svg

gg-svg

SVG export backend for gg's recording system.

Part of the GoGPU ecosystem.

Installation

go get github.com/gogpu/gg-svg

Usage

Import with a blank identifier to register the SVG backend:

import (
    "github.com/gogpu/gg/recording"
    _ "github.com/gogpu/gg-svg" // Register SVG backend
)

func main() {
    // Create a recorder
    rec := recording.NewRecorder(800, 600)

    // Draw something
    rec.SetFillRGBA(1, 0, 0, 1) // Red
    rec.DrawRectangle(100, 100, 200, 150)
    rec.Fill()

    // Finish recording
    r := rec.FinishRecording()

    // Create SVG backend
    backend, err := recording.NewBackend("svg")
    if err != nil {
        log.Fatal(err)
    }

    // Playback to SVG
    r.Playback(backend)

    // Save to file
    if fb, ok := backend.(recording.FileBackend); ok {
        fb.SaveToFile("output.svg")
    }
}

Features

• Solid color fills and strokes
• Linear and radial gradients (with spread modes)
• Path operations (fill, stroke, clip)
• Transformations (matrix)
• Stroke styles (width, cap, join, dash patterns)
• State management (Save/Restore via groups)
• Text rendering
• Image embedding (PNG data URI)
• XML escaping for security

Output Format

The backend generates standard SVG 1.1 with:

• XML declaration
• SVG namespace
• Definitions section for gradients and clip paths
• Proper attribute encoding

Example output:

<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" width="800" height="600" viewBox="0 0 800 600">
<defs>...</defs>
<path d="M100 100L300 100L300 250L100 250Z" fill="rgb(255,0,0)" stroke="none"/>
</svg>

Limitations

• Sweep gradients fallback to first stop color (SVG limitation)
• Text uses default font (custom font embedding not supported)
• Images are embedded as PNG data URIs (increases file size)

License

MIT License - see LICENSE for details.