CAShapeLayer's frame and bounds properties are 0 - ios

CGPoint startPoint = CGPointMake(50, 50);
CGPoint endPoint = CGPointMake(100, 100);
UIBezierPath* bezierPath = [UIBezierPath bezierPath];
[bezierPath moveToPoint:startPoint];
[bezierPath addLineToPoint:endPoint];
layer = [CAShapeLayer layer];
//layer.frame = CGRectMake(50, 50, 100, 100);
layer.backgroundColor = [UIColor redColor].CGColor;
layer.path = bezierPath.CGPath;
layer.strokeColor = [UIColor greenColor].CGColor;
layer.fillColor = nil;
[self.view.layer addSublayer:layer];
NSLog(#"%#",NSStringFromCGRect(layer.bounds));
NSLog(#"%#",NSStringFromCGRect(layer.frame));
The Log Message that i get is 0,0 for both frame and bound yet the layer is drawn on the Screen.
I am confused on how it is possible that a layer can be drawn on screen in spite of having 0 on both bounds and frames. I though every view or layer needed to have these properties set in order to be displayed on screen.

Related

Animation for Layer in iOS

I masked an image with BezierPath.
I want to animate that mask image.
My code is as follow:
UIBezierPath* bezierPath = [UIBezierPath bezierPath];
[bezierPath moveToPoint: CGPointMake(84.95, 205.11)];
[bezierPath addCurveToPoint: CGPointMake(122.89, 232.14) controlPoint1: CGPointMake(84.95, 205.11) controlPoint2: CGPointMake(110.81, 223.56)];
[bezierPath addCurveToPoint: CGPointMake(124.33, 233.04) controlPoint1: CGPointMake(123.37, 232.46) controlPoint2: CGPointMake(123.85, 232.78)];
[bezierPath closePath];
CAShapeLayer *maskImage = [CAShapeLayer layer];
maskImage.path = bezierPath.CGPath;
maskImage.fillColor = [[UIColor blackColor] CGColor];
_myImageView.layer.mask = maskImage;
CAShapeLayer *border = [CAShapeLayer layer];
border.path = bezierPath.CGPath;
border.strokeColor = [UIColor redColor].CGColor;
border.fillColor = [[UIColor clearColor] CGColor];
border.lineWidth = 5;
[_myImageView.layer addSublayer:border];
How can I animate this?
Thank you
Use following piece of code:
#property (nonatomic, retain) CAShapeLayer *animationLayer;
- (IBAction)drawPattern:(id)sender{
[self setup];
[self.animationLayer removeAllAnimations];
CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:#"strokeEnd"];
pathAnimation.duration = 10.0;
pathAnimation.fromValue = #(0);
pathAnimation.toValue = #(1);
[self.animationLayer addAnimation:pathAnimation forKey:#"strokeEnd"];
}
- (void)setup{
[self.animationLayer removeFromSuperlayer];
self.animationLayer = nil;
UIBezierPath* bezierPath = [UIBezierPath bezierPath];
[bezierPath moveToPoint: CGPointMake(84.95, 205.11)];
[bezierPath addCurveToPoint: CGPointMake(122.89, 232.14) controlPoint1: CGPointMake(84.95, 205.11) controlPoint2: CGPointMake(110.81, 223.56)];
[bezierPath addCurveToPoint: CGPointMake(124.33, 233.04) controlPoint1: CGPointMake(123.37, 232.46) controlPoint2: CGPointMake(123.85, 232.78)];
CAShapeLayer *pathLayer = [CAShapeLayer layer];
// provide frame & bounds so that path can be drawn over that.
pathLayer.frame = CGRectMake(35, 100, 250, 200);
pathLayer.bounds = CGRectMake(35, 100, 250, 200);
pathLayer.path = bezierPath.CGPath;
pathLayer.strokeColor = [UIColor redColor].CGColor;
pathLayer.fillColor = [[UIColor clearColor] CGColor];
pathLayer.lineWidth = 6.f;
pathLayer.lineJoin = kCALineJoinRound;
[self.view.layer addSublayer:pathLayer];
[self setAnimationLayer:pathLayer];
}
Please let me know if this works for you & also if anything else comes up.
At the end of your code try below one
CAShapeLayer *pathLayer;
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = [aPath CGPath];
shapeLayer.strokeColor = [[UIColor greenColor] CGColor];
shapeLayer.fillColor = nil;
shapeLayer.lineWidth = 5.0f;
shapeLayer.lineJoin = kCALineJoinBevel;
[myImageView.layer addSublayer:shapeLayer];
pathLayer = shapeLayer;
CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:#"strokeEnd"];
pathAnimation.duration = 3.0;
pathAnimation.fromValue = #(0.0f);
pathAnimation.toValue = #(1.0f);
[pathLayer addAnimation:pathAnimation forKey:#"strokeEnd"];
We can animate the image with path using CABasicAnimation.
CABasicAnimation has position,path,transform,opacity,shadow......which including all layers keypaths,shape layer keypaths,CA layer keypaths,Text layer keypaths,Mask layer keypaths,UIView layer keypaths,Effect,Emit and replicator keypaths.
According to your question for drawing path we can use path and strokeEnd.But most prepare strokeEnd for accessing shape style properties.
So I think strokeEnd is the best one for animating the mask image with bezier path.
Below I give the code for path and strokeEnd also I diffrecicate both.
If I use animationWithKeyPath is path
The shape to be rendered and animatable.It is specifying the shape path.
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"path"];
animation.fromValue = #(0);
animation.toValue = #(1);
animation.duration = 6.0f;
[maskImage addAnimation:animation forKey:#"animatePath"];
The Path is a collection of individual components like lines and arcs that can be drawn and also animated.It is fundamental concept of Quartz 2D.
In below code I use strokeEnd
Generally if we want to access the shape style properties we can use
strokeEnd
The relative location at which to stop stroking the path and animatable.
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"strokeEnd"];
animation.fromValue = #(0);
animation.toValue = #(1);
animation.duration = 6.0f;
[maskImage addAnimation:animation forKey:#"strokeEnd"];
The value of this property must be in the range 0.0 to 1.0. The default value of this property is 1.0.
Also strokeEnd defines following thing
Combined with the strokeStart property, this property defines the subregion of the path to stroke. The value in this property indicates the relative point along the path at which to finish stroking while the strokeStart property defines the starting point.

