Overview
Signature illusions trace a handwritten path via stroke-dasharray + stroke-dashoffset animation, with timing curves that mimic the cadence of a real pen (slow at loops, fast between letters). The path is hand-authored once; the timing does the personality.
When to use it
Reach for signature illusions on contract-signing surfaces, author by-lines, hero brand marks, anything where a personal handwritten signal carries weight. Skip it for utility chrome and for branding where the “signature” is actually typed; the draw illusion will read as theatrical.
How it works
The SVG path defining the signature has stroke-dasharray set to its pathLength (a custom attribute) so the dash unit becomes pathLength itself — portable across any actual path geometry. Animate stroke-dashoffset from pathLength down to 0 over the sequence duration. The personality comes from a non-linear timing function: use a multi-stop cubic-bezier that decelerates on the slow loops and accelerates on connecting strokes. For a truly hand-paced effect, split the signature into multiple path segments and chain them with animation-delay.
Production gotchas
Hand-authored signature paths often have hidden lift points (gaps where the pen stops); these render as unnatural pauses without a manual animation-delay between segments. If the signature is one continuous path, you lose the pen-lift rhythm entirely — structure the artwork as multiple<path> elements from the start. Some SVG export tools (Figma, Illustrator) merge paths on export; double-check the SVG source for separate <path> elements before wiring delays.
Accessibility
The signature is decorative — provide an <title> or aria-label on the SVG with the actual name being “signed” (e.g. “Jane Doe”) so screen readers announce who it represents. Under prefers-reduced-motion: reduce reveal the full signature instantly (set stroke-dashoffset: 0) so the brand mark appears without motion. The signature stroke color must meet at least 3:1 contrast against its surface.
References
Implementation depth
A signature reveal is convincing when the path direction matches the way handwriting would actually move. stroke-dashoffset can only hide or reveal along the path; it cannot fix a path authored in the wrong direction.
Use easing sparingly. Real signatures accelerate through simple strokes and slow near corners, but too much spring motion makes the line look like an icon trace rather than handwriting. Reduced motion should show the signed result.