Decorators

Decorators in Mix extend functionality by defining the widget composition tree structure, providing support for core widgets, external widgets, and third-party widgets without compromising the simplicity of core Mix.

$with

You can find all available decorators within the $with utility. This provides a single place to access all decorator functions.

Understanding the Mechanics

Take the scale attribute, for instance. The Container widget doesn't inherently possess the ability to scale. But, by employing a Transform widget as a decorator, we can introduce this effect.

Transform.scale(
  scale: 0.5,
  child: Container(
    child: const Text("Half sized box"),
  ),
)

Creating a decorator

We can achieve the same effect by creating a custom **WidgetDecorator**.

Creating a decorator is like creating a **StatelessWidget**. Extend **WidgetDecorator**. Define the properties you want to modify and the widget you want to decorate.

class ScaleDecorator extends WidgetDecorator<ScaleDecorator> {
  final double scale;
  const ScaleDecorator(this.scale, {super.key});
 
  @override
  ScaleDecorator lerp(ScaleDecorator? other, double t) {
    return ScaleDecorator(lerpDouble(scale, other?.scale, t) ?? scale);
  }
 
  @override
  get props => [scale];
 
  @override
  Widget build(MixData mix, Widget child) {
    return Transform.scale(
      key: key,
      scale: scale,
      child: child,
    );
  }
}
 

You can then create an extension of the

Crafting a decorator utility

To simplify decorator usage, you can design a utility function that automatically creates the decorator for you.

ScaleDecorator scale(double scale, {Key? key}) => ScaleDecorator(scale, key: key);

Using a decorator

final style = Style(
  $with.scale(0.5),
);
 
Box(
  style: style,
  child: const Text('Half sized box'),
);

Built-in decorators

Mix comes with a set of built-in decorators that can be used out of the box.

Scale Decorator

Decorates a Box with a Transform.scale widget

final style = Style(
  $with.scale(0.5),
);
 
// Equivalent to
Transform.scale(
  scale: 0.5,
  child: Box(
    child: const Text('Half sized box'),
  ),
);

Opacity

Decorates a Box with an Opacity widget

final style = Style(
  $with.opacity(0.5),
);
 
// Equivalent to
Opacity(
  opacity: 0.5,
  child: Box(
    child: const Text('Half transparent box'),
  ),
);

Rotate

Decorates a Box with a Transform.rotate widget. The parameter is quarter turns.

final style = Style(
  $with.rotate(1),
);
 
// Equivalent to
RotatedBox(
  quarterTurns: 1,
  child: Box(
    child: const Text('Rotated box'),
  ),
);

Helper methods

• $with.rotate(1): 90 degrees
• $with.rotate.d90(): 90 degrees
• $with.rotate(2): 180 degrees
• $with.rotate.d180(): 180 degrees
• $with.rotate(3): 270 degrees
• $with.rotate.d270(): 270 degrees

Aspect Ratio

Decorates a Box with an AspectRatio widget

final style = Style(
  $with.aspectRatio(6/9),
);
 
// Equivalent to
AspectRatio(
  aspectRatio: 6/9,
  child: Box(
    child: const Text('Aspect ratio box'),
  ),
);

Clip

Decorates a Box with different types of Clip widgets

final style = Style(
  $with.clipOval(),
);
 
Box(
  style: style,
  child: const Text('Oval box'),
);
 
// Equivalent to
ClipOval(
  child: Box(
    child: const Text('Oval box'),
  ),
);

Helper methods

• $with.clipOval(): Wraps with a ClipOval widget
• $with.clipRrect(): Wraps with a ClipRRect widget
• $with.clipRect(): Wraps with a ClipRect widget
• $with.clipPath(): Wraps with a ClipPath widget
• $with.clipTriangle(): Wraps with a ClipPath widget that clips to a triangle

Visibility

Decorates a Box with a Visibility widget

final style = Style(
  $with.visibility(false),
);
 
// Equivalent to
Visibility(
  visible: false,
  child: Box(
    child: const Text('Invisible box'),
  ),
);

IntrinsicHeight and IntrinsicWidth

Decorates a Box with a IntrinsicHeight or IntrinsicWidth widget

final style = Style(
  $with.intrinsicHeight(), // or intrinsicWidth()
);
 
// Equivalent to
IntrinsicHeight( // or IntrinsicWidth
  child: Box(
    child: const Text('Invisible box'),
  ),
);

Helper methods

• $with.show(): Wraps the Box with an Visibility widget that is visible
• $with.hide(): Wraps the Box with an Visibility widget that is invisible
• $with.visibility.on(): Wraps the Box with an Visibility widget that is visible
• $with.visibility.off(): Wraps the **Box** with an **Visibility** widget that is invisible

Flexible

Decorates a Flex Styled widget like FlexBox, HBox, VBox, with a Flexible widget

final style = Style(
  $with.flexible(flex:1, fit: FlexFit.tight),
);

• $with.flexible(flex:1, fit: FlexFit.tight): Wraps the Flex Styled widget with a Flexible widget

Helper methods

• $with.flexible.expanded(): Equivalent to Expanded widget, or flexible(fit: FlexFit.tight)
• $with.flexible.loose(): Equivalent to Flexible widget, or flexible(fit: FlexFit.loose)
• $with.flexible.tight(): Equivalent to flexible(fit: FlexFit.tight)
• $with.expanded(): Equivalent to Expanded widget, or flexible(fit: FlexFit.tight)

This is equivalent to wrapping the Flex Styled widget with a Flexible widget.

Flexible(
  flex: 1,
  fit: FlexFit.tight,
  child: FlexBox(
    children: [
       const Text('Flexible box'),
    ],
  ),
);