X-Ray.PS 26.10.7019

X-Ray.PS

Reads PostScript, Encapsulated PostScript and XPS documents and converts them to PDF and raster images, in pure managed C#. Part of the X-Ray family of .NET document libraries; documentation at https://xray.curiosity.ai/.

X-Ray.PS is a port of an MIT-licensed open-source Python PostScript/XPS library. It contains a PostScript interpreter, an XPS reader and writer, a render model shared by both inputs, a PDF writer with font embedding, and a raster renderer with PNG, JPEG, BMP and TIFF encoders. The core package has no native dependencies. X-Ray.PS.Skia is an optional add-on that draws pages with SkiaSharp instead, which reproduces the original library's default raster output.

Install

dotnet add package X-Ray.PS
dotnet add package X-Ray.PS.Skia   # optional: SkiaSharp raster output

Quick start

using XRay.PS;
using XRay.PS.PostScript;
using XRay.PS.Xps;

// PostScript or EPS to PDF and PNG
var ps = PsDocument.FromFile("drawing.ps");
File.WriteAllBytes("drawing.pdf", ps.ToPdf());
File.WriteAllBytes("drawing.png", ps.ToImage(new ImageSaveOptions(ImageFormat.Png, dpi: 150)));

// XPS to PDF, and one image per page
var xps = XpsDocument.FromFile("report.xps");
File.WriteAllBytes("report.pdf", xps.ToPdf());
List<byte[]> pages = xps.ToImages(new ImageSaveOptions(ImageFormat.Png, dpi: 96));

// Build and edit documents
var doc = PsDocument.Create(isEps: true, width: 200, height: 100);
doc.GetPage(0).Canvas.DrawText("Hello", 10, 10, "Helvetica", 12);
File.WriteAllBytes("hello.eps", doc.Save());

// Wrap a PNG, JPEG, BMP or TIFF in EPS
File.WriteAllBytes("logo.eps", ImageToEps.ConvertFile("logo.png"));

Streams, cancellation, limits and recovery

Every conversion also takes a CancellationToken (last parameter) and has overloads that write to a stream, so a large PDF never exists as one array:

using var token = new CancellationTokenSource(TimeSpan.FromSeconds(60));
var options = new PdfSaveOptions
{
    JpegQuality = 75,          // re-encode raw 8-bit gray/RGB images as JPEG when that is smaller
    SuppressErrors = true,     // keep what was drawn, record a warning, go on after the next showpage
    Limits = new PsInterpreterLimits { MaxOperators = 50_000_000 },
};
using var file = File.Create("drawing.pdf");
PsDocument.FromFile("drawing.ps", token.Token).ToPdf(file, options, token.Token);
foreach (var warning in options.Warnings)
    Console.WriteLine($"{warning.Source} {warning.Code}: {warning.Message}");

// XPS: the same, with an optional page limit
XpsDocument.FromFile("report.xps", token.Token).ToPdf(file, options, maxPages: 50, token.Token);

// One stream per page
xps.ToImages(new ImageSaveOptions(ImageFormat.Png), page => File.Create($"page{page + 1}.png"), null, token.Token);

PostScript is a programming language, so a hostile file can loop forever or ask for gigabytes. The interpreter polls the token, and PsInterpreterLimits bound it even without one: executed objects (400 million by default), operand stack depth, procedure nesting, source nesting and memory. A cancelled call throws OperationCanceledException (never turned into a warning); an exceeded limit throws PsResourceLimitError, which stopped does not catch.

Fonts: standard PostScript names resolve to the bundled Liberation Serif and Dingbats fonts or to fonts installed on the system. Set AdditionalFontsFolder on the save options to add a folder. A render model (BuildRenderModel) is available for both input kinds.

Differences from the Python original

• The raster output of RenderModelRasterWriter is the original's pure-Python renderer, ported pixel for pixel. The original's default writer is Skia; X-Ray.PS.Skia provides that.
• JPEG XR images are not decoded (the original needs an optional codec for them too).
• ICC-profile colors in XPS (ContextColor) use the original's fallback formula.

License

MIT, see LICENSE. Bundled fonts and the ICC profile carry their own licences, listed in NOTICE.