C4 Advent Calendar #4 SeekAndScale #BLOG

C4WorkSpace.m

//
//  C4WorkSpace.m
//  SeekAndScale
//
//  Created by SOMTD on 2013/12/04.
//

@implementation C4WorkSpace {
    C4Sample *sample;
    C4Slider *slider;
    
    //Level Circle
    C4Shape *levelCircle;
    
    //Masked Image
    C4Image *maskedImage;
    
    //Timer
    C4Timer *meterUpdateTimer;
}

-(void)setup {
    sample = [C4Sample sampleNamed:@"C4Loop.aif"];
    sample.loops = YES;
    
    //metering enable
    sample.meteringEnabled = YES;
    
    [sample play];
    
    [self setupCircle];
    
    [self setupSlider];
    
    meterUpdateTimer = [C4Timer timerWithInterval:1/30.0f target:self method:@"updateMeters" repeats:YES];
    [meterUpdateTimer start];
}

-(void)updateMeters {
    [sample updateMeters];
    
    CGFloat avg = [C4Math pow:10 raisedTo:0.05 * [sample averagePowerForChannel:0]];
    float scale;
    scale = 0.8 + (avg * 0.3);
    
    [UIView animateWithDuration:1/30.0f animations:^{
        CGAffineTransform myTransform = CGAffineTransformMakeScale(scale, scale);
        levelCircle.transform = myTransform;
        maskedImage.center = self.canvas.center;
        maskedImage.mask = levelCircle;
    }];

}

-(void)changeCurrentTime:(C4Slider *)aSlider {
    sample.currentTime = aSlider.value * sample.duration;
}

-(void)updateSlider {
    slider.value = sample.currentTime / sample.duration;
    [self runMethod:@"updateSlider" afterDelay:0.01f];
}

-(void)setupCircle
{
    maskedImage = [C4Image imageNamed:@"C4Sky.png"];
    maskedImage.width = self.canvas.width;
    maskedImage.center = self.canvas.center;
    
    levelCircle = [C4Shape ellipse:CGRectMake(0, 0, 240, 240)];
    levelCircle.center = CGPointMake(maskedImage.center.x, maskedImage.height/2) ;
    maskedImage.mask = levelCircle;
    [self.canvas addImage:maskedImage];
}

-(void)setupSlider {
    slider = [C4Slider slider:CGRectMake(0, 0, 320, 44)];
    slider.center = CGPointMake(self.canvas.center.x, self.canvas.height - 100);
    
    [slider runMethod:@"changeCurrentTime:" target:self forEvent:VALUECHANGED];
    
    [self.canvas addSubview:slider];
    [self updateSlider];
}
@end