PsychError SCREENPreference(void)  
{

	PsychArgFormatType		arg1Type;
	char					*preferenceName, *newFontName;
	const char				*tableCreator, *oldDefaultFontName;
	psych_bool				preferenceNameArgumentValid, booleanInput, ignoreCase, tempFlag, textAlphaBlendingFlag, suppressAllWarningsFlag;
	int						numInputArgs, i, newFontStyleNumber, newFontSize, tempInt, tempInt2, tempInt3, tempInt4;
	double					returnDoubleValue, inputDoubleValue;
	double					maxStddev, maxDeviation, maxDuration;
	int						minSamples;
    double                  *dheads = NULL;

	//all sub functions should have these two lines
	PsychPushHelp(useString, synopsisString,seeAlsoString);
	if(PsychIsGiveHelp()){PsychGiveHelp();return(PsychError_none);};
	
	//check for superfluous or missing arguments
	PsychErrorExit(PsychCapNumInputArgs(5));			
	PsychErrorExit(PsychRequireNumInputArgs(1));		   
	PsychErrorExit(PsychCapNumOutputArgs(4));
	
	numInputArgs=PsychGetNumInputArgs();
	arg1Type=PsychGetArgType(1);
	preferenceNameArgumentValid=FALSE;
	
	//Cases which require both a window pointer or screen number and preference name.  Argument 1 is the wposn and argument 2 is the preference name.
	if( numInputArgs >= 2 && (PsychIsScreenNumberArg(1) || PsychIsScreenNumberArg(1)) && PsychGetArgType(2)==PsychArgType_char ){
		PsychAllocInCharArg(2, kPsychArgRequired, &preferenceName);
		//preferences which require window pointer or screen number argument which we DO NOT support  
		for(i=0;i<kPsychNumUnsupportedMacVideoPreferences;i++){
			if(PsychMatch(preferenceName, unsupportedMacVideoPreferenceNames[i]))
				PsychErrorExit(PsychError_unsupportedOS9Preference);
		}
		//insert here conditionals  to act on prefernces which accept a window pointer or screen number argument which we DO support.
		PsychErrorExit(PsychError_unrecognizedPreferenceName);
	}

	//Cases which do not require a wposn.  Argument 1 is the preference name.  if present Argument 2 is the new value
	if(arg1Type==PsychArgType_char){
		PsychAllocInCharArg(1, kPsychArgRequired, &preferenceName);
		//Preferernces which we do not support and which do not require a wposn
		for(i=0;i<kPsychNumUnsupportedMacNonVideoPreferences;i++){
			if(PsychMatch(preferenceName, unsupportedMacNonVideoPreferenceNames[i]))
				PsychErrorExit(PsychError_unsupportedOS9Preference);
		}
		//Preferences which we do support
		if(PsychMatch(preferenceName, "IgnoreCase")){
			ignoreCase=!PsychIsPsychMatchCaseSensitive();
			PsychCopyOutFlagArg(1, kPsychArgOptional, ignoreCase);
			if(numInputArgs==2){
				PsychCopyInFlagArg(2, kPsychArgRequired, &booleanInput);
				PsychSetPsychMatchCaseSenstive(!booleanInput);			
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "Tick0Secs")){
			if(PsychCopyInDoubleArg(2, kPsychArgOptional, &inputDoubleValue) && inputDoubleValue==PsychGetNanValue())
				PsychEstimateGetSecsValueAtTickCountZero();
			returnDoubleValue=PsychGetEstimatedSecsValueAtTickCountZero();
			PsychCopyOutDoubleArg(1, kPsychArgOptional, returnDoubleValue);
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "PsychTableVersion")){
			if(numInputArgs==2)
				PsychErrorExit(PsychError_extraInputArg);
			PsychCopyOutDoubleArg(1, kPsychArgOptional, (double)PsychPrefStateGet_PsychTableVersion());
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "PsychTableCreator")){
			if(numInputArgs==2)
				PsychErrorExit(PsychError_extraInputArg);
			tableCreator=PsychPrefStateGet_PsychTableCreator();
			PsychCopyOutCharArg(1, kPsychArgOptional, tableCreator);
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "Process")){
			if(numInputArgs==2)
				PsychErrorExit(PsychError_extraInputArg);
			PsychCopyOutDoubleArg(1, kPsychArgOptional, (double) (psych_int64) getpid());
			preferenceNameArgumentValid=TRUE;


