canvas_core_runtime library
Classes
- CanvasAppearance
- Authored appearance shared by path, text, and icon sources.
- CanvasAssetRef
- CanvasBlobUrlAssetRef
- Browser blob URL reference.
- CanvasDataUriAssetRef
- Inline data URI reference.
- CanvasFieldKey
- Stable identity for a runtime-editable canvas field.
- CanvasFieldKeyConverter
- Serializes CanvasFieldKey as its stable string value.
- CanvasFields
- Built-in field keys for properties that exist in the base canvas_core runtime scene model.
- CanvasFileAssetRef
- Local file reference.
- CanvasFill
- Single source-of-truth fill for runtime. No backward-compat: only accepts the new {type: ...} JSON shape.
- CanvasFillGradient
- CanvasFillNone
- CanvasFillSolid
- CanvasIconData
- CanvasImageAsset
- Backing source and optional natural dimensions for a document image.
- CanvasImageAssetResolver
- Resolves logical canvas image source references for the current host.
- CanvasRawAssetRef
- Bare/raw source reference with no recognized syntax.
- CanvasSceneDocument
- CanvasSchemeAssetRef
- Opaque custom-scheme reference, such as:
- CanvasSourceUnderlay
- Ordered paint that derives independently from the original source silhouette and is painted before the authored foreground.
- CanvasStroke
- Authored stroke settings, including configurations that paint no pixels.
- CanvasUrlAssetRef
- Network URL reference.
- CanvasViewportTransform
- Renderer-neutral contain-fit transform.
- CircleSource
- CommandPathSource
- Normalized, absolute geometry in source coordinates, with no paint data.
- ComputedIcon
- Evaluated icon geometry and its centered, uniform viewBox fit. Commands stay in source coordinates; appearance is authored in node-local coordinates and is applied after fitting the source.
- ComputedScene
- Computed document/render geometry in document units; these maps are not serialized.
- ContentBoundsPolicy
- Generic runtime policy for content-bounds calculations.
- ContentBoundsSpec
- Runtime-owned spec for custom content-bounds computation.
- CoreServices
- DrawItem
- EllipseSource
- GradientStop
- One color sample along a gradient line.
- GroupBehaviorRef
- Generic runtime-owned behavior envelope for optional group semantics.
- IconResolver
- Synchronous lookup into the host's selected resource session. Downloads and source normalization happen before scene evaluation.
- ImageData
- ImageIntrinsics
- Synchronous intrinsic-image lookup used by core scene computation.
- LinearGradientSpec
- A linear gradient in the local coordinate space of its painted target.
- Node
- Runtime scene-graph node (hierarchical TRS).
- NodeGeometry
- NullableSize2DConverter
- NullableVec2Converter
- PathCmd
- PathData
- PathIR
- Immutable compiled geometry. Paint belongs to the authored node.
- PathSource
- PillSource
- PolylineSource
- Rect2D
- RectSource
- RegularPolygonSource
- ResolvedIcon
- A filled, recolorable vector symbol in its declared source viewBox.
- RoundRectSource
- SceneEvaluation
- An already-prepared scene and its derived geometry for painting and export.
- SceneTreeOps
- Size2D
- 2D size (width/height).
- Size2DConverter
- ---- Size2D ----
- StarSource
- TextData
- TextMeasurer
- Synchronous text measurement used by core scene computation.
- Transform2D
- UnderlineSource
- Vec2
- 2D point/vector.
- Vec2Converter
- ---- Vec2 ----
Extensions
- CanvasImageAssetPatterns on CanvasImageAsset
- Adds pattern-matching-related methods to CanvasImageAsset.
- CanvasSceneDocumentPatterns on CanvasSceneDocument
- Adds pattern-matching-related methods to CanvasSceneDocument.
- NodeEditingX on Node
- Common immutable edits that preserve node identity and tree structure.
- NodeFields on Node
- Rect2DX on Rect2D
Constants
- currentCanvasSceneFormatVersion → const int
- Current persisted Canvas scene format; independent of package version.
- shadowBlurExtentInSigmas → const double
- Practical Gaussian-tail estimate, not a hard pixel-enclosure guarantee. Raster padding remains a separate export policy.
Functions
-
aabbOfTransformedRect(
Rect2D r, Matrix4 m) → Rect2D -
collectAllNodeIds(
{CanvasSceneDocument? doc, Node? root}) → Set< ElementId> - Collect all node IDs from a document or a subtree root.
-
collectSceneFontFamilies(
CanvasSceneDocument scene, {Iterable< String> fallbackFontFamilies = const <String>[]}) → Set<String> - Collects logical font-family dependencies referenced by a scene.
