SystemFontSource Class

public class SystemFontSource : FontSourceBase

Public Class SystemFontSource
	Inherits FontSourceBase

public ref class SystemFontSource : public FontSourceBase

type SystemFontSource =  
    class
        inherit FontSourceBase
    end

Document doc = new Document();

// Create a font settings object for our document
doc.FontSettings = new FontSettings();

// By default we always start with a system font source
Assert.AreEqual(1, doc.FontSettings.GetFontsSources().Length);

SystemFontSource systemFontSource = (SystemFontSource)doc.FontSettings.GetFontsSources()[0];
Assert.AreEqual(FontSourceType.SystemFonts, systemFontSource.Type);
Assert.AreEqual(0, systemFontSource.Priority);

PlatformID pid = Environment.OSVersion.Platform;
bool isWindows = (pid == PlatformID.Win32NT) || (pid == PlatformID.Win32S) || (pid == PlatformID.Win32Windows) || (pid == PlatformID.WinCE);
if (isWindows)
{
    const string fontsPath = @"C:\WINDOWS\Fonts";
    Assert.AreEqual(fontsPath.ToLower(), SystemFontSource.GetSystemFontFolders().FirstOrDefault()?.ToLower());
}

foreach (string systemFontFolder in SystemFontSource.GetSystemFontFolders())
{
    Console.WriteLine(systemFontFolder);
}

// Set a font that exists in the windows fonts directory as a substitute for one that doesn't
doc.FontSettings.SubstitutionSettings.FontInfoSubstitution.Enabled = true;
doc.FontSettings.SubstitutionSettings.TableSubstitution.AddSubstitutes("Kreon-Regular", new string[] { "Calibri" });

Assert.AreEqual(1, doc.FontSettings.SubstitutionSettings.TableSubstitution.GetSubstitutes("Kreon-Regular").Count());
Assert.Contains("Calibri", doc.FontSettings.SubstitutionSettings.TableSubstitution.GetSubstitutes("Kreon-Regular").ToArray());

// Alternatively, we could add a folder font source in which the corresponding folder contains the font
FolderFontSource folderFontSource = new FolderFontSource(FontsDir, false);
doc.FontSettings.SetFontsSources(new FontSourceBase[] { systemFontSource, folderFontSource });
Assert.AreEqual(2, doc.FontSettings.GetFontsSources().Length);

// Resetting the font sources still leaves us with the system font source as well as our substitutes
doc.FontSettings.ResetFontSources();

Assert.AreEqual(1, doc.FontSettings.GetFontsSources().Length);
Assert.AreEqual(FontSourceType.SystemFonts, doc.FontSettings.GetFontsSources()[0].Type);
Assert.AreEqual(1, doc.FontSettings.SubstitutionSettings.TableSubstitution.GetSubstitutes("Kreon-Regular").Count());