feat(mobile): customize fonts, reply emphasis, and message sizes

apps/mobile/app.config.ts

@@ -264,6 +264,7 @@ const config: ExpoConfig = {
       `applinks:${HOSTED_APP_HOST}`,
     ],
     entitlements: {
+      "com.apple.developer.user-fonts": ["app-usage"],
       "keychain-access-groups": [`$(AppIdentifierPrefix)${variant.iosBundleIdentifier}`],
     },
     infoPlist: {

apps/mobile/global.css

@@ -46,10 +46,12 @@
 /* ─── Custom utilities ──────────────────────────────────────────────── */
 @utility font-t3-medium {
   font-family: var(--font-medium);
+  font-weight: 500;
 }
 
 @utility font-t3-bold {
   font-family: var(--font-bold);
+  font-weight: 700;
 }
 
 @utility font-t3-extrabold {

apps/mobile/modules/t3-composer-editor/android/src/main/java/expo/modules/t3composereditor/T3ComposerEditorView.kt

@@ -284,11 +284,11 @@ class T3ComposerEditorView(context: Context, appContext: AppContext) : ExpoView(
   }
 
   fun setFontFamily(fontFamily: String) {
-    editor.typeface = if (fontFamily.contains("Mono", ignoreCase = true)) {
-      Typeface.MONOSPACE
-    } else {
-      ReactFontManager.getInstance().getTypeface(fontFamily, Typeface.NORMAL, context.assets)
-    }
+    editor.typeface = ReactFontManager.getInstance().getTypeface(
+      fontFamily,
+      Typeface.NORMAL,
+      context.assets,
+    )
     applyLineHeight()
     editor.applyPlaceholder()
   }

apps/mobile/modules/t3-composer-editor/ios/T3ComposerEditorView.swift

@@ -1151,9 +1151,21 @@ public final class T3ComposerEditorView: ExpoView, UITextViewDelegate, UITextDro
     return nil
   }
 
+  private func resolvedComposerFont() -> UIFont {
+    if let font = UIFont(name: fontFamily, size: fontSize) {
+      return font
+    }
+    // Expo registers aliases through the family-name lookup, not UIFont(name:).
+    for name in UIFont.fontNames(forFamilyName: fontFamily) {
+      if let font = UIFont(name: name, size: fontSize) {
+        return font
+      }
+    }
+    return UIFont.systemFont(ofSize: fontSize)
+  }
+
   private func baseAttributes() -> [NSAttributedString.Key: Any] {
-    let font = UIFont(name: fontFamily, size: fontSize)
-      ?? UIFont.systemFont(ofSize: fontSize)
+    let font = resolvedComposerFont()
     let paragraph = NSMutableParagraphStyle()
     paragraph.minimumLineHeight = lineHeight
     paragraph.maximumLineHeight = lineHeight
@@ -1165,8 +1177,7 @@ public final class T3ComposerEditorView: ExpoView, UITextViewDelegate, UITextDro
   }
 
   private func applyTypography() {
-    let font = UIFont(name: fontFamily, size: fontSize)
-      ?? UIFont.systemFont(ofSize: fontSize)
+    let font = resolvedComposerFont()
     textView.font = font
     restoreBaseTypingAttributes()
     placeholderLabel.font = font

