My personal website
renderg.host
1import plugin from 'tailwindcss/plugin';
2
3/**
4 * Utility syntax (arbitrary values):
5 *
6 * - Font-size: fluid-[minPx_maxPx@vwMinPx_vwMaxPx] e.g. fluid-[28_88@360_1200]
7 * - Line-height (optional): fluid-lh-[minMax@vwMin_vwMax] values are plain numbers (unitless), e.g.
8 * fluid-lh-[1.15_1.25@360_1200]
9 * - Letter-spacing (optional, em): fluid-ls-[minEm_maxEm@vwMin_vwMax] e.g. fluid-ls-[-0.01_-0.02@360_1200]
10 *
11 * Notes:
12 *
13 * - Assumes 16px = 1rem.
14 * - Uses linear interpolation between vwMin and vwMax.
15 * - Guards with clamp() to cap at the ends.
16 */
17export default function fluidType() {
18 return plugin(function ({ matchUtilities }) {
19 const toNum = (s: string) => Number(s.trim());
20
21 const parse = (raw: string) => {
22 // "28_88@360_1200"
23 const [mm, rr] = raw.split('@');
24 if (!mm || !rr) throw new Error('Expected pattern min_max@vwMin_vwMax');
25 const [min, max] = mm.split('_').map(toNum);
26 const [vwMin, vwMax] = rr.split('_').map(toNum);
27 return { min, max, vwMin, vwMax };
28 };
29
30 // font-size in px -> rem
31 matchUtilities(
32 {
33 fluid: (value: string) => {
34 const { min, max, vwMin, vwMax } = parse(value);
35 const minRem = `${min / 16}rem`;
36 const maxRem = `${max / 16}rem`;
37 const slope = max - min; // px
38 const range = vwMax - vwMin; // px
39 // clamp(min, preferred, max)
40 // preferred = min + (slope) * ((100vw - vwMin) / range)
41 return {
42 fontSize: `clamp(${minRem}, calc(${minRem} + ${slope.toFixed(6)} * ((100vw - ${vwMin}px) / ${range})), ${maxRem})`,
43 };
44 },
45 },
46 { values: {}, type: 'any' },
47 );
48
49 // line-height (unitless)
50 matchUtilities(
51 {
52 'fluid-lh': (value: string) => {
53 const { min, max, vwMin, vwMax } = parse(value);
54 const slope = max - min;
55 const range = vwMax - vwMin;
56 return {
57 lineHeight: `clamp(${min}, calc(${min} + ${slope.toFixed(6)} * ((100vw - ${vwMin}px) / ${range})), ${max})`,
58 };
59 },
60 },
61 { values: {}, type: 'any' },
62 );
63
64 // letter-spacing in em
65 matchUtilities(
66 {
67 'fluid-ls': (value: string) => {
68 const { min, max, vwMin, vwMax } = parse(value);
69 const slope = max - min;
70 const range = vwMax - vwMin;
71 return {
72 letterSpacing: `clamp(${min}em, calc(${min}em + ${slope.toFixed(6)}em * ((100vw - ${vwMin}px) / ${range})), ${max}em)`,
73 };
74 },
75 },
76 { values: {}, type: 'any' },
77 );
78
79 // Typography scale presets
80 // Format: [minPx, maxPx, viewportMinPx, viewportMaxPx]
81 // Scales from mobile (360px) to desktop (1200px) viewports
82 const fsPresets: Record<string, [number, number, number, number]> = {
83 // sm: Small text (captions, footnotes, labels)
84 sm: [
85 14,
86 16,
87 360,
88 1200,
89 ],
90 // base: default text (body copy, paragraphs)
91 base: [
92 16,
93 32,
94 360,
95 1200,
96 ],
97 // md: Medium text (body copy, paragraphs)
98 md: [
99 24,
100 40,
101 360,
102 1200,
103 ],
104 // lg: Large text (subheadings, lead paragraphs)
105 lg: [
106 32,
107 48,
108 360,
109 1200,
110 ],
111 // xl: Extra large text (headings)
112 xl: [
113 40,
114 56,
115 360,
116 1200,
117 ],
118 // 2xl: Display text (hero headings, page titles)
119 '2xl': [
120 48,
121 64,
122 360,
123 1200,
124 ],
125
126 };
127
128 matchUtilities(
129 {
130 'fluid-preset': (key: string) => {
131 const p = fsPresets[key];
132 if (!p) return null;
133 const [
134 min,
135 max,
136 vwMin,
137 vwMax,
138 ] = p;
139 return {
140 fontSize: `clamp(${min / 16}rem, calc(${min / 16}rem + ${(max - min).toFixed(6)} * ((100vw - ${vwMin}px) / ${vwMax - vwMin})), ${max / 16}rem)`,
141 };
142 },
143 },
144 { values: Object.fromEntries(Object.keys(fsPresets).map((k) => [k, k])) },
145 );
146 });
147}