use appearance instead of system fonts in payment sheet

StripeCore/StripeCore/Source/UI/UIFont+Stripe.swift

@@ -16,6 +16,7 @@ import UIKit
     /// https://developer.apple.com/documentation/uikit/uifont/scaling_fonts_automatically
     private static let defaultSizeCategory: UIContentSizeCategory = .large
 
+    /// - Note: for Payment Sheet/Element contexts, use PaymentSheet.Appearance.scaledFont instead. This method uses the system font instead of a user's custom font.
     public static func preferredFont(
         forTextStyle style: TextStyle,
         weight: Weight,
@@ -36,6 +37,7 @@ import UIKit
     /// - Parameters:
     ///   - style: The style used to determine the font's size.
     ///   - weight: The weight to apply to the font.
+    /// - Note: for Payment Sheet/Element contexts, use PaymentSheet.Appearance.scaledFont instead. This method uses the system font instead of a user's custom font.
     public func withPreferredSize(
         forTextStyle style: TextStyle,
         weight: Weight? = nil

StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/USBankAccount/InstantDebitsPaymentMethodElement.swift

@@ -63,7 +63,7 @@ final class InstantDebitsPaymentMethodElement: ContainerElement {
         string.addAttributes(
             [
                 .paragraphStyle: style,
-                .font: UIFont.preferredFont(forTextStyle: .footnote),
+                .font: theme.fonts.footnote,
                 .foregroundColor: theme.colors.secondaryText,
             ],
             range: NSRange(location: 0, length: string.length)
@@ -390,7 +390,7 @@ private extension PaymentMethodIncentive {
         formattedString.addAttributes(
             [
                 .paragraphStyle: style,
-                .font: UIFont.preferredFont(forTextStyle: .footnote),
+                .font: appearance.fonts.footnote,
                 .foregroundColor: appearance.colors.secondaryText,
             ],
             range: NSRange(location: 0, length: formattedString.length)

StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Views/AUBECSMandate.swift

@@ -27,10 +27,8 @@ final class AUBECSLegalTermsView: UIView {
         let textView = UITextView()
         textView.isScrollEnabled = false
         textView.isEditable = false
-        textView.font = theme.fonts.caption
         textView.backgroundColor = .clear
         textView.attributedText = formattedLegalText()
-        textView.textColor = theme.colors.secondaryText
         textView.linkTextAttributes = [.foregroundColor: theme.colors.primary]
         textView.textContainerInset = .zero
         textView.textContainer.lineFragmentPadding = 0
@@ -52,7 +50,7 @@ final class AUBECSLegalTermsView: UIView {
 #if !os(visionOS)
     override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
         super.traitCollectionDidChange(previousTraitCollection)
-        textView.font = .preferredFont(forTextStyle: .caption1)
+        textView.font = theme.fonts.caption
     }
 #endif
 
@@ -62,7 +60,15 @@ final class AUBECSLegalTermsView: UIView {
             "Legal text shown when using AUBECS."
         )
         let string = String(format: template, configuration.merchantDisplayName)
-        return STPStringUtils.applyLinksToString(template: string, links: links)
+        let formattedString = STPStringUtils.applyLinksToString(template: string, links: links)
+        formattedString.addAttributes(
+            [
+                .font: theme.fonts.caption,
+                .foregroundColor: theme.colors.secondaryText,
+            ],
+            range: formattedString.extent
+        )
+        return formattedString
     }
 
 }

StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Views/CardScanningView.swift

@@ -43,6 +43,7 @@ class CardScanningView: UIView {
         }
     }
 
+    private let theme: ElementsAppearance
     private lazy var cardScanner: STPCardScanner? = nil
 
     private static let cardSizeRatio: CGFloat = 2.125 / 3.370  // ID-1 card size (in inches)
@@ -75,7 +76,7 @@ class CardScanningView: UIView {
         let label = UILabel()
         label.text = ""
         label.textAlignment = .center
-        label.font = .preferredFont(forTextStyle: .headline)
+        label.font = theme.fonts.sectionHeader
         label.translatesAutoresizingMaskIntoConstraints = false
         return label
     }()
@@ -85,7 +86,7 @@ class CardScanningView: UIView {
         label.text = String.Localized.allow_camera_access
         label.textAlignment = .center
         label.numberOfLines = 3
-        label.font = .preferredFont(forTextStyle: .subheadline)
+        label.font = theme.fonts.subheadline
         label.translatesAutoresizingMaskIntoConstraints = false
         label.textColor = .white
         label.isHidden = true
@@ -164,6 +165,7 @@ class CardScanningView: UIView {
     }
 
     init(theme: ElementsAppearance) {
+        self.theme = theme
         super.init(frame: .zero)
         self.setupBlurView()
 
@@ -268,7 +270,7 @@ class CardScanningView: UIView {
     }
 
     required init?(coder aDecoder: NSCoder) {
-        super.init(coder: aDecoder)
+        fatalError("init(coder:) has not been implemented")
     }
 }
 

StripePaymentSheet/StripePaymentSheetTests/PaymentSheet/PaymentSheetFormFactorySnapshotTest.swift

@@ -411,6 +411,20 @@ final class PaymentSheetFormFactorySnapshotTest: STPSnapshotTestCase {
         XCTAssertTrue(formElement.validationState.isValid)
     }
 
+    func testLpm_AUBecs_customFont() {
+        var configuration = PaymentSheet.Configuration()
+        configuration.appearance.font.base = UIFont(name: "Courier", size: 16)!
+        configuration.appearance.colors.textSecondary = .red
+        let factory = factory(
+            for: .AUBECSDebit,
+            configuration: configuration
+        )
+        let formElement = factory.make()
+        let view = formElement.view
+        view.autosizeHeight(width: 375)
+        STPSnapshotVerifyView(view)
+    }
+
     func testEPM_subtitle() {
         let configuration = PaymentSheet.Configuration()
         let factory = factory(for: .card, configuration: configuration)

StripePaymentSheet/StripePaymentSheetTests/PaymentSheet/PaymentSheetSnapshotTests.swift

@@ -633,8 +633,14 @@ class PaymentSheetSnapshotTests: STPSnapshotTestCase {
         stubCustomers()
         stubConsumerSession()
 
+        // Instant debits includes unqiue labels. Test with custom font to ensure it renders correctly.
+        var appearance = PaymentSheet.Appearance()
+        appearance.font.sizeScaleFactor = 1.15
+        appearance.font.base = UIFont(name: "AvenirNext-Regular", size: UIFont.labelFontSize)!
+
         preparePaymentSheet(
             currency: "usd",
+            appearance: appearance,
             override_payment_methods_types: ["link"],
             automaticPaymentMethods: false,
             useLink: false