Qml4Net 0.2.0

Qml4Net

A .NET library for reading and writing QGIS QML (.qml) layer style files.

Ported from qml4dart.

Status

v0.1.0 released — 31 tests passing, 95.6% line coverage.

Features

• QML Parsing -- Read QGIS .qml layer style files into a typed object model
• QML Writing -- Serialize the object model back to QML XML
• Renderer Types -- SingleSymbol, CategorizedSymbol, GraduatedSymbol, RuleRenderer (nested)
• Symbol Layers -- SimpleMarker, SvgMarker, SimpleLine, SimpleFill, RasterFill
• Property Formats -- Both new (<Option type="Map">, QGIS >= 3.26) and legacy (<prop k v>)
• Scale Visibility -- Document-level and rule-level scale-based visibility
• Zero Dependencies -- Only BCL APIs (System.Xml.Linq)

API

using Qml4Net;

var codec = new QmlCodec();

// Parse QML string
var result = codec.ParseString(qmlXml);
switch (result)
{
    case ReadQmlResult.Success { Document: var doc, Warnings: var warnings }:
        Console.WriteLine($"Renderer: {doc.Renderer.Type}");
        Console.WriteLine($"Symbols: {doc.Renderer.Symbols.Count}");
        foreach (var w in warnings)
            Console.WriteLine($"Warning: {w}");
        break;
    case ReadQmlResult.Failure { Message: var msg }:
        Console.WriteLine($"Error: {msg}");
        break;
}

// Parse QML file (async)
var fileResult = await codec.ParseFileAsync("style.qml");

// Encode to string
var writeResult = codec.EncodeString(doc);
if (writeResult is WriteQmlResult.Success { Xml: var xml })
    Console.WriteLine(xml);

// Encode to file (async)
await codec.EncodeFileAsync("output.qml", doc);

Supported QML Renderer Types

Supported Symbol Layer Types

Docker Build and Release

The repository includes a multi-stage Dockerfile for building, testing, and publishing.

• Solution: qml4net.sln
• Build stages: restore, build, test, pack, push
• Package output stage: artifacts
• Coverage gate in test: at least 90% line coverage
• Public API XML documentation comments are required (CS1591 enforced as error)

docker buildx build --target test -t qml4net:test .
docker buildx build --target artifacts --build-arg PACKAGE_VERSION=0.1.0 -o type=local,dest=./artifacts .
docker buildx build --target push --secret id=nuget_api_key,src=/path/to/nuget-api-key.txt --build-arg PACKAGE_VERSION=0.1.0 .

Notes:

• push publishes generated .nupkg files to https://api.nuget.org/v3/index.json
• The preferred credential flow is a BuildKit secret named nuget_api_key
• NUGET_API_KEY is also supported as a build argument for CI systems that cannot mount secrets

GitHub Actions

• .github/workflows/ci.yml -- runs on pushes to main and on pull requests
• .github/workflows/publish-qml4net.yml -- publishes the Qml4Net NuGet package on tags matching Qml4Net-v* or via manual workflow_dispatch

Required GitHub repository setup:

• Create a repository or environment secret named NUGET_API_KEY
• If you use GitHub environments, the publish workflow targets the nuget environment
• Publish tags must use the format Qml4Net-v<semver>, e.g. Qml4Net-v0.1.0

Example release flow:

git tag Qml4Net-v0.1.0
git push origin Qml4Net-v0.1.0

Requirements

• Target: .NET 10.0 (LTS)

Documentation

• Porting Design
• Architecture
• Releasing

Related Projects

• qml4dart -- Original Dart implementation

License

MIT