Updating bounds of custom CALayer in drawLayer:inContext: - ios

I've got a custom layer which is sub-layer of something else. The problem is, my layer can't know it's size until I'm in drawLayer:inContext:.
When I don't change the bounds/frame of my layer everything draws perfectly.
When I add in the the line to change frame/bounds, my background looks perfect, but my content doesn't exist. It looks like the content is clipping off the original bounds instead of the new (bigger) bounds so I see nothing but the background.
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)context {
CGFloat initialGraphContentsWidth = graph.frame.size.width - graph.leftMargin;
CGFloat initialGraphContentsHeight = graph.frame.size.height - graph.bottomMargin - graphHelper.topMargin;
self.frame = CGRectMake(0, 0, initialGraphContentsWidth, initialGraphContentsHeight);
self.position = CGPointMake(graphHelper.leftMargin + 1, graphHelper.topMargin + 1);
self.backgroundColor = [UIColor greenColor].CGColor;
CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);
CGContextAddRect(context, CGRectMake(0, 0, 20, 20));
}
So how to I dynamically change my bounds and still get my content to appear?
I tried setting up a CATransaction with a duration of 0, but that did nothing.

Have you tried calling setNeedsDisplay after you have updated the frame/bounds?
So for instance if you had a CALayer called layer, you could try the following:
layer.frame = CGRectMake(20, 40, 100, 300);
// tell the layer that it needs to refreshed
[layer setNeedsDisplay];

Related

create quarter transparent hole at right bottom on overlay UIView

Hi i want to create a quarter transparent hole at right bottom on overlay UIView.
i am able to solve it using below code. But it does not look right as i am creating a rectangle outside the bond of view.
What i have tried:
#implementation PartialTransparentView
- (id)initWithBottomRightCornerRadiusForView:(UIView *)view withRadius:(CGFloat)radius
{
[self commonInitWithRect:CGRectMake(view.frame.size.width - radius, view.frame.size.height - radius, radius*2, radius*2)];
self = [super initWithFrame:CGRectMake(0, 0, 5000, 5000)];//**it does not look right to me**
if (self) {
// Initialization code
self.opaque = NO;
}
return self;
}
-(void)commonInitWithRect:(CGRect)rect{
backgroundColor = [UIColor colorWithWhite:1 alpha:0.75];
rectToBeSurrounded = rect;
}
- (void)drawRect:(CGRect)rect {
[backgroundColor setFill];
UIRectFill(rect);
CGFloat x = rectToBeSurrounded.origin.x;
CGFloat y = rectToBeSurrounded.origin.y;
CGFloat width = rectToBeSurrounded.size.width;
CGFloat height = rectToBeSurrounded.size.height;
//create outer square
CGFloat outerX = (x - width/2);
CGFloat outerY = y - height/2;
CGFloat outerWidth = 2*width;
CGFloat outerHeight = outerWidth;
//create outer square
CGRect outerRect = CGRectMake(outerX, outerY, outerWidth, outerHeight);
CGRect holeRectIntersection = CGRectIntersection( outerRect, rect );
CGContextRef context = UIGraphicsGetCurrentContext();
if( CGRectIntersectsRect( holeRectIntersection, rect ) )
{
CGContextAddEllipseInRect(context, holeRectIntersection);
CGContextClip(context);
CGContextClearRect(context, holeRectIntersection);
CGContextSetFillColorWithColor( context, [UIColor clearColor].CGColor );
CGContextFillRect( context, holeRectIntersection);
}
}
Now i am using above code as :
PartialTransparentView *transparentView = [[PartialTransparentView alloc] initWithBottomRightCornerRadiusForView:self.view withRadius:50];
[self.view addSubview:transparentView];
Result as expected:
i know my solution will break if i have to acheive same thing but on top left of view.
what i am looking for just provide center (x, y) and radius for circle and get desired results.
