Crate fission_ir 

Intermediate representation for the Fission UI framework.

fission-ir defines the node graph that sits between the high-level widget tree and the low-level layout and paint pipelines. Every widget compiles down to one or more CoreNodes stored inside a CoreIR container. Each node carries a single Op that describes what it does: lay out children, draw something on screen, group subtrees, or declare accessibility semantics.

Architecture

Widget Tree  -->  fission-ir (CoreIR)  -->  Layout Engine  -->  Display List

The IR is platform-agnostic, serializable (via serde), and content-addressed (every NodeId is a BLAKE3 hash). This makes it cheap to diff across frames and safe to send across process boundaries.

Example

use fission_ir::{CoreIR, NodeId, Op, LayoutOp, FlexDirection, FlexWrap, AlignItems, JustifyContent};

let mut ir = CoreIR::new();

let child = NodeId::explicit("label");
ir.add_node(child, Op::Layout(LayoutOp::Box {
    width: Some(200.0), height: Some(40.0),
    min_width: None, max_width: None,
    min_height: None, max_height: None,
    padding: [4.0; 4],
    flex_grow: 0.0, flex_shrink: 1.0,
    aspect_ratio: None,
}), vec![]);

let root = NodeId::explicit("root");
ir.add_node(root, Op::Layout(LayoutOp::Flex {
    direction: FlexDirection::Column,
    wrap: FlexWrap::NoWrap,
    flex_grow: 1.0, flex_shrink: 1.0,
    padding: [8.0; 4], gap: Some(4.0),
    align_items: AlignItems::Start,
    justify_content: JustifyContent::Start,
}), vec![child]);

ir.set_root(root);
assert_eq!(ir.nodes.len(), 2);

Re-exports

pub use node_id::NodeId;

pub use op::AlignItems;

pub use op::EmbedKind;

pub use op::FlexDirection;

pub use op::FlexWrap;

pub use op::GridPlacement;

pub use op::GridTrack;

pub use op::JustifyContent;

pub use op::LayoutOp;

pub use op::Op;

pub use op::PaintOp;

pub use op::StructuralOp;

pub use semantics::ActionEntry;

pub use semantics::ActionSet;

pub use semantics::Role;

pub use semantics::Semantics;

pub use widget_id::WidgetNodeId;

Modules

node_id

Content-addressed node identity.

op

Operations that IR nodes can perform.

semantics

Accessibility and interaction semantics.

widget_id

Widget-level identity, separate from IR node identity.

Structs

CoreIR

The root container for an intermediate representation graph.

CoreNode

A single node in the intermediate representation graph.

Constants

IR_VERSION

The current version of the IR format.