自画Caption标题栏

要实现自己绘制窗口的标题栏，必须拦截两个消息 WM_NCPAINT 和 WM_NCACTIVATE。我在

这里给出部分关键的 C++ Builder 代码，其实用 Delphi 实现也是很容易的。

class TForm1 : public TForm

{

// 窗体类声明细节省略

private:

void __fastcall WMNCPaint(TMessage &Msg);

void __fastcall WMNCActivate(TWMNCActivate &Msg);

protected:

BEGIN_MESSAGE_MAP

VCL_MESSAGE_HANDLER(WM_NCPAINT, TMessage, WMNCPaint)

VCL_MESSAGE_HANDLER(WM_NCACTIVATE, TWMNCActivate, WMNCActivate)

END_MESSAGE_MAP(TForm)

};

void __fastcall TForm1::WMNCActivate(TWMNCActivate &Msg)

{

Msg.Result = true;

if(!Msg.Active)

{

DefWindowProc(this->Handle, Msg.Msg, Msg.active, 0);

return;

}

TMessage pm;

pm.Msg = Msg.Msg;

pm.WParam = Msg.Active;

WMNCPaint(pm);

}

void __fastcall TForm1::WMNCPaint(TMessage &Msg)

{

HDC hdc;

TRect cr;

TCanvas *wc = NULL;

DefWindowProc(this->Handle, Msg.Msg, Msg.WParam, Msg.LParam);

hdc = GetWindowDC(this->Handle);

try

{

wc = new TCanvas;

wc->Handle = hdc;

// 计算标题栏尺寸

cr.Left = GetSystemMetrics(SM_CXFRAME);

cr.Top = GetSystemMetrics(SM_CYFRAME);

cr.Right = this->Width - 4 * GetSystemMetrics(SM_CXSIZE);

cr.Bottom = cr.Top + GetSystemMetrics(SM_CYCAPTION) - 1;

// 获取标题栏的 Rect 后就可以直接在 wc 画布上画了，直接在标题栏上出效果！

// 绘画代码省略

// ... ...

}

__finally

{

ReleaseDC(this->Handle, hdc);

if(wc != NULL)

{

delete wc;

wc = NULL;

}

}

}

// 就这么简单