cgpath

问题 I have an open CGPath/UIBezierPath for which I want to detect if the user touches it, i.e. whether a point is within a certain distance from the path. The path is open (i.e. a line/curve, not a shape). It can contain both straight & curved elements. How do I get the distance to the path to hit-test it? 回答1: It seems neither CGPath/UIBezierPath has a function to do this. EDIT: As per @nielsbot's suggestion, you could write a custom implementation using CGPathApply(…) . Computing the distance

问题 I have a CGPath that represents an ellipse. I'd like to place a sprite node at a random point on that path. How can I get a random CGPoint on that CGPath? 回答1: Speaking about a closed CGPath and thinking to a fast method to obtain a random point between infinite points inside a CGPath , first of all I've translated to Swift this: extension CGPath { func forEach(@noescape body: @convention(block) (CGPathElement) -> Void) { typealias Body = @convention(block) (CGPathElement) -> Void func

问题 I saw many answers on Stack overflow, but none helped me. I created a DrawView where it's possible to draw. I created an instance of UIBezierPath for drawing. I want to transfer my drawing on a little view (the red one on the image). That's what I did: // This function is called when the user has finished to draw. override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) { let shapeLayer = CAShapeLayer() //The CAShapeLayer has the same path of the drawing (currentPath is the

问题 I am offsetting a CGPath using copy(strokingWithWidth:lineCap:lineJoin:miterLimit:transform‌​:). The problem is the offset path introduces all kinds of jagged lines that seem to be the result of a miter join. Changing the miterLimit to 0 has no effect, and using a bevel line join also makes no difference. In this image there is the original path (before applying strokingWithWidth ), an offset path using miter join, and an offset path using bevel join. Why doesn't using bevel join have any

问题 I am offsetting a CGPath using copy(strokingWithWidth:lineCap:lineJoin:miterLimit:transform‌​:). The problem is the offset path introduces all kinds of jagged lines that seem to be the result of a miter join. Changing the miterLimit to 0 has no effect, and using a bevel line join also makes no difference. In this image there is the original path (before applying strokingWithWidth ), an offset path using miter join, and an offset path using bevel join. Why doesn't using bevel join have any

问题 I fount this solution but I can't make it into swift code This what I try var pattern[2]:CGFloat; this var dashed: CGPathRef = CGPathCreateCopyByDashingPath(CGPathCreateCopyByDashingPath(path, transform, phase, lengths, count); var myShapeNode: SKShapeNode!; var CGPathCreateCopyByDashingPath:CGPathRef; 回答1: This is how you can draw a dashed line in swift. You can change the parameters as you want. let bezierPath = UIBezierPath() let startPoint = CGPointMake(0, 250) let endPoint = CGPointMake

问题 I have a UIView subclass on which the user can add a random CGPath. The CGPath is added by processing UIPanGestures. I would like to resize the UIView to the minimal rect possible that contains the CGPath. In my UIView subclass, I have overridden sizeThatFits to return the minimal size as such: - (CGSize) sizeThatFits:(CGSize)size { CGRect box = CGPathGetBoundingBox(sigPath); return box.size; } This works as expected and the UIView is resized to the value returned, but the CGPath is also

问题 I have a UIView subclass on which the user can add a random CGPath. The CGPath is added by processing UIPanGestures. I would like to resize the UIView to the minimal rect possible that contains the CGPath. In my UIView subclass, I have overridden sizeThatFits to return the minimal size as such: - (CGSize) sizeThatFits:(CGSize)size { CGRect box = CGPathGetBoundingBox(sigPath); return box.size; } This works as expected and the UIView is resized to the value returned, but the CGPath is also

问题 I have some CGPath (a poly with two circle) carried out on a CAShapeLayer . Can I trim/subtract paths like this? 回答1: Instead of do the math, the result can be achieved at drawing time using kCGBlendModeClear . // Create the poly. CGContextBeginPath(context); CGContextMoveToPoint (context, a_.x, a_.y); CGContextAddLineToPoint (context, b_.x, b_.y); CGContextAddLineToPoint (context, c_.x, c_.y); CGContextAddLineToPoint (context, d_.x, d_.y); CGContextClosePath(context); // Draw with the

问题 I have a CGPathRef for an oddly shaped polygon. I need to apply an alpha to the area outside of this path. This is pretty straightforward. CGContextAddPath(context, crazyPolygon); CGContextSetFillColor(context, someAlphaColor); CGContextEOFillPath(context); I need to do something similar with a circle, also straightforward. CGMutablePathRef circlePath = CGPathCreateMutable(); CGPathAddRect(circlePath, NULL, rect); CGPathAddEllipseInRect(circlePath, NULL, circleBox); CGContextAddPath(context,