Add system font size as a device attribute

[claude]

Requested by Jake Mor · Slack thread

Changes in this pull request

Before: Device attributes did not report the user's system-wide text-size setting, so paywalls and audience filters had no visibility into whether a user has enlarged or shrunk their system text (Dynamic Type).

After: Device attributes now include three complementary Dynamic Type attributes:

• fontScale — a Double scale multiplier where 1.0 is the system default. Values below 1.0 indicate smaller text; values above 1.0 indicate larger or accessibility sizes. Rounded to two decimal places.
• fontSize — a normalized integer point/px value where 16 corresponds to the system default ("Large") text size, scaling down for smaller sizes and up for larger/accessibility sizes.
• preferredContentSizeCategory — a clean Dynamic Type token describing the selected size category (e.g. large).

These give paywalls and audience filters both numeric (fontScale, fontSize) and categorical (preferredContentSizeCategory) views of the user's text-size preference, and are consistent cross-platform.

The preferredContentSizeCategory value is one of the following clean tokens:

xSmall, small, medium, large, xLarge, xxLarge, xxxLarge, accessibilityMedium, accessibilityLarge, accessibilityXLarge, accessibilityXXLarge, accessibilityXXXLarge, or unspecified.

How: Added fontScale and preferredContentSizeCategory computed properties to DeviceHelper (alongside the existing fontSize), following the file's existing #if os(visionOS) guarding and UIKit house style. fontScale derives the scaled value of a 16pt reference base via UIFontMetrics.default.scaledValue(for: 16.0) / 16.0, rounded to two decimals; fontSize rounds the same scaled value to a whole integer; and preferredContentSizeCategory maps UIApplication.sharedApplication?.preferredContentSizeCategory (falling back to UIScreen.main.traitCollection.preferredContentSizeCategory) to a clean token. On visionOS these return 1.0, 16, and "unspecified" respectively. All three attributes were added as fields on the DeviceTemplate Codable struct and wired through getTemplateDevice(). The UIContentSizeCategory-to-token mapping is extracted into a pure DeviceHelper.contentSizeCategoryToken(for:) and locked by unit tests, since these tokens are a backend audience-filter contract.

Checklist

• All unit tests pass.
• All UI tests pass.
• Demo project builds and runs on iOS.
• Demo project builds and runs on Mac Catalyst.
• Demo project builds and runs on visionOS.
• I added/updated tests or detailed why my change isn't tested.
• I added an entry to the CHANGELOG.md for any breaking changes, enhancements, or bug fixes.
• I have run swiftlint in the main directory and fixed any issues.
• I have updated the SDK documentation as well as the online docs.
• I have reviewed the contributing guide

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[greptile-apps]

PR author is not in the allowed authors list.

[pullfrog]

ℹ️ No critical issues — one coverage gap worth a look, plus a note.

Reviewed changes — adds the user's system-wide Dynamic Type text-size setting as three device attributes and bumps the SDK to 4.16.2.

• Add fontSize, fontScale, preferredContentSizeCategory to DeviceHelper — three computed properties derived from UIFontMetrics.default.scaledValue(for: 16.0) and the current preferredContentSizeCategory, each #if os(visionOS)-guarded with 16 / 1.0 / "unspecified" fallbacks.
• Wire the three attributes into getTemplateDevice() — passed through to the DeviceTemplate(...) init.
• Add three non-optional Codable fields to DeviceTemplate — fontSize: Int, fontScale: Double, preferredContentSizeCategory: String. DeviceTemplate is only ever constructed in-process and encoded via toDictionary(), never decoded from persisted data, so the new non-optional fields carry no backward-compat risk.
• Version bump 4.16.1 → 4.16.2 — updated across Constants.swift, SuperwallKit.podspec, and CHANGELOG.md.