		}else 
		if(PsychMatch(preferenceName, "DefaultFontName")){
			PsychPrefStateGet_DefaultFontName(&oldDefaultFontName);
			PsychCopyOutCharArg(1, kPsychArgOptional, oldDefaultFontName);
			if(numInputArgs==2){
				PsychAllocInCharArg(2, kPsychArgRequired, &newFontName);
				PsychPrefStateSet_DefaultFontName(newFontName);
			}
			preferenceNameArgumentValid=TRUE;			
		}else 
		if(PsychMatch(preferenceName, "TextEncodingLocale")){
			PsychCopyOutCharArg(1, kPsychArgOptional, PsychGetUnicodeTextConversionLocale());
			if(numInputArgs==2){
				PsychAllocInCharArg(2, kPsychArgRequired, &newFontName);
				if (!PsychSetUnicodeTextConversionLocale(newFontName)) PsychErrorExitMsg(PsychError_user, "Setting the 'TextEncodingLocale' failed, most likely because you provided an invalid/unknown locale setting string.");
			}
			preferenceNameArgumentValid=TRUE;			
		}else 
		if(PsychMatch(preferenceName, "DefaultFontStyle")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_DefaultTextStyle());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &newFontStyleNumber);
				PsychPrefStateSet_DefaultTextStyle(newFontStyleNumber);
			}
			preferenceNameArgumentValid=TRUE;
		}else
		if(PsychMatch(preferenceName, "OverrideMultimediaEngine")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_UseGStreamer());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_UseGStreamer(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else
		if(PsychMatch(preferenceName, "DefaultTextYPositionIsBaseline")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_TextYPositionIsBaseline());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_TextYPositionIsBaseline(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "TextAntiAliasing")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_TextAntiAliasing());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_TextAntiAliasing(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "TextRenderer")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_TextRenderer());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_TextRenderer(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "DefaultFontSize")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_DefaultTextSize());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &newFontSize);
				PsychPrefStateSet_DefaultTextSize(newFontSize);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "DebugMakeTexture")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_DebugMakeTexture());
			if(numInputArgs==2){
				PsychCopyInFlagArg(2, kPsychArgRequired, &tempFlag);
				PsychPrefStateSet_DebugMakeTexture(tempFlag);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "SkipSyncTests")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_SkipSyncTests());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_SkipSyncTests(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "VisualDebugLevel")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_VisualDebugLevel());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_VisualDebugLevel(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "VBLTimestampingMode")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_VBLTimestampingMode());
			if(numInputArgs>=2){
                            PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
                            PsychPrefStateSet_VBLTimestampingMode(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "SyncTestSettings")){
			PsychPrefStateGet_SynctestThresholds(&maxStddev, &minSamples, &maxDeviation, &maxDuration);
			PsychCopyOutDoubleArg(1, kPsychArgOptional, maxStddev);
			PsychCopyOutDoubleArg(2, kPsychArgOptional, minSamples);
			PsychCopyOutDoubleArg(3, kPsychArgOptional, maxDeviation);
			PsychCopyOutDoubleArg(4, kPsychArgOptional, maxDuration);
			if(numInputArgs>=2){
							PsychCopyInDoubleArg( 2, kPsychArgOptional, &maxStddev);
                            PsychCopyInIntegerArg(3, kPsychArgOptional, &minSamples);
							PsychCopyInDoubleArg( 4, kPsychArgOptional, &maxDeviation);
							PsychCopyInDoubleArg( 5, kPsychArgOptional, &maxDuration);
							PsychPrefStateSet_SynctestThresholds(maxStddev, minSamples, maxDeviation, maxDuration);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "VBLEndlineOverride")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_VBLEndlineOverride());
			if(numInputArgs>=2){
                            PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
