Qt基础 界面镜像

前几天遇到一个需求 镜像界面想到几个办法，先给效果图

1.图片镜像

先找到镜像窗口的句柄,保存成图片然后镜像

    #include 
    QString ClassName("Qt5QWindowIcon");
	QString AppName = QStringLiteral("你的类型");
	LPCWSTR app = reinterpret_cast(ClassName.data());
	LPCWSTR appCaption = reinterpret_cast(AppName.data());
	HWND hwnd = FindWindow(app, appCaption);
 
	if (hwnd == NULL)
	{
		return;
	}
	CaptureWindow(hwnd, TEXT("D:\\screenshot.png"));

void CNWMirrorDlg::CaptureWindow(HWND hWnd, LPCTSTR lpszFilePath)
{
	// 获取窗口DC
	HDC hDC = ::GetDC(hWnd);
	// 获取窗口大小
	RECT rect;
	::GetWindowRect(hWnd, &rect);
	int nWidth = rect.right - rect.left;
	int nHeight = rect.bottom - rect.top;
	// 创建兼容的DC
	HDC hMemDC = ::CreateCompatibleDC(hDC);
	// 创建位图
	CImage image;
	image.Create(nWidth, nHeight, 32);
	// 将位图选入兼容的DC
	HBITMAP hBitmap = (HBITMAP)::SelectObject(hMemDC, image);
	// 将窗口DC复制到兼容的DC
	::BitBlt(hMemDC, 0, 0, nWidth, nHeight, hDC, 0, 0, SRCCOPY);
	// 将位图保存为图片
	image.Save(lpszFilePath);
	// 释放资源
	::SelectObject(hMemDC, hBitmap);
	::DeleteDC(hMemDC);
	::ReleaseDC(hWnd, hDC);
}

2.屏幕截图发

与1类似不过是知道镜像窗口的大小,并截图转换成图片对象，缺点是由于是全图截屏,会出现鼠标情况,如果有同志解决留言告诉我方法

QImage xxxxx::GetScreen(HWND winId)
{
 
	RECT r;
	QImage image;
	QString ClassName("Qt5QWindowIcon");
	QString AppName = QStringLiteral("类名");
	LPCWSTR app = reinterpret_cast(ClassName.data());
	LPCWSTR appCaption = reinterpret_cast(AppName.data());
	HWND hwnd = FindWindow(app, appCaption);
 
	if (hwnd == NULL)
	{
		return image;
	}
	
	GetWindowRect(hwnd, &r);
	//hwnd = winId;
	//GetClientRect(hwnd, &r);
	int nWidght = r.right - r.left;
	int nHeight = r.bottom - r.top;
	HDC display_dc = GetDC(hwnd);
	HDC bitmap_dc = CreateCompatibleDC(display_dc);
	HBITMAP bitmap = CreateCompatibleBitmap(display_dc, nWidght, nHeight);
	HGDIOBJ null_bitmap = SelectObject(bitmap_dc, bitmap);
	bool bOk = BitBlt(bitmap_dc, 0, 0, nWidght, nHeight, display_dc, 0, 0, SRCCOPY | CAPTUREBLT);
 
	CURSORINFO ci;
	ci.cbSize = sizeof(CURSORINFO);
	GetCursorInfo(&ci);
 
	if ((ci.ptScreenPos.x > 0) && (ci.ptScreenPos.y > 0) && (ci.ptScreenPos.x < (0 + nWidght)) && (ci.ptScreenPos.y < (0 + nHeight)))
		DrawIcon(bitmap_dc, ci.ptScreenPos.x - 0, ci.ptScreenPos.y - 0, ci.hCursor);
 
	// clean up all but bitmap
	ReleaseDC(hwnd, display_dc);
	SelectObject(bitmap_dc, null_bitmap);
	DeleteDC(bitmap_dc);
 
	QPixmap pixmap = QtWin::fromHBITMAP(bitmap);
 
	DeleteObject(bitmap);
	image = pixmap.toImage();
	return image;
	
}

3.使用QTransform

QTransform有好几种形式具体可以参考博客

看了下构造由一下类型组成，

 当然我们操作视图还得用QGraphicsScene和View,详情介绍可以看下参考

 下面就直接给出部分代码,因为并不太难

    QWidget *m_pCopyShowPromptDlg;//需要镜像窗口 我贴了防止报错
    QWidget *m_pCopyWidget = new QWidget();
	QGraphicsScene* pScene = new QGraphicsScene();
	pScene->addWidget(m_pCopyShowPromptDlg, Qt::Widget);
	QGraphicsView* m_pCopyView = new QGraphicsView(pScene, m_pCopyWidget);
	//m_pCopyView->setInteractive(false);//QGraphicsView 不响应鼠标
	QTransform Transform(-1, 0, 0, 0, 1, 0, 0, 0, 1);    //翻转
	m_pCopyView->setTransform(Transform);
	m_pCopyWidget->setFixedSize(m_pCopyShowPromptDlg->size());    //设置大小
	m_pCopyWidget->show();

以上代码还有个问题是每当窗口放大或者缩小时候,镜像窗口该显示位置不正确，每次改变大小可以使用void QGraphicsView::fitInView方法

参考

[Qt5] QGraphics图形视图框架概述(Item、Scene和View)_丶布布的博客-CSDN博客

【精选】Qt图形视图框架：QGraphicsView 详解_友善啊，朋友的博客-CSDN博客

QTransform 进行平移、旋转、镜像等操作_北极熊的奋斗史的博客-CSDN博客