How do I access DWriteCore from a C# managed application?

Question

How do I access DWriteCore from a C# managed application?

I'm using .Net5 WindowsAppSDK Desktop.

I need to get a SYSTEM and CUSTOM FONT COLLECTION LIST using DWriteCore, but I need to do so from a C# App using WindowsAppSDK, which says it includes DWriteCore, but I could only find a C++ sample. All nuget packages have been installed.

Thank you, in advance, for any assistance.

Answer 1

From comments in the other thread, a DWriteCore test in C#/WindowsAppSDK with GetSystemFontCollection from IDWriteFactory7 :

At beginning :

using DWrite;  
using System.Text;  
using System.ComponentModel;  
using System.Collections.ObjectModel;  
  

Download DWrite.cs and add it to the project

Declarations :

 // As I could not get DWriteCore.dll from Microsoft.WindowAppSDK.DWrite package when I tested,  
    // I got it from https://github.com/microsoft/WindowsAppSDK-Samples/tree/main/Samples/TextRendering  
    // then it must be copied in executable directory  
    [DllImport("DWriteCore.dll", SetLastError = true, CharSet = CharSet.Auto)]  
    public static extern HRESULT DWriteCoreCreateFactory(DWRITE_FACTORY_TYPE factoryType, ref Guid iid, out IntPtr factory);  

    [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]  
    public static extern int GetUserDefaultLocaleName(StringBuilder lpLocaleName, int cchLocaleName);  

    public const int LOCALE_NAME_MAX_LENGTH = 85;  
      
  

Test IDWriteFactory7.GetSystemFontCollection in a button click :

    IDWriteFactory m_pDWriteFactory = null;  
    IDWriteFactory7 m_pDWriteFactory7 = null;  
    public System.Collections.ObjectModel.ObservableCollection<string> fonts = new System.Collections.ObjectModel.ObservableCollection<string>();  
      
    private void myButton_Click(object sender, RoutedEventArgs e)  
    {  
        fonts.Clear();  

        Guid CLSID_DWriteFactory = new Guid("B859EE5A-D838-4B5B-A2E8-1ADC7D93DB48");  
        Guid CLSID_DWriteFactory7 = new Guid("35D0E0B3-9076-4D2E-A016-A91B568A06B4");  
          
        IntPtr pDWriteFactoryPtr = IntPtr.Zero;  
        // HRESULT hr = DWriteCoreCreateFactory(DWRITE_FACTORY_TYPE.DWRITE_FACTORY_TYPE_SHARED, ref CLSID_DWriteFactory, out pDWriteFactoryPtr);  
        HRESULT hr = DWriteCoreCreateFactory(DWRITE_FACTORY_TYPE.DWRITE_FACTORY_TYPE_SHARED, ref CLSID_DWriteFactory7, out pDWriteFactoryPtr);  
        if (hr == HRESULT.S_OK)  
        {  
            // m_pDWriteFactory = Marshal.GetObjectForIUnknown(pDWriteFactoryPtr) as IDWriteFactory;  
            m_pDWriteFactory7 = Marshal.GetObjectForIUnknown(pDWriteFactoryPtr) as IDWriteFactory7;  
            //IDWriteFontCollection pFontCollection;  
            //hr = m_pDWriteFactory.GetSystemFontCollection(out pFontCollection);  
            IDWriteFontCollection3 pFontCollection;  
            hr = m_pDWriteFactory7.GetSystemFontCollection7(false, DWRITE_FONT_FAMILY_MODEL.DWRITE_FONT_FAMILY_MODEL_TYPOGRAPHIC, out pFontCollection);                 
            if (hr == HRESULT.S_OK)  
            {  
                uint nFamilyCount = pFontCollection.GetFontFamilyCount();  
                for (uint i = 0; i < nFamilyCount; i++)  
                {  
                    IDWriteFontFamily pFontFamily;  
                    hr = pFontCollection.GetFontFamily(i, out pFontFamily);  
                    IDWriteLocalizedStrings pFamilyNames;  
                    pFontFamily.GetFamilyNames(out pFamilyNames);  

                    // https://learn.microsoft.com/en-us/windows/win32/api/dwrite/nf-dwrite-idwritelocalizedstrings-findlocalename  
                    uint nIndex = 0;  
                    bool bExists = false;  
                    StringBuilder sbLocaleName = new StringBuilder(LOCALE_NAME_MAX_LENGTH);  
                    int nDefaultLocaleSuccess = GetUserDefaultLocaleName(sbLocaleName, LOCALE_NAME_MAX_LENGTH);  
                    if (nDefaultLocaleSuccess > 0)  
                    {  
                        hr = pFamilyNames.FindLocaleName(sbLocaleName.ToString(), out nIndex, out bExists);  
                    }  
                    if (hr == HRESULT.S_OK && !bExists)  
                    {  
                        hr = pFamilyNames.FindLocaleName("en-us", out nIndex, out bExists);  
                    }  
                    if (!bExists)  
                        nIndex = 0;  
                    hr = pFamilyNames.GetString(nIndex, sbLocaleName, LOCALE_NAME_MAX_LENGTH);  
                    string sName = sbLocaleName.ToString();  
                    //Console.WriteLine("Font : {0}", sName);  
                    //System.Diagnostics.Debug.WriteLine("Font : " + sName);  

                    fonts.Add(sName);  

                    Marshal.ReleaseComObject(pFamilyNames);  
                    Marshal.ReleaseComObject(pFontFamily);  
                }  
                Marshal.ReleaseComObject(pFontCollection);  
            }  
            //Marshal.ReleaseComObject(m_pDWriteFactory);  
            Marshal.ReleaseComObject(m_pDWriteFactory7);  
        }  
    }  
   
   

Button + Listbox in XAML

<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center">  
    <Button x:Name="myButton" Click="myButton_Click" Margin="100,100,0,0" >Click Me</Button>        
    <ListBox x:Name="FontsList" Height="200" Width="250" Margin="150,100,0,0" HorizontalContentAlignment="Stretch"  
     ItemsSource="{x:Bind fonts}"><!--DisplayMemberPath="Source">-->  
        <ListBox.ItemTemplate>  
        <DataTemplate x:DataType="x:String">  
            <TextBlock FontFamily="{x:Bind}"  
                       Text="{x:Bind}" />  
        </DataTemplate>  
    </ListBox.ItemTemplate>  
    </ListBox>        
</StackPanel>