---
title: "Highlight Wave"
url: "https://sanyam.sh/lab/highlight-wave"
date: "2026-10-06"
---

# Highlight Wave

Select some text, then pick a colour.

a page of notes you can mark up. select a run of text and a palette comes up over it, and picking a colour sends a wave along the selection: each character swells, glows in that colour and settles into it while the bar fills in behind.

key insight: the bars are drawn from the mark's own line fragments in a layer under the text rather than as a background on it, so each line rounds its own ends and the bar can sweep in a line at a time behind the characters. every character holds its old colour until the wave reaches it, so recolouring a mark runs the same wave from one colour to the next.

kerning is off on the notes, so a run split into characters for the wave sets at exactly the width it had as plain text and nothing reflows when it is marked.

- Reference: https://x.com/heydamir/status/2106779932659470606
- Source: https://github.com/SanyamPunia/www/blob/main/components/labs/highlight-wave/wave.ts