MyGreatAUEffectWithCocoaUI(SnowLeopard)/MyGreatAUEffectWithCocoaUI_CocoaView.m

/*
 
     File: MyGreatAUEffectWithCocoaUI_CocoaView.m
 Abstract: Audio Unit Cocoa View imlementation.
  Version: 1.0.1
 
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*/
 
#import "MyGreatAUEffectWithCocoaUI_CocoaView.h"
 
enum {
    kParam_One =0,
    kNumberOfParameters=1
};
 
#pragma mark ____ LISTENER CALLBACK DISPATCHER ____
void ParameterListenerDispatcher (void *inRefCon, void *inObject, const AudioUnitParameter *inParameter, Float32 inValue) {
    MyGreatAUEffectWithCocoaUI_CocoaView *SELF = (MyGreatAUEffectWithCocoaUI_CocoaView *)inRefCon;
    
    [SELF parameterListener:inObject parameter:inParameter value:inValue];
}
 
NSString *MyGreatAUEffectWithCocoaUI_GestureSliderMouseDownNotification = @"CAGestureSliderMouseDownNotification";
NSString *MyGreatAUEffectWithCocoaUI_GestureSliderMouseUpNotification = @"CAGestureSliderMouseUpNotification";
 
@implementation MyGreatAUEffectWithCocoaUI_GestureSlider
 
/*  We create our own custom subclass of NSSlider so we can do begin/end gesture notification
    We cannot override mouseUp: because it will never be called. Instead we do a clever trick in mouseDown to send mouseUp notifications */
- (void)mouseDown:(NSEvent *)inEvent {
    [[NSNotificationCenter defaultCenter] postNotificationName: MyGreatAUEffectWithCocoaUI_GestureSliderMouseDownNotification object: self];
    
    [super mouseDown: inEvent]; // this call does not return until mouse tracking is complete
                                // once tracking is done, we know the mouse has been released, so we can send our mouseup notification
 
    [[NSNotificationCenter defaultCenter] postNotificationName: MyGreatAUEffectWithCocoaUI_GestureSliderMouseUpNotification object: self];
}
    
@end
 
@implementation MyGreatAUEffectWithCocoaUI_CocoaView
#pragma mark ____ (INIT /) DEALLOC ____
- (void)dealloc {
    [self removeListeners];
    [super dealloc];
}
 
#pragma mark ____ PUBLIC FUNCTIONS ____
- (void)setAU:(AudioUnit)inAU {
    // remove previous listeners
    if (mAU) [self removeListeners];
    mAU = inAU;
    
    mParameter[0].mAudioUnit = inAU;
    mParameter[0].mParameterID = kParam_One;
    mParameter[0].mScope = kAudioUnitScope_Global;
    mParameter[0].mElement = 0; 
 
    // add new listeners
    [self addListeners];
    
    // initial setup
    [self synchronizeUIWithParameterValues];
}
 
#pragma mark ____ INTERFACE ACTIONS ____
- (IBAction)iaParam1Changed:(id)sender {
    float floatValue = [sender floatValue];
    
    OSStatus result = AUParameterSet(mParameterListener, sender, &mParameter[0], (Float32)floatValue, 0);
    NSAssert(result == noErr, @"[MyGreatAUEffectWithCocoaUI_CocoaView iaParam1Changed:] AUParameterSet()");
    
    if (sender == uiParam1Slider) {
        [uiParam1TextField setFloatValue:floatValue];
    } else {
        [uiParam1Slider setFloatValue:floatValue];
    }
}
 
#pragma mark ____ NOTIFICATIONS ____
 
// This routine is called when the user has clicked on the slider. We need to send a begin parameter change gesture to alert hosts that the parameter may be changing value
-(void) handleMouseDown: (NSNotification *) aNotification {
    if ([aNotification object] == uiParam1Slider) {
        AudioUnitEvent event;
        event.mArgument.mParameter = mParameter[0];
        event.mEventType = kAudioUnitEvent_BeginParameterChangeGesture;
        
        AUEventListenerNotify (NULL, self, &event);     // NOTE, if you have an AUEventListenerRef because you are listening to event notification, 
                                                        // pass that as the first argument to AUEventListenerNotify instead of NULL 
    }
}
 
