Hi all I need to realize borders around an UIImageView like these.
Left, top and right border like an half-moon
http://imageshack.com/a/img841/3269/o90p.png
How can i do it ?
You can user CALayer for the same.
CALayer *l = [_btn layer];
[l setMasksToBounds:YES];
[l setCornerRadius:8.0];
and add QuartzCore.framework
You may want to subclass UIView and override the drawRect: method. Then place add your image view as a subview. Your drawRect: method would look something like this (with clipsToBounds set to YES):
- (void)drawRect:(CGRect)rect
{
UIColor *fillColor = [UIColor clearColor];
UIColor *borderColor = [UIColor redColor];
float borderWidth = 2.0f;
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, fillColor.CGColor);
CGContextSetLineWidth(context, borderWidth);
CGContextSetStrokeColorWithColor(context, borderColor.CGColor);
CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMidY(rect));
CGContextAddArc(context, CGRectGetMidX(rect), CGRectGetMidY(rect), rect.size.height/2, 2*M_PI, M_PI, 1);
CGContextClosePath(context);
CGContextDrawPath(context, kCGPathFillStroke);
}
Alternatively you can look into masking with a semicircle image or creating a CAShapeLayer for the image view.
You need to:
Create a CAShapeLayer
Set its path to be a CGPathRef based on view.bounds but with only two rounded corners (probably by using [UIBezierPath
bezierPathWithRoundedRect:byRoundingCorners:cornerRadii:])
Set your view.layer.mask to be the CAShapeLayer
Just take in account that this have a bad effect on performance. This might help
Related
I have the following piece of code to round only specific corners of a view:
- (void)roundOnlySpecifiedCornersInView:(UIView *)view corners:(UIRectCorner)corners
{
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:(corners) cornerRadii:CGSizeMake(4.0, 4.0)];
CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.path = maskPath.CGPath;
view.layer.mask = maskLayer;
}
This works perfectly in isolation. Now I also want shadow in my view, but I specifically want to apply shadow in different cases:
on all sides
all sides except bottom
all sides except top
left/right sides only
All techniques I encountered work by creating an inset of the view. The problem with this, is that, say you want to only keep shadow on left/right sides, you offset bottom and top. Since the Rect is now less high, the shadow at the left and right does not cover the full height of the view. Also, the mask layer used for rounding corners causes the shadow to no longer appear.
Example code for this:
innerView.layer.shadowColor = [[UIColor colorWithWhite:0.0f alpha:0.1f] CGColor];
innerView.layer.shadowOpacity = 1.0f;
innerView.layer.shadowOffset = CGSizeMake(0.0f, 0.0f);
innerView.layer.shadowRadius = 6.0f;
CGRect shadowFrame = UIEdgeInsetsInsetRect(innerView.bounds, UIEdgeInsetsMake(9, 0, 9, 0));
CGPathRef shadowPath = [UIBezierPath bezierPathWithRect:shadowFrame].CGPath;
innerView.layer.shadowPath = shadowPath;
How can I round specific corners in a view and at the same time show shadow only at specified sides?
Answers in Swift are appreciated too!
Screenshot of what I want (this one is easy since all corners need to be rounded so I can use .layer.cornerRadius and it has shadow at all sides):
Now I just want to round only 2 of the corners (top left and top right, bottom left and bottom right) and add shadow to only some sides.
I'm not sure if it meet your demand. The code create an image with top and bottom shadow, and all rounding corner, you can modify the code to achieve what you need. You can use the image as the background of your cell(It's seems that it is UITableViewCell)
Let me know if it don't work for you.
