Push button (#40)

* Stub out buttons with corresponding Styles

* Stub out Fields and Labels with corresponding Styles

* Stub out Selectors

* Placeholder Indicators

* Remove stubs for RoundButton and BevelButton

Apple docs say not to use these

* Start working on PushButton

* Get PushButton color from style's primaryColor instead of PushButton's disabledColor

Also:
* Add button_states.dart
* Add PushButtonStyle stub to Style
* Add Diagnosticable mixin to PushButtonStyle

* Tweak PushButton's disabledColor

* Start work on PushButtonStyle

* Add color, disabledColor, padding, and borderRadius properties to class with contructor and corresponding debug properties
* Include PushButtonStyle when returning default style in theme.dart
* Get PushButton color from current style if possible, otherwise fall back to defaults
* Add todos for implementing other PushButtonStyle props in PushButton

* Use proper padding and border radius for small and large PushButtons

* Test PushButton in example app

* Export push_button_theme.dart, move todo

* Documentation updates

* Documentation for PushButtonTheme and PushButtonThemeData
* Tweak MacosThemeData documentation

* Revert stubs

* Update version and CHANGELOG.md

* Ensure text color is correct when PushButton is disabled

* Add PushButton section to README.md

* Try embedding PushButton images as an album

* Try embedding PushButton images as an album (2)

* Revert to individual images

Author: GroovinChip

CHANGELOG.md

@@ -1,3 +1,8 @@
+## [0.0.5]
+* Adds the `PushButton` widget along with `PushButtonTheme` and `PushButtonThemeData`
+* Removes the `height` property from `Typography`'s `TextStyle`s
+* Updates `Typography.headline`'s weight and letter spacing
+
 ## [0.0.4]
 * Major theme refactor that more closely resembles flutter/material and flutter/cupertino
   * The `Style` class is now `MacosThemeData`

README.md

@@ -10,6 +10,7 @@ Implements Apple's macOS Design System in Flutter. Based on the official documen
 - [Layout](#layout)
   - [Scaffold](#scaffold)
 - [Buttons](#buttons)
+  - [PushButton](#pushbutton)
   - [Switch](#switch)
 - [Indicators](#indicators)
   - [ProgressCircle](#progresscircle)
@@ -37,13 +38,27 @@ dragging left or right. See the documentation for all customization options.
 <img src="https://imgur.com/jTPXGuq.gif" width="75%"/>
 
 # Buttons
+
+## PushButton
+
+<img src="https://imgur.com/D7CSk09.jpg"/>
+<img src="https://imgur.com/JDPdmWo.jpg"/>
+<img src="https://imgur.com/E5gECIP.jpg"/>
+<img src="https://imgur.com/lpT18wZ.jpg"/>
+<img src="https://imgur.com/W8ZA9nv.jpg"/>
+<img src="https://imgur.com/uKRyLph.jpg"/>
+<img src="https://imgur.com/w4hvYZQ.jpg"/>
+<img src="https://imgur.com/ztwz6ut.jpg"/>
+
 ## Switch
 <img src="https://imgur.com/IBh5jkz.jpg" width="50%" height="50%"/>
 
 <img src="https://imgur.com/qK1VCVr.jpg" width="50%" height="50%"/>
 
 # Indicators
+
 ## ProgressCircle
+
 A `ProgressCircle` can be either determinate or indeterminate. If indeterminate, Flutter's
 `CupertinoActivityIndicator` will be shown.
 

example/lib/main.dart

@@ -1,5 +1,6 @@
 import 'package:macos_ui/macos_ui.dart';
 import 'package:provider/provider.dart';
+
 import 'theme.dart';
 
 void main() {
@@ -18,7 +19,7 @@ class MyApp extends StatelessWidget {
           theme: MacosThemeData.light(),
           darkTheme: MacosThemeData.dark(),
           themeMode: ThemeMode.dark,
-          debugShowCheckedModeBanner: false, //yay!
+          debugShowCheckedModeBanner: false,
           home: Demo(),
         );
       },
@@ -43,9 +44,10 @@ class _DemoState extends State<Demo> {
       body: Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: [
-          Switch(
-            value: value,
-            onChanged: (v) => setState(() => value = v),
+          PushButton(
+            buttonSize: ButtonSize.small,
+            child: Text('Button'),
+            onPressed: () {},
           ),
         ],
       ),

example/pubspec.lock

@@ -73,7 +73,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "0.0.4"
+    version: "0.0.5"
   matcher:
     dependency: transitive
     description:

lib/macos_ui.dart

@@ -1,5 +1,6 @@
 library macos_ui;
 
+/// todo: package-level docs
 export 'package:flutter/cupertino.dart'
     show CupertinoColors, CupertinoDynamicColor;
 export 'package:flutter/material.dart'
@@ -11,15 +12,24 @@ export 'package:flutter/material.dart'
         PageTransitionsBuilder,
         FlutterLogo,
         CircleAvatar;
+export 'package:flutter/widgets.dart' hide Icon, TextBox;
 
