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Introduction
Tired of using the Windows Control panel or QuickRes to change your graphics cards screen
depth & resolution? This program uses the command line sent to it to change the screen depth
& resolution. For example to change into 1024 * 768 in 24 bit color, just use the command
line
ResSwitch.exe 1024 768 24 0. With this structure you can create a number
of shortcuts to
ResSwitch on your desktop using different command lines which
will allow you to change mode with a simple double click on your desktop. By setting up
shortcut keys in the shortcut file to
ResSwitch you can quickly change modes
by just using the keyboard only. The size of the binary file itself is only 6K.
Also included is ResList which is a simple console app which lists the available
video modes which ResSwitch can use.
The source zip file contains the ResSwitch and ResList source
code, a very handy MFC class to wrap access to the two underlying APIs. ResSwitch
and ResList use and a prebuilt binary version of both programs. The enclosed
binary requires that you have the MFC 4.2b DLLs already installed. If you haven't already
got them on your machine (MFC42.DLL in your Windows system directory), then grab them from
Microsoft's web site at
http://activex.microsoft.com/controls/vc/mfc42.cab.
Usage
- To use the class in your code simply include videomod.cpp in your project and
#include videomod.h in which ever of your modules needs to make calls to the class.
- Your code will need to include MFC either statically or dynamically.
- You will also need to have afxtempl.h in your precompiled header.
- To see the class in action, have a look at the code in the main function in the module ResList.cpp
or the Winmain function in the module ResSwitch.cpp.
History
v1.1 (25 September 1997)
- Changed name
QuickerRes to QRes to avoid conflict with a
similarly named third party product.
- Now supports setting the monitor frequency (NT only according to the documentation).
- Inclusion of a new console mode program called
QList (binary & source
code) with enumerates all the video modes available. Comes in helpful if QRes
is reporting that some options you select are unavailable.
v1.2 (4 January 1999)
- Changed name (yet again) from
QRes to ResSwitch to avoid
conflict with another similarly named third party product.
- Source code now ships with Visual C++ 5 workspace files now as standard.
- All source code is now fully UNICODE enabled and UNICODE build configurations are now
provided.
- General tidy up of the codebase.
API Reference
The API consists of the public member functions of the classes CVideoMode & CVideoModes.
CVideoMode
CVideoModes::GetCurrentVideoMode
CVideoModes::GetAvailableVideoModes
CVideoModes::ChangeVideoModePermanently
CVideoModes::ChangeVideoModeTemporarily
CVideoModes::CanChangeVideoMode
CVideoModes::RevertVideoModeToDefault
- CVideoMode
- Remarks:
This class is an encapsulation of a video mode. It contains 4 public member variables, namely:
- m_dwBitsPerPixel -- Specifies in bits per pixel the colour resolution of the display device.
For example: 4 bits for 16 colours, 8 bits for 256 colours, or 16 bits for 65,536 colours.
- m_dwWidth -- Specifies the width, in pixels, of the display device.
- m_dwHeight -- Specifies the height, in pixels, of the display device.
- m_dwFrequency -- Specifies the frequency, in hertz of the display device in a particular mode.
On some early builds of Windows 95, changing the frequency of the display adapter is not
supported and this value should be set to 0 which means the default hardware value.
- CVideoModes::GetCurrentVideoMode
- static BOOL CVideoModes::GetCurrentVideoMode(CVideoMode& mode);
Return Value:
TRUE if the current video mode was retrieved successfully otherwise FALSE.
Parameters:
- mode -- Upon successful return this will contain the current video mode of the main display
adapter.
Remarks:
Internally this retrieves the current settings GetDeviceCaps() function on a device
context for the display.
- CVideoModes::GetAvailableVideoModes
- static BOOL CVideoModes::GetAvailableVideoModes(CAvailableVideoModes& modes);
Return Value:
TRUE if the available video modes were retrieved successfully otherwise FALSE.
Parameters:
- modes -- Upon successful return this will contain an array containing the available video modes
of the main display adapter.
Remarks:
Returns all the video modes which the display adapter supports.
CAvailableVideoModes is defined as follows:
typedef CArray<CVideoMode, CVideoMode&> CAvailableVideoModes;
- CVideoModes::ChangeVideoModePermanently
- static LONG CVideoModes::ChangeVideoModePermanently(const CVideoMode& mode);
Return Value:
Returns one of the following values:
| Value |
Meaning |
| DISP_CHANGE_SUCCESSFUL |
The settings change was successful. |
| DISP_CHANGE_RESTART |
The computer must be restarted in order for the graphics mode to work. |
| DISP_CHANGE_BADFLAGS |
An invalid set of flags was passed in. |
| DISP_CHANGE_FAILED |
The display driver failed the specified graphics mode. |
| DISP_CHANGE_BADMODE |
The graphics mode is not supported. |
| DISP_CHANGE_NOTUPDATED |
Unable to write settings to the registry. |
Parameters:
- mode -- The video mode to change into.
Remarks:
If this function succeeds then the changes are permanent, meaning that upon next boot of Windows the
video mode will be the preserved to that which you just changed into.
- CVideoModes::ChangeVideoModeTemporarily
- static LONG CVideoModes::ChangeVideoModeTemporarily(const CVideoMode& mode);
Return Value:
The return value is the same as ChangeVideoModePermanently.
Parameters:
- mode -- The video mode to change into.
Remarks:
If this function succeeds then the changes are not permanent, meaning that upon next boot of Windows
the video mode will be the the same as before you called this function.
- CVideoModes::CanChangeVideoMode
- static LONG CVideoModes::CanChangeVideoMode(const CVideoMode& mode);
Return Value:
The return value is the same as ChangeVideoModePermanently.
Parameters:
- mode -- he video mode to test whether or not the change can be made.
Remarks:
Using this function allows an application to determine if a specified graphics modes is actually valid,
without causing the system to change to that graphics mode.
- CVideoModes::RevertVideoModeToDefault
- static LONG CVideoModes::RevertVideoModeToDefault();
Return Value:
The return value is the same as ChangeVideoModePermanently.
Remarks:
Using this function allows an application to determine if a specified graphics modes is actually valid,
without causing the system to change to that graphics mode.
Contacting the Author
PJ Naughter
Email: pjn@indigo.ie
Web: http://www.naughter.com
4th January 1999
