Spiral made using a custom CGPath

C4WorkSpace.m

//
//  C4WorkSpace.m
//  Complex Shapes Tutorial
//
//  Created by Travis Kirton.
//

#import "C4WorkSpace.h"

@implementation C4WorkSpace 

-(void)setup {
    CGMutablePathRef spiralPath = CGPathCreateMutable();
    CGPathMoveToPoint(spiralPath, nil, 0, 0);
    
    //Un-comment each block and recompile, using only one block at a time
    for(int i = 1; i < 64; i++) {
        CGFloat radius = 4 * i;
        CGFloat angle = TWO_PI/16 * i;
        CGPoint nextPoint = CGPointMake(radius*[C4Math sin:angle], radius*[C4Math cos:angle]);

//        CGPathAddLineToPoint(spiralPath, nil, nextPoint.x, nextPoint.y);
        
//        CGPathAddRelativeArc(spiralPath, nil, nextPoint.x, nextPoint.y, radius, 0, TWO_PI/16);
        
//        CGPathAddRelativeArc(spiralPath, nil, nextPoint.x, nextPoint.y, radius, angle, TWO_PI/16);
        
//        CGPathAddRelativeArc(spiralPath, nil, 0,0, radius, angle, TWO_PI/16);
        
        //a smooth spiral
        CGPoint controlPoint = CGPointMake(radius*[C4Math sin:angle - TWO_PI/32],
                                           radius*[C4Math cos:angle - TWO_PI/32]);
        CGPathAddQuadCurveToPoint(spiralPath, nil, controlPoint.x, controlPoint.y, nextPoint.x, nextPoint.y);
        
//        radius *= 1.5f;
//        CGPoint controlPoint = CGPointMake(radius*[C4Math sin:angle - TWO_PI/32],
//                                           radius*[C4Math cos:angle - TWO_PI/32]);
//        CGPathAddQuadCurveToPoint(spiralPath, nil, controlPoint.x, controlPoint.y, nextPoint.x, nextPoint.y);
    }
    
    CGRect frame = CGPathGetBoundingBox(spiralPath);
    C4Shape *spiral = [C4Shape rect:frame];
    
    const CGAffineTransform translate = CGAffineTransformMakeTranslation(-frame.origin.x, -frame.origin.y);
    spiral.path = CGPathCreateCopyByTransformingPath(spiralPath, &translate);

    spiral.center = self.canvas.center;
    
    [self.canvas addShape:spiral];
}

@end