Thanks
Basd on Mr.T
UIView *transparentView = [[UIView alloc] initWithFrame:self.view.frame];
[transparentView setBackgroundColor:[UIColor colorWithWhite:1 alpha:0.75]];
[self.view addSubview:transparentView];
circleView *acircleView = [[circleView alloc] initWithFrame:CGRectMake(50, 50, 60, 60)];
[acircleView setBackgroundColor:[UIColor grayColor]];
[transparentView addSubview:acircleView];
and circleView.m
- (void)drawRect:(CGRect)rect {
// Drawing code
//// Oval Drawing
UIBezierPath* ovalPath = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(50, 50, 60, 60)];
[UIColor.grayColor setFill];
[ovalPath fill];
}
output:
My suggestions is to add the transparent view as a separate view on your view controller. This can be either done on storyboard,so that you can set the background color and the alpha value to give the transparent effect!!!
Now create another view to make the circle and add it to transparent view, , and move this view on the transparent view according to your need!!!
Create the circle using bezier path:
circleView.m
- (void)drawRect:(CGRect)frame {
//// Oval Drawing
UIBezierPath* ovalPath = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(CGRectGetMinX(frame), CGRectGetMinY(frame), 60, 60)];
[UIColor.grayColor setFill];
[ovalPath fill];
}
For testing purpose, I have created a circle view on my IB and created an outlet property in my view controller.
HEre is the screenshot.
Now to move the circle, I can simply change the frame of the circle view, wherever I need.
For example, If I want to move it to top left, I simply do:
-(void)moveCircleViewwithX:(float) x withY:(float) y{
_cView.frame=CGRectMake(x, y, _cView.frame.size.width, _cView.frame.size.height);
}
The result will be:
Update
Put the following the drawRect method of transparentView:
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGRect transparentPart = self.seeRect; //this is the rect of the circle view
CGContextAddEllipseInRect(ctx,transparentPart); //make the circle shape
CGContextClip(ctx);
CGContextClearRect(ctx, transparentPart);
and in your view controller:
when you want to apply the mask i.e the transparent for both circle and for the transparent layer:
-(void)applyMask{
[_cView setCircleColor:[UIColor clearColor]]; //circle view bezier path color
[_cView setNeedsDisplay];
[_tView setSeeRect:_cView.frame]; //set the transparency cut on transparency view
[_tView setNeedsDisplay];
}
Once you do this, you will get the transparency view!!!
You can move the circle by simply calling
[self moveCircleViewwithX:-30 withY:10]; //top left corner
and you can apply the transparency mask by simply calling:
[self applyMask];
So, the final result after you call the applyMask method will be:

CALayer draw outside of rect

I'm using this code to add a layer to a custom UIView and it works like a charm:
CGRect newrect = CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height);
CALayer* heartBackground = [CALayer layer];
heartBackground.contents = (__bridge id)([UIImage imageNamed:#"5HeartsGray"].CGImage);
heartBackground.frame = newrect;
[self.layer addSublayer:heartBackground];
But when I tried to use it in draw method using Quartz using a new Rect(like this)
CGContextSaveGState(context);
CGRect ratingRect = CGRectMake(250, 100, 150, 20);
CALayer* heartBackground = [CALayer layer];
heartBackground.contents = (__bridge id)([UIImage imageNamed:#"5HeartsGray"].CGImage);
heartBackground.frame = ratingRect;
[heartBackground renderInContext:context];
CGContextRestoreGState(context);
It renders in the beginning of the frame and not inside of ratingRect.
If I call [heartBackground setNeedsDisplay] it disappear. The same thing with heartBackground.masksToBounds = YES
What I'm doing wrong. Do I need To switch to CGLayer because I'm using CoreGraphics?
This is the output when working with CoreGraphics (as you see the hearts starts at coordinates x=0, y=0 and normally it starts at x=250, y=100):
It doesn't make sense to create and draw a CALayer inside draw function of a UIView. CALayer is an independently drawable unit and it draws itself on its parentLayer's context by default. Which means if you really want to use separate CALayers try adding as many subLayers to self.layer (inside a UIView) as you want, set their frames and they'll get drawn when their container view shows up. Regarding your problem, here's what you can try.
