/*

File: FrequencyLevelsLayer.m

Abstract: Container that creates and handles the frequency levels 

Version: 1.0

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*/ 

#import "FrequencyLevels.h"

#define LEVEL_OFFSET        8

#define LEVEL_WIDTH     30

#define LEVEL_HEIGHT        240

static UInt32 numberOfBandLevels    = 8;       // increase this number for more frequency bands

static UInt32 numberOfChannels       = 2;       // for StereoMix - If using DeviceMix, you need to get the channel count of the device.

@interface FrequencyLevels (internal)

    - (void)levelTimerMethod:(NSTimer*)theTimer;

@end

@implementation FrequencyLevels

//--------------------------------------------------------------------------------------------------

+ (FrequencyLevels*)levelsWithMovie:(QTMovie *)movie

{

    FrequencyLevels *levels;

    levels = [[FrequencyLevels alloc] init];

    [levels setMovie:movie];

    return [levels autorelease];

}

//--------------------------------------------------------------------------------------------------

- (id)init

{

    CGImageRef freqLevelImage = nil;

    self = [super init];

    // allocate memory for the QTAudioFrequencyLevels struct and set it up

    // depending on the number of channels and frequency bands you want    

    mFreqResults = malloc(offsetof(QTAudioFrequencyLevels, level[numberOfBandLevels * numberOfChannels]));

    mFreqResults->numChannels = numberOfChannels;

    mFreqResults->numFrequencyBands = numberOfBandLevels;

    // create an array and load up the UI elements, each NSLevelIndicator has

    // the appropriate tag added in IB

    mFrequencyLayers = [NSMutableArray array];

    [mFrequencyLayers retain];

    // load image for the level indicator layers

    NSURL *imageURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"penguin" ofType:@"png"]];

    CGImageSourceRef source = CGImageSourceCreateWithURL((CFURLRef)imageURL, nil);

    freqLevelImage = CGImageSourceCreateImageAtIndex(source, 0, nil);

    CFRelease (source);

    // create the layers

    mContainer = [[CALayer layer] retain];

    [mContainer setBounds:CGRectMake (0, 0, ((numberOfBandLevels * numberOfChannels) * (LEVEL_WIDTH + LEVEL_OFFSET)) + LEVEL_OFFSET, LEVEL_HEIGHT)];

    int         i, j;

    // setup the center of the first layer

    CGFloat     x = LEVEL_OFFSET + (LEVEL_WIDTH * 0.5);

    for(j = 0; j < numberOfChannels; j++)

    {

        for(i = 0; i < numberOfBandLevels; i++)

        {

            CALayer *levelLayer = [CALayer layer];

            [levelLayer setBounds:CGRectMake (0, 0, LEVEL_WIDTH, LEVEL_HEIGHT)];

            // add some shadow

            levelLayer.shadowOpacity = 0.75;

            // save the layer in our frequency layer's array

            [mFrequencyLayers addObject:levelLayer];

            // append the layer to the container's sublayers array

            [mContainer addSublayer:levelLayer];

            // position the layer

            levelLayer.position = CGPointMake(x, 0);

            // set image as the default content

            levelLayer.contents = (id)freqLevelImage;

            if(j > 0)   // flip the right channel horizontally so the images are facing each other

                levelLayer.transform = CATransform3DMakeScale(-1.0, 1.0, 1.0);

            x += LEVEL_OFFSET + LEVEL_WIDTH;

        }

    }

    return self;

}

//--------------------------------------------------------------------------------------------------

- (void)dealloc

{

    // cleanup

    [mContainer release];

    [mFrequencyLayers release];

    free(mFreqResults);

    [super dealloc];

}

//--------------------------------------------------------------------------------------------------

//--------------------------------------------------------------------------------------------------

- (void)invalidate

{

    if ([[mMovie attributeForKey:QTMovieHasAudioAttribute] boolValue]) 

    {

        // do this once per movie to establish metering

        (void)SetMovieAudioFrequencyMeteringNumBands([mMovie quickTimeMovie], kQTAudioMeter_StereoMix, &numberOfBandLevels);

    }

}

//--------------------------------------------------------------------------------------------------

- (void)setMovie:(QTMovie *)inMovie

{

    mMovie = inMovie;

    if (mMovie)

    {

        [self invalidate];

        [mContainer setNeedsDisplay];

    }

}

//--------------------------------------------------------------------------------------------------

- (CALayer*)layer

{

    return mContainer;

}

//--------------------------------------------------------------------------------------------------

// called when the button is pressed - turns the level meters on/off by setting up a timer

- (void)toggleFreqLevels:(NSCellStateValue)state

{

    if (NSOnState == state) 

    {

        // turning it on, set up a timer and add it to the run loop

        mTimer = [NSTimer timerWithTimeInterval:1.0/15 target:self selector:@selector(levelTimerMethod:) userInfo:nil repeats:YES];

        [[NSRunLoop currentRunLoop] addTimer:mTimer forMode:(NSString *)kCFRunLoopCommonModes];

        mContainer.hidden = NO;

    } 

    else 

    {

        // turning it off, stop the timer and hide the level layers

        [mTimer invalidate];

        mContainer.hidden = YES;

    }

}

//--------------------------------------------------------------------------------------------------

- (void)levelTimerMethod:(NSTimer*)theTimer

{

    UInt8 i, j;

    NSEnumerator *enumerator = [mFrequencyLayers objectEnumerator]; // get a enumerator for the array of NSLevelIndicator objects

    // get the levels from the movie

    OSStatus err = GetMovieAudioFrequencyLevels([mMovie quickTimeMovie], kQTAudioMeter_StereoMix, mFreqResults);

    if (!err) 

    {

        // iterate though the frequency level array and though the UI elements getting

        // and setting the levels appropriately

        for (i = 0; i < mFreqResults->numChannels; i++) 

        {

            for (j = 0; j < mFreqResults->numFrequencyBands; j++) 

            {

                // the frequency levels are Float32 values between 0. and 1.

                Float32 value = (mFreqResults->level[(i * mFreqResults->numFrequencyBands) + j]) * LEVEL_HEIGHT;

                CALayer     *layer = [enumerator nextObject];

                layer.bounds = CGRectMake(0, 0, LEVEL_WIDTH, value);

            }

        }

    }

}

@end