how to make a gradient border of UIView? - ios

Question

I want to make a gradient border of view like the following picture:
but I don't know how do it exactly , i.e. what the gradient color I should use to do it? how to set my view to show a border like the image?
I'm using the following code to get a border:
self.view.layer.borderColor = [UIColor orangeColor].CGColor;
self.view.layer.borderWidth = 2.0f;

Answer 1

This what i did and it worked perfectly
extension CALayer {
func addGradienBorder(colors:[UIColor],width:CGFloat = 1) {
let gradientLayer = CAGradientLayer()
gradientLayer.frame = CGRect(origin: CGPointZero, size: self.bounds.size)
gradientLayer.startPoint = CGPointMake(0.0, 0.5)
gradientLayer.endPoint = CGPointMake(1.0, 0.5)
gradientLayer.colors = colors.map({$0.CGColor})
let shapeLayer = CAShapeLayer()
shapeLayer.lineWidth = width
shapeLayer.path = UIBezierPath(rect: self.bounds).CGPath
shapeLayer.fillColor = nil
shapeLayer.strokeColor = UIColor.blackColor().CGColor
gradientLayer.mask = shapeLayer
self.addSublayer(gradientLayer)
}
}

Answer 2

Thanx Tiago Mendes for answer.
I improved functionality:
added corner radius.
And fixed some issues to ensure correct masking and given border width:
improved gradient layer frame;
improved mask path rounding rect.
Swift 5
public extension UIView {
private static let kLayerNameGradientBorder = "GradientBorderLayer"
func gradientBorder(width: CGFloat,
colors: [UIColor],
startPoint: CGPoint = CGPoint(x: 0.5, y: 0.0),
endPoint: CGPoint = CGPoint(x: 0.5, y: 1.0),
andRoundCornersWithRadius cornerRadius: CGFloat = 0) {
let existingBorder = gradientBorderLayer()
let border = existingBorder ?? CAGradientLayer()
border.frame = CGRect(x: bounds.origin.x, y: bounds.origin.y,
width: bounds.size.width + width, height: bounds.size.height + width)
border.colors = colors.map { return $0.cgColor }
border.startPoint = startPoint
border.endPoint = endPoint
let mask = CAShapeLayer()
let maskRect = CGRect(x: bounds.origin.x + width/2, y: bounds.origin.y + width/2,
width: bounds.size.width - width, height: bounds.size.height - width)
mask.path = UIBezierPath(roundedRect: maskRect, cornerRadius: cornerRadius).cgPath
mask.fillColor = UIColor.clear.cgColor
mask.strokeColor = UIColor.white.cgColor
mask.lineWidth = width
border.mask = mask
let exists = (existingBorder != nil)
if !exists {
layer.addSublayer(border)
}
}
private func gradientBorderLayer() -> CAGradientLayer? {
let borderLayers = layer.sublayers?.filter { return $0.name == UIView.kLayerNameGradientBorder }
if borderLayers?.count ?? 0 > 1 {
fatalError()
}
return borderLayers?.first as? CAGradientLayer
}
}
And for more readable declaration of startPoint and endPoint of gradient layer I use this code:
public extension CGPoint {
enum CoordinateSide {
case topLeft, top, topRight, right, bottomRight, bottom, bottomLeft, left
}
static func unitCoordinate(_ side: CoordinateSide) -> CGPoint {
switch side {
case .topLeft: return CGPoint(x: 0.0, y: 0.0)
case .top: return CGPoint(x: 0.5, y: 0.0)
case .topRight: return CGPoint(x: 1.0, y: 0.0)
case .right: return CGPoint(x: 0.0, y: 0.5)
case .bottomRight: return CGPoint(x: 1.0, y: 1.0)
case .bottom: return CGPoint(x: 0.5, y: 1.0)
case .bottomLeft: return CGPoint(x: 0.0, y: 1.0)
case .left: return CGPoint(x: 1.0, y: 0.5)
}
}
}
So final usage is:
view.gradientBorder(width: 3, colors: [.red, .orange], startPoint: .unitCoordinate(.top), endPoint: .unitCoordinate(.bottom), andRoundCornersWithRadius: 12)

