Split SVGDocument into separate svg package

README.mbt.md

@@ -76,7 +76,7 @@ test "basic_shapes" (it : @test.Test) {
     .close_path()
 
   // Create SVG output with advanced shapes
-  let svg_doc = @vg.new_svg(200.0, 200.0)
+  let svg_doc = @svg.new_svg(200.0, 200.0)
     .render_circle(@vg.Point::new(100.0, 100.0), 50.0, @color.red())
     .render_ellipse(@vg.Point::new(150.0, 100.0), 30.0, 20.0, @color.blue())
     .render_path(custom_path, @color.green())
@@ -225,7 +225,7 @@ test "paths examples" {
   }
 
   // Render path to SVG
-  let svg = @vg.new_svg(100.0, 100.0).render_path(path, @color.green())
+  let svg = @svg.new_svg(100.0, 100.0).render_path(path, @color.green())
 
   // Use the variables to avoid unused warnings
   ignore(rectangle)

REFACTORING_SVG_PACKAGE.md

@@ -0,0 +1,195 @@
+# SVG Package Refactoring
+
+**Date:** November 22, 2025
+
+## Overview
+
+This refactoring splits out the `SvgDocument` type and all SVG rendering utilities into a separate `svg` package to improve modularity and reduce coupling in the VG vector graphics library. This follows the same pattern previously used for the geometry and color package refactorings. Importantly, the `Image::render_image_to_svg` method is kept in the main `vg` package as it represents a rendering backend method for the Image type.
+
+## Changes Made
+
+### New Package Structure
+
+Created `svg/` package with:
+- `svg/types.mbt` - Core SvgDocument type definition
+- `svg/svg.mbt` - All SVG rendering methods and utilities
+- `svg/moon.pkg.json` - Package configuration with dependencies on geometry and color packages
+
+### Type Migration
+
+**Moved from `vg` package to `svg` package:**
+- `SvgDocument` struct - SVG document representation with width, height, and elements array
+
+**SVG functions moved:**
+- Document creation: `new_svg`
+- Document manipulation: `SvgDocument::add_element`, `SvgDocument::to_string`
+- Rendering methods: `SvgDocument::render_circle`, `SvgDocument::render_rectangle`, `SvgDocument::render_path`, `SvgDocument::render_line`, `SvgDocument::render_text`, `SvgDocument::render_ellipse`, `SvgDocument::render_polygon`, `SvgDocument::render_linear_gradient`
+- Helper functions: `color_to_svg`, `point_to_svg`, `path_to_svg_data`
+
+**Kept in `vg` package:**
+- `Image::render_image_to_svg` - Image rendering method (uses `@svg` namespace internally)
+
+### Dependency Management
+
+**Main package (`vg`) changes:**
+- Updated `moon.pkg.json` to import `bobzhang/vg/svg`
+- Modified `types.mbt` to re-export SvgDocument type using type alias:
+  ```moonbit
+  pub type SvgDocument = @svg.SvgDocument
+  ```
+- Updated `svg.mbt` to only contain `Image::render_image_to_svg` method
+- Image rendering method now uses `@svg.new_svg` to create SVG documents
+
+**SVG package dependencies:**
+- Imports `bobzhang/vg/geometry` for Point and Path types
+- Imports `bobzhang/vg/color` for Color type and utilities
+
+### Code Updates Required
+
+**In test files and documentation:**
+- Replaced `@vg.new_svg` with `@svg.new_svg`
+- All SvgDocument methods now accessed through the `@svg` namespace
+
+**Examples:**
+```moonbit
+// Before:
+let doc = @vg.new_svg(100.0, 100.0)
+  .render_circle(Point::new(50.0, 50.0), 25.0, @color.red())
+
+// After:
+let doc = @svg.new_svg(100.0, 100.0)
+  .render_circle(Point::new(50.0, 50.0), 25.0, @color.red())
+```
+
+**Files updated:**
+- All test files (svg_test.mbt, oo_api_test.mbt, renderer_test.mbt, hello_test.mbt, advanced_test.mbt)
+- README.mbt.md
+- svg.mbt (now only contains Image::render_image_to_svg)
+- types.mbt (added SvgDocument type re-export)
+- moon.pkg.json (added svg package import)
+
+### Backward Compatibility
+
+The SvgDocument type remains accessible through the main package:
+- The SvgDocument type is re-exported from the main package via type alias
+- All existing type references like `SvgDocument` still work
+- However, the creation and manipulation functions now require the `@svg` namespace
+- This is a breaking change in the public API (functions moved from `@vg` to `@svg` namespace)
+
+### Test Results
+
+- All 175 tests pass
+- No errors, only existing warnings about using package-qualified names in geometry package tests
+- Build verification: `moon check` and `moon test` both succeed
