I am drawing an animated circle using the UIBezierPath and CAShapeLayer. Now while adding the gradient effect the problem occurring is - CAGradientLayer adds it's gradient effect from upside down. But I want gradient effect from the starting point of the circle to the end point of the circle.
What I am getting is -
My code is - (it's a function)
circle.path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(radius+6,radius+6) radius:radius startAngle:DEGREES_TO_RADIANS(startAngle) endAngle:DEGREES_TO_RADIANS(endAngle) clockwise:isClockWise].CGPath;
//circle.position = CGPointMake(CGRectGetMidX(self.frame)-radius, CGRectGetMidY(self.frame)-radius);
circle.fillColor = fillColor.CGColor;
circle.strokeColor = strokeColor.CGColor;
circle.lineWidth = lineWidth;
circle.strokeEnd = percentToDraw/100;
circle.lineCap = kCALineCapRound;
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.startPoint = CGPointMake(0.5,1.0);
gradientLayer.endPoint = CGPointMake(0.5,0.0);
gradientLayer.frame = CGRectMake(0, 0, self.frame.size.width , self.frame.size.height);
NSMutableArray *colors = [NSMutableArray array];
[colors addObject:(id)[UIColor blackColor].CGColor];
[colors addObject:(id)strokeColor.CGColor];
gradientLayer.colors = colors;
[gradientLayer setMask:circle];
[self.layer addSublayer:gradientLayer];
CABasicAnimation *drawAnimation = [CABasicAnimation animationWithKeyPath:#"strokeEnd"];
drawAnimation.duration = duration;
drawAnimation.repeatCount = 1.0;
drawAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
drawAnimation.toValue = [NSNumber numberWithFloat:percentToDraw/100];
drawAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
[circle addAnimation:drawAnimation forKey:#"drawCircleAnimation"];
How do I add gradient so that it starts(with red) and goes forward to finish point(with black). ?
Assuming you are talking about a conical/angle gradient, then there is no system provided method for achieving that with CAGradientLayer. There are libraries such as AngleGradientLayer that try to provide this functionality, however, as with any 3rd party solution, it should be used with caution.
You can also look at approaches like ones discussed here or here, however they would require you to slightly refactor your logic.
Note that this suggestions would only work in a circular case.
Related
I want to approach the following scenario:
If I draw a rectangle using CGBezierPath and CAShapeLayer like the following:
CAShapeLayer *layerX = [CAShapeLayer layer];
layerX.path = path.CGPath;
layerX.lineWidth = 3;
layerX.strokeColor = [[UIColor whiteColor] CGColor];
layerX.fillColor = [[UIColor clearColor] CGColor];
[self.view.layer addSublayer: layerX];
And I want to add animation like the image I attached, this cleared area keeps moving around the rectangle path so it gives visual effect of the rectangle being drawn over and over. [Snake movement in old snake games]
I tried animating using CABasicAnimation but I literally couldn't achieve anything, thanks in advance.
Try this code may be helpful.
UIBezierPath *drawablePath = [UIBezierPath bezierPathWithRect:CGRectMake(100.0, 100.0, 150.0, 100.0)];
CAShapeLayer *squareLayer = [[CAShapeLayer alloc] init];
squareLayer.path = drawablePath.CGPath;
squareLayer.strokeColor = [UIColor redColor].CGColor;
squareLayer.lineWidth = 5.f;
squareLayer.fillColor = [UIColor clearColor].CGColor;
squareLayer.strokeEnd = 1.f;
//squareLayer.strokeEnd = 0.9; // this line use draw half line but some animation issue.
[self.view.layer addSublayer:squareLayer];
CABasicAnimation *drawAnimation = [CABasicAnimation animationWithKeyPath:#"strokeEnd"];
drawAnimation.fromValue = (id)[NSNumber numberWithFloat:0.10];
drawAnimation.toValue = (id)[NSNumber numberWithFloat:1.f];
drawAnimation.duration = 5.f;
drawAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
[squareLayer addAnimation:drawAnimation forKey:#"drawRectStroke"];
This code is use to draw rectangle with animation.
You have to animate both: strokeStart and strokeEnd and use a CAAnimationGroup to make them happen at the same time.
I found this link which does something similar but in swift. I think it might help.
I will try to implement it if you can't do it. But I can't right now.
