Migrate raster rendering backend from SkiaSharp to CanvasNet

.cspell.yaml

@@ -19,6 +19,7 @@ words:
   - Antlr
   - antlr
   - Blockquotes
+  - CanvasNet
   - Postconditions
   - buildmark
   - buildtransitive

.fileassert.yaml

@@ -12,21 +12,23 @@ tests:
 
   # --- PACKAGE ---
   # The Tool package previously ballooned to ~435 MB because native SkiaSharp runtime
-  # assets shipped with their debug symbols (.pdb) alongside the binaries. These tests
-  # just guard against that regression: the packed size stays under budget, the tool's
-  # main assembly and README are present, and no .pdb files leak into the native
-  # runtimes folder.
+  # assets shipped with their debug symbols (.pdb) alongside the binaries. Since the
+  # CanvasNet migration replaced SkiaSharp with a pure-managed renderer, the tool no
+  # longer ships any native runtime assets at all. These tests guard against a
+  # regression back to native assets: the packed size stays under a much smaller
+  # budget, the tool's main assembly and README are present, and no "runtimes" folder
+  # (native or otherwise) exists in the package.
 
   - name: Package_ToolSizeWithinLimit
     description: "Tool package stays within its size budget"
     tags: [package]
     files:
       - pattern: "artifacts/packages/DemaConsulting.SysML2Tools.Tool.*.nupkg"
         count: 1
-        max-size: 73400320  # 70 MiB
+        max-size: 10485760  # 10 MiB
 
   - name: Package_ToolContentsValid
-    description: "Tool package contains its main assembly and README, with no stray native symbol files"
+    description: "Tool package contains its main assembly and README, with no native runtime assets"
     tags: [package]
     files:
       - pattern: "artifacts/packages/DemaConsulting.SysML2Tools.Tool.*.nupkg"
@@ -37,9 +39,9 @@ tests:
             - pattern: "tools/net10.0/any/DemaConsulting.SysML2Tools.dll"
               min: 1
               max: 1
-            # Native SkiaSharp runtime assets must not ship with .pdb symbol files -
-            # this is what caused the historical ~435 MB package-size bloat.
-            - pattern: "tools/net10.0/any/runtimes/**/*.pdb"
+            # The tool is now a pure-managed package (post-CanvasNet migration):
+            # no "runtimes" folder of any kind - native or otherwise - should ship.
+            - pattern: "tools/net10.0/any/runtimes/**"
               max: 0
 
   # --- BUILD NOTES ---

AGENTS.md

@@ -8,7 +8,7 @@
   suitable for architecture documentation, CI/CD pipelines, and AI-assisted modeling
   workflows.
 - **languages**: C#
-- **technologies**: .NET, ANTLR4, SkiaSharp
+- **technologies**: .NET, ANTLR4, CanvasNet
 
 # Project Structure
 

README.md

@@ -42,7 +42,7 @@ documentation, CI/CD pipelines, and AI-assisted modeling workflows.
   engine with orthogonal specialization and membership edges, depth-coded fill colors, compartments,
   and configurable depth limiting
 - **SVG Output**: Zero external dependencies
-- **PNG Output**: Pixel-identical across Windows, Linux, and macOS via SkiaSharp and an
+- **PNG Output**: Pixel-identical across Windows, Linux, and macOS via CanvasNet and an
   embedded Noto Sans font
 - **NuGet Library**: Publishable packages with a stable public API — use the parser,
   semantic model, or layout engine independently of the CLI tool

ROADMAP.md

@@ -101,7 +101,7 @@ runs 9 tests following the `SysML2Tools_{Capability}SelfTest` naming convention:
 lint, SVG render, PNG render, dynamic-view SVG/PNG render, dynamic-view filtered render, and
 export — but every render test (SVG, PNG, and dynamic-view) exercises only the **General View**
 (`SelfTestModel`'s `GeneralView`). Add one SVG+PNG-validating test per remaining view kind so
-SkiaSharp native assets and each view's layout strategy are exercised on every OS:
+the rendering pipeline and each view's layout strategy are exercised on every OS:
 
 | Test | Proves |
 |---|---|
@@ -126,17 +126,15 @@ size bloat and verifying the main assembly/README are present with no stray nati
 open:
 
 1. **Tool smoke test:** install the packed tool from a local feed into a clean directory → run
-   `--version`, render a sample to **both SVG and PNG** (PNG proves SkiaSharp natives resolve),
-   and `--licenses`.
+   `--version`, render a sample to **both SVG and PNG** (PNG exercises the managed CanvasNet
+   renderer), and `--licenses`.
 2. **Library-consumer smoke test:** a throwaway project referencing each library package from the
-   local feed → restore → exercise parse→layout→render-to-SVG-in-memory and render-to-PNG (again
-   proving SkiaSharp natives for `.Png` consumers).
+   local feed → restore → exercise parse→layout→render-to-SVG-in-memory and render-to-PNG.
 
 ### Licensing, docs, gallery, publish
 
 - **Licensing/attribution:** `--licenses` output covering Noto Sans (SIL OFL 1.1) and other OTS;
-  per-package README notes incl. the SkiaSharp native-assets requirement for
-  `DemaConsulting.SysML2Tools.Png` consumers.
+  per-package README notes.
 - **Documentation:** README and User Guide state that the Geometry View is not yet supported.
   Finalise the layout-algorithm reference in `docs/` and wire it into CI (`build.yaml`,
   `.fileassert.yaml`, `.reviewmark.yaml`).

docs/design/introduction.md

@@ -274,14 +274,15 @@ Review-sets: defined in `.reviewmark.yaml`
 | Language / runtime | C# / .NET 8+ | MIT |
 | Parser generator | ANTLR4 (`Antlr4.Runtime.Standard`) | BSD-3-Clause |
 | SysML v2 grammar | `antlr/grammars-v4` (official OMG KEBNF) | MIT |
-| PNG rendering | SkiaSharp | MIT |
+| PNG rendering | CanvasNet | MIT |
 | Embedded font | Noto Sans | SIL OFL 1.1 |
 | Test results output | `DemaConsulting.TestResults` | — |
 | Unit testing | xUnit v3 | Apache 2.0 |
 
-No ImageSharp dependency. The off-the-shelf `DemaConsulting.Rendering.Skia` PNG renderer uses
-SkiaSharp, chosen over ImageSharp to avoid the Six Labors Split License, which would impose
-licensing obligations on library consumers embedding the renderer in commercial products.
+No ImageSharp dependency. The off-the-shelf `DemaConsulting.Rendering.CanvasNet` PNG renderer uses
+CanvasNet, a pure-managed rendering library, chosen over ImageSharp to avoid the Six Labors Split
+License, which would impose licensing obligations on library consumers embedding the renderer in
+commercial products.
 
 ## Architectural Decisions
 
@@ -293,10 +294,10 @@ in native graphics binaries. The `IRenderer` interface is the extension point.
 any user files are parsed. Single-file input is the degenerate case of a multi-file
 workspace; there is no single-file mode.
 
-**SkiaSharp over ImageSharp.** SkiaSharp is MIT-licensed. ImageSharp v2+ uses the
+**CanvasNet over ImageSharp.** CanvasNet is MIT-licensed. ImageSharp v2+ uses the
 Six Labors Split License which imposes obligations on commercial library consumers.
-SkiaSharp's native asset requirement is transparent for tool consumers (handled by
-NuGet at publish time) and is a known, documented constraint for library consumers.
+CanvasNet is a pure-managed library with no native asset requirement, so this
+constraint no longer applies to tool or library consumers.
 
 **Embedded Noto Sans font.** Ensures pixel-identical PNG output across all platforms.
 Noto Sans is licensed SIL OFL 1.1 which explicitly permits embedding in software.
@@ -351,10 +352,9 @@ tests the integrated tool, not just unit-level components.
 SARIF output can be added as a formatting option on the existing infrastructure
 without any breaking changes.
 
-**SkiaSharp native assets for library consumers.** Consumers referencing the off-the-shelf
-`DemaConsulting.Rendering.Skia` PNG renderer must ensure the appropriate
-`SkiaSharp.NativeAssets.*` package is included in their publish output. This must
-be documented clearly in the package README.
+**Pure-managed rendering — no native assets required.** Consumers referencing the
+off-the-shelf `DemaConsulting.Rendering.CanvasNet` PNG renderer have no native asset
+package to add: CanvasNet is a pure-managed .NET library with no P/Invoke dependency.
 
 **Noto Sans SIL OFL attribution.** OFL requires the copyright notice and license
 text to be included in distributions. Must appear in NuGet package notices and the

docs/design/sysml2-tools-core/rendering.md

@@ -4,7 +4,7 @@
 
 The Rendering subsystem wires together the rendering pipeline for SysML2 Tools. It bridges the
 Layout subsystem (which produces a `LayoutTree`) and the off-the-shelf renderer packages
-(`DemaConsulting.Rendering.Svg` and `DemaConsulting.Rendering.Skia`) using the contracts that
+(`DemaConsulting.Rendering.Svg` and `DemaConsulting.Rendering.CanvasNet`) using the contracts that
 both sides must satisfy.
 
