__declspec(dllexport) void GetCurrentTopology(DISPLAYCONFIG_TOPOLOGY_ID *peCurrentTopology) {
// Get the current topology - make sure that we aren't resetting the topology to the same that it
// currently is - otherwise it can cause unnecessary flashing on the screen.
LONG result;
UINT32 NumPathArrayElements;
UINT32 NumModeInfoArrayElements;
DISPLAYCONFIG_PATH_INFO *pPathInfoArray;
DISPLAYCONFIG_MODE_INFO *pModeInfoArray;
result = GetDisplayConfigBufferSizes(QDC_DATABASE_CURRENT, &NumPathArrayElements, &NumModeInfoArrayElements);
if (result != ERROR_SUCCESS)
return;
if (peCurrentTopology == NULL)
return;
// The only reason to allocate these structures is that the documentation says that QueryDisplayConfig
// cannot take null for the pPathInfoArray and pModeInfoArray elements. I have tried to have static
// structures that get passed in with only one element and have had things fail in the past
// The only way that I've gotten this interface to reliably work is to call GetDisplayConfigBufferSizes
// and then allocate AND ZERO the structures that are passed in. This interface is incredibly
// fragile and you are going to want to do everything that it expects, or it will return
// "invalid parameter"
pPathInfoArray = (DISPLAYCONFIG_PATH_INFO *)malloc(NumPathArrayElements * sizeof(DISPLAYCONFIG_PATH_INFO));
if (!pPathInfoArray)
return;
pModeInfoArray = (DISPLAYCONFIG_MODE_INFO *)malloc(NumModeInfoArrayElements * sizeof(DISPLAYCONFIG_MODE_INFO));
if (!pModeInfoArray)
{
if (pPathInfoArray)
free(pPathInfoArray);
return;
}
memset(pPathInfoArray, 0, NumPathArrayElements * sizeof(DISPLAYCONFIG_PATH_INFO));
memset(pModeInfoArray, 0, NumModeInfoArrayElements * sizeof(DISPLAYCONFIG_MODE_INFO));
result = QueryDisplayConfig(QDC_DATABASE_CURRENT,
&NumPathArrayElements,
pPathInfoArray,
&NumModeInfoArrayElements,
pModeInfoArray,
peCurrentTopology);
// Free the structures, don't care what is in them
free(pPathInfoArray);
free(pModeInfoArray);
if (result != ERROR_SUCCESS)
return;
return;
}
int getCurrentSettings(UINT32* num_of_paths, UINT32* num_of_modes, DISPLAYCONFIG_PATH_INFO** displayPaths, DISPLAYCONFIG_MODE_INFO** displayModes) {
// Get number of paths, and number of modes in query
if (!Result_DCGDI(GetDisplayConfigBufferSizes(QDC_ALL_PATHS, num_of_paths, num_of_modes)))
return 0;
// Allocate paths and modes dynamically
*displayPaths = (DISPLAYCONFIG_PATH_INFO*)calloc((int)num_of_paths, sizeof(DISPLAYCONFIG_PATH_INFO));
*displayModes = (DISPLAYCONFIG_MODE_INFO*)calloc((int)num_of_modes, sizeof(DISPLAYCONFIG_MODE_INFO));
// Query for the information (fill in the arrays above)
if (!Result_QDC(QueryDisplayConfig(QDC_ALL_PATHS, num_of_paths, (*displayPaths), num_of_modes, (*displayModes), NULL)))
return 0;
return 1;
}
// Get current refresh rate on Win7
double W7GetRefreshRate(int monitorIdx)
{
UINT32 uNumPathArrayElements = 0;
UINT32 uNumModeInfoArrayElements = 0;
DISPLAYCONFIG_PATH_INFO* pPathInfoArray = NULL;
DISPLAYCONFIG_MODE_INFO* pModeInfoArray = NULL;
DISPLAYCONFIG_TOPOLOGY_ID* pCurrentTopologyId = NULL;
LONG result;
double refreshRate = -1;
DISPLAY_DEVICE displayDevice;
displayDevice.cb = sizeof(DISPLAY_DEVICE);
DEVMODE devMode;
devMode.dmSize = sizeof(DEVMODE);
DEVMODE *paDeviceMode;
if(EnumDisplayDevices(NULL, monitorIdx, &displayDevice, 0))
{
EnumDisplaySettings(displayDevice.DeviceName, ENUM_CURRENT_SETTINGS, &devMode);
}
paDeviceMode = &devMode;
// Get size of buffers for QueryDisplayConfig
result = GetDisplayConfigBufferSizes(QDC_ONLY_ACTIVE_PATHS, &uNumPathArrayElements, &uNumModeInfoArrayElements);
if (result != 0)
{
return(refreshRate);
}
// allocate memory for QueryDisplayConfig buffers
pPathInfoArray = (DISPLAYCONFIG_PATH_INFO*)calloc(uNumPathArrayElements, sizeof(DISPLAYCONFIG_PATH_INFO));
if (pPathInfoArray == NULL)
{
return(refreshRate);
}
pModeInfoArray = (DISPLAYCONFIG_MODE_INFO*)calloc(uNumModeInfoArrayElements, sizeof(DISPLAYCONFIG_MODE_INFO));
if (pModeInfoArray == NULL)
{
// freeing memory
free(pPathInfoArray);
return(refreshRate);
}
// get display configuration
result = QueryDisplayConfig(QDC_ONLY_ACTIVE_PATHS,
&uNumPathArrayElements, pPathInfoArray,
&uNumModeInfoArrayElements, pModeInfoArray,
pCurrentTopologyId);
if (result == 0)
{
//// Get information from active target path and based on current dimension (support for multiple displays)
for (UINT i = 0; i < uNumPathArrayElements; ++i)
{
UINT iModIdx = pPathInfoArray[i].sourceInfo.modeInfoIdx;
if(pPathInfoArray[i].flags == DISPLAYCONFIG_PATH_ACTIVE && paDeviceMode[0].dmPosition.x == pModeInfoArray[iModIdx].sourceMode.position.x && paDeviceMode[0].dmPosition.y == pModeInfoArray[iModIdx].sourceMode.position.y)
{
if(paDeviceMode[0].dmPelsHeight == pModeInfoArray[iModIdx].sourceMode.height && paDeviceMode[0].dmPelsWidth == pModeInfoArray[iModIdx].sourceMode.width)
{
monitorIdx = i;
DISPLAYCONFIG_PATH_TARGET_INFO target;
target = pPathInfoArray[monitorIdx].targetInfo;
LONG numerator = target.refreshRate.Numerator;
LONG denominator = target.refreshRate.Denominator;
refreshRate = (double)numerator/(double)denominator;
break;
}
}
}
}
// freeing memory
free(pPathInfoArray);
free(pModeInfoArray);
return(refreshRate);
}