+
+## Migration Guide for External Users
+
+If you're using the VG library and upgrading:
+
+### Using SVG Functions
+
+SVG functions must now be accessed through the `@svg` namespace:
+
+```moonbit
+// Creating SVG documents
+let doc = @svg.new_svg(200.0, 200.0)
+
+// Rendering shapes
+let doc = @svg.new_svg(100.0, 100.0)
+  .render_circle(@vg.Point::new(50.0, 50.0), 25.0, @color.red())
+  .render_rectangle(10.0, 10.0, 80.0, 80.0, @color.blue())
+  .render_text("Hello", @vg.Point::new(50.0, 50.0), 16.0, @color.black())
+
+// Converting to string
+let svg_string = doc.to_string()
+```
+
+### Using the SvgDocument Type
+
+The SvgDocument type is still available through the main package via type alias:
+
+```moonbit
+// Type references work as before
+let doc : SvgDocument = @svg.new_svg(100.0, 100.0)
+let doc2 : @vg.SvgDocument = @svg.new_svg(100.0, 100.0)
+```
+
+### Image to SVG Rendering
+
+The `Image::render_image_to_svg` method remains in the main `vg` package:
+
+```moonbit
+let img = @vg.Image::circle(@color.red(), 25.0)
+let svg_string = img.render_image_to_svg(100.0, 100.0, 20)
+```
+
+### Migration from Previous Version
+
+If you have existing code that used `@vg.new_svg`, update to use `@svg`:
+
+```moonbit
+// Before:
+let doc = @vg.new_svg(100.0, 100.0)
+
+// After:
+let doc = @svg.new_svg(100.0, 100.0)
+```
+
+## Benefits
+
+1. **Modularity** - SVG rendering types and utilities can be used independently of the full VG library
+2. **Clarity** - Clear separation between SVG rendering backend and core image/graphics functionality
+3. **Testability** - SVG package can have its own focused test suite
+4. **Reusability** - Other packages can depend on just the svg package if needed for SVG generation
+5. **Type Safety** - No change in type safety, all benefits of strong typing preserved
+6. **Consistency** - Follows the same pattern as the geometry and color package refactorings
+7. **Proper Architecture** - Keeps Image methods in the main package while SVG document operations are in the svg package
+
+## Files Modified
+
+- `svg/` - New package directory with types and rendering utilities
+- `types.mbt` - Added SvgDocument type re-export
+- `svg.mbt` - Reduced to only contain Image::render_image_to_svg method
+- All test files - Updated from `@vg.new_svg()` to `@svg.new_svg()`
+- `README.mbt.md` - Updated all examples to use `@svg` namespace
+- `moon.pkg.json` - Added svg package import
+
+## Files Structure
+
+```
+vg/
+├── color/
+│   ├── types.mbt        # Color struct definition
+│   ├── color.mbt        # Color utilities and functions
+│   ├── color_test.mbt   # Color-specific tests
+│   └── moon.pkg.json    # Color package configuration
+├── geometry/            # Geometry package (previously refactored)
+│   ├── types.mbt
+│   ├── point.mbt
+│   ├── path.mbt
+│   ├── transform.mbt
+│   └── moon.pkg.json
+├── svg/
+│   ├── types.mbt        # SvgDocument struct definition
+│   ├── svg.mbt          # SVG rendering methods and utilities
+│   └── moon.pkg.json    # SVG package configuration (depends on geometry and color)
+├── types.mbt            # Type re-exports (Color, Point, Path, SvgDocument, etc.)
+├── svg.mbt              # Image::render_image_to_svg only
+└── moon.pkg.json        # Main package configuration (imports color, geometry, svg packages)
+```
+
+## Notes
+
+- The svg package depends on both geometry and color packages
+- Type aliases ensure SvgDocument type is available through `@vg.SvgDocument`
+- All SVG functions must be accessed via `@svg` namespace (no re-export wrappers)
+- `Image::render_image_to_svg` remains in the main `vg` package as specified in the requirements
+- This refactoring changes the public API - SVG functions moved from `@vg` to `@svg` namespace
+- The pattern matches geometry and color packages: types re-exported, functions in dedicated namespace
+
+## Future Work
+
+With geometry, color, and svg now separated into independent packages, the library has a clean modular architecture. Future work could include:
+- Additional rendering backends (Canvas, PDF) as separate packages
+- Image composition and manipulation utilities as a separate package
+- More advanced SVG features (filters, animations, etc.)