Option 1: Take this code
CGRect ratingRect = CGRectMake(250, 100, 150, 20);
CALayer* heartBackground = [CALayer layer];
heartBackground.contents = (__bridge id)([UIImage imageNamed:#"5HeartsGray"].CGImage);
heartBackground.frame = ratingRect;
[self.layer addSubLayer:heartBackground];
Out of the drawRect: method and write it in initWithFrame: and in drawRect simply do [heartBackground renderInContext:UIGraphicsGetCurrentContext];
Option 2: Draw your hearts without a CALayer.
CGRect ratingRect = CGRectMake(250, 100, 150, 20);
[[UIImage imageNamed:#"5HeartsGray"] drawInRect:ratingRect];

iOS stroke layer outside of it's bounds

I'm trying to build a category method on UIView to allow to stroke the UIView, similarly to the Photoshop function: Stroke-Outside. While CALayer properties borderWidth and borderColor work flawlessly to stroke on the inside, I cannot find a good way to stroke the view on the outside.
This is the solution I came up at first:
Using sublayers I add another CALayer with frame larger than the superlayer's bounds. The layer is then inserted in the UIView's sublayers.
- (void)strokeViewWithColor:(UIColor *)color borderWidth:(CGFloat)borderWidth
{
CALayer *borderLayer = [CALayer layer];
CGRect borderFrame = CGRectMake(-borderWidth, -borderWidth, (self.frame.size.width) + (borderWidth * 2), (self.frame.size.height) + (borderWidth * 2));
[borderLayer setBackgroundColor:[[UIColor clearColor] CGColor]];
[borderLayer setFrame:borderFrame];
//
// Copy current border layer radius
//
[borderLayer setCornerRadius:self.layer.cornerRadius];
[borderLayer setBorderWidth:borderWidth];
[borderLayer setBorderColor:[color CGColor]];
[self.layer addSublayer:borderLayer];
}
This works for all the UIView's that have layer's property masksToBounds or view's property clipsToBounds set to NO. But this disables the functionality to use cornerRadius property, which I want to have.
So my second attempt was to use UIView's, since obviously I must go out of the view I want to stroke (the same logic could be applied to layer and superlayer relationship I assume).
I came up with this solution:
- (void)strokeViewWithColor:(UIColor *)color borderWidth:(CGFloat)borderWidth
{
UIView* superview = self.superview;
//
// Fix frame
//
CGRect frame = self.frame;
frame.origin.x -= borderWidth;
frame.origin.y -= borderWidth;
frame.size.width += (2 * borderWidth);
frame.size.height += (2 * borderWidth);
UIView* strokeView = [[UIView alloc] initWithFrame:frame];
strokeView.layer.borderWidth = borderWidth;
strokeView.layer.cornerRadius = self.layer.cornerRadius + borderWidth;
strokeView.layer.borderColor = [color CGColor];
[superview insertSubview:strokeView aboveSubview:self];
}
This works, but the problem would be with auto layout. Because the strokeView has no auto layout constraints, it probably would not work correctly when constraints are added.
That is why I am looking for any other solutions.
What would be the best way to solve this problem? Should I write some code to handle the auto layout issue on second part of the code? Or should I approach the problem from different perspective? If so, how?
I'm mostly looking for suggestions on how to approach the problem.
Thanks for help!

On iOS, drawRect cannot draw outside of the view's bounds?

