= Doppelganger - SVG DSL for Kotlin :toc: left :toclevels: 3 :source-highlighter: highlightjs :icons: font

A comprehensive and type-safe DSL for creating and rendering SVG graphics in Compose Multiplatform applications and Kobweb sites.

== Overview

Doppelganger is an SVG wrapper library that provides a Kotlin DSL for creating SVG graphics in Compose Multiplatform applications. Write SVG markup using type-safe Kotlin code and render it seamlessly across all supported platforms.

== Features

• 🎨 Type-safe DSL - Kotlin-first API for building SVG elements
• 🌐 Multiplatform - Works on JVM, Android, iOS, JS, and WebAssembly
• 🧩 Composable - Integrates seamlessly with Compose UI
• 🌐 Kobweb Support - First-class support for Kobweb web applications (JS-only)
• 📐 Comprehensive - Supports all major SVG elements and attributes
• 🎭 Gradients & Effects - Built-in support for gradients, clipping, and masking
• 🔧 Path DSL - Intuitive API for creating complex paths

== Quick Start

=== Installation

Add Doppelganger to your Compose Multiplatform project:

=== Basic Usage

Create an SVG circle in your Composable:

@Composable fun MyCircle() { SvgImage(modifier = Modifier.size(100.dp)) { width(100) height(100) viewBox(0, 0, 100, 100)

    circle {
        cx(50)
        cy(50)
        r(40)
        fill("steelblue")
        stroke("navy")
        strokeWidth(2)
    }
}

=== Kobweb Usage

Doppelganger includes special support for https://github.com/varabyte/kobweb[Kobweb] applications. See link:KOBWEB_USAGE.md[Kobweb Usage Guide] for detailed documentation.

=== Supported Elements

• Basic Shapes: rect, circle, ellipse, line, polyline, polygon
• Path: Complete path DSL with moveTo, lineTo, curveTo, arcTo, etc.
• Text: text and tspan elements with full styling
• Containers: g (group), defs, symbol, use
• Gradients: linearGradient, radialGradient with stops
• Effects: clipPath, mask

== Building from Source

To build the library:

To run tests:

To generate documentation:

== Publishing to Maven Central

This template uses a similar packaging secret method as other Malefic projects, making it easy to set up automated publishing.

For publishing to work, the following GitHub secrets must be configured in your repository:

• GPG_KEY_ID: The ID of your GPG key
• GPG_PASSPHRASE: The passphrase for your GPG key
• GPG_PRIVATE_KEY: Your GPG private key
• SONATYPE_TOKEN_XML: Your Sonatype Central Portal user token in XML format ====

=== Setting Up Secrets

==== GPG Key Setup

1. Generate a GPG key pair: [source,bash]

---

2. Export your private key: [source,bash]

---

3. Get your key ID: [source,bash]

---

4. Upload your public key to a keyserver: [source,bash]

---

==== Sonatype Setup

1. Create an account on https://central.sonatype.com/
2. Register your namespace (e.g., io.github.yourusername)
3. Generate a user token from the Account page
4. Copy the XML token block for the GitHub secret

=== Publishing Process

The template includes a GitHub Actions workflow that automatically publishes releases:

1. Create a new release on GitHub
2. The workflow will automatically build and publish to Maven Central
3. Artifacts will be available after Sonatype review (usually 15-30 minutes)

To publish manually:

== Project Structure

== Configuration

All project configuration is centralized in gradle.properties:

user=YourGitHubUsername dev=Your Full Name mail=your.email@example.com devURL=https://your-website.com

repo=YourRepositoryName g=your.group.id artifact=your-artifact-name desc=Your library description inception=2025

== Example Usage

The template includes a simple Fibonacci sequence generator as an example. Replace this with your own library code:

// Common code fun generateFibi() = sequence { var a = firstElement yield(a) var b = secondElement yield(b) while (true) { val c = a + b yield(c) a = b b = c } }

expect val firstElement: Int expect val secondElement: Int

== License

This template is licensed under the MIT License. Update the LICENSE file with your chosen license.

== Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Submit a pull request

== Resources

• https://kotlinlang.org/docs/multiplatform.html[Kotlin Multiplatform Documentation]
• https://central.sonatype.org/[Maven Central Portal]
• https://vanniktech.github.io/gradle-maven-publish-plugin/[Vanniktech Maven Publish Plugin]
• https://github.com/touchlab/Kermit[Kermit Logging Library]