Core Graphics AddQuadCureToPoint from Center of View/Circle - objective-c

Question

What I am trying to accomplish is drawing curved lines from a center of a view. So far with the help of much googling and this site...I've accomplished the image below.
http://www.flickr.com/photos/57562417#N00/9100635690/
What I would like to do is have curved lines like the following image...
http://www.flickr.com/photos/57562417#N00/9100634674/
Any and all help would be appreciated. I've included the code thus far.
#import <UIKit/UIKit.h>
#interface ChartView : UIView
#property (nonatomic,assign) int angle;
#end
----------------------------------------------------------------------
#import "ChartView.h"
#import <QuartzCore/QuartzCore.h>
/** Helper Functions **/
#define degree_to_radians(deg) ( (M_PI * (deg)) / 180.0 )
#define radians_to_degrees(rad) ( (180.0 * (rad)) / M_PI )
#interface ChartView(){
int radius;
}
#end
#implementation ChartView
-(id)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if(self){
self.backgroundColor = [UIColor whiteColor];
[self.layer setBorderWidth:1.0];
[self.layer setBorderColor:[UIColor redColor].CGColor];
//Define the circle radius taking into account the safe area
radius = self.frame.size.width/2;
//Initialize the Angle at 0
self.angle = 360;
}
return self;
}
-(void)drawRect:(CGRect)rect{
//Circle center
int numberOfSections = 96; //24 major lines
CGFloat angleSize = 2 * M_PI/numberOfSections;
CGContextRef context = UIGraphicsGetCurrentContext();
//draw the main outside circle
CGRect circleRect = CGRectMake(0.0, 0.0, 720., 720.);
CGContextSetLineWidth(context, .5);
CGContextSetRGBStrokeColor(context, 0.0, 2.0, 4.0, 1.0);
CGContextStrokeEllipseInRect(context, circleRect);
CGPoint centerPoint = CGPointMake(circleRect.size.width/2 , circleRect.size.height/2);
//setup for drawing lines from center, straight lines, need curved lines
CGContextTranslateCTM(context, 0.0, 0.0);
for (int x = 0; x < numberOfSections; x++) {
CGContextSetLineWidth(context, .5);
CGContextSetRGBStrokeColor(context, 0.0, 2.0, 4.0, 1.0);
CGContextMoveToPoint(context, self.frame.size.width/2, self.frame.size.height/2);
CGContextAddLineToPoint(context, centerPoint.x + radius * cos(angleSize * x) ,centerPoint.y + radius * sin(angleSize * x));
CGContextStrokePath(context);
}
CGContextSetLineWidth(context, .5);
CGContextSetRGBStrokeColor(context, 0.0, 2.0, 4.0, 1.0);
CGContextSetRGBFillColor(context, 1., 1., 1., 1.0);
//Taken from Hypnotizer code
float maxRadius = 360.0;
CGContextSetLineWidth(context, 0.5f);
CGContextSetRGBStrokeColor(context, 0.0, 2.0, 4.0, 1.0);
//need to add 100 lines form a certain radius to a max radius
for (float currentRadius = maxRadius; currentRadius > 99; currentRadius -=2.6) {
CGContextAddArc(context, centerPoint.x, centerPoint.y, currentRadius, 0.0, M_PI * 2.0, YES);
CGContextStrokePath(context);
}
}
#end

Answer 1

Alright, I've got some code for you that I tried out and does the curved line effect you mentioned in that second picture:
- (void)drawRect:(CGRect)rect {
radius = self.frame.size.width / 2;
// Circle center
int numberOfSections = 96; // 24 major lines
CGFloat angleSize = 2 * M_PI/ numberOfSections;
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect circleRect = CGRectMake(0.0, 0.0, 720., 720.);
CGPoint centerPoint = CGPointMake(circleRect.size.width / 2, circleRect.size.height / 2);
/* Create mask to create 'hole' in the center */
CGContextAddArc(context, centerPoint.x, centerPoint.y, 720 / 2.0, 0.0, M_PI * 2.0, YES);
CGContextAddArc(context, centerPoint.x, centerPoint.y, 100, 0.0, M_PI * 2.0, NO);
CGContextClip(context);
// draw the main outside circle
CGContextSetLineWidth(context, .5);
CGContextSetRGBStrokeColor(context, 0.0, 2.0, 4.0, 1.0);
CGContextStrokeEllipseInRect(context, circleRect);
// setup for drawing lines from center, straight lines, need curved lines
CGContextTranslateCTM(context, 0.0, 0.0);
for (int x = 0; x < numberOfSections; x++) {
CGContextSetLineWidth(context, .5);
CGContextSetRGBStrokeColor(context, 0.0, 2.0, 4.0, 1.0);
double angle = angleSize * x;
CGPoint outsidePoint = CGPointMake(centerPoint.x + radius * cos(angle), centerPoint.y + radius * sin(angle));
CGPoint control1 = CGPointMake(centerPoint.x + radius/3 * cos(angle-0.5), centerPoint.y + radius/3 * sin(angle-0.5));
CGPoint control2 = CGPointMake(centerPoint.x + (2*radius/3) * cos(angle-0.5), centerPoint.y + (2*radius/3) * sin(angle-0.5));
UIBezierPath *bezierPath = [UIBezierPath bezierPath];
[bezierPath moveToPoint:CGPointMake(circleRect.size.width / 2, circleRect.size.height / 2)];
[bezierPath addCurveToPoint:outsidePoint controlPoint1:control1 controlPoint2:control2];
CGContextAddPath(context, bezierPath.CGPath);
CGContextStrokePath(context);
}
CGContextSetLineWidth(context, .5);
CGContextSetRGBStrokeColor(context, 0.0, 2.0, 4.0, 1.0);
CGContextSetRGBFillColor(context, 1., 1., 1., 1.0);
// Taken from Hypnotizer code
float maxRadius = 360.0;
CGContextSetLineWidth(context, 0.5f);
CGContextSetRGBStrokeColor(context, 0.0, 2.0, 4.0, 1.0);
// need to add 100 lines form a certain radius to a max radius
for (float currentRadius = maxRadius; currentRadius > 99; currentRadius -= 2.6) {
CGContextAddArc(context, centerPoint.x, centerPoint.y, currentRadius, 0.0, M_PI * 2.0, YES);
CGContextStrokePath(context);
}
}