                            PsychPrefStateSet_VBLEndlineOverride(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else
			if(PsychMatch(preferenceName, "DefaultVideocaptureEngine")){
				PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_VideoCaptureEngine());
				if(numInputArgs==2){
					PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
					PsychPrefStateSet_VideoCaptureEngine(tempInt);
				}
			preferenceNameArgumentValid=TRUE;
		}else
			if(PsychMatch(preferenceName, "WindowShieldingLevel")){
				PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_WindowShieldingLevel());
				if(numInputArgs==2){
					PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
					PsychPrefStateSet_WindowShieldingLevel(tempInt);
				}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "ConserveVRAM") || PsychMatch(preferenceName, "Workarounds1")){
					PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_ConserveVRAM());
					if(numInputArgs==2){
						PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
						PsychPrefStateSet_ConserveVRAM(tempInt);
					}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "Verbosity")){
					PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_Verbosity());
					if(numInputArgs==2){
						PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
						PsychPrefStateSet_Verbosity(tempInt);
					}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "FrameRectCorrection")){
					PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_FrameRectCorrection());
					if(numInputArgs==2){
						PsychCopyInDoubleArg(2, kPsychArgRequired, &inputDoubleValue);
						PsychPrefStateSet_FrameRectCorrection(inputDoubleValue);
					}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "EmulateOldPTB")){
				PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_EmulateOldPTB());
				if(numInputArgs==2){
					PsychCopyInFlagArg(2, kPsychArgRequired, &tempFlag);
					PsychPrefStateSet_EmulateOldPTB(tempFlag);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "Enable3DGraphics")){
				PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_3DGfx());
				if(numInputArgs==2){
					PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
					PsychPrefStateSet_3DGfx(tempInt);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "TextAlphaBlending")){
				textAlphaBlendingFlag=PsychPrefStateGet_TextAlphaBlending();
				PsychCopyOutFlagArg(1, kPsychArgOptional, textAlphaBlendingFlag);
				if(numInputArgs==2){
					PsychCopyInFlagArg(2, kPsychArgRequired, &booleanInput);
					PsychPrefStateSet_TextAlphaBlending(booleanInput);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "SuppressAllWarnings")){
				suppressAllWarningsFlag=PsychPrefStateGet_SuppressAllWarnings();
				PsychCopyOutFlagArg(1, kPsychArgOptional, suppressAllWarningsFlag);
				if(numInputArgs==2){
					PsychCopyInFlagArg(2, kPsychArgRequired, &booleanInput);
					PsychPrefStateSet_SuppressAllWarnings(booleanInput);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "SynchronizeDisplays")){
				if(numInputArgs >= 2) {
					// This is a special call: It currently doesn't set a preference setting,
					// but instead triggers an instantaneous synchronization of all available
					// display heads, if possible. We may have a more clever and "standard" interface
					// interface for this later on, but for first tests this will do.
					// Syncmethod is hard-coded to 0 -> Use whatever's available to sync.
					// timeout for retries is 5.0 seconds.
					// Acceptable residual offset is +/- 2 scanlines.
					// Returns the real residual offset after sync.
					PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
					if (!PsychCopyInIntegerArg(3, kPsychArgOptional, &tempInt3)) {
                        // No screenId specified: Resync default screen or whatever...
                        tempInt2 = 0;
                        if (PsychSynchronizeDisplayScreens(&tempInt2, NULL, &tempInt, tempInt, 5.0, 2)!=PsychError_none) PsychErrorExitMsg(PsychError_user, "Sync failed for reasons mentioned above.");
                    } else {
                        // Specific screenId provided: Resync crtc's associated with this screenId if possible:
                        tempInt2 = 1;
                        if (PsychSynchronizeDisplayScreens(&tempInt2, &tempInt3, &tempInt, tempInt, 5.0, 2)!=PsychError_none) PsychErrorExitMsg(PsychError_user, "Sync failed for reasons mentioned above.");
                    }
                    
