I see the code in MTAnimatedLabel
CAGradientLayer *gradientLayer = (CAGradientLayer *)self.layer;
gradientLayer.backgroundColor = [super.textColor CGColor];
gradientLayer.startPoint = CGPointMake(-self.gradientWidth, 0.);
gradientLayer.endPoint = CGPointMake(0., 0.);
gradientLayer.colors = [NSArray arrayWithObjects:(id)[self.textColor CGColor],(id)[self.tint CGColor], (id)[self.textColor CGColor], nil];
self is an UILabel. From the document, the layer should be readonly but I don't know why in this repo, it works.
So I try these code in my program.
UIView *gradientView = [[UIView alloc] initWithFrame:textLayer.frame];
[self.view addSubview:gradientView];
CAGradientLayer *gradient = (CAGradientLayer*)gradientView.layer;
gradient.startPoint = CGPointMake(-0.4, 0.0);
gradient.endPoint = CGPointMake(0.0, 0.0);
gradient.colors = #[(id)[UIColor darkGrayColor].CGColor, (id)[UIColor whiteColor].CGColor, (id)[UIColor darkGrayColor].CGColor];
gradient.backgroundColor = [UIColor clearColor].CGColor;
gradient.frame = textLayer.frame
It throw an error:
-[CALayer setColors:]: unrecognized selector sent to instance 0x8f8dca0
I can't understand why my code is no able to run. Hope anyone can help me.
looks you missed add
+ (Class)layerClass
{
return [CAGradientLayer class];
}
to make view layer gradient, by default this method return CALayer, that not have colors property see UIView class reference
Related
I have used below code to set gradient background color of my view.
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.view.bounds;
gradient.colors = #[(id)[UIColor colorWithRed:44/255 green:58/255 blue:76/255 alpha:1].CGColor, (id)[UIColor colorWithRed:17/255 green:22/255 blue:30/255 alpha:1].CGColor];
[self.view.layer insertSublayer:gradient atIndex:0];
But its not working. Screen will appear with black color. But when I try to set color like below
gradient.colors = #[(id)[UIColor blueColor].CGColor, (id)[UIColor redColor].CGColor];
then it working fine.I am getting correct output. Can anyone help me to fine why gradient color is not working with UIColor colorWithRed function.
Thanks in advance.
For the original poster's code to work, he just has to divide each color component by 255.0 instead of 255, if not the result is truncated to an int.
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.view.bounds;
gradient.colors = #[(id)[UIColor colorWithRed:44/255.0 green:58/255.0 blue:76/255.0 alpha:1].CGColor, (id)[UIColor colorWithRed:17/255.0 green:22/255.0 blue:30/255.0 alpha:1].CGColor];
[self.view.layer insertSublayer:gradient atIndex:0];
Alternatively, make the dividend a float value:
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.view.bounds;
gradient.colors = #[(id)[UIColor colorWithRed:44.0/255 green:58.0/255 blue:76.0/255 alpha:1].CGColor, (id)[UIColor colorWithRed:17.0/255 green:22.0/255 blue:30.0/255 alpha:1].CGColor];
[self.view.layer insertSublayer:gradient atIndex:0];
Or the most easy to follow solution, make both numbers in the division a float value:
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.view.bounds;
gradient.colors = #[(id)[UIColor colorWithRed:44.0/255.0 green:58.0/255.0 blue:76.0/255.0 alpha:1].CGColor, (id)[UIColor colorWithRed:17.0/255.0 green:22.0/255.0 blue:30.0/255.0 alpha:1].CGColor];
[self.view.layer insertSublayer:gradient atIndex:0];
Try this:
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor colorWithRed:202.0/255.0 green:107.0/255.0 blue:122.0/255.0 alpha:1] CGColor], (id)[[UIColor colorWithRed:192.0/255.0 green:144.0/255.0 blue:120.0/255.0 alpha:1] CGColor], nil];
gradient.frame = self.view.bounds;
[self.view.layer insertSublayer:gradient atIndex:0];
Try like this!
-(CAGradientLayer *)makeGradientView :(UIColor *)topColor BottomColor:(UIColor *)bottomColor withFrame:(CGRect )rect
{
CAGradientLayer *theViewGradient = [CAGradientLayer layer];
NSArray *gradientLocations = [NSArray arrayWithObjects:[NSNumber numberWithInt:0.0],[NSNumber numberWithInt:1.0], nil];
theViewGradient.locations = gradientLocations;
theViewGradient.colors = [NSArray arrayWithObjects: (id)topColor.CGColor,(id)bottomColor.CGColor,(id)bottomColor.CGColor,(id)bottomColor.CGColor, (id)bottomColor.CGColor, nil];
theViewGradient.frame = rect;
theViewGradient.startPoint = CGPointMake(1,1);
theViewGradient.endPoint = CGPointMake(1.0,0.1);
return theViewGradient;
}
And you can use like this!
