[cupertino_ui] CupertinoButtonSize.medium is taller and rounder than UIKit's medium #196373

What package does this bug report belong to?

cupertino_ui

What target platforms are you seeing this bug on?

iOS

Have you already upgraded your packages?

Yes

Dependency versions

  cupertino_ui:
    dependency: "direct main"
    description:
      name: cupertino_ui
      sha256: "369e39a1c5c030a6212589c3da1809920b1c2cfade7b02aade7695bfa4b88c3a"
      url: "https://pub.dev"
    source: hosted
    version: "1.1.6"

Steps to reproduce

1. Run the code sample beside a UIKit UIButton.Configuration.tinted() at buttonSize = .medium.
2. Compare them.

Expected results

CupertinoButtonSize.medium matches the UIKit tiers.

Actual results

5.7 taller, and a capsule where UIKit draws a 6pt rounded rect. iPhone 16 Pro, iOS 18.5, label "Save". Same numbers on 26.2.

kCupertinoButtonPadding's medium is vertical: 10, horizontal: 15 versus UIKit's insets of 7 and 12. kCupertinoButtonSizeBorderRadius's medium is 40, which clamps to half the height, against UIKit's drawn 6.

Small and large are close. Medium is the one that misses, and it is the tier UIKit and SwiftUI pick by default.

Code sample

import 'package:cupertino_ui/cupertino_ui.dart';

void main() => runApp(
  CupertinoApp(
    home: ColoredBox(
      color: CupertinoColors.white,
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        spacing: 40,
        children: <Widget>[
          for (final sizeStyle in CupertinoButtonSize.values)
            CupertinoButton.tinted(sizeStyle: sizeStyle, onPressed: () {}, child: const Text('Save')),
        ],
      ),
    ),
  ),
);

Screenshots or Videos

Small, medium and large, top to bottom.

cupertino_ui

UIKit

Logs

small  frame=53.3x28.0  insets=t5 l10 b5    radius=14.00
medium frame=61.0x34.3  insets=t7 l12 b7    radius=6.00
large  frame=77.0x50.3  insets=t15 l20 b15  radius=8.67

Flutter Doctor output

[✓] Flutter (Channel stable, 3.47.9, on macOS 15.7.9 24G830 darwin-arm64, locale en-US)
    • Framework revision c197ca5199 (13 days ago), 2026-10-29 10:10:20 -0400