The image:
// create a shadow image
CGSize size = CGSizeMake(ScreenWidth, ScreenWidth);
UIGraphicsBeginImageContextWithOptions(size, NO, 0);
CGContextRef context = UIGraphicsGetCurrentContext();
UIColor *backgroundColor = [UIColor colorWithRed:246.0/255.0 green:246.0/255.0 blue:246.0/255.0 alpha:1.0];
UIColor *fillColor = [UIColor whiteColor];
CGRect rect = CGRectMake(10, 10, 100, 44);
// re-draw the background
CGContextSetFillColorWithColor(context, backgroundColor.CGColor);
CGContextFillRect(context, CGRectMake(0, 0, size.width, size.height));
// set top and bottom shadow
CGRect rectTop = CGRectMake(rect.origin.x, rect.origin.y, rect.size.width, 5);
CGContextSaveGState(context);
CGContextSetShadowWithColor(context, CGSizeMake(0, -5), 5, [UIColor colorWithRed:0 green:0 blue:0 alpha:0.1].CGColor);
CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
CGContextFillRect(context, rectTop);
CGContextRestoreGState(context);
CGRect rectBottom = CGRectMake(rect.origin.x, rect.origin.y+rect.size.height-5, rect.size.width, 5);
CGContextSaveGState(context);
CGContextSetShadowWithColor(context, CGSizeMake(0, 5), 5, [UIColor colorWithRed:0 green:0 blue:0 alpha:0.1].CGColor);
CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
CGContextFillRect(context, rectBottom);
CGContextRestoreGState(context);
// re-draw the background
CGContextSetFillColorWithColor(context, backgroundColor.CGColor);
CGContextFillRect(context, rect);
CGContextSaveGState(context);
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:UIRectCornerAllCorners cornerRadii:CGSizeMake(4.0, 4.0)];
[maskPath addClip];
CGContextSetFillColorWithColor(context, fillColor.CGColor);
CGContextFillRect(context, rect);
CGContextRestoreGState(context);
You can modify the code to get a top left shadow:
// create a shadow image
CGSize size = CGSizeMake(ScreenWidth, ScreenWidth);
UIGraphicsBeginImageContextWithOptions(size, NO, 0);
CGContextRef context = UIGraphicsGetCurrentContext();
UIColor *backgroundColor = [UIColor colorWithRed:246.0/255.0 green:246.0/255.0 blue:246.0/255.0 alpha:1.0];
UIColor *fillColor = [UIColor whiteColor];
CGRect rect = CGRectMake(10, 10, 100, 44);
// re-draw the background
CGContextSetFillColorWithColor(context, backgroundColor.CGColor);
CGContextFillRect(context, CGRectMake(0, 0, size.width, size.height));
// set top and left shadow
CGRect rectTop = CGRectMake(rect.origin.x, rect.origin.y, rect.size.width, 5);
CGContextSaveGState(context);
CGContextSetShadowWithColor(context, CGSizeMake(0, -5), 5, [UIColor colorWithRed:0 green:0 blue:0 alpha:0.1].CGColor);
CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
CGContextFillRect(context, rectTop);
CGContextRestoreGState(context);
CGRect rectLeft = CGRectMake(rect.origin.x, rect.origin.y, 5, rect.size.height);
CGContextSaveGState(context);
CGContextSetShadowWithColor(context, CGSizeMake(-5, 0), 5, [UIColor colorWithRed:0 green:0 blue:0 alpha:0.1].CGColor);
CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
CGContextFillRect(context, rectLeft);
CGContextRestoreGState(context);
// re-draw the background
CGContextSetFillColorWithColor(context, backgroundColor.CGColor);
CGContextFillRect(context, rect);
CGContextSaveGState(context);
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:UIRectCornerAllCorners cornerRadii:CGSizeMake(4.0, 4.0)];
[maskPath addClip];
CGContextSetFillColorWithColor(context, fillColor.CGColor);
CGContextFillRect(context, rect);
CGContextRestoreGState(context);
HTH
In many, many cases you would want to achieve this with drawing the shadow, of course. However, you may consider the following approach: using a stretchable image with the shadow just on the sides that you need, e.g. something similar to (this one has shadow on all sides though):
Just before you say: "Ewwwww! He's using an image for a simple shadow!" let me emphasise that this will work much better in terms of performance. For instance, if you have a lot of cells in a UICollectionView and each one is re-drawing its shadow it could significantly slow down your app during scrolling, whereas with an image-based shadow it's going to be essentially the same.
I would go even further and suggest that you could actually use a stretchable image for masking the view with rounded corners, too! Now, this may look like going a bit too far, but if you notice a drastic decrease in performance I would give it a shot. What you essentially need to do is prepare another stretchable image with a transparent "middle" part and rounded corners of the same colour as your background. Something like:
And again, before you downvote this bizarre way of doing something that can be easily achieved with two lines of code...
view.layer.cornerRadius = 20
view.layer.masksToBounds = true
...Let me point out that this will work ridiculously faster in cases when you have to display a bunch of those masked views simultaneously: for instance, masking UICollectionViewCells. Basically, if you set a mask on a UIView's layer, this mask is going to be re-calculated and applied in real time, which would cost you a lot in terms of performance during frequent redrawing of the UIView contents — when scrolling a UITableView or UICollectionView, for example.
