Goo.SvgCompiler 0.5.0

Goo SVG compiler

Goo.SvgCompiler converts the accepted SVG subset into deterministic little-endian GCV1 bytes.

Install the framework-dependent .NET tool:

dotnet tool install --global Goo.SvgCompiler --version 0.5.0
goo-svgc --check input.svg
goo-svgc input.svg output.gcv1

The tool targets .NET 10 and has no runtime package dependencies. It emits a compact GCV1 asset for embedding by an application that references Goo.

dotnet run --project tools/Goo.SvgCompiler -c Release -- \
  tools/Goo.SvgCompiler/samples/s13-representative.svg /tmp/s13.gcv1

--check compiles twice, verifies byte-for-byte deterministic output, validates the current 11-section GCV1 header, sections, and track/keyframe contents without writing a file, and reports the SHA-256. --goo-check performs the same deterministic check before loading the bytes through Goo.CompiledVectorAsset.Load.

dotnet run --project tools/Goo.SvgCompiler -c Release -- --check \
  tools/Goo.SvgCompiler/samples/s13-animated.svg

The static subset includes a positive viewBox, groups, affine transforms, inherited opacity, paths, rectangles, ellipses, lines, polylines, polygons, solid paints, local linear and radial gradients with stops for fills, solid-color strokes and dashes, and user-space path clips. Gradient strokes are rejected because the GCV1 stroke path has no compatible gradient representation. Object-bounding-box gradient transforms are rejected because their coordinate space is not retained by GCV1. Radial gradient focal attributes, user-space radius percentages, and non-axis-aligned gradient transforms are rejected because the Vulkan radial primitive preserves only center and axis-aligned radii.

The controlled animation subset includes animateTransform for matrix, translate, scale, rotate, skewX, and skewY values. animate supports node opacity, solid fill and stroke colors, stroke width, miter limit, line cap, line join, and dash offset. Values use values or from and to. Key times, linear, step, and cubic spline easing are bounded and deterministic. Begin must be immediate, additive and accumulate modes must be replace and none, restart must be always, and fill must be freeze. Finite integer repeats from one through 64 are unrolled. repeatCount="indefinite" emits the GCV1 loop flag. Path morph animation uses attributeName="d" or attributeName="path", normalizes every target with the same path parser as static geometry, and requires identical contour count, curve count, closed flags, and endpoint connectivity. Morph keyframes use the same linear, step, and cubic spline easing fields as regular keyframes.

The compiler rejects event-driven or delayed timing, CSS animation, additive or accumulate semantics, general SMIL elements, filters, masks, scripts, selectors, external references, runtime DOM features, unsupported paint or stroke properties, and incompatible path morph targets. It reports a deterministic line and column diagnostic when a target has incompatible topology.

The emitted morph ABI is:

1. Use the current 11-section, 172-byte GCV1 header. Section 10 is MorphCurves with 24-byte records containing X0, Y0, CX, CY, X1, and Y1 float32 values.
2. Add Morph as track kind 4 and value kind 4. A morph track uses the existing 24-byte track record and points at existing 48-byte keyframes.
3. A morph node stores its track index at node byte offset 44. The base node contours define the topology and curve count.
4. A morph keyframe stores Time as float32 at offset 0, TargetCurveStart as uint32 at offset 4, and TargetCurveCount as uint32 at offset 8. Offsets 12 through 24 remain zero. Offsets 28 through 44 use the regular keyframe easing and cubic control fields. The target count must equal the sum of base curve counts, and the target range must lie in MorphCurves.
5. Each target curve sequence must preserve base contour count, curve count, open or closed state, and exact endpoint continuity. The runtime validates this topology before accepting the asset.

This tool emits morph tracks without changing the Goo ABI.