					PsychCopyOutDoubleArg(1, kPsychArgOptional, tempInt);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "ScreenToHead")){
				// screenId is required:
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				if (tempInt < 0 || tempInt >= PsychGetNumDisplays() || tempInt >= kPsychMaxPossibleDisplays) PsychErrorExitMsg(PsychError_user, "Invalid screenId provided. Out of valid range!");

				// Return old mappings for this screenId:
                for (tempInt2 = 0; (tempInt2 < kPsychMaxPossibleCrtcs) && (PsychPrefStateGet_ScreenToHead(tempInt, tempInt2) >= 0); tempInt2++);
                PsychAllocOutDoubleMatArg(1, kPsychArgOptional, 2, tempInt2, 1, &dheads);
                
                tempInt4 = 0;
                for (tempInt3 = 0; tempInt3 < tempInt2; tempInt3++) {
                    dheads[tempInt4++] = (double) PsychPrefStateGet_ScreenToHead(tempInt, tempInt3);
                    dheads[tempInt4++] = (double) PsychPrefStateGet_ScreenToCrtcId(tempInt, tempInt3);
                }
                
                // Optionally retrieve and set new mappings for this screenId:
				if(numInputArgs>=3) {
					// Set new headId for screenId:
					PsychCopyInIntegerArg(3, kPsychArgRequired, &tempInt2);
					if (tempInt2 < 0) PsychErrorExitMsg(PsychError_user, "Invalid negative headId provided!");

					// Set new crtcId for screenId:
					PsychCopyInIntegerArg(4, kPsychArgRequired, &tempInt3);
					if (tempInt3 < 0) PsychErrorExitMsg(PsychError_user, "Invalid negative crtcId provided!");

                    // Assign primary head by default (index 0), but allow optionally others as well:
                    tempInt4 = 0;
					PsychCopyInIntegerArg(5, kPsychArgOptional, &tempInt4);
					if (tempInt4 < 0 || tempInt4 >= kPsychMaxPossibleCrtcs) PsychErrorExitMsg(PsychError_user, "Invalid rankId provided! Too many heads for one screen!");

					PsychPrefStateSet_ScreenToHead(tempInt, tempInt2, tempInt3, tempInt4);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			PsychErrorExit(PsychError_unrecognizedPreferenceName);
	}
	
	if(!preferenceNameArgumentValid)
		PsychErrorExitMsg(PsychError_user, "Invalid arguments to preferences command");
		
	return(PsychError_none);
}
PsychError SCREENPreference(void)  
{

	PsychArgFormatType		arg1Type;
	char					*preferenceName, *newFontName;
	const char				*tableCreator, *oldDefaultFontName;
	Boolean					preferenceNameArgumentValid, booleanInput, ignoreCase, tempFlag, textAlphaBlendingFlag, suppressAllWarningsFlag;
	int						numInputArgs, i, newFontStyleNumber, newFontSize, tempInt, tempInt2, tempInt3;
	double					returnDoubleValue, inputDoubleValue;
	
	//all sub functions should have these two lines
	PsychPushHelp(useString, synopsisString,seeAlsoString);
	if(PsychIsGiveHelp()){PsychGiveHelp();return(PsychError_none);};
	
	//check for superfluous or missing arguments
	PsychErrorExit(PsychCapNumInputArgs(3));			
	PsychErrorExit(PsychRequireNumInputArgs(1));		   
	PsychErrorExit(PsychCapNumOutputArgs(1));
	
	numInputArgs=PsychGetNumInputArgs();
	arg1Type=PsychGetArgType(1);
	preferenceNameArgumentValid=FALSE;
	
	//Cases which require both a window pointer or screen number and preference name.  Argument 1 is the wposn and argument 2 is the preference name.
	if( numInputArgs >= 2 && (PsychIsScreenNumberArg(1) || PsychIsScreenNumberArg(1)) && PsychGetArgType(2)==PsychArgType_char ){
		PsychAllocInCharArg(2, kPsychArgRequired, &preferenceName);
		//preferences which require window pointer or screen number argument which we DO NOT support  
		for(i=0;i<kPsychNumUnsupportedMacVideoPreferences;i++){
			if(PsychMatch(preferenceName, unsupportedMacVideoPreferenceNames[i]))
				PsychErrorExit(PsychError_unsupportedOS9Preference);
		}
		//insert here conditionals  to act on prefernces which accept a window pointer or screen number argument which we DO support.
		PsychErrorExit(PsychError_unrecognizedPreferenceName);
	}