#property (weak, nonatomic) IBOutlet UIView *mainView;
CAGradientLayer *theViewGradient = [self makeGradientView:[UIColor colorWithRed:189/255.0 green:227/255.0 blue:106/255.0 alpha:0.5] BottomColor:[UIColor colorWithRed:13/255.0 green:184/255.0 blue:196/255.0 alpha:0.5] withFrame:self.view.bounds];
[_mainView.layer addSublayer:theViewGradient];
I am trying to set gradient on my main View with custom colors. View is displayed completely white though. What's wrong with this record?
CAGradientLayer *gradient = [CAGradientLayer new];
gradient.colors = #[(id)[UIColor colorWithRed:92.0 green:196.0 blue:244.0 alpha:1].CGColor,
(id)[UIColor colorWithRed:47.0 green:146.0 blue:229.0 alpha:1].CGColor];
gradient.frame = self.backGroundView.bounds;
gradient.locations = #[#0.5, #0.5];
[self.backGroundView.layer insertSublayer:gradient atIndex:0];
This is properly displayed with blue and red cut in half of view's height.
CAGradientLayer *gradient = [CAGradientLayer new];
gradient.colors = #[(id)[UIColor redColor].CGColor, (id)[UIColor blueColor].CGColor];
gradient.frame = self.backGroundView.bounds;
gradient.locations = #[#0.5, #0.5];
[self.backGroundView.layer insertSublayer:gradient atIndex:0];
your colors are wrong. the UIColor initializer expects values between 0 and 1. try this:
gradient.colors = #[(id)[UIColor colorWithRed:92/255.0 green:196/255.0 blue:244/255.0 alpha:1].CGColor,
(id)[UIColor colorWithRed:47/255.0 green:146/255.0 blue:229/255.0 alpha:1].CGColor];
I have an issue with the gradient color, I'm not able to make the gradient color appear as circular, it always appear like linear, i need the exact gradient in the following image:
PS: this is the code i use:
UIView *view = [[UIView alloc] initWithFrame:self.view.frame];
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = view.bounds;
gradient.startPoint = CGPointMake(0.0,0.4);
gradient.endPoint = CGPointMake(0.0,0.6);
view.layer.masksToBounds = YES;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor colorWithRed:153.0/255.0 green:204.0/255.0 blue:0.0/255.0 alpha:1.0] CGColor], (id)[[UIColor whiteColor] CGColor], nil];
[view.layer insertSublayer:gradient atIndex:0];
[self.view addSubview:view];
There is a CGContextDrawRadialGradient in CGContext. I hope it will help you
I have this code to create a gradient background
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.bounds;
UIColor *startColour = [UIColor colorWithHexString:#"#bcdef6"];
UIColor *endColour = [UIColor colorWithHexString:#"#fad7e6"];
UIColor *middleColor = [UIColor colorWithHexString:#"#ffffff"];
gradient.colors = [NSArray arrayWithObjects:(id)[startColour CGColor],(id)middleColor, (id)[endColour CGColor], nil];
gradient.endPoint = CGPointMake(1, 0);
gradient.startPoint = CGPointMake(0, 1);
[self.layer insertSublayer:gradient atIndex:0];
how do i get rid of the greyish effect in the middle ?
this is the desired result:
this is the actual result:
I can see a bug with your colors array, you have not taken the CGColor of the middle color (white). By changing the array to this, I can get your desired result.
gradient.colors = #[(id)startColour.CGColor, (id)middleColor.CGColor, (id)endColour.CGColor];
By playing around with the gradient locations, you can also see more of the blue and pink colors should that create a better effect.
gradient.locations = #[#0.2f, #0.5f, #0.8f];
How to create gradient colour look like following image programatically.
When you say "apply it over the image as a gradient", do you mean as a mask (revealing the image at the top, having it fade the image to transparent at the bottom)? If that's the case, you can apply that gradient as a mask, using CAGradientLayer:
CAGradientLayer *gradientMask = [CAGradientLayer layer];
gradientMask.frame = self.imageView.bounds;
gradientMask.colors = #[(id)[UIColor whiteColor].CGColor,
(id)[UIColor clearColor].CGColor];
self.imageView.layer.mask = gradientMask;
The above does a simple vertical gradient (because the default is vertical, linear gradient). But you asked about startPoint, endPoint, and locations. If for example, you wanted your mask applied horizontally, you would do:
gradientMask.startPoint = CGPointMake(0.0, 0.5); // start at left middle
gradientMask.endPoint = CGPointMake(1.0, 0.5); // end at right middle
If you wanted to have two gradients, one at the first 10% and another at the last 10%, you'd do:
gradientMask.colors = #[(id)[UIColor clearColor].CGColor,
(id)[UIColor whiteColor].CGColor,
(id)[UIColor whiteColor].CGColor,
(id)[UIColor clearColor].CGColor];
gradientMask.locations = #[#0.0, #0.10, #0.90, #1.0];
If you want a simple gradient by itself (not as a mask), you'd create a view and then add the gradient layer to it:
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = view.bounds;
gradient.colors = #[(id)[UIColor whiteColor].CGColor,
(id)[UIColor blackColor].CGColor];
[view.layer addSublayer:gradient];
See the CAGradientLayer class reference.