I thought from some point on for OS X, and always true for iOS, that content can appear outside of the view's bounds? (for UIView) But if I create a brand new Single View app, and created a MyView class that subclasses UIView, and implement its drawRect:
- (void)drawRect:(CGRect)rect
{
// Drawing code
UIBezierPath *path = [UIBezierPath bezierPathWithRect:
CGRectMake(-20, -20, 600, 600)];
[[UIColor greenColor] set];
[path fill];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [[UIColor blueColor] CGColor]);
CGContextFillRect(context, CGRectMake(-20, -20, 600, 600));
}
I use both UI and CG to draw a rectangle each, just in case one works and the other doesn't. And the view is added in viewDidAppear:
- (void)viewDidAppear:(BOOL)animated {
MyView *myView = [[MyView alloc] initWithFrame:CGRectMake(20, 20, 260, 260)];
[self.view addSubview:myView];
}
But no matter what, the colored box won't go beyond the (20, 20, 260, 260) region. Is it true that only the CALayers can be freely added and appear outside of a view's bounds? Can it be because of the graphics context is limited to this (20, 20, 260, 260) to begin with? If so, is there a way to make drawRect content appear outside of the view's bound, in all four top, down, left, right directions?
Your problem is that "drawRect" is automatically clipped to the view that you are drawing in.
Instead of doing the drawing in the view itself, add a second (sub)view to the first view, that is outside the bounds of the first view. This will allow you to do drawing that is dependent on the placement of the first view, but is outside the first view's bounds.
Hope this helps.
Try this on a view, where you have added the scrollView:
self.scrollView.backgroundColor = [UIColor darkGrayColor];
self.scrollView.layer.cornerRadius = 10.0f;
self.scrollView.layer.masksToBounds = YES;
It should display a gray scrollview with rounded corners, as you want.
Remember you need to import the QuartzCore FrameWork

Round two corners in UIView

A little while ago I posted a question about rounding just two corners of a view, and got a great response, but am having problems implementing it. Here is my drawRect: method:
- (void)drawRect:(CGRect)rect {
//[super drawRect:rect]; <------Should I uncomment this?
int radius = 5;
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextBeginPath(context);
CGContextAddArc(context, rect.origin.x + radius, rect.origin.y + rect.size.height - radius, radius, M_PI, M_PI / 2, 1);
CGContextAddArc(context, rect.origin.x + rect.size.width - radius, rect.origin.y + rect.size.height - radius, radius, M_PI / 2, 0.0f, 1);
CGContextClosePath(context);
CGContextClip(context);
}
The method is being called, but doesn't seem to affect the outcome of the view. Any ideas why?
CACornerMask introduced in iOS 11, which help to define topleft, topright, bottomleft, bottom right in view layer. Below is example to use.
Here I try to rounded only two top corner:
myView.clipsToBounds = true
myView.layer.cornerRadius = 10
myView.layer.maskedCorners = [.layerMinXMinYCorner,.layerMaxXMinYCorner]
FYI Ref:
as far as I know, if you also need to mask the subviews, you could use CALayer masking. There are 2 ways to do this. The first one is a bit more elegant, the second one is a workaround :-) but it's also fast. Both are based on CALayer masking. I've used both methods in a couple of projects last year then I hope you can find something useful.
Solution 1
First of all, I created this function to generate an image mask on the fly (UIImage) with the rounded corner I need. This function essentially needs 5 parameters: the bounds of the image and 4 corner radius (top-left, top-right, bottom-left and bottom-right).
