aleclarson · Oct 8, 2026
diff --git a/packages/core/ui/styling/font.android.spec.ts b/packages/core/ui/styling/font.android.spec.ts
@@ -0,0 +1,99 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+vi.hoisted(() => {
+	const builderCalls: { path: string; settings: string }[] = [];
+	(globalThis as any).__builderCalls = builderCalls;
+	// Families listed here build fine with every variation setting; entries in
+	// `__rejectWght` throw when the settings string mentions the wght axis,
+	// modelling Typeface.Builder's failure on fonts that lack it.
+	(globalThis as any).__rejectWght = new Set<string>();
+	(globalThis as any).android = {
+		graphics: {
+			Typeface: {
+				Builder: class {
+					settings: string;
+					constructor(public path: string) {}
+					setFontVariationSettings(s: string) {
+						this.settings = s;
+					}
+					build() {
+						builderCalls.push({ path: this.path, settings: this.settings });
+						if (this.settings?.includes('wght') && (globalThis as any).__rejectWght.has(this.path)) {
+							throw new Error(`Font does not support the 'wght' axis: ${this.path}`);
+						}
+						return { built: this.settings, path: this.path };
+					}
+				},
+				SANS_SERIF: 'sans-serif-typeface',
+				SERIF: 'serif-typeface',
+				MONOSPACE: 'monospace-typeface',
+				BOLD: 1,
+				ITALIC: 2,
+				create: (...args: any[]) => ({ created: args }),
+			},
+		},
+	};
+});
+
+vi.mock('../../utils/constants', () => ({ SDK_VERSION: 30 }));
+vi.mock('../../application/helpers-common', () => ({
+	getNativeApp: () => ({ getApplicationContext: () => ({ getAssets: () => ({}) }) }),
+}));
+vi.mock('../../file-system', () => ({
+	path: { join: (...parts: string[]) => parts.join('/').replace(/\/+/g, '/') },
+	knownFolders: { currentApp: () => ({ path: '/app' }) },
+	File: { exists: () => true },
+}));
+
+import { Font } from './font.android';
+
+function builderSettings(): string[] {
+	return (globalThis as any).__builderCalls.map((c) => c.settings);
+}
+
+describe('loadFontFromFile wght axis (API 26+)', () => {
+	beforeEach(() => {
+		(globalThis as any).__builderCalls.length = 0;
+		(globalThis as any).__rejectWght.clear();
+	});
+
+	it('maps fontWeight onto the wght variation axis', () => {
+		const font = new Font('WghtSpecA', undefined, undefined, '700');
+		font.getAndroidTypeface();
+		expect(builderSettings()).toEqual(["'wght' 700"]);
+	});
+
+	it('keeps an explicit wght axis instead of deriving one from fontWeight', () => {
+		const font = new Font('WghtSpecB', undefined, undefined, '700', 1, [{ axis: 'wght', value: 500 }]);
+		font.getAndroidTypeface();
+		expect(builderSettings()).toEqual(["'wght' 500"]);
+	});
+
+	it('appends wght after explicit variation settings', () => {
+		const font = new Font('WghtSpecC', undefined, undefined, '300', 1, [{ axis: 'wdth', value: 75 }]);
+		font.getAndroidTypeface();
+		expect(builderSettings()).toEqual(["'wdth' 75, 'wght' 300"]);
+	});
+
+	it('falls back to the explicit settings when the font lacks the wght axis', () => {
+		(globalThis as any).__rejectWght.add('/app/fonts/WghtSpecD.ttf');
+		const font = new Font('WghtSpecD', undefined, undefined, '400');
+		expect(() => font.getAndroidTypeface()).not.toThrow();
+		expect(builderSettings()).toEqual(["'wght' 400", '']);
+	});
+
+	it('uses the default typeface when an explicit wght axis fails', () => {
+		(globalThis as any).__rejectWght.add('/app/fonts/WghtSpecE.ttf');
+		const font = new Font('WghtSpecE', undefined, undefined, '400', 1, [{ axis: 'wght', value: 500 }]);
+		// The build error propagates to loadFontFromFile's outer catch, so the
+		// explicit request is NOT retried — the font falls back to the default.
+		expect(() => font.getAndroidTypeface()).not.toThrow();
+		expect(builderSettings()).toEqual(["'wght' 500"]);
+	});
+
+	it('keys the typeface cache by fontWeight', () => {
+		new Font('WghtSpecF', undefined, undefined, '400').getAndroidTypeface();
+		new Font('WghtSpecF', undefined, undefined, '700').getAndroidTypeface();
+		expect(builderSettings()).toEqual(["'wght' 400", "'wght' 700"]);
+	});
+});
diff --git a/packages/core/ui/styling/font.android.ts b/packages/core/ui/styling/font.android.ts
@@ -54,7 +54,7 @@ export class Font extends FontBase {
 
 function computeFontCacheKey(fontFamily: string, font: Font) {
 	const sep = ':';
-	return [fontFamily, String(FontVariationSettings.toString(font.fontVariationSettings)).replace(/'/g, '').replace(/[\s,]/g, '_')].join(sep);
+	return [fontFamily, String(getNumericFontWeight(font.fontWeight)), String(FontVariationSettings.toString(font.fontVariationSettings)).replace(/'/g, '').replace(/[\s,]/g, '_')].join(sep);
 }
 
 function loadFontFromFile(fontFamily: string, font: Font): android.graphics.Typeface {
@@ -93,8 +93,25 @@ function loadFontFromFile(fontFamily: string, font: Font): android.graphics.Type
 				if (SDK_VERSION >= 26) {
 					const builder = new android.graphics.Typeface.Builder(fontAssetPath);
 					if (builder) {
-						builder.setFontVariationSettings(font.fontVariationSettings?.length ? FontVariationSettings.toString(font.fontVariationSettings) : '');
-						result = builder.build();
+						const explicitSettings = FontVariationSettings.toString(font.fontVariationSettings) || '';
+						const variationSettings = font.fontVariationSettings?.length ? [...font.fontVariationSettings] : [];
+						const hasWeightAxis = variationSettings.some(({ axis }) => axis.toLowerCase() === 'wght');
+						if (!hasWeightAxis) {
+							variationSettings.push({ axis: 'wght', value: getNumericFontWeight(font.fontWeight) });
+						}
+						try {
+							builder.setFontVariationSettings(FontVariationSettings.toString(variationSettings) || '');
+							result = builder.build();
+						} catch (e) {
+							if (hasWeightAxis) {
+								throw e;
+							}
+						}
+						if (!result && !hasWeightAxis) {
+							const fallbackBuilder = new android.graphics.Typeface.Builder(fontAssetPath);
+							fallbackBuilder.setFontVariationSettings(explicitSettings);
+							result = fallbackBuilder.build();
+						}
 					} else {
 						result = android.graphics.Typeface.createFromFile(fontAssetPath);
 						if (Trace.isEnabled()) {