1 files changed, 83 insertions, 13 deletions

diff --git a/src/components/Typography.tsx b/src/components/Typography.tsx
index 66cf0720d..64aa6d1a4 100644
--- a/src/components/Typography.tsx
+++ b/src/components/Typography.tsx
@@ -1,11 +1,50 @@
 import React from 'react'
-import {Text as RNText, TextProps} from 'react-native'
+import {Text as RNText, TextStyle, TextProps} from 'react-native'
 
 import {useTheme, atoms, web, flatten} from '#/alf'
 
+/**
+ * Util to calculate lineHeight from a text size atom and a leading atom
+ *
+ * Example:
+ *   `leading(atoms.text_md, atoms.leading_normal)` // => 24
+ */
+export function leading<
+  Size extends {fontSize?: number},
+  Leading extends {lineHeight?: number},
+>(textSize: Size, leading: Leading) {
+  const size = textSize?.fontSize || atoms.text_md.fontSize
+  const lineHeight = leading?.lineHeight || atoms.leading_normal.lineHeight
+  return size * lineHeight
+}
+
+/**
+ * Ensures that `lineHeight` defaults to a relative value of `1`, or applies
+ * other relative leading atoms.
+ *
+ * If the `lineHeight` value is > 2, we assume it's an absolute value and
+ * returns it as-is.
+ */
+function normalizeTextStyles(styles: TextStyle[]) {
+  const s = flatten(styles)
+  // should always be defined on these components
+  const fontSize = s.fontSize || atoms.text_md.fontSize
+
+  if (s?.lineHeight) {
+    if (s.lineHeight <= 2) {
+      s.lineHeight = fontSize * s.lineHeight
+    }
+  } else {
+    s.lineHeight = fontSize
+  }
+
+  return s
+}
+
 export function Text({style, ...rest}: TextProps) {
   const t = useTheme()
-  return <RNText style={[atoms.text_sm, t.atoms.text, style]} {...rest} />
+  const s = normalizeTextStyles([atoms.text_sm, t.atoms.text, flatten(style)])
+  return <RNText style={s} {...rest} />
 }
 
 export function H1({style, ...rest}: TextProps) {
@@ -19,7 +58,12 @@ export function H1({style, ...rest}: TextProps) {
     <RNText
       {...attr}
       {...rest}
-      style={[atoms.text_5xl, atoms.font_bold, t.atoms.text, flatten(style)]}
+      style={normalizeTextStyles([
+        atoms.text_5xl,
+        atoms.font_bold,
+        t.atoms.text,
+        flatten(style),
+      ])}
     />
   )
 }
@@ -35,7 +79,12 @@ export function H2({style, ...rest}: TextProps) {
     <RNText
       {...attr}
       {...rest}
-      style={[atoms.text_4xl, atoms.font_bold, t.atoms.text, flatten(style)]}
+      style={normalizeTextStyles([
+        atoms.text_4xl,
+        atoms.font_bold,
+        t.atoms.text,
+        flatten(style),
+      ])}
     />
   )
 }
@@ -51,7 +100,12 @@ export function H3({style, ...rest}: TextProps) {
     <RNText
       {...attr}
       {...rest}
-      style={[atoms.text_3xl, atoms.font_bold, t.atoms.text, flatten(style)]}
+      style={normalizeTextStyles([
+        atoms.text_3xl,
+        atoms.font_bold,
+        t.atoms.text,
+        flatten(style),
+      ])}
     />
   )
 }
@@ -67,7 +121,12 @@ export function H4({style, ...rest}: TextProps) {
     <RNText
       {...attr}
       {...rest}
-      style={[atoms.text_2xl, atoms.font_bold, t.atoms.text, flatten(style)]}
+      style={normalizeTextStyles([
+        atoms.text_2xl,
+        atoms.font_bold,
+        t.atoms.text,
+        flatten(style),
+      ])}
     />
   )
 }
@@ -83,7 +142,12 @@ export function H5({style, ...rest}: TextProps) {
     <RNText
       {...attr}
       {...rest}
-      style={[atoms.text_xl, atoms.font_bold, t.atoms.text, flatten(style)]}
+      style={normalizeTextStyles([
+        atoms.text_xl,
+        atoms.font_bold,
+        t.atoms.text,
+        flatten(style),
+      ])}
     />
   )
 }
@@ -99,7 +163,12 @@ export function H6({style, ...rest}: TextProps) {
     <RNText
       {...attr}
       {...rest}
-      style={[atoms.text_lg, atoms.font_bold, t.atoms.text, flatten(style)]}
+      style={normalizeTextStyles([
+        atoms.text_lg,
+        atoms.font_bold,
+        t.atoms.text,
+        flatten(style),
+      ])}
     />
   )
 }
@@ -110,15 +179,16 @@ export function P({style, ...rest}: TextProps) {
     web({
       role: 'paragraph',
     }) || {}
-  const _style = flatten(style)
-  const lineHeight =
-    (_style?.lineHeight || atoms.text_md.lineHeight) *
-    atoms.leading_normal.lineHeight
   return (
     <RNText
       {...attr}
       {...rest}
-      style={[atoms.text_md, t.atoms.text, _style, {lineHeight}]}
+      style={normalizeTextStyles([
+        atoms.text_md,
+        atoms.leading_normal,
+        t.atoms.text,
+        flatten(style),
+      ])}
     />
   )
 }