Obviously this wouldn't work if your background is not of a solid colour, and has a gradient for instance. However, in many other cases this may help you achieve much smoother UI performance. Another advantage in your particular case is that you can easily control which corners to mask and where the shadow should drop.
Again, I'm not implying that this is the way to go in each and every case. What I'm saying is that there are a lot of cases when this could help increase the performance significantly: for example, if you are masking far too many views that are rendered on the screen at the same time, and the layout is expected to be redrawn frequently.
for specific corner set corner radius
refer from : how to set cornerRadius for only top-left and top-right corner of a UIView?
UIBezierPath *maskPath;
maskPath = [UIBezierPathbezierPathWithRoundedRect:_backgroundImageView.bounds
byRoundingCorners:(UIRectCornerBottomLeft|UIRectCornerBottomRight)
cornerRadii:CGSizeMake(3.0, 3.0)];
CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.frame = self.bounds;
maskLayer.path = maskPath.CGPath;
_imageView.layer.mask = maskLayer;
[maskLayer release];
I am trying to draw a Bezier path, an arc of a given angle, in response to a pan gesture. Here's what I have inside the function called by the pan gesture:
UIGraphicsBeginImageContext(self.frame.size);
UIBezierPath *path = [self createArcPath];
[[UIColor blackColor] setStroke];
[[UIColor redColor] setFill];
CGContextRef *ref = UIGraphicsGetCurrentContext();
path.lineWidth = 5;
[path fill];
[path stroke];
UIGraphicsEndImageContext();
And here is createArcPath:
- (UIBezierPath *)createArcPath
{
UIBezierPath *aPath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150)
radius:75
startAngle:0
endAngle:DEGREES_TO_RADIANS(135)
clockwise:YES];
return aPath;
}
I don't get an error, but I just don't get anything on my screen relating to the arc. What am I missing? This is in a method of a UIView subclass.
I also tried the following method in - (id)initWithFrame:
UIColor *color =[UIColor redColor];
UIGraphicsBeginImageContext(self.frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, width);
CGContextSetFillColorWithColor(context, color.CGColor);
CGContextSetStrokeColorWithColor(context, color.CGColor);
CGRect myOval = {100, 100, self.radius, self.radius};
CGContextAddEllipseInRect(context, myOval);
UIGraphicsEndImageContext();
I also don't see anything. What am I missing? Can these methods not be called from a UIView?
The UIGraphicsBeginImageContext/UIGraphicsEndImageContext calls create an off-screen context that you can draw into, then extract an image from. Since it's an off-screen context nothing shows on the screen.
What you probably want to do is create a custom subclass of UIView that overrides drawRect. In your code that responds to user gestures, change the data structure(s) that represent your drawing, then call setNeedsDisplay to trigger the system to ask your view to redraw itself by calling your drawRect method.
As an alternative you can set up your custom view to install a CAShapeLayer in the view, then change the path on the layer, then call setNeedsDisplay on the layer.
I am overriding drawRect method in order to draw ellipse
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 2.0);
CGContextSetStrokeColorWithColor(context, [UIColor mainColorYellow].CGColor);
CGRect rectangle = CGRectMake(0.0, 2.0, rect.size.width , rect.size.height - 4.0);
CGContextAddEllipseInRect(context, rectangle);
CGContextStrokePath(context);
}
How can I change fill color on ellipse? I tried using CGContextSetFillColorWithColor(CGContextRef c, CGColorRef color) but without result.
There is two different operations, fill and stroke. Stroke es the border, fill is the inside. You are only doing the border. You can control the fill and border color independently. You have, however, to render both explicitly. For example:
[[UIColor yellowColor] setFill];
[[UIColor blackColor] setStroke];
UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0.0, 2.0, rect.size.width , rect.size.height - 4.0)];
path.lineWidth = 2.0;
[path fill];
[path stroke];
Notice I wrote the code in a more modern quartz. The context is implicit. Hope it helps.
Just add below:
CGContextFillEllipseInRect(context, rectangle);
I have a label in my view. Now I want to draw a line above the label, which means you can see the label is under the line.
So far I can draw a line using quartz2D but always under the label. Is there any way to solve my problems?
