1.有时候，我们需要包装窗口的标题栏，同时又不想让窗口的非客户区全部由自己来控制刷新，比如边框，菜单。
从WM_NCPAINT中的参数wParam可以得到需要刷新的区域：
hrgn = (HRGN) wParam; // handle of update region
因此，可以重载WndProc函数，对此区域中剔除标题栏所占的区域，代码如下：
case WM_NCPAINT:
{
HRGN hrgnSrc; // handle to Src WindowDC update region
HRGN hRgnCaption; // handle to Combine region
HRGN hRgnNew; // handle to New WindowDC update region
hrgnSrc = (HRGN) Msg.WParam;
TRect *winrect =new TRect();
GetWindowRect(ParentForm->Handle,winrect);
TRect rc;
rc= TRect(winrect->left,winrect->top,winrect->right,winrect->top+ GetSystemMetrics(SM_CYCAPTION)+3);
hRgnCaption = CreateRectRgnIndirect(&rc);
hRgnNew = CreateRectRgnIndirect(&rc);
if ((WORD)hrgnSrc > 1 && !RectInRegion(hrgnSrc, &rc))
{
DeleteObject(hRgnNew );
DeleteObject(hRgnCaption);
DeleteObject(hrgnSrc);
delete winrect;
break;
}
if ((WORD)hrgnSrc>1)
{
CombineRgn(hRgnNew ,hrgnSrc,hRgnCaption,RGN_DIFF);
}
else
{
HRGN hRgnAll = ::CreateRectRgnIndirect(winrect);
CombineRgn(hRgnNew, hRgnAll, hRgnCaption, RGN_DIFF);
DeleteObject(hRgnAll);
}
Msg.Result = DefWindowProc( ParentForm->Handle, Msg.Msg,(int)hRgnNew, Msg.LParam);
DrawCaption();// custom draw caption
DeleteObject(hRgnNew );
DeleteObject(hRgnCaption);
DeleteObject(hrgnSrc);
delete winrect;
return;
}
2.怎么调整标题栏的宽度
换言之，也就是调整窗口客户区的大小，自然也就修改了非客户区的大小。我们可以对WM_NCCALCSIZE消息进行处理，注意的是此方法不适用于窗口有主菜单的情况。
WM_NCCALCSIZE参数wParam和lParam的意义：
fCalcValidRects = (BOOL) wParam; // valid area flag
lpncsp = (LPNCCALCSIZE_PARAMS) lParam; // points to size calculation data
or
lpncsp = (LPRECT) lParam; // points to new window coordinates
具体代码：
case WM_NCCALCSIZE:
{// calculate window's client
bool fCalcValidRects = (bool) Msg.WParam;
if (fCalcValidRects)
{
RECT rtSave;
CopyRect(&rtSave,(LPRECT)Msg.LParam);
rtSave.top+=TitleHeight - GetSystemMetrics(SM_CYCAPTION)-yEdge;
if (HaveBorder)
{
rtSave.left +=4 -xEdge;
rtSave.right-=4- xEdge;
rtSave.bottom -=4- yEdge;
}
CopyRect((LPRECT)Msg.LParam,&rtSave);
}
else
{
RECT rtSave;
LPRECT prtClt;
LPNCCALCSIZE_PARAMS pNC;
pNC=(LPNCCALCSIZE_PARAMS)Msg.LParam;
prtClt=&(pNC->rgrc[0]);
CopyRect(&rtSave,prtClt);
CopyRect( &(pNC->rgrc[2]), &(pNC->rgrc[1]));
(pNC->rgrc[2]).top+=TitleHeight - GetSystemMetrics(SM_CYCAPTION)-yEdge;
rtSave.top+=TitleHeight - GetSystemMetrics(SM_CYCAPTION)-yEdge-1;
if (HaveBorder)
{
(pNC->rgrc[2]).left +=4 -xEdge;
(pNC->rgrc[2]).right-=4- xEdge;
(pNC->rgrc[2]).bottom -=4- yEdge;
rtSave.left +=4 -xEdge;
rtSave.right-=4- xEdge;
rtSave.bottom -=4- yEdge;
}
CopyRect(prtClt,&rtSave);
}
break;
}
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