box has to be derived from font metrics, not from a fixed line-height, or descenders get clipped the moment the typeface changes. While working through it with Claude I went looking for whether the same assumption existed elsewhere, found it here, and verified it in the browser.

Everything above is measured, not inferred. But two caveats worth stating plainly: I have not run your visual regression setup or checked the Shuffle demo page after the change, and I have not tested the left/right shuffle directions where the wrapper height is auto and the bug does not apply. Treat the numbers as solid and the visual sign-off as still owed.

The clip wrapper is sized from the char box (Shuffle.jsx: `ch.getBoundingClientRect().height`),
and `.shuffle-char` pins that box to `line-height: 1`. Every typeface has a
content area taller than 1em, so the mask is shorter than the glyph and the
bottom of g/j/p/q/y is cut off.

Measured at font-size 64px, clip box vs content:
  Outfit             64px vs 72px  ->  8px cut
  Playfair Display   64px vs 75px  -> 11px cut
  Poppins            64px vs 77px  -> 13px cut

Invisible in the demo because the default face is Press Start 2P with
text-transform: uppercase, and uppercase Latin has no descenders.

Setting the char's own line-height to `normal` resolves it to the font's
ascent + descent, so the wrapper is sized correctly per face. Line spacing
stays with .shuffle-parent.
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

1 participant