Answer 3

You can make gradient border of view and corner radius(if you want) using this--
self.yourView.layer.cornerRadius=4;
self.yourView.layer.masksToBounds=YES;
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.yourView.bounds;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor colorWithRed:255/255.0 green:226/255.0 blue:138/255.0 alpha:1.0] CGColor], (id)[[UIColor colorWithRed:255/255.0 green:198/255.0 blue:91/255.0 alpha:0.9] CGColor],(id)[[UIColor colorWithRed:255/255.0 green:226/255.0 blue:138/255.0 alpha:1.0] CGColor], nil];
gradient.startPoint = CGPointMake(0.0, 0.0);
gradient.endPoint = CGPointMake(1, 1);
CAShapeLayer *shapeLayer =[[CAShapeLayer alloc] init];
shapeLayer.lineWidth = 15; // higher number higher border width
shapeLayer.path = [UIBezierPath bezierPathWithRect:self.yourView.bounds].CGPath;
shapeLayer.fillColor = nil;
shapeLayer.strokeColor = [UIColor blackColor].CGColor;
gradient.mask = shapeLayer;
[self.yourView.layer insertSublayer:gradient atIndex:0];
this will help you! Thanks

Answer 4

Here is another solution that is working on swift 4
import UIKit
public extension UIView {
private static let kLayerNameGradientBorder = "GradientBorderLayer"
func setGradientBorder(
width: CGFloat,
colors: [UIColor],
startPoint: CGPoint = CGPoint(x: 0.5, y: 0),
endPoint: CGPoint = CGPoint(x: 0.5, y: 1)
) {
let existedBorder = gradientBorderLayer()
let border = existedBorder ?? CAGradientLayer()
border.frame = bounds
border.colors = colors.map { return $0.cgColor }
border.startPoint = startPoint
border.endPoint = endPoint
let mask = CAShapeLayer()
mask.path = UIBezierPath(roundedRect: bounds, cornerRadius: 0).cgPath
mask.fillColor = UIColor.clear.cgColor
mask.strokeColor = UIColor.white.cgColor
mask.lineWidth = width
border.mask = mask
let exists = existedBorder != nil
if !exists {
layer.addSublayer(border)
}
}
private func gradientBorderLayer() -> CAGradientLayer? {
let borderLayers = layer.sublayers?.filter { return $0.name == UIView.kLayerNameGradientBorder }
if borderLayers?.count ?? 0 > 1 {
fatalError()
}
return borderLayers?.first as? CAGradientLayer
}
}
How to use:
view.setGradientBorder(width: 10, colors: [UIColor(red: 47, green: 198, blue: 176), UIColor(red: 67, green: 210, blue: 128)])

Answer 5

Here is how you would do it with Core Graphics. Create a UIView subclass and in its drawRect: create a gradient and overlay that with a black content rectangle:
- (void)drawRect:(CGRect)rect
{
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
// Create and draw the gradient
UIColor *gradientColorTop = [UIColor orangeColor];
UIColor *gradientColorBottom = [UIColor yellowColor];
NSArray *gradientColors = #[(id) gradientColorTop.CGColor, (id) gradientColorBottom.CGColor];
CGFloat locations[] = {0.1, 0.80};
CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (__bridge CFArrayRef)(gradientColors), locations);
CGPoint startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
CGPoint endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect));
UIBezierPath *gradientBorder = [UIBezierPath bezierPathWithRoundedRect:rect
byRoundingCorners:UIRectCornerAllCorners cornerRadii:CGSizeMake(10.0, 10.0)];
[gradientBorder addClip];
CGContextDrawLinearGradient(ctx, gradient, startPoint, endPoint, 0);
// Draw the inner content rectangle
UIBezierPath *contentPath = [UIBezierPath bezierPathWithRect:CGRectInset(rect, 20.0, 20.0)];
[[UIColor blackColor] setFill];
[contentPath fill];
CGGradientRelease(gradient);
CGColorSpaceRelease(colorSpace);
}
That would produce a result similar to what you are trying to achieve.

Answer 6

objective-c version of Christos Hadjikyriacou's answer
#implementation CALayer(Border)
-(void) addGradientBorder {
CAGradientLayer *gradientLayer = [[CAGradientLayer alloc] init];
gradientLayer.frame = CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height);
gradientLayer.startPoint = CGPointMake(0.0, 0.5);
gradientLayer.endPoint = CGPointMake(1.0, 0.5);
gradientLayer.colors = #[(id)[UIColor redColor].CGColor, (id)[UIColor blueColor].CGColor];
CAShapeLayer *shapeLayer =[[CAShapeLayer alloc] init];
shapeLayer.lineWidth = 0.5;
shapeLayer.path = [UIBezierPath bezierPathWithRect:self.bounds].CGPath;
shapeLayer.fillColor = nil;
shapeLayer.strokeColor = [UIColor blackColor].CGColor;
gradientLayer.mask = shapeLayer;
[self addSublayer : gradientLayer];
}
#end