advanced_test.mbt

@@ -11,7 +11,7 @@ test "quadratic bezier curves" (it : @test.Test) {
     qcurve_path,
     content="Path([MoveTo({x: 10, y: 50}), QCurveTo({x: 50, y: 10}, {x: 90, y: 50}), QCurveTo({x: 50, y: 90}, {x: 10, y: 50}), Close])",
   )
-  let doc = @vg.new_svg(100.0, 100.0)
+  let doc = @svg.new_svg(100.0, 100.0)
     .render_rectangle(0.0, 0.0, 100.0, 100.0, @color.gray(0.95))
     .render_path(qcurve_path, @color.blue())
   let svg_string = doc.to_string()
@@ -30,7 +30,7 @@ test "elliptical arcs" (it : @test.Test) {
     arc_path,
     content="Path([MoveTo({x: 20, y: 50}), EArcTo(30, 20, 0, false, true, {x: 80, y: 50}), EArcTo(30, 20, 0, false, true, {x: 20, y: 50}), Close])",
   )
-  let doc = @vg.new_svg(100.0, 100.0)
+  let doc = @svg.new_svg(100.0, 100.0)
     .render_rectangle(0.0, 0.0, 100.0, 100.0, @color.gray(0.95))
     .render_path(arc_path, @color.green())
   let svg_string = doc.to_string()
@@ -53,7 +53,7 @@ test "smooth curve stitching" (it : @test.Test) {
     smooth_path,
     content="Path([MoveTo({x: 10, y: 50}), CurveTo({x: 30, y: 10}, {x: 50, y: 10}, {x: 70, y: 50}), CurveTo({x: 90, y: 90}, {x: 110, y: 90}, {x: 130, y: 50}), CurveTo({x: 150, y: 10}, {x: 150, y: 10}, {x: 170, y: 50})])",
   )
-  let doc = @vg.new_svg(180.0, 100.0)
+  let doc = @svg.new_svg(180.0, 100.0)
     .render_rectangle(0.0, 0.0, 180.0, 100.0, @color.gray(0.95))
     .render_path(smooth_path, @color.purple())
   let svg_string = doc.to_string()
@@ -126,7 +126,7 @@ test "checkerboard pattern" (it : @test.Test) {
 
 ///|
 test "advanced path showcase" (it : @test.Test) {
-  let doc = @vg.new_svg(400.0, 300.0)
+  let doc = @svg.new_svg(400.0, 300.0)
     .render_rectangle(0.0, 0.0, 400.0, 300.0, @color.gray(0.98))
     .render_text(
       "Advanced Path Features",

hello_test.mbt

@@ -69,7 +69,7 @@ test "path to SVG integration" {
     .close_path()
 