-(void) handleMouseUp: (NSNotification *) aNotification {
    if ([aNotification object] == uiParam1Slider) {
        AudioUnitEvent event;
        event.mArgument.mParameter = mParameter[0];
        event.mEventType = kAudioUnitEvent_EndParameterChangeGesture;
    
        AUEventListenerNotify (NULL, self, &event);     // NOTE, if you have an AUEventListenerRef because you are listening to event notification, 
                                                        // pass that as the first argument to AUEventListenerNotify instead of NULL 
    }
}
 
 
#pragma mark ____ PRIVATE FUNCTIONS ____
- (void)addListeners {
    OSStatus result = AUListenerCreate( ParameterListenerDispatcher, self, 
                                    CFRunLoopGetCurrent(), kCFRunLoopDefaultMode, 0.100, // 100 ms
                                    &mParameterListener );
    NSAssert(result == noErr, @"[MyGreatAUEffectWithCocoaUI_CocoaView _addListeners] AUListenerCreate()");
    
    int i;
    for (i = 0; i < kNumberOfParameters; ++i) {
        mParameter[i].mAudioUnit = mAU;
        result = AUListenerAddParameter (mParameterListener, NULL, &mParameter[i]);
        NSAssert(result == noErr, @"[MyGreatAUEffectWithCocoaUI_CocoaView _addListeners] AUListenerAddParameter()");
    }
    
    [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(handleMouseDown:) name:MyGreatAUEffectWithCocoaUI_GestureSliderMouseDownNotification object: uiParam1Slider];
    [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(handleMouseUp:) name:MyGreatAUEffectWithCocoaUI_GestureSliderMouseUpNotification object: uiParam1Slider];
}
 
- (void)removeListeners {
    OSStatus result;
    int i;
    for (i = 0; i < kNumberOfParameters; ++i) {
        result = AUListenerRemoveParameter(mParameterListener, NULL, &mParameter[i]);
        NSAssert(result == noErr, @"[MyGreatAUEffectWithCocoaUI_CocoaView _removeListeners] AUListenerRemoveParameter()");
    }
    
    result = AUListenerDispose(mParameterListener);
    NSAssert(result == noErr, @"[MyGreatAUEffectWithCocoaUI_CocoaView _removeListeners] AUListenerDispose()");
    
    [[NSNotificationCenter defaultCenter] removeObserver: self name:MyGreatAUEffectWithCocoaUI_GestureSliderMouseDownNotification object: uiParam1Slider];
    [[NSNotificationCenter defaultCenter] removeObserver: self name:MyGreatAUEffectWithCocoaUI_GestureSliderMouseUpNotification object: uiParam1Slider];
}
 
- (void)synchronizeUIWithParameterValues {
    OSStatus result;
    Float32 value;
    int i;
    
    for (i = 0; i < kNumberOfParameters; ++i) {
        // only has global parameters
        result = AudioUnitGetParameter(mAU, mParameter[i].mParameterID, kAudioUnitScope_Global, 0, &value);
        NSAssert(result == noErr, @"[MyGreatAUEffectWithCocoaUI_CocoaView synchronizeUIWithParameterValues] (x.1)");
        
        result = AUParameterSet (mParameterListener, self, &mParameter[i], value, 0);
        NSAssert(result == noErr, @"[MyGreatAUEffectWithCocoaUI_CocoaView synchronizeUIWithParameterValues] (x.2)");
        
        result = AUParameterListenerNotify (mParameterListener, self, &mParameter[i]);
        NSAssert(result == noErr, @"[MyGreatAUEffectWithCocoaUI_CocoaView synchronizeUIWithParameterValues] (x.3)");
    }
}
 
#pragma mark ____ LISTENER CALLBACK DISPATCHEE ____
- (void)parameterListener:(void *)inObject parameter:(const AudioUnitParameter *)inParameter value:(Float32)inValue {
    //inObject ignored in this case.
    
    switch (inParameter->mParameterID) {
        case kParam_One:
                    [uiParam1Slider setFloatValue:inValue];
                    [uiParam1TextField setStringValue:[[NSNumber numberWithFloat:inValue] stringValue]];
                    break;
    }
}
 
 
@end