如何更改主题DrawThemeTextEx字体颜色？

Question

我正在使用DrawThemeTextEx来绘制文本.我试图使用结构的crTextCOLORREF成员以特定颜色绘制它DTTOPS:

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;

不幸的是,文本颜色总是黑色,而不是我的代码指定的明亮的柠檬绿颜色:

我可以改变字体,其用于通过选择新的字体到设备上下文,即:

   SelectObject(dc, font.Handle);

但既不SetTextColor,也不设定crText与DTT_TEXTCOLOR所述的选择DTTOPS的结构,改变所使用的文字颜色.

令人困惑的是,DTTOPS结构允许我指定一种颜色:

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
    ...

以及DTT_TEXTCOLOR标志以指示我正在使用该成员:

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

我想要完成的是记录,但它不能正常工作.显然我做错了什么.

使用DrawThemeTextEx绘制文本时如何指定文本颜色？

Answer 1

该crText成员是ColorRef.MSDN称高位字节"必须为零".