static inline UIImage* MTDContextCreateRoundedMask( CGRect rect, CGFloat radius_tl, CGFloat radius_tr, CGFloat radius_bl, CGFloat radius_br ) {
CGContextRef context;
CGColorSpaceRef colorSpace;
colorSpace = CGColorSpaceCreateDeviceRGB();
// create a bitmap graphics context the size of the image
context = CGBitmapContextCreate( NULL, rect.size.width, rect.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast );
// free the rgb colorspace
CGColorSpaceRelease(colorSpace);
if ( context == NULL ) {
return NULL;
}
// cerate mask
CGFloat minx = CGRectGetMinX( rect ), midx = CGRectGetMidX( rect ), maxx = CGRectGetMaxX( rect );
CGFloat miny = CGRectGetMinY( rect ), midy = CGRectGetMidY( rect ), maxy = CGRectGetMaxY( rect );
CGContextBeginPath( context );
CGContextSetGrayFillColor( context, 1.0, 0.0 );
CGContextAddRect( context, rect );
CGContextClosePath( context );
CGContextDrawPath( context, kCGPathFill );
CGContextSetGrayFillColor( context, 1.0, 1.0 );
CGContextBeginPath( context );
CGContextMoveToPoint( context, minx, midy );
CGContextAddArcToPoint( context, minx, miny, midx, miny, radius_bl );
CGContextAddArcToPoint( context, maxx, miny, maxx, midy, radius_br );
CGContextAddArcToPoint( context, maxx, maxy, midx, maxy, radius_tr );
CGContextAddArcToPoint( context, minx, maxy, minx, midy, radius_tl );
CGContextClosePath( context );
CGContextDrawPath( context, kCGPathFill );
// Create CGImageRef of the main view bitmap content, and then
// release that bitmap context
CGImageRef bitmapContext = CGBitmapContextCreateImage( context );
CGContextRelease( context );
// convert the finished resized image to a UIImage
UIImage *theImage = [UIImage imageWithCGImage:bitmapContext];
// image is retained by the property setting above, so we can
// release the original
CGImageRelease(bitmapContext);
// return the image
return theImage;
}
Now you just need few lines of code. I put stuff in my viewController viewDidLoad method because it's faster but you can use it also in your custom UIView with the layoutSubviews method in example.
- (void)viewDidLoad {
// Create the mask image you need calling the previous function
UIImage *mask = MTDContextCreateRoundedMask( self.view.bounds, 50.0, 50.0, 0.0, 0.0 );
// Create a new layer that will work as a mask
CALayer *layerMask = [CALayer layer];
layerMask.frame = self.view.bounds;
// Put the mask image as content of the layer
layerMask.contents = (id)mask.CGImage;
// set the mask layer as mask of the view layer
self.view.layer.mask = layerMask;
// Add a backaground color just to check if it works
self.view.backgroundColor = [UIColor redColor];
// Add a test view to verify the correct mask clipping
UIView *testView = [[UIView alloc] initWithFrame:CGRectMake( 0.0, 0.0, 50.0, 50.0 )];
testView.backgroundColor = [UIColor blueColor];
[self.view addSubview:testView];
[testView release];
[super viewDidLoad];
}
Solution 2
This solution is a bit more "dirty". Essentially you could create a mask layer with the rounded corner you need (all corners). Then you should increase the height of the mask layer by the value of the corner radius. In this way the bottom rounded corners are hidden and you can only see the upper rounded corner. I put the code just in the viewDidLoad method because it's faster but you can use it also in your custom UIView with the layoutSubviews method in example.
- (void)viewDidLoad {
// set the radius
CGFloat radius = 50.0;
// set the mask frame, and increase the height by the
// corner radius to hide bottom corners
CGRect maskFrame = self.view.bounds;
maskFrame.size.height += radius;
// create the mask layer
CALayer *maskLayer = [CALayer layer];
maskLayer.cornerRadius = radius;
maskLayer.backgroundColor = [UIColor blackColor].CGColor;
maskLayer.frame = maskFrame;
// set the mask
self.view.layer.mask = maskLayer;
// Add a backaground color just to check if it works
self.view.backgroundColor = [UIColor redColor];
// Add a test view to verify the correct mask clipping
UIView *testView = [[UIView alloc] initWithFrame:CGRectMake( 0.0, 0.0, 50.0, 50.0 )];
testView.backgroundColor = [UIColor blueColor];
[self.view addSubview:testView];
[testView release];
[super viewDidLoad];
}
Hope this helps. Ciao!
Combing through the few answers & comments, I found out that using UIBezierPath bezierPathWithRoundedRect and CAShapeLayer the simplest and most straight forward way. It might not be appropriate for very complex cases, but for occasional rounding of corners, it works fast and smoothly for me.
