Trait intuitive::components::Component
source · pub trait Component {
// Required method
fn render(&self) -> AnyElement;
}Expand description
A trait describing structures that can be rendered to an Element.
Before implementing the Component trait directly, make sure that what you are trying
to do can’t be done through the component attribute macro, as there are
a few nuances and implicit requirements when implementing Component.
Implementing Component
The general idea behind the Component trait is that it orchestrates the construction
of Elements. Elements know how to be drawn and how to handle keys.
Before implementing component, it’s important to understand the implicit expectations that Intuitive makes when rendering components.
Invariants & Expectations
- When rendering a frame,
Component::rendermust be called on everyComponent, even if it is not being drawn this frame.- This is to ensure that hooks, such as
use_state, are always called in the same order. - This can typically be guaranteed by always calling
Component::renderon your component’s children.
- This is to ensure that hooks, such as
Component::rendermust never be called outside ofComponent::render. This is to continue the assurances made in the previous point.- Structures implementing
Component, must also implementDefault. - Structures implementing
Componentmust have all of their fields public. - Structures implementing
Componentshould have anon_keyparameter if they also take inchildren. Thison_keyparameter should be of typeKeyHandlerand should default to forwarding the key events to the children.
Refer to the Section component source as an example component that
adheres to these invariants.
Custom Appearance
In order to customize how a component is drawn by the Terminal, you must
create a struct that implements Element. This is typically done by
creating two structs, one that implements Component, and a “frozen” struct
that implements Element, and the one implementing Component returns the
custom Element on Component::render.
Typically, when a component accepts Children<N> and returns a custom Element,
the “frozen” structure that is constructed takes in [AnyElement; N] as its
children, because Component::render was called on the Children<N>. Again,
refer to the Section component source that also returns a custom Element.