-/// todo: package-level docs
-export 'package:flutter/widgets.dart' hide Icon, IconTheme, TextBox;
-
+export 'src/buttons/push_button.dart';
+export 'src/buttons/push_button_theme.dart';
+export 'src/buttons/switch.dart';
+export 'src/buttons/switch.dart';
+export 'src/buttons/switch.dart';
 export 'src/buttons/switch.dart';
 export 'src/indicators/progress_indicators.dart';
+export 'src/indicators/progress_indicators.dart';
+export 'src/layout/scaffold.dart';
+export 'src/layout/scaffold.dart';
 export 'src/layout/scaffold.dart';
 export 'src/macos_app.dart';
+export 'src/macos_app.dart';
 export 'src/styles/macos_theme.dart';
 export 'src/styles/macos_theme_data.dart';
 export 'src/styles/typography.dart';
+export 'src/styles/typography.dart';
+export 'src/util.dart';
 export 'src/util.dart';

lib/src/buttons/push_button.dart

@@ -0,0 +1,251 @@
+import 'package:flutter/foundation.dart';
+import 'package:macos_ui/macos_ui.dart';
+
+enum ButtonSize {
+  large,
+  small,
+}
+
+const EdgeInsetsGeometry _kSmallButtonPadding =
+    EdgeInsets.symmetric(vertical: 3.0, horizontal: 8.0);
+const EdgeInsetsGeometry _kLargeButtonPadding =
+    EdgeInsets.symmetric(vertical: 6.0, horizontal: 8.0);
+
+const BorderRadius _kSmallButtonRadius =
+    const BorderRadius.all(Radius.circular(5.0));
+const BorderRadius _kLargeButtonRadius =
+    const BorderRadius.all(Radius.circular(7.0));
+
+/// A macOS-style button.
+class PushButton extends StatefulWidget {
+  const PushButton({
+    Key? key,
+    required this.child,
+    required this.buttonSize,
+    this.padding,
+    this.color,
+    this.disabledColor,
+    this.onPressed,
+    this.pressedOpacity = 0.4,
+    this.borderRadius = const BorderRadius.all(Radius.circular(4.0)),
+    this.alignment = Alignment.center,
+  })  : assert(pressedOpacity == null ||
+            (pressedOpacity >= 0.0 && pressedOpacity <= 1.0)),
+        super(key: key);
+
+  /// The widget below this widget in the tree.
+  ///
+  /// Typically a [Text] widget.
+  final Widget child;
+
+  /// The size of the button.
+  ///
+  /// Must be either [ButtonSize.small] or [ButtonSize.large].
+  ///
+  /// Small buttons have a `padding` of [_kSmallButtonPadding] and a
+  /// `borderRadius` of [_kSmallButtonRadius]. Large buttons have a `padding`
+  /// of [_kLargeButtonPadding] and a `borderRadius` of [_kLargeButtonRadius].
+  final ButtonSize buttonSize;
+
+  /// The amount of space to surround the child inside the bounds of the button.
+  ///
+  /// Leave blank to use the default padding provided by [_kSmallButtonPadding]
+  /// or [_kLargeButtonPadding].
+  final EdgeInsetsGeometry? padding;
+
+  /// The color of the button's background.
+  final Color? color;
+
+  /// The color of the button's background when the button is disabled.
+  ///
+  /// Ignored if the [PushButton] doesn't also have a [color].
+  ///
+  /// Defaults to [CupertinoColors.quaternarySystemFill] when [color] is
+  /// specified. Must not be null.
+  final Color? disabledColor;
+
+  /// The callback that is called when the button is tapped or otherwise activated.
+  ///
+  /// If this is set to null, the button will be disabled.
+  final VoidCallback? onPressed;
+
+  /// The opacity that the button will fade to when it is pressed.
+  /// The button will have an opacity of 1.0 when it is not pressed.
+  ///
+  /// This defaults to 0.4. If null, opacity will not change on pressed if using
+  /// your own custom effects is desired.
+  final double? pressedOpacity;
+
+  /// The radius of the button's corners when it has a background color.
+  ///
+  /// Leave blank to use the default radius provided by [_kSmallButtonRadius]
+  /// or [_kLargeButtonRadius].
+  final BorderRadius? borderRadius;
+
+  /// The alignment of the button's [child].
+  ///
+  /// Typically buttons are sized to be just big enough to contain the child and its
+  /// [padding]. If the button's size is constrained to a fixed size, for example by
+  /// enclosing it with a [SizedBox], this property defines how the child is aligned
+  /// within the available space.
+  ///
+  /// Always defaults to [Alignment.center].
+  final AlignmentGeometry alignment;
+
+  /// Whether the button is enabled or disabled. Buttons are disabled by default. To
+  /// enable a button, set its [onPressed] property to a non-null value.
+  bool get enabled => onPressed != null;
+
+  @override
+  _PushButtonState createState() => _PushButtonState();
+}
+
+class _PushButtonState extends State<PushButton>