-
computePaddedContentBounds(
{required CanvasSceneDocument scene, required ComputedScene computed, ContentBoundsPolicy policy = const ContentBoundsPolicy(), double paddingPx = 0}) → Rect2D? -
computeScene(
CanvasSceneDocument doc, CoreServices services) → ComputedScene -
computeViewport(
{required Rect2D sourceBounds, required double targetW, required double targetH, double? minUniformScale, double? maxUniformScale}) → CanvasViewportTransform -
Contains
sourceBoundsinside the target dimensions. -
decodeCanvasScene(
Map< String, Object?> json) → CanvasSceneDocument - Decodes current persisted JSON: strict wire checks, decoding, then integrity.
-
encodeCanvasScene(
CanvasSceneDocument scene) → Map< String, Object?> - Checks runtime integrity before recursive encoding to the current format.
-
estimateAppearancePaintBounds(
{required Rect2D? sourceBounds, required bool foregroundPresent, required Iterable< CanvasSourceUnderlay> underlays}) → Rect2D? - Estimates visible paint for a text/icon appearance.
-
estimateSourceUnderlayPaintBounds(
Rect2D sourceBounds, CanvasSourceUnderlay underlay) → Rect2D? - Returns the paint estimate produced by one underlay from the ORIGINAL source bounds.
-
evaluateScene(
CanvasSceneDocument preparedScene, CoreServices services, {ContentBoundsSpec? contentBounds}) → SceneEvaluation - Evaluate the prepared scene using the caller's stable service bundle.
-
fillContributesToPaint(
CanvasFill fill) → bool - Whether a foreground has any visible color. Geometry and node visibility are evaluated separately; source underlays do not depend on this result.
-
findById(
CanvasSceneDocument doc, ElementId id) → Node? - Find a node anywhere in the tree.
-
findParentOf(
CanvasSceneDocument doc, ElementId id) → ParentRef? -
Find parent + child-index of node
id. If the node is a root child, returns (parent: null, index: i). -
nodesInFrontToBackOrder(
List< Node> children) → List<Node> - Layer panels typically show frontmost first.
-
nodesInPaintOrder(
List< Node> children) → List<Node> - Sibling order is paint order:
-
parseCanvasAssetRef(
String input) → CanvasAssetRef -
replaceById(
CanvasSceneDocument doc, ElementId id, Node updated) → CanvasSceneDocument -
Replace node
idwithupdatedanywhere in the tree. -
requireCanvasSceneIntegrity(
CanvasSceneDocument document) → void - Rejects invalid generic scene data before recursive processing or resource work.
-
rewritePostOrder(
Node n, Node fn(Node), {bool skip(Node)?, bool prune(Node)?}) → Node - Post-order tree rewrite:
-
rewriteSceneDocument(
CanvasSceneDocument doc, Node rewriteRoot(Node)) → CanvasSceneDocument - Rewrite every root subtree in a scene document and preserve identity when no root changed.
-
shadowContributesToPaint(
ShadowEffect shadow) → bool - Invalid numeric/color values are skipped defensively by bounds/rendering. The document validator still reports invalid authored data, including for disabled effects.
-
sourceUnderlayContributesToPaint(
CanvasSourceUnderlay underlay) → bool -
strokeContributesToPaint(
CanvasStroke? stroke) → bool - Whether the configured stroke can paint pixels. Invalid colors and widths are skipped defensively; validation still reports them on invisible strokes.
-
upgradeCanvasScene(
Map< String, Object?> json, {bool legacyUnversioned = false, bool? resolveLegacyIconWasGlyph(String iconRef)?}) → Map<String, Object?> - Brings persisted scene JSON to the current Canvas scene format.
-
visitSceneNodes(
CanvasSceneDocument doc, {bool includeHidden = false, required void visit(Node node)}) → void - Pure traversal: iterate all nodes (optionally skipping hidden subtrees).
Typedefs
- CanvasAssetId = String
- Document-local identifier for an entry in a scene's asset registry.
- Color32 = int
-
32-bit ARGB color. Same layout as Flutter's
Colorunder the hood: 0xAARRGGBB (e.g., 0xFF112233). - ContentBoundsElementSelector = ElementId? Function(CanvasSceneDocument scene)
-
ContentBoundsFallbackSelector
= Iterable<
ElementId> Function(CanvasSceneDocument scene) - ElementId = String
- FontWeightNum = int
- Numeric font weight (100, 200, …, 900). Common values: 400 (normal), 700 (bold).
- ImagePlacement = ({Rect2D dst, Rect2D src})
- ScenePreparer = CanvasSceneDocument Function(CanvasSceneDocument scene, CoreServices services)
- Pure, synchronous transformation from one runtime scene to another.