 The SysML-agnostic rendering contracts — `IRenderer` (low-level render interface), `Theme`
@@ -179,7 +179,7 @@ flowchart TD
   `DemaConsulting.SysML2Tools.Semantic`; the `using` directive `using DemaConsulting.SysML2Tools.Semantic;`
   is required in `ILayoutStrategy.cs` and `DiagramRenderer.cs`.
 - The `IRenderer` implementations come from the off-the-shelf `DemaConsulting.Rendering.Svg` and
-  `DemaConsulting.Rendering.Skia` packages, referenced by the Tool via `<PackageReference>`.
+  `DemaConsulting.Rendering.CanvasNet` packages, referenced by the Tool via `<PackageReference>`.
 
 ### Requirements Traceability
 

docs/design/sysml2-tools-tool/render.md

@@ -143,7 +143,7 @@ future-locale story, which applies identically here.
   qualified view names, and `SynthesizeDynamicView` used by `TryProcessDynamicView` to build the
   ad-hoc view node for `--view-type`/`--view-target`/`--filter`
 - `SvgRenderer` (in `DemaConsulting.Rendering.Svg`) — produces SVG output
-- `PngRenderer` (in `DemaConsulting.Rendering.Skia`) — produces PNG output
+- `PngRenderer` (in `DemaConsulting.Rendering.CanvasNet`) — produces PNG output
 - `Themes.Light` (in `DemaConsulting.Rendering.Abstractions`) — default theme
 - `Context`/`RenderCommandOptions`/`RenderArgumentParser` (in `DemaConsulting.SysML2Tools.Cli`
   and `DemaConsulting.SysML2Tools.Render`) — reads arguments; writes output

docs/design/sysml2-tools-tool/self-test/validation.md

@@ -76,15 +76,12 @@ with `WorkspaceLoader.LoadAsync`, calls `DiagramRenderer.RenderWorkspace` with
 `outputs.Count > 0 && outputs[0].Data.Length > 0`. Records pass or fail. Any exception is
 caught and recorded via `HandleTestException`.
 
-**RunRenderPngSelfTestAsync**: Verifies that `SelfTestModel` renders to a non-empty PNG stream,
-or skips gracefully when SkiaSharp is unavailable.
+**RunRenderPngSelfTestAsync**: Verifies that `SelfTestModel` renders to a non-empty PNG stream.
 
 - *Parameters*: `Context context`, `DemaConsulting.TestResults.TestResults testResults`.
 - *Returns*: `Task`.
 
-Calls `NativeLibrary.TryLoad("libSkiaSharp", ...)` first. If the library is absent, records
-the test as `Passed` with a skip message and returns early. Otherwise frees the handle, writes
-`SelfTestModel` to a temp file, loads the workspace, calls `DiagramRenderer.RenderWorkspace`
+Writes `SelfTestModel` to a temp file, loads the workspace, calls `DiagramRenderer.RenderWorkspace`
 with `new PngRenderer()`, and asserts non-empty output. Records pass or fail. Any exception
 is caught and recorded via `HandleTestException`.
 
@@ -105,9 +102,7 @@ distinct failure message when `diagnostic` is non-null or workspace loading fail
 exception is caught and recorded via `HandleTestException`.
 
 **RunRenderDynamicViewPngSelfTestAsync**: Mirrors
-`RunRenderDynamicViewSvgSelfTestAsync` but with the PNG renderer, skipping gracefully (same
-`NativeLibrary.TryLoad("libSkiaSharp", ...)` guard) when the native SkiaSharp library is
-unavailable.
+`RunRenderDynamicViewSvgSelfTestAsync` but with the PNG renderer.
 
 - *Parameters*: `Context context`, `DemaConsulting.TestResults.TestResults testResults`.
 - *Returns*: `Task`.

docs/reqstream/ots/dema-rendering.yaml

@@ -3,7 +3,7 @@
 #
 # Requirements for the DemaConsulting.Rendering package family (DemaConsulting.Rendering,
 # DemaConsulting.Rendering.Abstractions, DemaConsulting.Rendering.Layout,
-# DemaConsulting.Rendering.Svg, DemaConsulting.Rendering.Skia) that SysML2Tools consumes for
+# DemaConsulting.Rendering.Svg, DemaConsulting.Rendering.CanvasNet) that SysML2Tools consumes for
 # SysML-agnostic layout and rendering. Each requirement is verified indirectly through SysML2Tools
 # tests that drive the package family end-to-end.
 
@@ -91,7 +91,7 @@ sections:
             title: >-
               DemaConsulting.Rendering shall render a laid-out layout tree to a valid PNG image.
             justification: |
-              SysML2Tools produces raster output through the package's Skia-based PngRenderer. The
+              SysML2Tools produces raster output through the package's CanvasNet-based PngRenderer. The
               renderer must turn a LayoutTree into a valid PNG image, evidenced by PNG bytes
               produced from an empty tree and from full workspace renders.
             tags: [ots]