vite-plugin-capsize-radix

Generate bulletproof typography css for @radix-ui/themes

Now changing fonts is as easy as changing colors.

Why

Getting fonts to look right on the web is hard — so most peoply rely on a few typography frameworks and fonts. But it doesn't have to be that way. Capsize fixes text sizing and layout allowing for precise text alignment so changing fonts is as easy as changing colors.

https://github.com/KyleAMathews/vite-plugin-capsize-radix-ui/assets/71047/3ec5d6ca-bf00-4b79-8552-4e3da3454f52

Capsize makes fonts render the way you expect them to. With Capsize, if you assign a font to occupy 16px of height, it actually will.

This plugin glues Capsize with the fantastic Radix theming components.

Similar plugins could be built for other meta-frameworks & component libraries — open an issue if you're interested on collaborating on one.

How to use

Install

npm install vite-plugin-capsize-radix

Add to vite.config.ts

A sample React config:

import { defineConfig } from "vite"
import react from "@vitejs/plugin-react-swc"
import { capsizeRadixPlugin } from "vite-plugin-capsize-radix"
import merriweather from "@capsizecss/metrics/merriweather"
import merriweatherSans from "@capsizecss/metrics/merriweatherSans"
import sourceCodePro from "@capsizecss/metrics/sourceCodePro"
import arial from "@capsizecss/metrics/arial"

export default defineConfig({
  plugins: [
    react(),
    capsizeRadixPlugin({
      // Import this file into your app after you import Radix's CSS.
      outputPath: `./public/merriweather.css`,
      // Pass in Capsize font metric objects.
      defaultFontStack: [merriweather, arial],
      headingFontStack: [merriweatherSans, arial],
      codingFontStack: [sourceCodePro, arial],
    }),
  ]
})

Using with Radix UI

This plugin overrides all typography related CSS for Radix so you can simply use their typography components as normal (e.g. <Heading>, <Text>, <Strong>, etc)

The plugin sets the variables for Radix's Type scale and Font family for Radix. It doesn't set Font weight. It sets the strong, em, and quote to use the default font family. You can set the default, heading, and coding font stacks separately.

See e.g. the documentation for <Text>.

They all share a size prop from "1" to "10". This corresponds to the optional fontSizes array passed to the plugin e.g. size="0" is the first value of the array, etc. <Text> defaults to size="2" and <Heading> defaults to size="6".

As Capsize trims all space around text, you'll find that <Flex gap="[space]"> becomes your best friend for controlling spacing between elements e.g.

Fallback fonts

Another great freebie Capsize gives you is it automatically generates CSS for aligning your fallback font with your main font, which can dramatically improve the Cumulative Layout Shift metric for sites that depend on a web font

Custom fonts

Capsize has precalculated metrics for system and many open source fonts. If you're using a custom font, you can calculate the font metrics using their @capsizecss/unpack package.

Responsive styles

This plugin automatically generates responsive styles. Typically you want your mobile font-size to be slightly smaller than on desktop. We do that by shifting the text a size smaller on mobile.

Parameters:

• outputPath (string): Required. The file path where the generated CSS or design tokens should be saved.
• textStyles (TextStyle[]): Optional. An array of objects, each representing a text style. Each object contains two properties: fontSize and lineHeight, which are numerical values, pixels for fontSize and pixels or relative value for lineHeight. Defaults to:

  [
    { fontSize: 9, lineHeight: 21 },
    { fontSize: 11, lineHeight: 23 },
    { fontSize: 12, lineHeight: 25 },
    { fontSize: 14, lineHeight: 27 },
    { fontSize: 18, lineHeight: 29 },
    { fontSize: 24, lineHeight: 36 },
    { fontSize: 36, lineHeight: 44 },
    { fontSize: 48, lineHeight: 52 },
    { fontSize: 64, lineHeight: 64 }
  ]

• defaultFontStack (FontMetrics[]): Optional. An array of FontMetrics objects. Defaults to a System Font stack.
• headingFontStack (FontMetrics[]): Optional. An array of FontMetrics objects. Defaults to your defaultFontStack.
• codingFontStack (FontMetrics[]): Optional. An array of FontMetrics objects. Defaults to your defaultFontStack.