I had created a simplified helper that sets the appropriate corner in the mask:
-(void) setMaskTo:(UIView*)view byRoundingCorners:(UIRectCorner)corners
{
UIBezierPath* rounded = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:corners cornerRadii:CGSizeMake(10.0, 10.0)];
CAShapeLayer* shape = [[CAShapeLayer alloc] init];
[shape setPath:rounded.CGPath];
view.layer.mask = shape;
}
To use it, simply call with the appropriate UIRectCorner enum, e.g.:
[self setMaskTo:self.photoView byRoundingCorners:UIRectCornerTopLeft|UIRectCornerBottomLeft];
Please note that for me, I use it to round corners of photos in a grouped UITableViewCell, the 10.0 radius works fine for me, if need to just change the value as appropriate.
EDIT: just notice a previously answered very similarly as this one (link). You can still use this answer as a added convenience function if needed.
EDIT: Same code as UIView extension in Swift 3
extension UIView {
func maskByRoundingCorners(_ masks:UIRectCorner, withRadii radii:CGSize = CGSize(width: 10, height: 10)) {
let rounded = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: masks, cornerRadii: radii)
let shape = CAShapeLayer()
shape.path = rounded.cgPath
self.layer.mask = shape
}
}
To use it, simple call maskByRoundingCorner on any UIView:
view.maskByRoundingCorners([.topLeft, .bottomLeft])
I couldn't fit this all in a comment to #lomanf's answer. So I'm adding it as an answer.
Like #lomanf said, you need to add a layer mask to prevent sublayers from drawing outside of your path's bounds. It's a lot easier to do now, though. As long as you're targeting iOS 3.2 or higher, you don't need to create an image with quartz and set it as the mask. You can simply create a CAShapeLayer with a UIBezierPath and use that as the mask.
Also, when using layer masks, make sure that the layer you're masking is not part of any layer hierarchy when you add the mask. Otherwise the behavior is undefined. If your view is already in the hierarchy, you need to remove it from its superview, mask it, then put it back where it was.
CAShapeLayer *maskLayer = [CAShapeLayer layer];
UIBezierPath *roundedPath =
[UIBezierPath bezierPathWithRoundedRect:maskLayer.bounds
byRoundingCorners:UIRectCornerTopLeft |
UIRectCornerBottomRight
cornerRadii:CGSizeMake(16.f, 16.f)];
maskLayer.fillColor = [[UIColor whiteColor] CGColor];
maskLayer.backgroundColor = [[UIColor clearColor] CGColor];
maskLayer.path = [roundedPath CGPath];
//Don't add masks to layers already in the hierarchy!
UIView *superview = [self.view superview];
[self.view removeFromSuperview];
self.view.layer.mask = maskLayer;
[superview addSubview:self.view];
Due to the way Core Animation rendering works, masking is a relatively slow operation. Each mask requires an extra rendering pass. So use masks sparingly.
One of the best parts of this approach is that you no longer need to create a custom UIView and override drawRect:. This should make your code simpler, and maybe even faster.
