Trait fungui::Extension

pub trait Extension {
    type NodeData: Sized;
    type Value: Clone + PartialEq + Sized;

    fn new_data() -> Self::NodeData;
    fn style_properties<'a, F>(prop: F)
    where
        F: FnMut(StaticKey) + 'a;
    fn update_data(
        styles: &Styles<Self>,
        nc: &NodeChain<'_, Self>,
        rule: &Rule<Self>,
        data: &mut Self::NodeData
    ) -> DirtyFlags
    where
        Self: Sized;
    fn reset_unset_data(
        used_keys: &FnvHashSet<StaticKey>,
        data: &mut Self::NodeData
    ) -> DirtyFlags;

    fn check_flags(_data: &mut Self::NodeData, _flags: DirtyFlags) { ... }
}

Extensions extend stylish to allow custom style properties to be added

Required Associated Types

type NodeData: Sized

The type of the data that will be stored on every node

Can be acccessed via the .ext field on NodeInner

type Value: Clone + PartialEq + Sized

The type of the extra Values that will be used to extend the fungui Value in ExtValue type.

This is normally an enum

Required Methods

fn new_data() -> Self::NodeData

Creates a new empty NodeData to be stored on a Node.

fn style_properties<'a, F>(prop: F)where
    F: FnMut(StaticKey) + 'a,

Called to add new style keys that can be used by style rules

Example

static MY_PROP: StaticKey = StaticKey("my_prop");

// ...

fn style_properties<'a, F>(mut prop: F)
    where F: FnMut(StaticKey) + 'a
{
    prop(MY_PROP);
}

fn update_data(
    styles: &Styles<Self>,
    nc: &NodeChain<'_, Self>,
    rule: &Rule<Self>,
    data: &mut Self::NodeData
) -> DirtyFlagswhere
    Self: Sized,

Called to apply a given style rule on a node

Its recomended to use the eval! macro to check for relevant properties as it also skips ones that have already been set by a another rule.

Example

fn update_child_data(&mut self, styles: &Styles<E>, nc: &NodeChain<E>, rule: &Rule<E>, data: &mut Self::ChildData) -> DirtyFlags {
    let mut flags = DirtyFlags::empty();
    eval!(styles, nc, rule.X => val => {
        let new = val.convert();
        if data.x != new {
            data.x = new;
            flags |= DirtyFlags::POSITION;
        }
    });
    flags
}

fn reset_unset_data(
    used_keys: &FnvHashSet<StaticKey>,
    data: &mut Self::NodeData
) -> DirtyFlags

Called after applying all relevant rules to reset any properties that weren’t set.

This is needed because a node could have a property set previously and then later (e.g. when a property is changed) no longer have it set. Due to it no longer being set update_data would not be called for that property leaving it stuck with its previous value.

used_keys will contain every property key that was used by rules in this update, if the key isn’t in this set it should be reset.

Provided Methods

fn check_flags(_data: &mut Self::NodeData, _flags: DirtyFlags)

Called with the flags of a node to allow the data to be updated based on the dirty state of the node.

This is useful to marking a node as needing a redraw when it moves.

Implementors