cant add a shape layer into a view's layer

I'm working on CAShapeLayer by creating a layer using CAShapeLayer like following:
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.frame = CGRectMake(150, 50, 200, 200);
shapeLayer.fillColor = [UIColor whiteColor].CGColor;
shapeLayer.strokeColor = [UIColor orangeColor].CGColor;
[self.view.layer addSublayer:shapeLayer];
However, when I execute the codes and I cant see my shapeLayer in the simulator/device.
What I am missing here.
PS : If I am using CALayer *shapeLayer = [CALayer layer]; it works.Confused
add a path to it, like
shapeLayer.path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 2.0*radius, 2.0*radius)
cornerRadius:radius].CGPath;
A shaped layer needs a shape…
I put this in my View Controller and it works fine:
- (void)viewDidLoad
{
[super viewDidLoad];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.frame = CGRectMake(150, 50, 200, 200);
shapeLayer.fillColor = [UIColor whiteColor].CGColor;
shapeLayer.strokeColor = [UIColor orangeColor].CGColor;
NSUInteger radius = 90;
shapeLayer.path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 2.0*radius, 2.0*radius)
cornerRadius:radius].CGPath;
[self.view.layer addSublayer:shapeLayer];
}
If you change the path like
shapeLayer.path = [UIBezierPath bezierPathWithRect:shapeLayer.bounds].CGPath;
it'll result in

Why does a CAShapeLayer's stroke extend out of the frame?