I've taken Nathan's example and created a category on UIView to allow one to adhere to DRY principles. Without further ado:
UIView+Roundify.h
#import <UIKit/UIKit.h>
#interface UIView (Roundify)
-(void)addRoundedCorners:(UIRectCorner)corners withRadii:(CGSize)radii;
-(CALayer*)maskForRoundedCorners:(UIRectCorner)corners withRadii:(CGSize)radii;
#end
UIView+Roundify.m
#import "UIView+Roundify.h"
#implementation UIView (Roundify)
-(void)addRoundedCorners:(UIRectCorner)corners withRadii:(CGSize)radii {
CALayer *tMaskLayer = [self maskForRoundedCorners:corners withRadii:radii];
self.layer.mask = tMaskLayer;
}
-(CALayer*)maskForRoundedCorners:(UIRectCorner)corners withRadii:(CGSize)radii {
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = self.bounds;
UIBezierPath *roundedPath = [UIBezierPath bezierPathWithRoundedRect:
maskLayer.bounds byRoundingCorners:corners cornerRadii:radii];
maskLayer.fillColor = [[UIColor whiteColor] CGColor];
maskLayer.backgroundColor = [[UIColor clearColor] CGColor];
maskLayer.path = [roundedPath CGPath];
return maskLayer;
}
#end
To call:
[myView addRoundedCorners:UIRectCornerBottomLeft | UIRectCornerBottomRight
withRadii:CGSizeMake(20.0f, 20.0f)];
To expand a little on P.L's answer I rewrote the method like so as it wasn't rounding certain objects such as UIButton correctly
- (void)setMaskTo:(id)sender byRoundingCorners:(UIRectCorner)corners withCornerRadii:(CGSize)radii
{
// UIButton requires this
[sender layer].cornerRadius = 0.0;
UIBezierPath *shapePath = [UIBezierPath bezierPathWithRoundedRect:[sender bounds]
byRoundingCorners:corners
cornerRadii:radii];
CAShapeLayer *newCornerLayer = [CAShapeLayer layer];
newCornerLayer.frame = [sender bounds];
newCornerLayer.path = shapePath.CGPath;
[sender layer].mask = newCornerLayer;
}
And call it by
[self setMaskTo:self.continueButton byRoundingCorners:UIRectCornerBottomLeft|UIRectCornerBottomRight withCornerRadii:CGSizeMake(3.0, 3.0)];
If you want to do it in Swift you could use an extension of a UIView. By doing so, all subclasses will be able to use the following method:
import QuartzCore
extension UIView {
func roundCorner(corners: UIRectCorner, radius: CGFloat) {
let maskPath = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
let maskLayer = CAShapeLayer()
maskLayer.frame = bounds
maskLayer.path = maskPath.CGPath
layer.mask = maskLayer
}
}
Example usage:
self.anImageView.roundCorner(.topRight, radius: 10)
Extending the accepted answer, let us add backward compatibility to it. Prior to iOS 11, view.layer.maskedCorners is not available. So we can do like this
if #available(iOS 11.0, *) {
myView.layer.maskedCorners = [.layerMinXMinYCorner,.layerMaxXMinYCorner]
} else {
myView.maskByRoundingCorners([.topLeft, .topRight])
}
extension UIView{
func maskByRoundingCorners(_ masks:UIRectCorner, withRadii radii:CGSize = CGSize(width: 10, height: 10)) {
let rounded = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: masks, cornerRadii: radii)
let shape = CAShapeLayer()
shape.path = rounded.cgPath
self.layer.mask = shape
}
}
We have written maskByRoundingCorners as an UIView extension so that it improves code reuse.
Credits to #SachinVsSachin and #P.L :) I have combined their codes to make it better.
UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(5, 5, self.bounds.size.width-10, self.bounds.size.height-10)
byRoundingCorners:UIRectCornerAllCorners
cornerRadii:CGSizeMake(12.0, 12.0)];
change "AllCorners" according to your need.
All the solutions provided achieves the goal. But, UIConstraints can blow this up sometimes.
For example, the bottom corners needs to be rounded. If height or
bottom spacing constraint are set to the UIView that needs to be rounded, the
code snippets that rounds the corners needs to be moved to
viewDidLayoutSubviews method.
Highlighting:
UIBezierPath *maskPath = [UIBezierPath
bezierPathWithRoundedRect:roundedView.bounds byRoundingCorners:
(UIRectCornerTopRight | UIRectCornerBottomRight) cornerRadii:CGSizeMake(16.0, 16.0)];
The code snippet above will only round the top right corner if this code set in viewDidLoad. Because roundedView.bounds is going to change after the constraints updates the UIView.
Create a mask and set it on the view's layer
Starting with your code, you might go with something like the snippet below.
