Questions about PDF printing and PDF generation in Avalonia

[Sabbmasterinio]

I have almost finished porting my WPF application to Avalonia, and I am considering purchasing an Avalonia Pro subscription. The main features I am interested in are PDF preview and printing. I am aware that Avalonia provides a built-in PDF preview component, but I would like to clarify a couple of things before making a decision.

1. Silent PDF printing and cross-platform printer access

Does Avalonia Pro, or Avalonia more generally, provide a cross-platform printing API that supports the following?

• Retrieving the available printers on the current system.
• Printing a PDF document directly to a specified printer without displaying the PDF preview component or any other dialog.
• Supporting silent printing, where the application can programmatically select a printer and send a document to it without requiring any user interaction.

This functionality is particularly important for my application, as I need to print documents directly from the application without interrupting the user's workflow.

2. Generating PDFs from AXAML

Is there a supported way to generate PDFs directly from Avalonia UI controls or AXAML, similar to how WPF can use XPS to represent and print visual content? If this functionality is not currently available, are there any plans to support it? At the moment, the only approach I can think of is rendering Avalonia UI content to images and then combining those images into a PDF. However, I would prefer a solution that preserves text and vector graphics rather than rasterizing the entire document, particularly for documents that need to be printed. Any clarification regarding the current capabilities of Avalonia Pro, existing alternatives, or planned features would be greatly appreciated. I would like to understand whether these requirements can be met before deciding on a subscription.

[kgeminicdev]

I can't speak for what Pro includes. Ask Avalonia sales directly before you buy. I can tell you where open-source Avalonia stands, though, because it shapes your options either way.

Printing: Avalonia has no printing API, and nothing to list printers or print silently. Most people call the OS directly:

• Linux / macOS: CUPS handles PDF natively. lpstat -e lists printers and lp -d <printer> file.pdf prints with no dialog. Run them with Process.Start, or P/Invoke libcups if you want it cleaner.
• Windows: PrinterSettings.InstalledPrinters gives you the list. For silent PDF printing, render pages with PDFium (for example PDFtoImage or a PDFium wrapper) and send them through PrintDocument, or shell out to SumatraPDF with -print-to "<printer>" -silent.

Hide both behind a small IPrinterService interface with one implementation per OS. In practice it's about a day of work, and you own it.

PDF from AXAML, vector, no rasterizing: this already works. Skia can write PDFs, and Avalonia can draw any visual onto a Skia canvas:

using var stream = File.Create("out.pdf");
using var doc = SKDocument.CreatePdf(stream);

var size = new Size(595, 842); // A4 in points
control.Measure(size);
control.Arrange(new Rect(size));

using (var canvas = doc.BeginPage((float)size.Width, (float)size.Height))
{
    await DrawingContextHelper.RenderAsync(canvas, control);
}
doc.EndPage();
doc.Close();

DrawingContextHelper is in Avalonia.Skia.Helpers, and its doc comment mentions SKDocument.BeginPage as the intended use case. Text stays real text and shapes stay vectors. The two limits: you handle page breaks yourself (one control per page works well), and bitmap effects like blur get rasterized.

Generate the PDF this way, then print it with the OS path above. That covers the WPF/XPS workflow without depending on Pro.

[maxkatz6]

NativeWebView (Avalonia.Controls.WebView) includes APIs to print current page. It's not primarily designed for PDF, but can work with it. It also has pretty limited customization.

[Bobsoftru]

Could you please tell me if the print settings include options for landscape orientation, margins, and printing without a preview?

[maxkatz6]

NativeWebView has a PrintToPdfStreamAsync overload accepting WebViewPrintSettings, including orientation and margins. But this method is only supported on Windows and some Linux platforms. Not macOS.
There also is a PrintToPdfStreamAsync overload without WebViewPrintSettings (i.e., no control over margins/orientation), that does work on macOS.
All of that without showing a preview. There is actually a separate method ShowPrintUI for that, if anybody else needs it.

In short, macOS native web browser control doesn't allow customization of print options.

Avalonia.Controls.WebView is now free, so you can test it for your needs without getting a license.