	//Cases which do not require a wposn.  Argument 1 is the preference name.  if present Argument 2 is the new value
	if(arg1Type==PsychArgType_char){
		PsychAllocInCharArg(1, kPsychArgRequired, &preferenceName);
		//Preferernces which we do not support and which do not require a wposn
		for(i=0;i<kPsychNumUnsupportedMacNonVideoPreferences;i++){
			if(PsychMatch(preferenceName, unsupportedMacNonVideoPreferenceNames[i]))
				PsychErrorExit(PsychError_unsupportedOS9Preference);
		}
		//Preferences which we do support
		if(PsychMatch(preferenceName, "IgnoreCase")){
			ignoreCase=!PsychIsPsychMatchCaseSensitive();
			PsychCopyOutFlagArg(1, kPsychArgOptional, ignoreCase);
			if(numInputArgs==2){
				PsychCopyInFlagArg(2, kPsychArgRequired, &booleanInput);
				PsychSetPsychMatchCaseSenstive(!booleanInput);			
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "Tick0Secs")){
			if(PsychCopyInDoubleArg(2, kPsychArgOptional, &inputDoubleValue) && inputDoubleValue==PsychGetNanValue())
				PsychEstimateGetSecsValueAtTickCountZero();
			returnDoubleValue=PsychGetEstimatedSecsValueAtTickCountZero();
			PsychCopyOutDoubleArg(1, kPsychArgOptional, returnDoubleValue);
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "PsychTableVersion")){
			if(numInputArgs==2)
				PsychErrorExit(PsychError_extraInputArg);
			PsychCopyOutDoubleArg(1, kPsychArgOptional, (double)PsychPrefStateGet_PsychTableVersion());
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "PsychTableCreator")){
			if(numInputArgs==2)
				PsychErrorExit(PsychError_extraInputArg);
			tableCreator=PsychPrefStateGet_PsychTableCreator();
			PsychCopyOutCharArg(1, kPsychArgOptional, tableCreator);
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "Process")){
			if(numInputArgs==2)
				PsychErrorExit(PsychError_extraInputArg);
			PsychCopyOutDoubleArg(1, kPsychArgOptional, (double)getpid());
			preferenceNameArgumentValid=TRUE;


		}else 
		if(PsychMatch(preferenceName, "DefaultFontName")){
			PsychPrefStateGet_DefaultFontName(&oldDefaultFontName);
			PsychCopyOutCharArg(1, kPsychArgOptional, oldDefaultFontName);
			if(numInputArgs==2){
				PsychAllocInCharArg(2, kPsychArgRequired, &newFontName);
				PsychPrefStateSet_DefaultFontName(newFontName);
			}
			preferenceNameArgumentValid=TRUE;
			