+    with SingleTickerProviderStateMixin {
+  // Eyeballed values. Feel free to tweak.
+  static const Duration kFadeOutDuration = Duration(milliseconds: 10);
+  static const Duration kFadeInDuration = Duration(milliseconds: 100);
+  final Tween<double> _opacityTween = Tween<double>(begin: 1.0);
+
+  late AnimationController _animationController;
+  late Animation<double> _opacityAnimation;
+
+  @override
+  void initState() {
+    super.initState();
+    _animationController = AnimationController(
+      duration: const Duration(milliseconds: 200),
+      value: 0.0,
+      vsync: this,
+    );
+    _opacityAnimation = _animationController
+        .drive(CurveTween(curve: Curves.decelerate))
+        .drive(_opacityTween);
+    _setTween();
+  }
+
+  @override
+  void didUpdateWidget(PushButton old) {
+    super.didUpdateWidget(old);
+    _setTween();
+  }
+
+  void _setTween() {
+    _opacityTween.end = widget.pressedOpacity ?? 1.0;
+  }
+
+  @override
+  void dispose() {
+    _animationController.dispose();
+    super.dispose();
+  }
+
+  bool _buttonHeldDown = false;
+
+  void _handleTapDown(TapDownDetails event) {
+    if (!_buttonHeldDown) {
+      _buttonHeldDown = true;
+      _animate();
+    }
+  }
+
+  void _handleTapUp(TapUpDetails event) {
+    if (_buttonHeldDown) {
+      _buttonHeldDown = false;
+      _animate();
+    }
+  }
+
+  void _handleTapCancel() {
+    if (_buttonHeldDown) {
+      _buttonHeldDown = false;
+      _animate();
+    }
+  }
+
+  void _animate() {
+    if (_animationController.isAnimating) return;
+    final bool wasHeldDown = _buttonHeldDown;
+    final TickerFuture ticker = _buttonHeldDown
+        ? _animationController.animateTo(1.0, duration: kFadeOutDuration)
+        : _animationController.animateTo(0.0, duration: kFadeInDuration);
+    ticker.then<void>((void value) {
+      if (mounted && wasHeldDown != _buttonHeldDown) _animate();
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final bool enabled = widget.enabled;
+    final MacosThemeData theme = MacosTheme.of(context);
+    final Color? backgroundColor = widget.color == null
+        ? theme.pushButtonTheme.color
+        : CupertinoDynamicColor.maybeResolve(widget.color, context);
+
+    final Color? disabledColor = widget.disabledColor == null
+        ? theme.pushButtonTheme.disabledColor
+        : CupertinoDynamicColor.maybeResolve(widget.disabledColor, context);
+
+    final EdgeInsetsGeometry? buttonPadding = widget.padding == null
+        ? widget.buttonSize == ButtonSize.small
+            ? _kSmallButtonPadding
+            : _kLargeButtonPadding
+        : widget.padding;
+
+    final BorderRadius? borderRadius = widget.borderRadius == null
+        ? widget.buttonSize == ButtonSize.small
+            ? _kSmallButtonRadius
+            : _kLargeButtonRadius
+        : widget.borderRadius;
+
+    final Color? foregroundColor = widget.enabled
+        ? textLuminance(backgroundColor!)
+        : theme.brightness!.isDark
+            ? Color.fromRGBO(255, 255, 255, 0.25)
+            : Color.fromRGBO(0, 0, 0, 0.25);
+
+    final TextStyle textStyle =
+        theme.typography!.headline!.copyWith(color: foregroundColor);
+
+    return GestureDetector(
+      behavior: HitTestBehavior.opaque,
+      onTapDown: enabled ? _handleTapDown : null,
+      onTapUp: enabled ? _handleTapUp : null,
+      onTapCancel: enabled ? _handleTapCancel : null,
+      onTap: widget.onPressed,
+      child: Semantics(
+        button: true,
+        child: ConstrainedBox(
+          constraints: BoxConstraints(
+            minWidth: 49,
+            minHeight: 20,
+          ),
+          child: FadeTransition(
+            opacity: _opacityAnimation,
+            child: DecoratedBox(
+              decoration: BoxDecoration(
+                borderRadius: borderRadius,
+                color: !enabled
+                    ? CupertinoDynamicColor.resolve(disabledColor!, context)
+                    : backgroundColor,
+              ),
+              child: Padding(
+                padding: buttonPadding!,
+                child: Align(
+                  alignment: widget.alignment,
+                  widthFactor: 1.0,
+                  heightFactor: 1.0,
+                  //todo: show proper text color in light theme
+                  child: DefaultTextStyle(
+                    style: textStyle,
+                    child: widget.child,
+                  ),
+                ),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}