ℹ️ No test for the preferredContentSizeCategory token mapping

The new preferredContentSizeCategory switch is pure, deterministic logic that maps UIContentSizeCategory cases to a fixed set of dashboard tokens, and the token strings (e.g. .accessibilityExtraLarge → "accessibilityXLarge") are a contract the backend / audience filters depend on. There's no unit test locking that mapping in, and the PR checklist's tests box is unchecked, so a future rename or a mistyped token could silently ship. The CLAUDE.md workflow also asks for a unit test alongside new SDK functionality.

Technical details

# No test for the `preferredContentSizeCategory` token mapping

## Affected sites
- `Sources/SuperwallKit/Network/Device Helper/DeviceHelper.swift:227-249` — `preferredContentSizeCategory` switch mapping `UIContentSizeCategory` → token string.

## Required outcome
- A test that asserts the token strings emitted for each `UIContentSizeCategory` case, so an accidental token rename fails CI. The category source can be exercised by driving `UITraitCollection(preferredContentSizeCategory:)` through the mapping (extract the switch into a small pure function taking a `UIContentSizeCategory` if that makes it directly testable), covering at least the `xSmall`/`large`/`accessibilityXLarge`/`unspecified` boundaries.

## Open questions for the human
- Are these token strings a hard contract with the dashboard/backend? If so, a mapping test is the cheapest guard against a silent break.

ℹ️ preferredContentSizeCategory reads main-thread-only UIKit off-thread (pre-existing pattern)

getTemplateDevice() is async with no main-thread guarantee, and the new preferredContentSizeCategory reads UIScreen.main.traitCollection / UIApplication.sharedApplication — both main-thread-only — potentially off the main thread. This is not a regression: the pre-existing interfaceStyle property already does the identical thing the same way, so this PR is consistent with the file's established style. Flagging only for awareness, since the nearby cached-ScreenMetrics code exists specifically because UIScreen is main-thread-only.

Technical details

# `preferredContentSizeCategory` reads main-thread-only UIKit off-thread

## Affected sites
- `Sources/SuperwallKit/Network/Device Helper/DeviceHelper.swift:227-249` — new property.
- `Sources/SuperwallKit/Network/Device Helper/DeviceHelper.swift:189-208` — pre-existing `interfaceStyle` doing the same off-thread `UIScreen.main.traitCollection` read.
- `Sources/SuperwallKit/Network/Device Helper/DeviceHelper.swift:125-162` — `makeScreenMetrics()` caches screen metrics on the main thread at init precisely because `UIScreen` is main-thread-only.

## Required outcome
- No change required for this PR (matches existing house style). If the SDK ever hardens off-thread UIKit access, `interfaceStyle` and `preferredContentSizeCategory` should be addressed together, ideally via the same main-thread-cached approach as `ScreenMetrics`.

  ^{｜ Fix it ➔ ｜ View workflow run ｜ Using Claude Opus ｜ 𝕏}

[pullfrog]

✅ No new issues found.

Reviewed changes — the commits since the prior pullfrog review address that review's one actionable finding by making the Dynamic Type token mapping directly testable and locking it with tests.

• Extract token mapping into a pure static contentSizeCategoryToken(for:) — the UIContentSizeCategory → dashboard-token switch was pulled out of the preferredContentSizeCategory computed property into a standalone pure function, so the mapping can be exercised without touching main-thread UIKit state. Behavior is unchanged; preferredContentSizeCategory now just delegates.
• Add DeviceHelperTests coverage for the token mapping — a test asserting all 12 explicit UIContentSizeCategory cases plus two default cases (.unspecified and an unknown raw value), guarding the backend audience-filter contract against a silent token rename. Adds import UIKit for the category type.

The test expectations match the switch exactly (e.g. .extraLarge → xLarge, .accessibilityExtraLarge → accessibilityXLarge). The prior review's second finding (off-thread UIKit read) was explicitly marked "no change required" and remains consistent with the pre-existing interfaceStyle house style.

  ^{｜ View workflow run ｜ Using Claude Opus ｜ 𝕏}