I just wrote an UIImage extension for Swift 2.0. Maybe it's of some use. You call it with an array of UIColor (any number) and a frame where the gradient should be drawn.
extension UIImage {
class func convertGradientToImage(colors: [UIColor], frame: CGRect) -> UIImage {
// start with a CAGradientLayer
let gradientLayer = CAGradientLayer()
gradientLayer.frame = frame
// add colors as CGCologRef to a new array and calculate the distances
var colorsRef = [CGColor]()
var locations = [NSNumber]()
for i in 0 ... colors.count-1 {
colorsRef.append(colors[i].CGColor as CGColorRef)
locations.append(Float(i)/Float(colors.count-1))
}
gradientLayer.colors = colorsRef
gradientLayer.locations = locations
// now build a UIImage from the gradient
UIGraphicsBeginImageContext(gradientLayer.bounds.size)
gradientLayer.renderInContext(UIGraphicsGetCurrentContext()!)
let gradientImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
// return the gradient image
return gradientImage
}
}
Call it like this:
let colors = [
UIColor.blueColor(),
UIColor.greenColor()
// and many more if you wish
]
let gradientImage = UIImage.convertGradientToImage(colors, frame: navigationBar.bounds)
and apply with:
.backgroundColor = UIColor(patternImage: gradientImage)
or
.setBackgroundImage(gradientImage, forBarMetrics: .Default)
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.view.bounds;
gradient.startPoint = CGPointMake(1.0, 1.0); //Dark From bottom
gradient.endPoint = CGPointMake(1.0, 0);
gradient.colors = [NSArray arrayWithObjects:
(id)[[UIColor blackColor] CGColor],
(id)[[UIColor clearColor] CGColor], nil];
[self.view.layer insertSublayer:gradient atIndex:0];
This is the best approach, working for me as requirement
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = yourImageView.layer.bounds;
gradientLayer.colors = [NSArray arrayWithObjects:
(id)[UIColor colorWithWhite:1.0f alpha:1.0f].CGColor,
(id)[UIColor colorWithWhite:0.0f alpha:0.9f].CGColor,
nil];
gradientLayer.locations = [NSArray arrayWithObjects:
[NSNumber numberWithFloat:0.0f],
[NSNumber numberWithFloat:1.0f],
nil];
[yourImageView.layer addSublayer:gradientLayer];
-(void) drawGradientinBounds: (CGRect) currentBounds withColors:(NSArray*) colors andPercentages:(NSArray *)percentages andGradientDirectionIsVertical:(BOOL)isGradientDirectionVertical
{
CGContextRef currentContext = UIGraphicsGetCurrentContext();
CGGradientRef glossGradient;
CGColorSpaceRef rgbColorspace;
size_t num_locations = [percentages count];
CGFloat locations[num_locations];
for(int i=0;i<num_locations;i++)
locations[i] = [[percentages objectAtIndex:i] floatValue];
int comps = [colors count]*4;
CGFloat components[comps];
for(int i = [colors count]-1;i>=0;i--)
{
comps--;
UIColor *c = [colors objectAtIndex:i];
const CGFloat *cg = CGColorGetComponents([c CGColor]);
components[comps] = cg[3];
comps--;
components[comps] = cg[2];
comps--;
components[comps] = cg[1];
comps--;
components[comps] = cg[0];
}
rgbColorspace = CGColorSpaceCreateDeviceRGB();
glossGradient = CGGradientCreateWithColorComponents(rgbColorspace, components, locations, num_locations);
CGPoint topCenter;
CGPoint endCenter;
if(isGradientDirectionVertical)
{
topCenter = CGPointMake(CGRectGetMidX(currentBounds), currentBounds.origin.y);
endCenter = CGPointMake(CGRectGetMidX(currentBounds), CGRectGetHeight(currentBounds)+currentBounds.origin.y);
}
else
{
topCenter = CGPointMake( currentBounds.origin.x,CGRectGetMidY(currentBounds));
endCenter = CGPointMake(CGRectGetWidth(currentBounds)+currentBounds.origin.x,CGRectGetMidY(currentBounds));
}
CGContextDrawLinearGradient(currentContext, glossGradient, topCenter, endCenter, 0);
CGGradientRelease(glossGradient);
CGColorSpaceRelease(rgbColorspace);
}
And the input to this method are bounds, colorArray:
[NSArray arrayWithObjects:[UIColor blackColor], [UIColor whiteColor], nil]
percentageArray:
[NSArray arrayWithObjects:[NSNumber numberWithFloat:0.0], [NSNumber numberWithFloat:1.0], nil]