public struct OUTLINETEXTMETRIC

    public TEXTMETRIC otmTextMetrics;

    Private Structure OUTLINETEXTMETRIC

        Public otmTextMetrics As TEXTMETRIC

TEXTMETRIC

public struct TEXTMETRIC

public struct TEXTMETRICW

public struct TEXTMETRICA

     Public Structure TEXTMETRIC

     Public Structure TEXTMETRICW

     Public Structure TEXTMETRICA

public extern static Int32 GetThemeTextMetrics(IntPtr hTheme, IntPtr hdc, int iPartId, int iStateId, out TEXTMETRIC textMetric);

Declare Function GetThemeTextMetrics Lib "uxtheme.dll" (TODO) As TODO

Public Shared Function GetThemeTextMetrics(hTheme As IntPtr, hdc As IntPtr, iPartId As Integer, iStateId As Integer, ByRef textMetric As TEXTMETRIC) As Int32

    public struct NEWTEXTMETRIC

    public struct NEWTEXTMETRICEX

    NEWTEXTMETRIC ntmTm;

    public delegate int EnumFontExDelegate(ref ENUMLOGFONTEX lpelfe, ref NEWTEXTMETRICEX lpntme, int FontType, int lParam);

    public int callback1(ref ENUMLOGFONTEX lpelfe, ref NEWTEXTMETRICEX lpntme, int FontType, int lParam)

        public struct TEXTMETRIC

        public struct NEWTEXTMETRIC

            public NEWTEXTMETRIC TextMetric;

        public delegate Int32 FONTENUMPROC(ref ENUMLOGFONT lpelf, ref NEWTEXTMETRIC lpntm, UInt32 FontType, IntPtr lParam);

        public static int EnumFontFamExProc(ref ENUMLOGFONT lpelf, ref NEWTEXTMETRIC lpntm, uint FontType, IntPtr lParam)

            allFontData.Add(new FontData() { LogFont = lpelf, TextMetric = lpntm, FontType = FontType });

    public struct NEWTEXTMETRIC

    public struct NEWTEXTMETRICEX

    NEWTEXTMETRIC ntmTm;

    public delegate int EnumFontExDelegate(ref ENUMLOGFONTEX lpelfe, ref NEWTEXTMETRICEX lpntme, int FontType, int lParam);

    public int callback1(ref ENUMLOGFONTEX lpelfe, ref NEWTEXTMETRICEX lpntme, int FontType, int lParam)

        public struct TEXTMETRIC

        public struct NEWTEXTMETRIC

            public NEWTEXTMETRIC TextMetric;

        public delegate Int32 FONTENUMPROC(ref ENUMLOGFONT lpelf, ref NEWTEXTMETRIC lpntm, UInt32 FontType, IntPtr lParam);

        public static int EnumFontFamExProc(ref ENUMLOGFONT lpelf, ref NEWTEXTMETRIC lpntm, uint FontType, IntPtr lParam)

            allFontData.Add(new FontData() { LogFont = lpelf, TextMetric = lpntm, FontType = FontType });

static extern uint GetOutlineTextMetrics(IntPtr hdc, uint cbData, IntPtr ptrZero);

OUTLINETEXTMETRIC

Since otmpFamilyName, otmpFaceName, otmpStyleName, otmpFullName are actually offsets into the structure from the beginning of the structure you need double call GetOutlineTextMetrics.

    uint cbBuffer = GetOutlineTextMetrics(hdc, 0, IntPtr.Zero);

        if (GetOutlineTextMetrics(hdc, cbBuffer, buffer) != 0)

            OUTLINETEXTMETRIC otm = new OUTLINETEXTMETRIC();

            otm = (OUTLINETEXTMETRIC)Marshal.PtrToStructure(buffer, typeof(OUTLINETEXTMETRIC));

static extern bool GetTextMetrics(IntPtr hdc, out TEXTMETRIC lptm);

private static extern bool GetTextMetricsW(IntPtr hdc, out TEXTMETRICW lptm);

private static extern bool GetTextMetricsA(IntPtr hdc, out TEXTMETRICA lptm);

TEXTMETRIC

It's very important to use the same charset on the TEXTMETRIC structure and the extern function.

public static TEXTMETRIC GetTextMetrics(Graphics graphics, Font font)

   TEXTMETRIC textMetric;

     bool result = GetTextMetrics(hDC, out textMetric);

   return textMetric;

static extern bool GetTextMetrics(IntPtr hdc, out TEXTMETRIC lptm);

internal struct TEXTMETRIC

public ref struct TEXTMETRIC

static bool GetTextMetrics(IntPtr hdc, [Out] TEXTMETRIC% lptm);

TEXTMETRIC^ GetTextMetricsReal(Graphics^ g, Font^ font)

   TEXTMETRIC^ textMetric = gcnew TEXTMETRIC;

      bool result = Win32::GetTextMetrics(hDC, *textMetric);

   return textMetric;