1 files changed, 111 insertions, 0 deletions
diff --git a/src/alf/fonts.ts b/src/alf/fonts.ts
new file mode 100644
index 000000000..ce658fa05
--- /dev/null
+++ b/src/alf/fonts.ts
@@ -0,0 +1,111 @@
+import {useFonts as defaultUseFonts} from 'expo-font'
+
+import {isNative, isWeb} from '#/platform/detection'
+import {Device, device} from '#/storage'
+
+const FAMILIES = `-apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Liberation Sans", Helvetica, Arial, sans-serif`
+
+const factor = 0.0625 // 1 - (15/16)
+const fontScaleMultipliers: Record<Device['fontScale'], number> = {
+  '-2': 1 - factor * 3,
+  '-1': 1 - factor * 2,
+  '0': 1 - factor * 1, // default
+  '1': 1,
+  '2': 1 + factor * 1,
+}
+
+export function computeFontScaleMultiplier(scale: Device['fontScale']) {
+  return fontScaleMultipliers[scale]
+}
+
+export function getFontScale() {
+  return device.get(['fontScale']) ?? '0'
+}
+
+export function setFontScale(fontScale: Device['fontScale']) {
+  device.set(['fontScale'], fontScale)
+}
+
+export function getFontFamily() {
+  return device.get(['fontFamily']) || 'theme'
+}
+
+export function setFontFamily(fontFamily: Device['fontFamily']) {
+  device.set(['fontFamily'], fontFamily)
+}
+
+/*
+ * Unused fonts are commented out, but the files are there if we need them.
+ */
+export function useFonts() {
+  /**
+   * For native, the `expo-font` config plugin embeds the fonts in the
+   * application binary. But `expo-font` isn't supported on web, so we fall
+   * back to async loading here.
+   */
+  if (isNative) return [true, null]
+  return defaultUseFonts({
+    // 'Inter-Thin': require('../../assets/fonts/inter/Inter-Thin.otf'),
+    // 'Inter-ThinItalic': require('../../assets/fonts/inter/Inter-ThinItalic.otf'),
+    // 'Inter-ExtraLight': require('../../assets/fonts/inter/Inter-ExtraLight.otf'),
+    // 'Inter-ExtraLightItalic': require('../../assets/fonts/inter/Inter-ExtraLightItalic.otf'),
+    // 'Inter-Light': require('../../assets/fonts/inter/Inter-Light.otf'),
+    // 'Inter-LightItalic': require('../../assets/fonts/inter/Inter-LightItalic.otf'),
+    'Inter-Regular': require('../../assets/fonts/inter/Inter-Regular.otf'),
+    'Inter-Italic': require('../../assets/fonts/inter/Inter-Italic.otf'),
+    'Inter-Medium': require('../../assets/fonts/inter/Inter-Medium.otf'),
+    'Inter-MediumItalic': require('../../assets/fonts/inter/Inter-MediumItalic.otf'),
+    'Inter-SemiBold': require('../../assets/fonts/inter/Inter-SemiBold.otf'),
+    'Inter-SemiBoldItalic': require('../../assets/fonts/inter/Inter-SemiBoldItalic.otf'),
+    'Inter-Bold': require('../../assets/fonts/inter/Inter-Bold.otf'),
+    'Inter-BoldItalic': require('../../assets/fonts/inter/Inter-BoldItalic.otf'),
+    'Inter-ExtraBold': require('../../assets/fonts/inter/Inter-ExtraBold.otf'),
+    'Inter-ExtraBoldItalic': require('../../assets/fonts/inter/Inter-ExtraBoldItalic.otf'),
+    'Inter-Black': require('../../assets/fonts/inter/Inter-Black.otf'),
+    'Inter-BlackItalic': require('../../assets/fonts/inter/Inter-BlackItalic.otf'),
+  })
+}
+
+/*
+ * Unused fonts are commented out, but the files are there if we need them.
+ */
+export function applyFonts(
+  style: Record<string, any>,
+  fontFamily: 'system' | 'theme',
+) {
+  if (fontFamily === 'theme') {
+    style.fontFamily =
+      {
+        // '100': 'Inter-Thin',
+        // '200': 'Inter-ExtraLight',
+        // '300': 'Inter-Light',
+        '100': 'Inter-Regular',
+        '200': 'Inter-Regular',
+        '300': 'Inter-Regular',
+        '400': 'Inter-Regular',
+        '500': 'Inter-Medium',
+        '600': 'Inter-SemiBold',
+        '700': 'Inter-Bold',
+        '800': 'Inter-ExtraBold',
+        '900': 'Inter-Black',
+      }[style.fontWeight as string] || 'Inter-Regular'
+
+    if (style.fontStyle === 'italic') {
+      if (style.fontFamily === 'Inter-Regular') {
+        style.fontFamily = 'Inter-Italic'
+      } else {
+        style.fontFamily += 'Italic'
+      }
+    }
+
+    // fallback families only supported on web
+    if (isWeb) {
+      style.fontFamily += `, ${FAMILIES}`
+    }
+  } else {
+    // fallback families only supported on web
+    if (isWeb) {
+      style.fontFamily = style.fontFamily || FAMILIES
+    }
+  }
+}