		}else 
		if(PsychMatch(preferenceName, "DefaultFontStyle")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_DefaultTextStyle());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &newFontStyleNumber);
				PsychPrefStateSet_DefaultTextStyle(newFontStyleNumber);
			}
			preferenceNameArgumentValid=TRUE;
		}else
		if(PsychMatch(preferenceName, "DefaultTextYPositionIsBaseline")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_TextYPositionIsBaseline());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_TextYPositionIsBaseline(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "TextAntiAliasing")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_TextAntiAliasing());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_TextAntiAliasing(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "TextRenderer")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_TextRenderer());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_TextRenderer(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "DefaultFontSize")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_DefaultTextSize());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &newFontSize);
				PsychPrefStateSet_DefaultTextSize(newFontSize);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
		if(PsychMatch(preferenceName, "DebugMakeTexture")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_DebugMakeTexture());
			if(numInputArgs==2){
				PsychCopyInFlagArg(2, kPsychArgRequired, &tempFlag);
				PsychPrefStateSet_DebugMakeTexture(tempFlag);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "SkipSyncTests")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_SkipSyncTests());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_SkipSyncTests(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "VisualDebugLevel")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_VisualDebugLevel());
			if(numInputArgs==2){
				PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
				PsychPrefStateSet_VisualDebugLevel(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "VBLTimestampingMode")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_VBLTimestampingMode());
			if(numInputArgs>=2){
                            PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
                            PsychPrefStateSet_VBLTimestampingMode(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "VBLEndlineOverride")){
			PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_VBLEndlineOverride());
			if(numInputArgs>=2){
                            PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
                            PsychPrefStateSet_VBLEndlineOverride(tempInt);
			}
			preferenceNameArgumentValid=TRUE;
		}else
			if(PsychMatch(preferenceName, "DefaultVideocaptureEngine")){
				PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_VideoCaptureEngine());
				if(numInputArgs==2){
					PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
					PsychPrefStateSet_VideoCaptureEngine(tempInt);
				}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "ConserveVRAM") || PsychMatch(preferenceName, "Workarounds1")){
					PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_ConserveVRAM());
					if(numInputArgs==2){
						PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
						PsychPrefStateSet_ConserveVRAM(tempInt);
					}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "Verbosity")){
					PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_Verbosity());
					if(numInputArgs==2){
						PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
						PsychPrefStateSet_Verbosity(tempInt);
					}
			preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "EmulateOldPTB")){
				PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_EmulateOldPTB());
				if(numInputArgs==2){
					PsychCopyInFlagArg(2, kPsychArgRequired, &tempFlag);
					PsychPrefStateSet_EmulateOldPTB(tempFlag);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "Enable3DGraphics")){
				PsychCopyOutDoubleArg(1, kPsychArgOptional, PsychPrefStateGet_3DGfx());
				if(numInputArgs==2){
					PsychCopyInFlagArg(2, kPsychArgRequired, &tempFlag);
					PsychPrefStateSet_3DGfx(tempFlag);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "TextAlphaBlending")){
				textAlphaBlendingFlag=PsychPrefStateGet_TextAlphaBlending();
				PsychCopyOutFlagArg(1, kPsychArgOptional, textAlphaBlendingFlag);
				if(numInputArgs==2){
					PsychCopyInFlagArg(2, kPsychArgRequired, &booleanInput);
					PsychPrefStateSet_TextAlphaBlending(booleanInput);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "SuppressAllWarnings")){
				suppressAllWarningsFlag=PsychPrefStateGet_SuppressAllWarnings();
				PsychCopyOutFlagArg(1, kPsychArgOptional, suppressAllWarningsFlag);
				if(numInputArgs==2){
					PsychCopyInFlagArg(2, kPsychArgRequired, &booleanInput);
					PsychPrefStateSet_SuppressAllWarnings(booleanInput);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			if(PsychMatch(preferenceName, "SynchronizeDisplays")){
				if(numInputArgs==2){
					// This is a special call: It currently doesn't set a preference setting,
					// but instead triggers an instantaneous synchronization of all available
					// display heads, if possible. We may have a more clever and "standard" interface
					// interface for this later on, but for first tests this will do.
					// Syncmethod is hard-coded to 0 -> Use whatever's available to sync.
					// timeout for retries is 5.0 seconds.
					// Acceptable residual offset is +/- 2 scanlines.
					// Returns the real residual offset after sync.
					PsychCopyInIntegerArg(2, kPsychArgRequired, &tempInt);
					tempInt2 = 0;
					if (PsychSynchronizeDisplayScreens(&tempInt2, NULL, &tempInt, tempInt, 5.0, 2)!=PsychError_none) PsychErrorExitMsg(PsychError_user, "Sync failed for reasons mentioned above.");
					PsychCopyOutDoubleArg(1, kPsychArgOptional, tempInt);
				}
				preferenceNameArgumentValid=TRUE;
		}else 
			PsychErrorExit(PsychError_unrecognizedPreferenceName);
	}
	
	if(!preferenceNameArgumentValid)
		PsychErrorExitMsg(PsychError_user, "Invalid arguments to preferences command");
		
	return(PsychError_none);
}
PsychError SCREENTextFont(void) 
{
    psych_bool			doSetByName, doSetByNumber, foundFont;
    PsychWindowRecordType	*windowRecord;
#if PSYCH_SYSTEM == PSYCH_OSX
    PsychFontStructType		*fontRecord;
#endif
    int				oldTextFontNumber, inputTextFontNumber;
    char			*oldTextFontName, *inputTextFontName;
    int             oldTextStyle, newTextStyle;
    
    //all subfunctions should have these two lines.  
    PsychPushHelp(useString, synopsisString, seeAlsoString);
    if(PsychIsGiveHelp()){PsychGiveHelp();return(PsychError_none);};
    
