Rendering HTML to PDF is common, but the default settings are not always ideal for print, archiving, or executive summaries. With Aspose.HTML for .NET, you can precisely control page size, margins, orientation, and CSS media rules to produce consistent, professional PDFs. This guide shows a clean setup and a complete C# sample you can drop into your project.

Key Takeaways

  • Use Converter.ConvertHTML with PdfSaveOptions for reliable HTML → PDF rendering.
  • Configure PageSetup.AnyPage to set page size and margins (A4, A3, or custom sizes).
  • Switch Css.MediaType between Screen and Print to honor the correct CSS rules.
  • Create multiple outputs: A4 for print, A3 landscape for wide layouts, and custom trim sizes for booklets.

Step‑by‑Step Guide

1) Load an HTML document

Load from file when available, or create an HTMLDocument from a string with a base URI to resolve relative assets.

2) Configure page geometry and CSS media

Define page size and margins via PageSetup.AnyPage. Select MediaType.Print to apply @media print styles, or MediaType.Screen to render screen styles.

3) Render to PDF

Call Converter.ConvertHTML(document, options, outputPath) to produce your PDF.

Complete Example (Compilable C#)

using System;
using System.IO;
using Aspose.Html;
using Aspose.Html.Converters;
using Aspose.Html.Saving;            // PdfSaveOptions
using Aspose.Html.Rendering;         // MediaType
using Aspose.Html.Drawing;           // Length, Size, Margin, Page

namespace AsposeHtmlAdvancedPdfDemo
{
    internal static class Program
    {
        // How to run:
        // 1) dotnet new console -n AsposeHtmlAdvancedPdfDemo
        // 2) cd AsposeHtmlAdvancedPdfDemo
        // 3) dotnet add package Aspose.HTML
        // 4) Replace Program.cs with this file's contents
        // 5) dotnet run -- "path-to-input.html"   (argument optional)
        private static void Main(string[] args)
        {
            // Ensure output folder exists
            string outDir = Path.Combine(Directory.GetCurrentDirectory(), "out");
            Directory.CreateDirectory(outDir);

            // Prepare an HTMLDocument: from file path (if provided) or from inline HTML
            HTMLDocument document;
            if (args.Length > 0 && File.Exists(args[0]))
            {
                document = new HTMLDocument(args[0]);
            }
            else
            {
                string html = "<!DOCTYPE html>" +
                              "<html><head><meta charset=\\\"utf-8\\\">" +
                              "<title>Advanced PDF Output</title>" +
                              "<style>body{font-family:Arial,Helvetica,sans-serif;margin:24px}" +
                              "h1{margin:0 0 12px} .lead{color:#444} .wide{width:100%;border-collapse:collapse}" +
                              ".wide th,.wide td{border:1px solid #ddd;padding:6px 8px;text-align:left}" +
                              "@media print { body{font-size:12pt} .lead{color:#000} }</style>" +
                              "</head><body>" +
                              "<h1>Aspose.HTML PDF Output</h1>" +
                              "<p class=\\\"lead\\\">This PDF is rendered with custom page size, margins, and media rules.</p>" +
                              "<table class=\\\"wide\\\"><tr><th>Item</th><th>Qty</th><th>Price</th></tr>" +
                              "<tr><td>Widget A</td><td>4</td><td>$12.00</td></tr>" +
                              "<tr><td>Widget B</td><td>2</td><td>$9.50</td></tr></table>" +
                              "</body></html>";
                document = new HTMLDocument(html, ".");
            }

            using (document)
            {
                // A4 portrait with 12.7 mm margins, using print CSS
                var a4 = new PdfSaveOptions();
                a4.Css.MediaType = MediaType.Print;
                var mm = Length.FromMillimeters;
                a4.PageSetup.AnyPage = new Page(
                    new Size(mm(210), mm(297)),               // A4
                    new Margin(mm(12.7), mm(12.7), mm(12.7), mm(12.7))
                );
                string a4Path = Path.Combine(outDir, "document-a4.pdf");
                Converter.ConvertHTML(document, a4, a4Path);
                Console.WriteLine($"Saved: {a4Path}")
;
                // A3 landscape (420 x 297 mm) with tighter margins, using screen CSS
                var a3Landscape = new PdfSaveOptions();
                a3Landscape.Css.MediaType = MediaType.Screen;
                a3Landscape.PageSetup.AnyPage = new Page(
                    new Size(mm(420), mm(297)),               // A3 landscape
                    new Margin(mm(10), mm(10), mm(10), mm(10))
                );
                string a3Path = Path.Combine(outDir, "document-a3-landscape.pdf");
                Converter.ConvertHTML(document, a3Landscape, a3Path);
                Console.WriteLine($"Saved: {a3Path}");

                // Custom trim size 6 x 9 inches with narrow margins
                var custom = new PdfSaveOptions();
                custom.Css.MediaType = MediaType.Print;
                custom.PageSetup.AnyPage = new Page(
                    new Size(Length.FromInches(6), Length.FromInches(9)),
                    new Margin(mm(5), mm(5), mm(5), mm(5))
                );
                string customPath = Path.Combine(outDir, "document-6x9.pdf");
                Converter.ConvertHTML(document, custom, customPath);
                Console.WriteLine($"Saved: {customPath}");
            }
        }
    }
}

How to Run

  1. Create a console app:

    dotnet new console -n AsposeHtmlAdvancedPdfDemo
cd AsposeHtmlAdvancedPdfDemo

  2. Add the package:

    dotnet add package Aspose.HTML

  3. Replace Program.cs with the Complete Example above.

  4. Run with an HTML file (optional):

    dotnet run -- ../path/to/sample.html

What this code does

  • Loads an HTML file (or uses inline HTML for a quick start).
  • Configures PdfSaveOptions for A4 portrait, A3 landscape, and a custom 6×9 inch trim size.
  • Applies MediaType.Print or MediaType.Screen to match your CSS rules.
  • Exports three tailored PDFs to an out/ folder.

Troubleshooting & Tips

  • Wrong CSS rules: toggle options.Css.MediaType between Print and Screen to match your stylesheet.
  • Clipped or cramped content: increase margins or page size; consider larger formats for wide tables.
  • Fonts missing: ensure fonts are available to the renderer or embed via @font-face in your HTML.
  • Performance: simplify heavy DOM/CSS where possible; cache static assets.

FAQ

Q1. How do I set page size and margins for PDF? Use PdfSaveOptions.PageSetup.AnyPage = new Page(Size, Margin) with units from Length (millimeters or inches).

Q2. Can I force print styles during rendering? Yes. Set options.Css.MediaType = MediaType.Print so @media print rules apply.

Q3. How do I render landscape pages? Specify a landscape Size (for example A3 420 × 297 mm) when creating the Page.

Q4. How can I export multiple variants (print vs screen)? Create separate PdfSaveOptions instances with different Css.MediaType and page setups, then call Converter.ConvertHTML for each.

Q5. Do I need a running browser engine? No. Aspose.HTML renders server‑side without external browsers.

Conclusion

With PdfSaveOptions and media‑aware CSS, you can produce PDFs that fit print, archival, or executive needs. Start with A4 portrait for general use, add A3 landscape for wide layouts, and keep a custom trim size for booklets or reports. Test with representative documents to lock in defaults that match your brand and stakeholders.

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