Happy coding.
let drawablePath = UIBezierPath(rect: CGRect(x: 100, y: 100, width: 150, height: 150))
let squareLayer = CAShapeLayer()
squareLayer.path = drawablePath.cgPath;
squareLayer.strokeColor = UIColor.red.cgColor;
squareLayer.lineWidth = 5;
squareLayer.fillColor = UIColor.clear.cgColor;
squareLayer.strokeEnd = 1;
//squareLayer.strokeEnd = 0.9; // this line use draw half line but some animation issue.
flowerView.layer.addSublayer(squareLayer)
let drawAnimation = CABasicAnimation(keyPath: "strokeEnd")
drawAnimation.fromValue = 0.1
drawAnimation.toValue = 1.0
drawAnimation.duration = 5
drawAnimation.timingFunction = CAMediaTimingFunction(name:.linear)
squareLayer.add(drawAnimation, forKey:"drawRectStroke")
Not really an answer to the original question but here's a Swift 5 version of Dixit Akabari's answer, which was useful in itself in that it demonstrates how to animate drawing a UIBezierPath by animating strokeEnd.
I am working on one of the school application. In which, based on the percentage achieved by student respective piechart should be drawn with an animation.
For example, if student got only 50%, the pie chart needs to be filled with 50% with an animation.
Can you please help me on this. I used the below code,
// Set up the shape of the circle
int radius = 60;
CAShapeLayer *circle = [CAShapeLayer layer];
// Make a circular shape
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 redColor].CGColor;
circle.lineWidth = 10;
// Add to parent layer
[self.view.layer addSublayer:circle];
// Configure animation
CABasicAnimation *drawAnimation = [CABasicAnimation animationWithKeyPath:#"strokeEnd"];
drawAnimation.duration = 10.0; // "animate over 10 seconds or so.."
drawAnimation.repeatCount = 1.0; // Animate only once..
// Animate from no part of the stroke being drawn to the entire stroke being drawn
drawAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
drawAnimation.toValue = [NSNumber numberWithFloat:0.75f];
// Experiment with timing to get the appearence to look the way you want
drawAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
// Add the animation to the circle
[circle addAnimation:drawAnimation forKey:#"drawCircleAnimation"];
I would like to stop the animation at 50%.
Please use the circle.strokeEnd = 0.5f;
It will automatically stops at 50%,
if you give 1.0f it goes to 100%
Referring to the accepted answer found here I'm trying to implement this and running into an issue with the path of the CAShapeLayerThe code I have is as follows:
-(void)drawGradientArc{
UIBezierPath *bezierPath = [UIBezierPath bezierPath];
CAShapeLayer *circleLayer = [CAShapeLayer new];
circleLayer.lineWidth = 25;
circleLayer.fillColor = [UIColor clearColor].CGColor;
circleLayer.strokeColor = [UIColor redColor].CGColor;
CGFloat radius = 150;
[bezierPath addArcWithCenter:self.view.center radius:radius startAngle:0 endAngle:M_PI clockwise:YES];
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.startPoint = CGPointMake(0,0);
gradientLayer.endPoint = CGPointMake(1,0);
NSMutableArray *colors = [NSMutableArray array];
for (int i = 0; i < 10; i++) {
[colors addObject:(id)[[UIColor colorWithHue:(0.1 * i) saturation:1 brightness:.8 alpha:1] CGColor]];
}
gradientLayer.colors = colors;
[gradientLayer setMask:circleLayer];
circleLayer.path = bezierPath.CGPath;
[self.view.layer addSublayer:circleLayer];
}
This will draw the half circle arc correctly but the path for the gradients is not being set correctly and I was unable to piece together how exactly to configure the code to get this to work using a gradient. There is a CGPathCreateCopyByStrokingPath that I think I may also need to call to set the path properly for the gradient but was not quite sure how. Any help on how to structure the code to get this working would be appreciated. I've also included an image of the gradient that I'm trying to reproduce. a CAShapeLayer and CAGradientLayerapproach would be ideal.
Problem 1: Your layers have no frames. Add this:
gradientLayer.frame = self.view.layer.bounds;
circleLayer.frame = gradientLayer.bounds;
Problem 2: You are adding the wrong layer to your view's layer. Where you have:
[self.view.layer addSublayer:circleLayer];
say this instead:
[self.view.layer addSublayer:gradientLayer];
Result:
with Xcode for iOS, I have animated a drawn line.