I'm not sure if this is the sort of result you're after. Worth noting, too, that if/when the system calls drawRect: again, asking for only part of the rect to be redrawn, this is going to behave very strangely. Nevan's approach, noted above, might be a better way to go.
// make sure the view's background is set to [UIColor clearColor]
- (void)drawRect:(CGRect)rect
{
CGFloat radius = 10.0;
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(context, rect.size.width/2, rect.size.height/2);
CGContextRotateCTM(context, M_PI); // rotate so image appears right way up
CGContextTranslateCTM(context, -rect.size.width/2, -rect.size.height/2);
CGContextBeginPath(context);
CGContextMoveToPoint(context, rect.origin.x, rect.origin.y);
CGContextAddArc(context, rect.origin.x + radius, rect.origin.y + rect.size.height - radius, radius, M_PI, M_PI / 2, 1);
CGContextAddArc(context, rect.origin.x + rect.size.width - radius, rect.origin.y + rect.size.height - radius, radius, M_PI / 2, 0.0f, 1);
CGContextAddLineToPoint(context, rect.origin.x + rect.size.width, rect.origin.y);
CGContextClip(context);
// now do your drawing, e.g. draw an image
CGImageRef anImage = [[UIImage imageNamed:#"image.jpg"] CGImage];
CGContextDrawImage(context, rect, anImage);
}
A slightly hacky, but relatively simple (no subclassing, masking, etc) way to this is to have two UIViews. Both with clipToBounds = YES. Set rounded corners on the child view, then position it within the parent view so the corners you want straight are cropped.
UIView* parent = [[UIView alloc] initWithFrame:CGRectMake(10,10,100,100)];
parent.clipsToBounds = YES;
UIView* child = [[UIView alloc] new];
child.clipsToBounds = YES;
child.layer.cornerRadius = 3.0f;
child.backgroundColor = [UIColor redColor];
child.frame = CGRectOffset(parent.bounds, +4, -4);
[parent addSubView:child];
Doesn't support the case where you want two diagonally opposite corners rounded.
Bezier path is the anwer, if you need additional code this one worked for me: https://stackoverflow.com/a/13163693/936957
UIBezierPath *maskPath;
maskPath = [UIBezierPath bezierPathWithRoundedRect:_backgroundImageView.bounds
byRoundingCorners:(UIRectCornerBottomLeft | UIRectCornerBottomRight)
cornerRadii:CGSizeMake(3.0, 3.0)];
CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.frame = self.bounds;
maskLayer.path = maskPath.CGPath;
_backgroundImageView.layer.mask = maskLayer;
[maskLayer release];
UIBezierPath solution.
- (void) drawRect:(CGRect)rect {
[super drawRect:rect];
//Create shape which we will draw.
CGRect rectangle = CGRectMake(2,
2,
rect.size.width - 4,
rect.size.height - 4);
//Create BezierPath with round corners
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:rectangle
byRoundingCorners:UIRectCornerTopLeft | UIRectCornerTopRight
cornerRadii:CGSizeMake(10.0, 10.0)];
//Set path width
[maskPath setLineWidth:2];
//Set color
[[UIColor redColor] setStroke];
//Draw BezierPath to see it
[maskPath stroke];
}
This can only work if some things are set correctly:
clipsToBounds must be set to YES
opaque has to be NO
backgroundColor should be "clearColor" (i am not fully sure on this)
contentMode has to be "UIContentModeRedraw" as drawRect is not called often if it's not
[super drawRect:rect] has to be called after the CGContextClip
Your view may not contain arbitrary subviews (not sure on this)
Be sure to set "needsDisplay:" at least once to trigger your drawrect
I realize that you're trying to round the top two corners of a UITableView, but for some reason I've found that the best solution is to use:
self.tableView.layer.cornerRadius = 10;
Programmatically it should round all four corners, but for some reason it only rounds the top two. **Please see the screenshot below to see the effect of the code I've written above.
I hope this helps!
You probably have to clip to bounds. Add the line
self.clipsToBounds = YES
somewhere in the code to set that property.

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