Struct LayoutComponent 

pub struct LayoutComponent {
    pub available_width: f32,
    pub authored_available_width: SizeDimension,
    pub available_height: Option<f32>,
    pub authored_available_height: Option<SizeDimension>,
    pub dirty: bool,
    pub unit_scale: f32,
    pub inspect: bool,
    pub computed_size_wu: Option<(f32, f32)>,
    /* private fields */
}

The viewport of a self-contained layout subtree — analogous to the browser’s initial containing block.

LayoutComponent does not participate in flow itself; it defines the space available to the first HtmlElementComponent child (usually Body).

Multiple LayoutComponent nodes can coexist — one per panel, one per HUD region, one per workspace.

available_width is in glyph units (1.0 = one monospace character cell). World-space scaling stays in TransformComponent.

Set dirty = true to signal the LayoutSystem to recompute the subtree on the next tick.

Fields

available_width: f32

Available inline (X-axis) width for children, in glyph units.

authored_available_width: SizeDimension

Authored available width as entered in MMS.

available_height: Option<f32>

Optional block (Y-axis) constraint. Used for overflow/clip; None = unconstrained.

authored_available_height: Option<SizeDimension>

Authored available height as entered in MMS.

dirty: bool

When true, the layout system will recompute this subtree on the next tick.

unit_scale: f32

Scale factor to convert glyph units → local coordinates of the nearest ancestor TransformComponent.

When the parent TransformComponent already has scale = TEXT_SCALE (i.e. the whole subtree is in glyph-unit space), leave this at the default 1.0.

When the parent TransformComponent has scale = 1.0 (world units) and the StyleComponent heights are authored in glyph units, set unit_scale = TEXT_SCALE (e.g. 0.08) so the emitted UpdateTransform translations land in world space.

inspect: bool

When true, the layout pass spawns box-model viz quads (padding, content, margin) for each styled item in this subtree. Per-tree dynamic toggle — flipped via IntentValue::SetLayoutInspect (MMS: layout.set_inspect(bool)). Static MMS declarations can also enable viz by attaching an InspectLayoutComponent child to the LayoutRoot.

computed_size_wu: Option<(f32, f32)>

Computed total extent of this layout root’s direct children, in world units, populated after each successful layout pass. None before the first layout.

Implementations

impl LayoutComponent

pub fn new(available_width: f32) -> Self

pub fn with_height(self, h: f32) -> Self

pub fn with_unit_scale(self, scale: f32) -> Self

pub fn mark_dirty(&mut self)

Mark this layout root as needing a recompute.

pub fn set_available_width(&mut self, w: f32)

Update available_width and flag this root for recompute on the next tick.

pub fn set_available_width_dimension(&mut self, width: SizeDimension)

pub fn set_available_height(&mut self, h: f32)

pub fn set_available_height_dimension(&mut self, height: SizeDimension)

pub fn set_unit_scale(&mut self, scale: f32)

Trait Implementations

impl Clone for LayoutComponent

fn clone(&self) -> LayoutComponent

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Component for LayoutComponent

fn name(&self) -> &'static str

Short debug/type name for this component kind (e.g. “transform”, “camera”).

fn set_id(&mut self, id: ComponentId)

fn as_any(&self) -> &dyn Any

fn as_any_mut(&mut self) -> &mut dyn Any

fn to_mms_ast(&self, _world: &World) -> ComponentExpression

Encode this component as an MMS Component Expression AST node.

fn init(&mut self, _emit: &mut dyn SignalEmitter, _component: ComponentId)

Called when component is added to the World

fn cleanup(&mut self, _emit: &mut dyn SignalEmitter, _component: ComponentId)

Called when component is removed from the World.

fn encode(&self) -> HashMap<String, Value>

Encode component data to a HashMap for serialization.

fn decode(&mut self, _data: &HashMap<String, Value>) -> Result<(), String>

Decode component data from a HashMap after deserialization.

impl Debug for LayoutComponent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.