   // Render to SVG
-  let doc = @vg.new_svg(150.0, 100.0).render_path(path, @color.magenta())
+  let doc = @svg.new_svg(150.0, 100.0).render_path(path, @color.magenta())
   let svg_string = doc.to_string()
   if not(svg_string.contains("path")) {
     fail("Should contain path element")
@@ -154,7 +154,7 @@ test "color operations" {
 ///|
 test "complete vg library showcase" (it : @test.Test) {
   // Create a comprehensive demo showcasing all VG features
-  let doc = @vg.new_svg(600.0, 500.0)
+  let doc = @svg.new_svg(600.0, 500.0)
     .render_rectangle(0.0, 0.0, 600.0, 500.0, @color.gray(0.97)) // Light background
     .render_text(
       "MoonBit VG Library - Complete Showcase",

moon.pkg.json

@@ -2,6 +2,7 @@
   "is-main": false,
   "import": [
     "bobzhang/vg/geometry",
-    "bobzhang/vg/color"
+    "bobzhang/vg/color",
+    "bobzhang/vg/svg"
   ]
 }

oo_api_test.mbt

@@ -3,7 +3,7 @@
 ///|
 test "svg oo-style api" (it : @test.Test) {
   // Demonstrate fluent OO-style API for SVG
-  let doc = @vg.new_svg(300.0, 200.0)
+  let doc = @svg.new_svg(300.0, 200.0)
     .render_rectangle(0.0, 0.0, 300.0, 200.0, @color.gray(0.95))
     .render_circle(@vg.Point::new(80.0, 100.0), 30.0, @color.red())
     .render_rectangle(150.0, 70.0, 60.0, 60.0, @color.green())
@@ -83,7 +83,7 @@ test "oo-style path with document integration" (it : @test.Test) {
     .close_path()
 
   // Use the same path across all OO-style renderers
-  let svg_doc = @vg.new_svg(250.0, 150.0)
+  let svg_doc = @svg.new_svg(250.0, 150.0)
     .render_rectangle(0.0, 0.0, 250.0, 150.0, @color.white())
     .render_path(custom_path, @color.purple())
     .render_text(
@@ -125,7 +125,7 @@ test "oo-style api comparison" (it : @test.Test) {
   // Compare functional vs OO-style APIs
 
   // Functional style (original)
-  let svg_functional = @vg.new_svg(200.0, 100.0)
+  let svg_functional = @svg.new_svg(200.0, 100.0)
     .render_circle(@vg.Point::new(100.0, 50.0), 25.0, @color.red())
     .render_text(
       "Functional Style",
@@ -135,7 +135,7 @@ test "oo-style api comparison" (it : @test.Test) {
     )
 
   // OO style (new)  
-  let svg_oo = @vg.new_svg(200.0, 100.0)
+  let svg_oo = @svg.new_svg(200.0, 100.0)
     .render_circle(@vg.Point::new(100.0, 50.0), 25.0, @color.red())
     .render_text("OO Style", @vg.Point::new(100.0, 80.0), 12.0, @color.black())
 
@@ -175,7 +175,7 @@ test "complete oo-style showcase" (it : @test.Test) {
     .smooth_ccurve_to(@vg.Point::new(225.0, 125.0), @vg.Point::new(275.0, 75.0))
     .earc_to(25.0, 15.0, 0.0, false, true, @vg.Point::new(225.0, 100.0))
     .close_path()
-  let svg_showcase = @vg.new_svg(350.0, 200.0)
+  let svg_showcase = @svg.new_svg(350.0, 200.0)
     .render_rectangle(0.0, 0.0, 350.0, 200.0, @color.gray(0.98))
     .render_text(
       "Complete OO-Style API Showcase",

renderer_test.mbt

@@ -137,7 +137,7 @@ test "renderer comparison showcase" (it : @test.Test) {
   // Create the same graphics with all three renderers
 
   // SVG version
-  let svg_doc = @vg.new_svg(250.0, 150.0)
+  let svg_doc = @svg.new_svg(250.0, 150.0)
     .render_rectangle(0.0, 0.0, 250.0, 150.0, @color.gray(0.95))
     .render_circle(@vg.Point::new(125.0, 75.0), 40.0, @color.red())
     .render_text("VG Demo", @vg.Point::new(125.0, 30.0), 16.0, @color.black())
@@ -195,7 +195,7 @@ test "complete feature showcase all renderers" (it : @test.Test) {
     .close_path()
 
   // SVG with all advanced features
-  let svg_doc = @vg.new_svg(350.0, 200.0)
+  let svg_doc = @svg.new_svg(350.0, 200.0)
     .render_rectangle(0.0, 0.0, 350.0, 200.0, @color.white())
     .render_text(
       "Complete VG Feature Showcase",