Module limn_core::style

Contains types relevant to declaring styleable components, and the theming engine which allows styleable components to inherit values from an application theme.

Styleable components are arbitrary structs that can inherit values from a theme by defining a style struct that can be converted into the original struct by implementing the trait ComponentStyle.

Currently this can be used for structs that implement Draw and WidgetModifier and so can be used to style both drawable types, and complex widgets.

The macro component_style! can be used to simplify defining styleable types:

component_style!{pub struct Button<name="button", style=ButtonStyle> {
    color: Color = BLUE,
    text: Option<String> = None,
}}

This declares two structs:

struct Button {
    color: Color,
    text: Option<String>,
}
struct ButtonStyle {
    color: Option<Color>,
    text: Option<Option<String>>,
}

and implements various traits on them, but most importantly:

impl ComponentStyle<Component = Button> for ButtonStyle

If you then implement WidgetModifier for Button, you can define how to initialize a button using the rect and text fields. Then by passing a ButtonStyle in place of a Button to initialize a widget, you can specify only the fields you want to be specific to that widget, with the remaining fields inherited from the theme.

The theme will prioritize which values to use by (currently) simple specificity rules:

-The specific style passed to a widget -Styles registered in the theme for named style classes that can be applied to widgets, eg. "alert_button" -The base style for the type, ie. ButtonStyle, registered in the theme -In values are found no where else, the default values specified in component_style!, in this example, RectStyle::default() and None

Structs

DrawState
DrawStyle
Theme

Traits

Component	A type that implements Component is any type that can have values stored in and retrieved from the Theme
ComponentStyle	ComponentStyle corresponds to the style type for a given Component, or the set of optional values that can be merged with other ComponentStyles, from the theme, for instance, to produce a Component
DrawComponentStyle
ModifierComponentStyle
WidgetModifier