I wish to delete it (or fade away) almost immediately.
I have tried to repeat the code with the colour set to clear (red for the tests) as my background is a grid pattern. But I only get the last colour line drawn.
Any ideas on drawing the lines in sequence one after each other?
{
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(0.0,100.0)];
[path addLineToPoint:CGPointMake(150.0, 100.0)];
[path addLineToPoint:CGPointMake(155.0, 50.0)];
[path addLineToPoint:CGPointMake(160.0, 150.0)];
[path addLineToPoint:CGPointMake(165.0, 100.0)];
[path addLineToPoint:CGPointMake(350.0, 100.0)];
CAShapeLayer *pathLayer = [CAShapeLayer layer];
pathLayer.frame = self.view.bounds;
pathLayer.path = path.CGPath;
pathLayer.strokeColor = [[UIColor greenColor] CGColor];
pathLayer.fillColor = nil;
pathLayer.lineWidth = 2.0f;
pathLayer.lineJoin = kCALineJoinBevel;
[self.view.layer addSublayer:pathLayer];
CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:#"strokeEnd"];
pathAnimation.duration = 1.0;
pathAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
pathAnimation.toValue = [NSNumber numberWithFloat:1.0f];
[pathLayer addAnimation:pathAnimation forKey:#"strokeEnd"];
}
Thanks
Add:
pathAnimation.autoreverses = true;
pathAnimation.removedOnCompletion = false;
pathAnimation.fillMode = kCAFillModeForwards;
You'll also probably want to use the animation delegate functions to remove the layer on completion.
Alternatively, if you want a delay (even slight) before the animation reverses, or want to fade it out in a different manner than reversing the animation, you can use a CAAnimationGroup to execute a series of animations on the same timeline.
Thanks for all the help.
I managed to find and successfully use code from the "Core Animation" Apple documentation. This is the first time I've managed that. Sorry for being slow, learning all the time. I had to replace "titleLayer" with "pathLayer". I'm sure that would have helped some of the suggestions.
Thanks again.
Here's my working code. Added after the code I posted above, before the last curly bracket.
CABasicAnimation* fadeAnim = [CABasicAnimation animationWithKeyPath:#"opacity"];
fadeAnim.fromValue = [NSNumber numberWithFloat:1.0];
fadeAnim.toValue = [NSNumber numberWithFloat:0.0];
fadeAnim.duration = 1.5;
[pathLayer addAnimation:fadeAnim forKey:#"opacity"];
// Change the actual data value in the layer to the final value.
pathLayer.opacity = 0.0;
I have a CaLayer that is moving with a CAKeyframeAnimation. I want to end the movement of the Layer before it reaches the end, because a random number of Layers are moving towards a single destination from different locations, and when they reach it, it looks like a snowflake.
CGPoint startPoints = [self convertDegreesToPoints:latLonArr];
CGPoint endPoints = [self convertDegreesToPoints:[NSArray arrayWithObjects:#"41.0311",#"21.3403", nil]];
UIBezierPath *linePath = [UIBezierPath bezierPath];
[linePath moveToPoint:startPoints];
[linePath addLineToPoint:endPoints];
//gradient layer for the line
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = CGRectMake(0, 0, 150.0, 2.0);
gradient.cornerRadius = 5.0f;
gradient.startPoint = CGPointMake(0.0, 0.5);
gradient.endPoint = CGPointMake(1.0, 0.5);
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor clearColor] CGColor],(id)[[colors objectAtIndex:i] CGColor],(id)[[colors objectAtIndex:i] CGColor],(id)[[UIColor clearColor] CGColor], nil];
[scrollViewContent.layer addSublayer:gradient];
CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:#"position"];
anim.path = [linePath CGPath];
anim.rotationMode = kCAAnimationRotateAuto;
anim.repeatCount = 0;
anim.duration = 1;
[gradient addAnimation:anim forKey:#"gradient"];
and here is how it looks:
This question is referral to https://stackoverflow.com/questions/20125910/cagradientlayer-to-blend-in-with-the-end-location-of-the-cakeyframeanimation
I decided to ask again because maybe I was not clear enough in the previous one, or title was to strange for someone who knows how, to look into it.