apps/mobile/modules/t3-native-controls/ios/T3InstalledFonts.swift

@@ -0,0 +1,100 @@
+import CoreText
+import UIKit
+
+@MainActor
+enum T3InstalledFonts {
+  static func describe(_ font: UIFont, name: String? = nil) -> [String: Any] {
+    func variant(_ weight: UIFont.Weight) -> String {
+      let descriptor = UIFontDescriptor(fontAttributes: [
+        .family: font.familyName,
+        .traits: [UIFontDescriptor.TraitKey.weight: weight],
+      ])
+      let candidate = UIFont(descriptor: descriptor, size: font.pointSize)
+      return candidate.familyName == font.familyName ? candidate.fontName : font.fontName
+    }
+    // CoreText reports medium as 0.20 while UIKit requests 0.23.
+    var emphasisFaces: [String: String] = [:]
+    for (key, weight) in [("500", UIFont.Weight.medium), ("600", .semibold), ("700", .bold)] {
+      let name = variant(weight)
+      guard let candidate = UIFont(name: name, size: font.pointSize),
+            let traits = candidate.fontDescriptor.object(forKey: .traits) as? [UIFontDescriptor.TraitKey: Any],
+            let actual = traits[.weight] as? NSNumber,
+            abs(actual.doubleValue - Double(weight.rawValue)) < 0.04 else { continue }
+      emphasisFaces[key] = name
+    }
+    return [
+      "name": name ?? font.fontName,
+      "label": font.familyName,
+      "regular": font.fontName,
+      "medium": variant(.medium),
+      "bold": variant(.bold),
+      "emphasisFaces": emphasisFaces,
+    ]
+  }
+
+  static func resolve(_ names: [String], completion: @escaping ([[String: Any]]) -> Void) {
+    guard !names.isEmpty else { completion([]); return }
+    // Provider fonts must be requested again for each process. Persist names,
+    // not file URLs: iOS owns the files and the picker grants family access.
+    let descriptors = names.map { CTFontDescriptorCreateWithAttributes([kCTFontNameAttribute: $0] as CFDictionary) }
+    CTFontManagerRequestFonts(descriptors as CFArray) { _ in
+      DispatchQueue.main.async {
+        completion(names.compactMap { name in
+          guard let font = UIFont(name: name, size: 16) else { return nil }
+          return describe(font, name: name)
+        })
+      }
+    }
+  }
+}
+
+@MainActor
+final class T3FontPickerPresentation: NSObject, UIFontPickerViewControllerDelegate, UIAdaptivePresentationControllerDelegate {
+  private let completion: ([String: Any]?) -> Void
+  private var picker: UIFontPickerViewController?
+  private var finished = false
+
+  init(completion: @escaping ([String: Any]?) -> Void) {
+    self.completion = completion
+  }
+
+  func present(from presenter: UIViewController, selectedName: String?) {
+    let configuration = UIFontPickerViewController.Configuration()
+    configuration.includeFaces = false
+    let picker = UIFontPickerViewController(configuration: configuration)
+    if let selectedName, let font = UIFont(name: selectedName, size: 16) {
+      picker.selectedFontDescriptor = font.fontDescriptor
+    }
+    picker.delegate = self
+    self.picker = picker
+    presenter.present(picker, animated: true)
+    picker.presentationController?.delegate = self
+  }
+
+  func fontPickerViewControllerDidPickFont(_ viewController: UIFontPickerViewController) {
+    guard let descriptor = viewController.selectedFontDescriptor else { dismiss(); return }
+    let result = T3InstalledFonts.describe(UIFont(descriptor: descriptor, size: 16))
+    viewController.dismiss(animated: true) { self.finish(result) }
+  }
+
+  func fontPickerViewControllerDidCancel(_ viewController: UIFontPickerViewController) {
+    dismiss()
+  }
+
+  func presentationControllerDidDismiss(_ presentationController: UIPresentationController) {
+    finish(nil)
+  }
+
+  func dismiss() {
+    guard let picker else { finish(nil); return }
+    picker.dismiss(animated: true) { self.finish(nil) }
+  }
+
+  private func finish(_ result: [String: Any]?) {
+    guard !finished else { return }
+    finished = true
+    picker?.delegate = nil
+    picker = nil
+    completion(result)
+  }
+}

apps/mobile/modules/t3-native-controls/ios/T3NativeControlsModule.swift

@@ -10,6 +10,7 @@ public final class T3NativeControlsModule: Module {
   private let presentationSources = T3PresentationSources()
   private var videoPresentation: T3NativeVideoPresentation?
   private var filePresentation: T3NativeFilePresentation?
+  private var fontPresentation: T3FontPickerPresentation?
   /// The last file preview that closed. Written on main, read synchronously from JS.
   private let filePreviewActivity = NSLock()
   private var finishedFilePreview: String?
@@ -66,6 +67,29 @@ public final class T3NativeControlsModule: Module {
       try T3DpopKeys.sign(privateKey: privateKey, signingInput: signingInput)
     }
 
+    AsyncFunction("pickInstalledFont") { (selectedName: String?, promise: Promise) in
+      MainActor.assumeIsolated {
+        guard self.fontPresentation == nil,
+          let presenter = self.appContext?.utilities?.currentViewController()
+        else {
+          promise.reject("ERR_FONT_PICKER", "Cannot present the font picker right now.")
+          return
+        }
+        let presentation = T3FontPickerPresentation { [weak self] result in
+          self?.fontPresentation = nil
+          promise.resolve(result)
+        }
+        self.fontPresentation = presentation
+        presentation.present(from: presenter, selectedName: selectedName)
+      }
+    }.runOnQueue(.main)
+
+    AsyncFunction("resolveInstalledFonts") { (names: [String], promise: Promise) in
+      MainActor.assumeIsolated {
+        T3InstalledFonts.resolve(names) { promise.resolve($0) }
+      }
+    }.runOnQueue(.main)
+
     AsyncFunction("presentVideo") { (url: URL, title: String, sourceIdentifier: String, identifier: String, promise: Promise) in
       try self.presentVideo(
         url: url,
@@ -111,9 +135,11 @@ public final class T3NativeControlsModule: Module {
     OnDestroy {
       let presentation = self.videoPresentation
       let file = self.filePresentation
+      let font = self.fontPresentation
       DispatchQueue.main.async {
         presentation?.dismiss()
         file?.dismiss()
+        font?.dismiss()
       }
     }
 

