How to change theme DrawThemeTextEx font color?

Question

i am using DrawThemeTextEx to draw text. i am trying to draw it in a particular color using the crText COLORREF member of DTTOPS structure:

procedure DrawThemeText(dc: HDC; text: WideString; font: TFont; pt: TPoint; foreColor: COLORREF);
var
   R: TRect;
   dttOpts: TDttOpts;
   hOldFont: HFONT;
   oldColor: COLORREF;
begin
   foreColor := $FF00FF00; //bright lime green
   font.

   R := Rect(pt.x, pt.y, $7fffffff, $7fffffff);

   ZeroMemory(@dttOpts, SizeOf(TDTTOpts));
   dttOpts.dwSize := SizeOf(TDTTOpts);
   dttOpts.iGlowSize := 1;
   dttOpts.crText := foreColor;
   dttOpts.dwFlags := DTT_GLOWSIZE or DTT_TEXTCOLOR;

   hOldFont := SelectObject(dc, font.Handle);
   oldColor := SetTextColor(dc, foreColor);
   try
      hr := DrawThemeTextEx(ThemeServices.Theme[teWindow], DC, WP_CAPTION, CS_ACTIVE, 
            PWideChar(Text), Length(Text),
            DT_LEFT or DT_TOP or DT_SINGLELINE or DT_NOPREFIX, R, dttOpts);
   finally
      SetTextColor(dc, oldColor);
      SelectObject(dc, hOldFont);
   end;

Unfortunately the text color always comes out black, rather than the bright lime green color my code is specifying:

i can alter the font that is used by selecting the new font into the device context, i.e.:

   SelectObject(dc, font.Handle);

but neither SetTextColor, nor setting the crText and DTT_TEXTCOLOR options of the DTTOPS structure, alter the text color used.

What's confusing is that the DTTOPS structure allows me to specify a color:

typedef struct _DTTOPTS
{
    DWORD             dwSize;              // size of the struct
    DWORD             dwFlags;             // which options have been specified
    COLORREF          crText;              // color to use for text fill
    COLORREF          crBorder;            // color to use for text outline
    COLORREF          crShadow;            // color to use for text shadow
    ...

along with the DTT_TEXTCOLOR flag to indicate i'm using that member:

   #define DTT_TEXTCOLOR       (1UL << 0)      // crText has been specified

What i want to accomplish is documented, but it's not working right. Obviously i'm doing something wrong.

How do i specify the text color when drawing text using DrawThemeTextEx?

Answer 1

The crText member is a ColorRef. MSDN says the high-order byte "must be zero."