C++获取屏幕缩放

1、改变缩放后需要重启系统

    // 获取窗口当前显示的监视器
    HWND hWndScreen = GetDesktopWindow();
    HMonITOR hMonScreen = MonitorFromWindow(hWndScreen, MONITOR_DEFAULTTONEAREST);

    //获取监视器的逻辑宽度
    MonITORINFOEX monitorInfoex;
    monitorInfoex.cbSize = sizeof(monitorInfoex);
    GetMonitorInfo(hMonScreen, &monitorInfoex);

    //获取监视器的物理宽度
	DEVMODE devMode;
	devMode.dmSize = sizeof(devMode);
	devMode.dmDriverExtra = 0;
	EnumDisplaySettings(monitorInfoex.szDevice, ENUM_CURRENT_SETTINGS, &devMode);
	float fRes = devMode.dmLogPixels / 96.0;
	
    //返回缩放比
	return fRes;

2、改变缩放后不需要重启系统

    // 获取窗口当前显示的监视器
	HWND hWnd = GetDesktopWindow();//根据需要可以替换成自己程序的句柄 
	HMonITOR hMonitor = MonitorFromWindow(hWnd, MONITOR_DEFAULTTONEAREST);

	// 获取监视器逻辑宽度与高度
	MonITORINFOEX miex;
	miex.cbSize = sizeof(miex);
	GetMonitorInfo(hMonitor, &miex);
	int cxLogical = (miex.rcMonitor.right - miex.rcMonitor.left);
	int cyLogical = (miex.rcMonitor.bottom - miex.rcMonitor.top);

	// 获取监视器物理宽度与高度
	DEVMODE dm;
	dm.dmSize = sizeof(dm);
	dm.dmDriverExtra = 0;
	EnumDisplaySettings(miex.szDevice, ENUM_CURRENT_SETTINGS, &dm);
	int cxPhysical = dm.dmPelsWidth;
	int cyPhysical = dm.dmPelsHeight;

	//缩放比例计算
	double horzScale = ((double)cxPhysical / (double)cxLogical);
	double vertScale = ((double)cyPhysical / (double)cyLogical);

	//返回缩放比
	return horzScale;