apps/mobile/src/components/ComposerEditor.ios.test.tsx

@@ -130,6 +130,12 @@ vi.mock("../lib/contextChipIconSource", () => ({ contextChipIconUri: () => "" })
 vi.mock("../features/settings/appearance/useScaledTextRole", () => ({
   useComposerTextRole: () => ({ fontSize: 16, lineHeight: 22 }),
 }));
+vi.mock("../features/settings/appearance/AppearancePreferencesProvider", () => ({
+  useAppearancePreferences: () => ({
+    fonts: { composer: { regular: "System" } },
+    composerFontSize: 16,
+  }),
+}));
 vi.mock("../lib/uuid", () => ({ uuidv4: () => "uuid", randomHex: () => "0000" }));
 vi.mock("../state/assets", () => ({ assetEnvironment: {} }));
 vi.mock("../state/attachments", () => ({ attachmentEnvironment: {} }));

apps/mobile/src/features/files/FileMarkdownPreview.tsx

@@ -9,7 +9,6 @@ import { ScrollView, View } from "react-native";
 import { RefreshControl } from "../../components/ui/RefreshControl";
 
 import { tryOpenExternalUrl } from "../../lib/openExternalUrl";
-import { FONT_FAMILIES } from "../../lib/fontFamilies";
 import { resolveNativeMarkdownTypography } from "../../lib/appearancePreferences";
 import { useUniwindTheme } from "../../lib/useUniwindTheme";
 import {
@@ -40,8 +39,8 @@ interface MarkdownPreviewStyles {
 }
 
 export function useMarkdownPreviewStyles(): MarkdownPreviewStyles {
-  const { appearance } = useAppearancePreferences();
-  const nativeMarkdownTypography = resolveNativeMarkdownTypography(appearance.baseFontSize);
+  const { fonts, replyFontSize, replyEmphasisFontFamily } = useAppearancePreferences();
+  const nativeMarkdownTypography = resolveNativeMarkdownTypography(replyFontSize);
   const theme = useUniwindTheme();
   const body = theme["--color-md-body"];
   const strong = theme["--color-md-strong"];
@@ -50,8 +49,8 @@ export function useMarkdownPreviewStyles(): MarkdownPreviewStyles {
   const codeBackground = theme["--color-md-code-bg"];
   const codeText = theme["--color-md-code-text"];
   const horizontalRule = theme["--color-md-hr"];
-  const regularFontFamily = FONT_FAMILIES.regular;
-  const boldFontFamily = FONT_FAMILIES.bold;
+  const regularFontFamily = fonts.reply.regular;
+  const boldFontFamily = fonts.reply.bold;
 
   return {
     nativeTextStyle: {
@@ -69,9 +68,10 @@ export function useMarkdownPreviewStyles(): MarkdownPreviewStyles {
       fontSize: nativeMarkdownTypography.fontSize,
       lineHeight: nativeMarkdownTypography.lineHeight,
       headingFontSizes: nativeMarkdownTypography.headingFontSizes,
+      codeFontFamily: fonts.code.regular,
       fontFamily: regularFontFamily,
       headingFontFamily: boldFontFamily,
-      boldFontFamily,
+      boldFontFamily: replyEmphasisFontFamily,
     },
   };
 }

apps/mobile/src/features/settings/SettingsAppearanceRouteScreen.tsx

@@ -6,6 +6,7 @@ import { useSafeAreaInsets } from "react-native-safe-area-context";
 import { SettingsScreen } from "./components/SettingsScreen";
 import { CodeAppearanceSection } from "./appearance/sections/CodeAppearanceSection";
 import { TerminalAppearanceSection } from "./appearance/sections/TerminalAppearanceSection";
+import { FontAppearanceSection } from "./appearance/sections/FontAppearanceSection";
 import { TextAppearanceSection } from "./appearance/sections/TextAppearanceSection";
 import { ThemeAppearanceSection } from "./appearance/sections/ThemeAppearanceSection";
 import { ToolCallsAppearanceSection } from "./appearance/sections/ToolCallsAppearanceSection";
@@ -27,6 +28,7 @@ export function SettingsAppearanceRouteScreen() {
         <ThemeAppearanceSection />
         {Platform.OS === "android" ? <AndroidNavigationAppearanceSection /> : null}
         <TextAppearanceSection />
+        <FontAppearanceSection />
         <TerminalAppearanceSection />
         <CodeAppearanceSection />
         <ToolCallsAppearanceSection />