    //check for valid number of arguments
    PsychErrorExit(PsychRequireNumInputArgs(1));
    PsychErrorExit(PsychCapNumInputArgs(3));
    PsychErrorExit(PsychCapNumOutputArgs(3));
    
    //Get the window record
    PsychAllocInWindowRecordArg(kPsychUseDefaultArgPosition, TRUE, &windowRecord);
    
    //Save the old text font value and return it.
    oldTextFontNumber=windowRecord->textAttributes.textFontNumber;
    PsychCopyOutDoubleArg(2, FALSE, (double)oldTextFontNumber);
    oldTextFontName=(char*) windowRecord->textAttributes.textFontName;
    PsychCopyOutCharArg(1, FALSE, oldTextFontName);
    oldTextStyle = windowRecord->textAttributes.textStyle;
    PsychCopyOutDoubleArg(3, FALSE, (double) oldTextStyle);
	
    //Fetch and set the new font if specified by name or number
    PsychCheckInputArgType(2, kPsychArgOptional, PsychArgType_double | PsychArgType_char);  //if the argument is there check that it is the right type.
    doSetByNumber= PsychCopyInIntegerArg(2, kPsychArgAnything, &inputTextFontNumber);
    doSetByName= PsychAllocInCharArg(2, kPsychArgAnything, &inputTextFontName);
    foundFont=0;
#if PSYCH_SYSTEM == PSYCH_OSX
    if(doSetByNumber) {
        foundFont=PsychGetFontRecordFromFontNumber(inputTextFontNumber, &fontRecord);
    }
    
    if(doSetByName) {
        if (PsychCopyInIntegerArg(3, FALSE, &newTextStyle)) windowRecord->textAttributes.textStyle = newTextStyle;
        foundFont=PsychGetFontRecordFromFontFamilyNameAndFontStyle(inputTextFontName, windowRecord->textAttributes.textStyle, &fontRecord);
    }
    
    if(foundFont) {
        strncpy((char*) windowRecord->textAttributes.textFontName, (char*) fontRecord->fontFMFamilyName, 255);
        windowRecord->textAttributes.textFontNumber = fontRecord->fontNumber;
        windowRecord->textAttributes.textStyle = fontRecord->fontFMStyle;
    }
	else {
		// Font not found. Is this textrenderer 2 with a font given by name?
		if (doSetByName && (PsychPrefStateGet_TextRenderer() > 1)) {
			// Yes: Must be a special font specifier string for the renderer plugin. Just assign it directly:
			strncpy((char*) windowRecord->textAttributes.textFontName, inputTextFontName, 255);

			// Don't have a valid fontNumber: Just assign a zero...
			windowRecord->textAttributes.textFontNumber = 0;
		}
        else {
            // Restore old text style setting:
            windowRecord->textAttributes.textStyle = oldTextStyle;
        }
	}
    
    return(PsychError_none);
#else
    // Special case for MS-Windows and Linux:
    if(doSetByNumber) printf("PTB-WARNING: Sorry, selecting font by number in Screen('TextFont') is not yet supported on Windows or Linux. Command ignored.\n");
    if(doSetByName && (strncmp(windowRecord->textAttributes.textFontName, inputTextFontName, 255 )!=0)) {
      strncpy(windowRecord->textAttributes.textFontName, inputTextFontName, 255);
      windowRecord->textAttributes.textFontNumber= 0;
      // Set the rebuild flag:
      windowRecord->textAttributes.needsRebuild=TRUE;
    }
    
    // New and different text style provided?
    if (PsychCopyInIntegerArg(3, FALSE, &newTextStyle) && (windowRecord->textAttributes.textStyle != newTextStyle)) {
        windowRecord->textAttributes.textStyle = newTextStyle;
        // Set the rebuild flag:
        windowRecord->textAttributes.needsRebuild=TRUE;
    }

    return(PsychError_none);
#endif
}
PsychError SCREENTextBounds(void)
{
    PsychWindowRecordType  *winRec;
    char			       *textString;
    int                    stringl, i;
	PsychRectType		   resultPsychRect, resultPsychNormRect;
    float                  accumWidth, maxHeight;
	PsychError			   dterr;
	
