Fork from Source Page. Update the project to Visual Studio 2010. Add ReadMe.md file. Nothing else is changed.
Eveyrything you ever wanted to know about the API for multiple monitors is described in a very well written article by David Campbell in the June 1997 issue of MSJ.
The API itself is simple and straightforward. It has some new constants to pass to GetSystemMetrics and a couple methods to enumerate all of the monitors currently attached to the system and get the properties of a given monitor.
All of the types and functions are defined by the platform SDK in the file multimon.h . If you #define WINVER to be greater than 0x400 you don't need to link to multimon.h, as the API gets defined in windef.h for Windows 98 and later targeted builds. Multimon.h also provides some stub functions that allow calls to be safely made on Windows 95/NT4 machines. These wrappers interrogate the runtime OS and either make fall-through calls into the actual API or return the propeties of the one (and only) monitor on those older platforms.
The multi monitor classes take care of including multimon.h correctly depending on the value of WINVER.
CMointor is a basic MFC class that allows you to safely use the multi-monitor API on any Win32 platform.
There are three classes in this library:
CMonitors represents the collection of monitors currently attached to the system and wraps the EnumDisplayMonitors API function.
//CMonitors' interface
CMonitor GetMonitor( const int index ) const;
int GetCount() const;
//returns the monitor closest to the specified item
static CMonitor GetNearestMonitor( const LPRECT lprc );
static CMonitor GetNearestMonitor( const POINT pt );
static CMonitor GetNearestMonitor( const CWnd* pWnd );
//is the specificed item visible on any monitor
static BOOL IsOnScreen( const POINT pt );
static BOOL IsOnScreen( const CWnd* pWnd );
static BOOL IsOnScreen( const LPRECT lprc );
//returns the rectangle encompassing all monitors
static void GetVirtualDesktopRect( LPRECT lprc );
//determines whether the given handle is a valid monitor handle
static BOOL IsMonitor( const HMONITOR hMonitor );
static CMonitor GetPrimaryMonitor();
static BOOL AllMonitorsShareDisplayFormat();
static int GetMonitorCount();CMonitor is a wrapper around an HMONITOR handle (returned from EnumDisplayMonitors) and the GetMonitorInfo function. With CMonitor you can get at the characteristics of a given monitor.
//The interface of CMonitor
void Attach( const HMONITOR hMonitor );
HMONITOR Detach();
void ClipRectToMonitor( LPRECT lprc,
const BOOL UseWorkAreaRect = FALSE ) const;
void CenterRectToMonitor( LPRECT lprc,
const BOOL UseWorkAreaRect = FALSE ) const;
void CenterWindowToMonitor( CWnd* const pWnd,<BR> const BOOL UseWorkAreaRect = FALSE ) const;
//creates a device context for the monitor - the client is responsible for
// DeleteDC HDC CreateDC() const;
void GetMonitorRect( LPRECT lprc ) const;
//the work area is the monitor rect minus the start bar
void GetWorkAreaRect( LPRECT lprc ) const;
void GetName( CString& string ) const;
int GetBitsPerPixel() const;
//determines if the specified item on the monitor
BOOL IsOnMonitor( const POINT pt ) const;
BOOL IsOnMonitor( const CWnd* pWnd ) const;
BOOL IsOnMonitor( const LPRECT lprc ) const;
BOOL IsPrimaryMonitor() const;
BOOL IsMonitor() const;CMonitorDC is a CDC derived class that represents a monitor specific device context. I haven't really gone to far with this class but it seemed like a logical part of the library.
CMonitor and CMonitors rely on the assumption that a monitor handle does not change. This has proved to be a safe assumption empirically but isn't nessecarily a guarantee.
- 02/20/2003 - Initial Release
- 08/25/2003 - Made changes to make compatible with VC6 environment
This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL).