CODEWITHSUNDEEP
iphoneioscore-location
rajesh.k
rajesh.k

Reputation: 125

Drawing a circle for CLLocationManger region

I have a requirement where I have to draw a Circle with a given radius. For example, say 200 meters for CLLocationManager.

CLLocationDistance radius = 100.0;
CLRegion *region = [[CLRegion alloc]initCircularRegionWithCenter:center radius:radius identifier:@"Apple"];

How do I draw the circle Using CGpoint? I am not using any map.

Upvotes: 1

Views: 270

Answers (2)

Dharmbir Singh
Dharmbir Singh

Reputation: 17535

You can draw like this and change it according to you what you wanna. And you need to import QuartzCore.framework for it 

int radius = 100;
CAShapeLayer *circle = [CAShapeLayer layer];

circle.path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 2.0*radius, 2.0*radius) 
                                         cornerRadius:radius].CGPath;
// Center the shape in self.view
circle.position = CGPointMake(CGRectGetMidX(self.view.frame)-radius, 
                              CGRectGetMidY(self.view.frame)-radius);

// Configure the apperence of the circle
circle.fillColor = [UIColor clearColor].CGColor;
circle.strokeColor = [UIColor blackColor].CGColor;
circle.lineWidth = 5;

// Add to parent layer
[self.view.layer addSublayer:circle];

Upvotes: 0

Rob
Rob

Reputation: 437882

There are at least two approaches:

  1. Add QuartzCore.framework to your project, create a UIBezierPath, then create CAShapeLayer specifying its path, and then add the CAShapeLayer as a sublayer of your current view's layer. For example, I could call this from my view controller:

    #import <QuartzCore/QuartzCore.h>

- (void)addCircle
{
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path addArcWithCenter:CGPointMake(self.view.layer.bounds.size.width / 2.0, self.view.layer.bounds.size.height / 2.0) radius:self.view.layer.bounds.size.width * 0.40 startAngle:0.0 endAngle:M_PI * 2.0 clockwise:YES];

    CAShapeLayer *layer = [CAShapeLayer layer];
    layer.path = [path CGPath];
    layer.strokeColor = [[UIColor darkGrayColor] CGColor];
    layer.fillColor = [[UIColor lightGrayColor] CGColor];
    layer.lineWidth = 3.0;

    [self.view.layer addSublayer:layer];
}

  2. Subclass UIView and override drawRect to draw the circle with Core Graphics.

    @implementation CircleView

- (void)drawRect:(CGRect)rect
{
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextAddArc(context, self.bounds.size.width / 2.0, self.bounds.size.height / 2.0, self.bounds.size.width * 0.40, 0, M_PI * 2.0, YES);

    CGContextSetStrokeColorWithColor(context, [[UIColor redColor] CGColor]);
    CGContextSetFillColorWithColor(context, [[UIColor blueColor] CGColor]);
    CGContextSetLineWidth(context, 3.0);

    CGContextDrawPath(context, kCGPathFillStroke);
}

@end

Both are valid. If you're not used to subclassing UIView, the former technique is probably easier.

References

The Quartz 2D Programming Guide

Upvotes: 1

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