    // All subfunctions should have these two lines.  
    PsychPushHelp(useString, synopsisString, seeAlsoString);
    if(PsychIsGiveHelp()){PsychGiveHelp();return(PsychError_none);};
    
    PsychErrorExit(PsychCapNumInputArgs(5));   	
    PsychErrorExit(PsychRequireNumInputArgs(2)); 	
    PsychErrorExit(PsychCapNumOutputArgs(2));  

    #if PSYCH_SYSTEM == PSYCH_WINDOWS
		 // Use GDI based text renderer on Windows, instead of display list based one?
		 if (PsychPrefStateGet_TextRenderer()==1) {
			// Call the GDI based renderer function in 'TextBounds' mode. It will calculate
			// the bounding box for us:
			if ((dterr=SCREENDrawTextGDI(&resultPsychRect))!=PsychError_none) return(dterr);
			
			// Ok, have a valid resultPsychRect bounding box. Calculate normalized bounding box
			// as well:
			PsychNormalizeRect(resultPsychRect, resultPsychNormRect);
			 
			// Return optional values:
			PsychCopyOutRectArg(1, FALSE, resultPsychNormRect);
			PsychCopyOutRectArg(2, FALSE, resultPsychRect);
			
			// Done.
			return(PsychError_none);			
	 	 }
	#endif

    //Get the window structure for the onscreen window.
    PsychAllocInWindowRecordArg(1, TRUE, &winRec);
    
    //Get the text string (it is required)
    PsychAllocInCharArg(2, kPsychArgRequired, &textString);
	if(strlen(textString) < 1) PsychErrorExitMsg(PsychError_user, "You asked me to compute the bounding box of an empty text string?!? Sorry, that's a no no...");

    PsychCopyInDoubleArg(3, kPsychArgOptional, &(winRec->textAttributes.textPositionX));
    PsychCopyInDoubleArg(4, kPsychArgOptional, &(winRec->textAttributes.textPositionY));

	 // Enable GL context of this window - we might need it:
    PsychSetGLContext(winRec);

    // Does the font (== it's display list) need to be build or rebuild, because
    // font name, size or settings have changed?
    // This routine will check it and perform all necessary ops if so...
    PsychOSRebuildFont(winRec);

    // Top-Left bounds of text are current (x,y) position of text drawing cursor:
    resultPsychRect[kPsychLeft] = winRec->textAttributes.textPositionX;
    resultPsychRect[kPsychTop]  = winRec->textAttributes.textPositionY;

    // Compute text x and y increments:
    stringl=strlen(textString);
    accumWidth=0;
    maxHeight=0;
    for (i=0; i<stringl; i++) {
      accumWidth+=winRec->textAttributes.glyphWidth[textString[i]];
      maxHeight=(fabs(winRec->textAttributes.glyphHeight[textString[i]]) > maxHeight) ? fabs(winRec->textAttributes.glyphHeight[textString[i]]) : maxHeight;
    }

    accumWidth*=(PSYCH_SYSTEM == PSYCH_WINDOWS) ? winRec->textAttributes.textSize : 1.0;
    maxHeight*=(PSYCH_SYSTEM == PSYCH_WINDOWS) ? winRec->textAttributes.textSize : 1.0;

    resultPsychRect[kPsychRight]  = winRec->textAttributes.textPositionX + accumWidth;

    // MK: This should work according to spec, but f%$!*g Windows only returns zero values for
	 // for glyphHeight, so maxHeight is always zero :(
    // resultPsychRect[kPsychBottom] = winRec->textAttributes.textPositionY + maxHeight;

    // As fallback, we use this: It gives correct Bottom-Bound for character strings with characters that
    // don't contain descenders. The extra height of characters with descenders is not taken into account.
    resultPsychRect[kPsychBottom] = winRec->textAttributes.textPositionY + winRec->textAttributes.textSize;


    // Compute normalized version which just encodes text bounding box, not text position box:
	 PsychNormalizeRect(resultPsychRect, resultPsychNormRect);

    // Return optional values:
	 PsychCopyOutRectArg(1, FALSE, resultPsychNormRect);
	 PsychCopyOutRectArg(2, FALSE, resultPsychRect);

    // Done.
    return(PsychError_none);
}