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PODrawing circles using CGContext
 

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    <p>Using the code below, I am constructing polygons with various number of sides.</p> <p>Can somebody advise how I can add code to circumscribe a circle and also inscribe a circle in each polygon returned?</p> <pre><code>-(void) drawRect:(CGRect)rect{ CGContextRef context = UIGraphicsGetCurrentContext(); CGContextBeginPath (context); CGContextSetLineWidth(context,5); NSArray * points = [PolygonUIView pointsForPolygonInRect:[self bounds] numberOfSides:polygon.numberOfSides]; NSLog(@"%d", [points count]); NSLog(@"%d", polygon.numberOfSides); for(NSValue * point in points) { CGPoint val = [point CGPointValue]; if([points indexOfObject:point]==0) { CGContextMoveToPoint (context, val.x, val.y); } else { CGContextAddLineToPoint (context, val.x, val.y); } } CGContextClosePath(context); [[UIColor clearColor] setFill]; [[UIColor blackColor] setStroke]; CGContextDrawPath (context, kCGPathFillStroke); polygonLabel.text = polygon.name; } + (NSArray *)pointsForPolygonInRect:(CGRect)rect numberOfSides:(int)numberOfSides { CGPoint center = CGPointMake(rect.size.width / 2.0, rect.size.height / 2.0); float radius = 0.90 * center.x; NSLog(@"%f rad",radius); NSMutableArray *result = [NSMutableArray array]; float angle = (2.0 * M_PI) / numberOfSides; float exteriorAngle = M_PI - angle; float rotationDelta = angle - (0.5 * exteriorAngle); for (int currentAngle = 0; currentAngle &lt; numberOfSides; currentAngle++) { float newAngle = (angle * currentAngle) - rotationDelta; float curX = cos(newAngle) * radius; float curY = sin(newAngle) * radius; [result addObject:[NSValue valueWithCGPoint:CGPointMake(center.x + curX, center.y + curY)]]; } return result; } </code></pre>
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