Module widget 

Widget trait and related types.

This module defines the core Widget trait and supporting types for building UI components in Presentar.

Widget Lifecycle (Brick Architecture - PROBAR-SPEC-009)

Widgets follow a verify-measure-layout-paint cycle:

1. Verify: Check all Brick assertions pass (Popperian falsification)
2. Measure: Compute intrinsic size given constraints
3. Layout: Position self and children within allocated bounds
4. Paint: Generate draw commands for rendering (only if verified)

Brick Integration

When the brick feature is enabled, all Widgets must implement the Brick trait from jugar_probar. This enforces the “tests define interface” philosophy:

• Assertions are verified before every paint
• Budget violations trigger Jidoka (stop-the-line)
• Rendering is blocked if any assertion fails

Examples

use presentar_core::{WidgetId, TypeId, Transform2D};

// Create widget identifiers
let id = WidgetId::new(42);
assert_eq!(id.0, 42);

// Get type IDs for widget type comparison
let string_type = TypeId::of::<String>();
let i32_type = TypeId::of::<i32>();
assert_ne!(string_type, i32_type);

// Create transforms for rendering
let translate = Transform2D::translate(10.0, 20.0);
let scale = Transform2D::scale(2.0, 2.0);

Re-exports

pub use crate::brick_types::Brick;

pub use crate::brick_types::BrickAssertion;

pub use crate::brick_types::BrickBudget;

pub use crate::brick_types::BrickError;

pub use crate::brick_types::BrickPhase;

pub use crate::brick_types::BrickResult;

pub use crate::brick_types::BrickVerification;

pub use crate::brick_types::BudgetViolation;

Structs

LayoutResult

Result of laying out a widget.

TextStyle

Text style for rendering.

Transform2D

2D affine transform.

TypeId

Type identifier for widget types (used for diffing).

WidgetId

Unique identifier for a widget instance.

Enums

AccessibleRole

Accessible role for screen readers.

FontStyle

Font style.

FontWeight

Font weight.

Traits

Canvas

Canvas trait for paint operations.

Widget

Core widget trait that all UI elements implement.