Here's sample code:
//Called by VC:
HICircleView *circleView = [[HICircleView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
// init of circle view
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
CAShapeLayer *borderLayer = [CAShapeLayer layer];
borderLayer.fillColor = [UIColor whiteColor].CGColor;
borderLayer.path = [UIBezierPath bezierPathWithOvalInRect:self.frame].CGPath;
borderLayer.strokeColor = [[UIColor redColor] CGColor];
borderLayer.lineWidth = 5;
[self.layer addSublayer:borderLayer];
}
return self;
}
OK, thanks for the answer. to shift i:
CGRect rect = CGRectMake(3, 3, self.frame.size.width, self.frame.size.height);
borderLayer.path = [UIBezierPath bezierPathWithOvalInRect:rect].CGPath;
And made 6 the line width.
Setting the lineWidth draws a line, where the actual path is exactly in the middle of the drawn line.
If you want the drawn line to line up with something, you will have to shift the path by half the lineWidth.
You can shift the path by using - (void)applyTransform:(CGAffineTransform)transform on UIBezierPath and apply a translate transform.
If you want a drawn path to be contained in a certain area, shifting the path doesn't help. In that case just create a smaller path. If you want to draw a 100ptx100pt rect with a line width of 5, you have to draw a path in a 95pt*95pt rect (2.5pt space on either side).
You'd rather choose your view's bounds property for calculation. Frame property won't work properly if it's origin is greater than (0,0). You can use CGRectInsets to adjust your circle's rectangle instead of performing transform calculations. This will automatically position the rectangle centered within the original rectangle.
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
CAShapeLayer *borderLayer = [CAShapeLayer layer];
borderLayer.fillColor = [UIColor whiteColor].CGColor;
CGFloat lineWidth = 5;
CGRect rect = CGRectInset(self.bounds, lineWidth / 2, lineWidth / 2);
borderLayer.path = [UIBezierPath bezierPathWithOvalInRect:rect].CGPath;
borderLayer.strokeColor = [[UIColor redColor] CGColor];
borderLayer.lineWidth = lineWidth;
[self.layer addSublayer:borderLayer];
}
return self;
}

BezierPath and masking

I want to set up UIBezierPath as mask into my view:
The goal is something like this:
So i draw the View with frame:
CGFloat round = 80;
UIView *myView = [[UIView alloc] initWithFrame:CGRectMake(self.frame.size.width/2-105, 0, 210, 60+round)];
myView.backgroundColor = [UIColor redColor];
And then try to add BezierMask:
UIBezierPath *aPath = [UIBezierPath bezierPath];
CGSize viewSize = CGSizeMake(myView.frame.size.width, myView.frame.size.height); //(210,80)
CGPoint startPoint = CGPointMake(myView.frame.origin.x,myView.frame.origin.y); //(279,0)
[aPath moveToPoint:startPoint]; //(279,0)
[aPath addLineToPoint:CGPointMake(startPoint.x+viewSize.width,startPoint.y)]; //(489,0)
[aPath addLineToPoint:CGPointMake(startPoint.x+viewSize.width,startPoint.y+viewSize.height-round)]; //(489,60)
[aPath addQuadCurveToPoint:CGPointMake(startPoint.x,startPoint.y+viewSize.height-round) controlPoint:CGPointMake(startPoint.x+(viewSize.width/2),80)]; //(279,60) : (384,80)
[aPath closePath];
CAShapeLayer *layer = [CAShapeLayer layer];
layer.frame = myView.bounds;
layer.path = aPath.CGPath;
myView.layer.mask = layer;
[self addSubview:myView];
But my view is disappearing after that. Why?
I guess you are using improper coordinations for your mask layer. Your mask layer must be positioned within the view which it masks, not in the view's superview.
Try these changes:
CGSize viewSize = myView.bounds.size;
CGPoint startPoint = CGPointZero;
Your code with those little modifications works OK for me.

iOS - Set dashed line for a circle

CAShapeLayer *circle = [CAShapeLayer layer];
circle.path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 2.0*radius, 2.0*radius) cornerRadius:radius].CGPath;
// Configure the apperence of the circle
circle.fillColor = [UIColor clearColor].CGColor;
circle.strokeColor = [UIColor whiteColor].CGColor;
circle.lineWidth = 1;
// Add to parent layer
[[background layer] addSublayer:circle];
I have drawn a circle and added it as a sublayer. What I don't understand is how to make the circle line dashed? I have added my circle code above.
You need to set the lineDashPattern property of circle. For example:
circle.lineDashPattern = #[#2, #3];

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