www.pudn.com > chscrres_src.zip > chscrres.c

#include  
 
struct DDList { 
	DISPLAY_DEVICE	Device; 
	struct DDList	*Next; 
}; 
static void DDList_Build(struct DDList **ppDD); 
static void DDList_Clean(struct DDList **ppDD); 
static BOOL DDList_Pop(struct DDList **ppDD, DISPLAY_DEVICE	*device); 
 
static BOOL getResolution(int argc, char **argv, int *width, int *height); 
 
int main(int argc, char **argv) { 
	DISPLAY_DEVICE	device		= {0}; 
	struct DDList	*ddList		= NULL; 
	DEVMODE			deviceMode	= {0}; 
	int				newWidth	= 0; 
	int				newHeight	= 0; 
	int				actualWidth	= 0; 
	int				actualHeight= 0; 
 
	if(!getResolution(argc, argv, &newWidth, &newHeight)) { 
		return 1; 
	} 
 
	//	build display devices list 
	DDList_Build(&ddList); 
 
	//	get the first display device, if any (...);  
	//	decision is with user, or relying on other considerations 
	device.cb = sizeof(device); 
	if(DDList_Pop(&ddList, &device)) { 
		//	now change the display settings 
			//	enumerate current (we can user NULL instead of device.DeviceName,  
			//	but this is more generic) 
		deviceMode.dmSize			= sizeof(deviceMode); 
		deviceMode.dmDriverExtra	= 0; 
		if(EnumDisplaySettingsEx(device.DeviceName, ENUM_CURRENT_SETTINGS, &deviceMode, 0)) { 
			actualWidth = deviceMode.dmPelsWidth; 
			actualHeight = deviceMode.dmPelsHeight; 
			if((actualWidth != newWidth) || (actualHeight != newHeight)) { 
				//	change requested 
				deviceMode.dmPelsWidth	= newWidth; 
				deviceMode.dmPelsHeight	= newHeight; 
				if(ChangeDisplaySettingsEx(device.DeviceName, &deviceMode, 					 
					NULL, 0, NULL) == DISP_CHANGE_SUCCESSFUL) { 
					//	broadcast change to system 
					SendMessage(HWND_BROADCAST, WM_DISPLAYCHANGE,  
						(WPARAM)(deviceMode.dmBitsPerPel),  
						MAKELPARAM(newWidth, newHeight)); 
				} 
			} 
		} 
	} 
 
	//	clear list 
	DDList_Clean(&ddList); 
 
	return 0; 
} 
 
static void DDList_Build(struct DDList **ppDD) { 
	DWORD			deviceNum	= 0; 
	DISPLAY_DEVICE	device		= {0}; 
	struct DDList	*ddList		= NULL; 
	struct DDList	*dd			= NULL; 
	struct DDList	*ddLastNode	= NULL; 
 
	if(ppDD == NULL) { 
		return; 
	} 
	*ppDD = NULL; 
 
	//	build display devices list 
	device.cb = sizeof(device); 
	do { 
		if(!EnumDisplayDevices(NULL, deviceNum, &device, 0)) { 
			break; 
		} 
		if(device.StateFlags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP) { 
			dd = (struct DDList *)malloc(sizeof(struct DDList)); 
			if(!dd) { 
				break; 
			} 
			dd->Device	= device; 
			dd->Next	= NULL; 
 
			if(ddList) { 
				ddLastNode->Next = dd; 
				ddLastNode = dd; 
			} 
			else { 
				ddList = dd; 
				ddLastNode = ddList; 
			} 
		} 
		deviceNum++; 
	} while(1); 
 
	*ppDD = ddList; 
} 
 
static void DDList_Clean(struct DDList **ppDD) { 
	struct DDList	*ddList		= NULL; 
	struct DDList	*dd			= NULL; 
 
	if(ppDD == NULL) { 
		return; 
	} 
	ddList = *ppDD; 
	//	clear list 
	while(ddList) { 
		dd = ddList; 
		ddList = ddList->Next; 
		free(dd); 
	} 
} 
 
static BOOL DDList_Pop(struct DDList **ppDD, DISPLAY_DEVICE	*device) { 
	struct DDList *ddList = NULL; 
	struct DDList *ddHead = NULL; 
	size_t cbDD = sizeof(DISPLAY_DEVICE); 
 
	if(ppDD == NULL) { 
		return FALSE; 
	} 
	if(device == NULL) { 
		return FALSE; 
	} 
	if(device->cb < cbDD) { 
		return FALSE; 
	} 
	ddList = *ppDD; 
	CopyMemory(device, &ddList->Device, cbDD); 
 
	ddHead = ddList; 
	ddList = ddList->Next; 
	free(ddHead); 
 
	*ppDD = ddList; 
	return TRUE; 
} 
 
static BOOL getResolution(int argc, char **argv, int *width, int *height) { 
	char *arg = NULL; 
	int n = 0; 
 
	if(width == NULL || height == NULL) { 
		return FALSE; 
	} 
	if(argc != 3) { 
		return FALSE; 
	} 
	//	width 
	arg = argv[1]; 
	n = atoi(arg); 
	if(n <= 0) { 
		return FALSE; 
	} 
	*width = n; 
	//	height 
	arg = argv[2]; 
	n = atoi(arg); 
	if(n <= 0) { 
		return FALSE; 
	} 
	*height = n; 
 
	return TRUE; 
}