Basic example of how to create a CGPath to use for a visible object's shadowPath property

C4WorkSpace.m

//
//  C4WorkSpace.m
//  test
//
//  Created by moi on 13-01-20.
//  Copyright (c) 2013 moi. All rights reserved.
//
 
#import "C4WorkSpace.h"
 
@implementation C4WorkSpace {
    C4Shape *s;
}
 
-(void)setup {
    CGFloat width = 100, height = 100;
    
    s = [C4Shape ellipse:CGRectMake(0, 0, width, height)];
    [self.canvas addShape:s];
 
    CGMutablePathRef newShadowPath = CGPathCreateMutable();
    CGPathMoveToPoint(newShadowPath, nil, 0, 0);
    CGPathAddLineToPoint(newShadowPath, nil, width, 0);
    CGPathAddLineToPoint(newShadowPath, nil, width, height);
    CGPathAddLineToPoint(newShadowPath, nil, 0, height);
    CGPathAddLineToPoint(newShadowPath, nil, 0, 0);
 
    s.animationDuration = 1.0f;
    s.shadowOffset = CGSizeMake(width/2,height/2);
    s.shadowOpacity = 0.8;
    s.shadowPath = newShadowPath;
}
 
@end