FormCanvasBlock class

A live canvas scene embed.

Unlike FormImageBlock (static bitmap) or FormChartBlock (structured data), this block references a scene in the host project and is rendered against the current project state at document render time by a CanvasBindingResolver. Typical uses: embed a schematic page, a PCB top view, a mechanical 3D assembly, or a generated UI preview inside a design-spec document.

The block is format-agnostic at the data layer: it carries a target reference plus render hints. The host (e.g. Designer) wires a resolver that knows how to project the current scene into bytes of the requested format. Renderers that cannot consume vector output fall back to fallback — typically a bitmap.

Inheritance

Constructors

FormCanvasBlock({required String blockId, required int index, Map<String, dynamic>? style, required String target, String mode = 'canvas', String format = 'svg', String fallback = 'bitmap', Map<String, dynamic>? viewport, double? maxWidth, double? aspectRatio, String? caption, String? alt})
FormCanvasBlock.fromJson(Map<String, dynamic> json)
factory

Properties

alt → String?
Alternative text for accessibility / fallback text formats.
final
aspectRatio → double?
Aspect ratio (width / height). Enforced by the renderer so page layout stays stable across scene updates.
final
blockId → String
Unique block identifier.
finalinherited
caption → String?
Optional caption — rendered below the scene by most renderers.
final
fallback → String
Fallback strategy when format is not supported by the active renderer. 'bitmap' (default) raster-rasterises into PNG at the block's physical size; 'skip' emits a placeholder.
final
format → String
Preferred output format. One of: 'svg', 'png', 'pdf-vector', 'json'. If the active document renderer does not support the requested format it SHOULD downgrade via fallback.
final
hashCode → int
The hash code for this object.
no setterinherited
index → int
Block ordering index.
finalinherited
maxWidth → double?
Maximum rendered width in logical pixels (renderer decides how to scale if narrower, e.g. to fit document width).
final
mode → String
Canvas editor mode the resolver should render in. One of: 'canvas' (2D/3D engineering), 'ui' (UI editor runtime), 'form' (nested document — resolver may reject).
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
style → Map<String, dynamic>?
Optional style properties.
finalinherited
target → String
Scene reference — resolver-specific. Examples: canvas://schematic.main canvas://pcb.top-view canvas://mechanical.assembly#exploded
final
type → FormBlockType
Type of this block.
finalinherited
viewport → Map<String, dynamic>?
Optional viewport hint — resolver-specific map (e.g. {zoom: 1.2, center: [x, y]}). Opaque to mcp_form; passed through to the resolver.
final

Methods

baseToJson() → Map<String, dynamic>
Serialize common base fields to a map.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toJson() → Map<String, dynamic>
Convert to JSON.
override
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited