[WTL/ATL]_[初级]_[无边框窗口拉伸]_onnclbuttondown 拉伸-优快云博客

本文链接：https://blog.youkuaiyun.com/infoworld/article/details/91960284

本文详细介绍了在开发无边框窗口时，如何通过编码实现界面的自定义拉伸，包括响应鼠标操作、改变鼠标样式及调整界面大小。文中提供了具体的代码示例，如WM_NCHITTEST、WM_SETCURSOR和WM_NCLBUTTONDOWN消息映射的实现。

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场景

在开发无边框的窗口时，没有了系统自带的边框后，也需要我们自己对界面进行编码拉伸. 如何实现？
如果想保留系统自带的边框，不想自己编码实现界面拉伸如何做？

说明

如果需要自带系统的边框，那么在创建窗口时加上WS_SIZEBOX

if(wndMain.CreateEx(NULL,NULL,WS_SIZEBOX|WS_CLIPCHILDREN | WS_CLIPSIBLINGS|WS_POPUP) == NULL)

创建无边框窗口,WS_POPUP是关键

if(wndMain.CreateEx(NULL,NULL,WS_CLIPCHILDREN | WS_CLIPSIBLINGS|WS_POPUP) == NULL)

创建无边框窗口后，其实需要自己响应几个鼠标操作:

鼠标移动到窗口的边界时，鼠标能边为箭头;
鼠标左键按下后移动鼠标，界面随着鼠标移动的方向拉伸改变大小，并且鼠标的箭头不变。
无边框窗口拉伸后，标题栏的按钮能随着拉伸后改变位置。

实现拉伸的方式应该不止一种，我这里列举的是其中一种方法.

实现3个消息映射WM_NCHITTEST,WM_SETCURSOR,WM_NCLBUTTONDOWN

	BEGIN_MSG_MAP_EX(CMainFrame)
		MSG_WM_NCHITTEST(OnNcHitTest)
		MSG_WM_SETCURSOR(OnSetCursor)
		MSG_WM_NCLBUTTONDOWN(OnNcLButtonDown)
		CHAIN_MSG_MAP(CUpdateUI<CMainFrame>)
		CHAIN_MSG_MAP(CFrameWindowImpl<CMainFrame>)
	END_MSG_MAP()

#define RESIZE_REGION_SIZE  5
UINT CMainFrame::OnNcHitTest(CPoint pt)
{
	RECT rcWindow;
	::GetWindowRect(m_hWnd, &rcWindow);
 
	// 最好将四个角的判断放在前面
	if (pt.x <= rcWindow.left + RESIZE_REGION_SIZE && pt.y <= rcWindow.top + RESIZE_REGION_SIZE)
		return HTTOPLEFT;
	else if (pt.x >= rcWindow.right - RESIZE_REGION_SIZE && pt.y <= rcWindow.top + RESIZE_REGION_SIZE)
		return HTTOPRIGHT;
	else if (pt.x <= rcWindow.left + RESIZE_REGION_SIZE && pt.y >= rcWindow.bottom - RESIZE_REGION_SIZE)
		return HTBOTTOMLEFT;
	else if (pt.x >= rcWindow.right - RESIZE_REGION_SIZE && pt.y >= rcWindow.bottom - RESIZE_REGION_SIZE)
		return HTBOTTOMRIGHT;
	else if (pt.x <= rcWindow.left + RESIZE_REGION_SIZE)
		return HTLEFT;
	else if (pt.x >= rcWindow.right - RESIZE_REGION_SIZE)
		return HTRIGHT;
	else if (pt.y <= rcWindow.top + RESIZE_REGION_SIZE)
		return HTTOP;
	else if (pt.y >= rcWindow.bottom - RESIZE_REGION_SIZE)
		return HTBOTTOM;
	 
	return HTCAPTION; 
}

BOOL CMainFrame::OnSetCursor(CWindow wnd, UINT nHitTest, UINT message)
{ 
	switch (nHitTest)
	{
	case HTTOP:
	case HTBOTTOM:
		SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENS)));
		return TRUE;
	
	case HTLEFT:
	case HTRIGHT:
		SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZEWE)));
		return TRUE;
 
	case HTTOPLEFT:
	case HTBOTTOMRIGHT:
		SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENWSE)));
		return TRUE;
 
	case HTTOPRIGHT:
	case HTBOTTOMLEFT:
		SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENESW)));
		return TRUE;
 
	default:
		return FALSE;
	}
}
 
void CMainFrame::OnNcLButtonDown(UINT nHitTest, CPoint point)
{
	switch (nHitTest)
	{
	case HTTOP:
		SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_TOP, MAKELPARAM(point.x, point.y));
		break;
	case HTBOTTOM:
		SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOM, MAKELPARAM(point.x, point.y));
		break;
	case HTLEFT:
		SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_LEFT, MAKELPARAM(point.x, point.y));
		break;
	case HTRIGHT:
		SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_RIGHT, MAKELPARAM(point.x, point.y));
		break;
	case HTTOPLEFT:
		SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_TOPLEFT, MAKELPARAM(point.x, point.y));
		break;
	case HTTOPRIGHT:
		SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_TOPRIGHT, MAKELPARAM(point.x, point.y));
		break;
	case HTBOTTOMLEFT:
		SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOMLEFT, MAKELPARAM(point.x, point.y));
		break;
	case HTBOTTOMRIGHT:
		SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOMRIGHT, MAKELPARAM(point.x, point.y));
		break;
	default:
		SetMsgHandled(FALSE);
		break;
	}
}