olve-openraster

Olve.OpenRaster

Read-only access to OpenRaster (.ora) layered image files. Source: Olve.Utilities/src/Olve.OpenRaster/.

Reference docs: README | Models | Operations

API docs: https://olivervea.github.io/Olve.Utilities/api/Olve.OpenRaster.html

Quick usage

Read an .ora file

var operation = new ReadOpenRasterFile();
var request = new ReadOpenRasterFile.Request(filePath);

var result = operation.Execute(request);
if (result.TryPickProblems(out var problems, out var file))
{
    return problems.Prepend("Failed to read .ora file");
}

// file.Version, file.Width, file.Height, file.Layers, file.Groups

Inspect layers

foreach (var layer in file.Layers)
{
    // layer.Name, layer.Source, layer.Opacity, layer.Visible
    // layer.X, layer.Y, layer.CompositeOperation, layer.Groups
}

Read a layer image with a custom parser

public class PngLayerParser : ILayerParser<Png>
{
    public Result<Png> ParseLayer(Stream stream)
    {
        var ms = new MemoryStream();
        stream.CopyTo(ms);
        ms.Position = 0;
        return Png.Open(ms);
    }
}

var parser = new PngLayerParser();
var request = new ReadLayerAs<Png>.Request(filePath, "data/layer0.png", parser);
var result = new ReadLayerAs<Png>().Execute(request);

Composite operations

var result = CompositeOperation.FromKey("svg:multiply");
if (result.TryPickValue(out var op, out _))
{
    // op.BlendingFunction == BlendingFunction.Multiply
    // op.CompositingOperator == CompositingOperator.SourceOver
}

Key points

• All operations return Result<T> from Olve.Results -- never throws.
• The library does NOT bundle an image decoder. Implement ILayerParser<T> with your preferred image library.
• .ora files are ZIP archives containing stack.xml (metadata) and layer image files.
• Layers track their parent Groups and groups track their child Layers (bidirectional).