Mix is a simple and intuitive styling system for Flutter, enabling the creation of beautiful and consistent UIs with ease.

Mix brings industry-proven design system concepts to Flutter. It separates style semantics from widgets while maintaining an easy-to-understand and manageable relationship between them.

• Easily compose, merge, and apply styles across widgets.
• Write cleaner, more maintainable styling definitions.
• Apply styles conditionally based on the BuildContext.

Why Mix?

Flutter developers often face challenges when it comes to styling widgets and maintaining a consistent look and feel across their apps. Flutter is heavily dependent on the Material Design System and theming, and that can be challenging, especially when creating your own design system.

Mix addresses these challenges by creating a styling system that uses utility functions for a more intuitive and composable way to style. This approach can be kept consistent across widgets and files.

Goals with Mix

• Define visual properties outside the widget's build method while still allowing access to the BuildContext. This is done by having the style definition resolved during widget build, similar to how the current Theme.of works, but with much more flexibility.
• Ensure consistent styling throughout your app. By having separate style definitions, you can reuse not only specific values, like colors and typography, but also entire style definitions across other styles.
• Quickly adapt to changing design requirements. By promoting style composability and inheritance, you can more easily maintain a DRY approach to managing your design system.
• Create adaptive designs and layouts by leveraging style variants, which are based on existing styles but can be applied conditionally or responsively.
• Type-safe composability. Mix leverages the power of Dart's type system and class to create a type-safe styling experience.

Guiding Principles

• Simple Abstraction: A low-cost layer over the Flutter API, letting you style widgets without altering their core behavior, ensuring they remain compatible and predictable.
• Consistent: Even though we are creating a new styling system, we should always keep the styling API consistent with its Flutter equivalents.
• Composable: Styles should be easily composable by combining simple, reusable elements, promoting code reuse and maintainability.
• Extensible: Mix should allow for reasonable overrides and reuse of its utilities, making it easy to fit your own needs.

Key Features

Powerful Styling API:

Styles are easily defined using the Style class, which allows you to define a style's properties and values. Here's an example of defining a style:

final style = Style(
  $box.height(100),
  $box.width(100),
  $box.color.purple(),
  $box.borderRadius(10),
);

Learn more about styling

First-Class Variant Support:

First-class support for variants, allowing you to define styling variations that can be applied conditionally or responsively.

const onOutlined = Variant('outlined');

final baseStyle = Style(
  $box.borderRadius(10),
  $box.color.black(),
  $text.style.color.white(),

  onOutlined(
    $box.color.transparent(),
    $box.border.color.black(),
    $text.style.color.black(),
  ),
);

final outlinedStyle = baseStyle.applyVariant(onOutlined);

Learn more about variants

BuildContext Responsive Styling:

Mix allows you to define styles that are context-aware, allowing you to apply styles conditionally based on the BuildContext.

final style = Style(
  $box.color.black(),
  $text.style.color.white(),
  $on.dark(
    $box.color.white(),
    $text.style.color.black(),
  ),
);

Learn more about context variants

Design Tokens and Theming:

Mix goes beyond the Material Theme definitions by allowing the definition of design tokens and properties that can be used across all styling utilities.

Utility-First Approach:

A complete set of utility primitives allows you to define styling properties and values in a more intuitive and composable way.

$box.padding(20); /// Padding 20 on all sides
$box.padding(20, 10); /// Padding 20 on top and bottom, 10 on left and right

$box.padding.top(20); /// Padding 20 on top
$box.padding.horizontal(20); /// Padding 20 on left and right

Learn more about utilities

Contributors