You can create a CAShapeLayer like this:
CAShapeLayer *lineLayer = [CAShapeLayer layer];
lineLayer.frame = self.label.bounds;
lineLayer.strokeColor = [UIColor redColor].CGColor;
CGRect rect = CGRectMake(0, CGRectGetMidY(lineLayer.bounds), lineLayer.bounds.size.width, 2);
lineLayer.path = [UIBezierPath bezierPathWithRect:rect].CGPath;
And then add it to the UILabel like this:
[self.label.layer addSublayer:lineLayer];
To be honest, the easiest thing to do is to create a 2x2 pixel image called line#2x.png, and have the bottom 2 pixels black, the top 2 transparent, then use it as the background image for an image view. Stretch the image view to whatever width you need by using it as a pattern image. The 1x image should be a 1x1px, all black.
UIView *lineView = [[UIView alloc] initWithFrame:frame]; // Whatever frame the line needs
// Add the line image as a pattern
UIColor *patternColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"line.png"]];
lineView.backgroundColor = patternColor;
[self.view addSubview:lineView];
If this is a label you will be using a lot, you could make a sub-class of UILabel and override the drawRect function.
- (void) drawRect:(CGRect)r
{
[super drawRect:r];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
CGContextSetLineWidth(context, 1.0);
CGContextMoveToPoint(context, 1.0, 1.0);
CGContextAddLineToPoint(context, self.bounds.size.width - 1.0, 1.0);
CGContextStrokePath(context);
CGContextRestoreGState(context);
}
The advantage here is that the line will be "baked" into the view and only be draw once. Other methods such as CAShapeLayer or UIView will be re-rendered every frame.
For bonus points, you can make the color and line width properties :)
self.myPath=[UIBezierPath bezierPathWithArcCenter:center
radius:200
startAngle:0
endAngle:180
clockwise:YES];
(This much I was able to get up running with some web searching).
I have this path. Now I want to fill the reverse of this path, so leaving this portion and filling everything else. How can I finish the coding? I don't have much info on this.
The problem
The area it is showing after using Cemal Answer previously it only showed a circle with red stroke.
Edit
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
self.backgroundColor = [UIColor whiteColor];
self.punchedOutPath =
[UIBezierPath bezierPathWithOvalInRect:CGRectMake(50, 50, 400, 400)];
self.fillColor = [UIColor redColor];
self.alpha = 0.8;
}
return self;
}
- (void)drawRect:(CGRect)rect
{
[[self fillColor] set];
UIRectFill(rect);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSetBlendMode(ctx, kCGBlendModeDestinationOut);
[[self punchedOutPath] fill];
CGContextSetBlendMode(ctx, kCGBlendModeNormal);
}
Use bezierPathByReversingPath. From the docs (iOS 6.0+ only):
Creates and returns a new bezier path object with the reversed contents of the current path.
so to reverse your path, you'd just:
UIBezierPath* aPath = [UIBezierPath bezierPathWithArcCenter:center
radius:200
startAngle:0
endAngle:180
clockwise:YES];
self.myPath = [aPath bezierPathByReversingPath];
Here's an alternative that doesn't require reversing the path at all.
You have a portion of a view you essentially want to "clip out":
Let's say you want the white area to be [UIColor whiteColor] with 75% alpha. Here's how you do it quickly:
You create a new UIView subclass.
This view has two properties:
#property (retain) UIColor *fillColor;
#property (retain) UIBezierPath *punchedOutPath;
You override its -drawRect: method to do this:
- (void)drawRect:(CGRect)rect {
[[self fillColor] set];
UIRectFill(rect);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSetBlendMode(ctx, kCGBlendModeDestinationOut);
[[self punchedOutPath] fill];
CGContextSetBlendMode(ctx, kCGBlendModeNormal);
}
There's a caveat here: The fillColor of the view must not include the alpha component. So in your case, you'd want that to just be [UIColor whiteColor]. You then apply the alpha bit yourself by calling [myView setAlpha:0.75].
What's going on here: This is using a blend mode called "Destination Out". Mathematically it's defined as R = D*(1 - Sa), but in layman's terms it means "Destination image wherever destination image is opaque but source image is transparent, and transparent elsewhere."
So it's going to use the destination (i.e., what's already in the context) wherever the new stuff is transparent (i.e. outside of the bezier path), and then where the bezier path would be opaque, that stuff is going to become transparent. However, the destination stuff must already be opaque. If it's not opaque, the blending doesn't do what you want. This is why you have to provide an opaque UIColor and then do any transparency you want with the view directly.
I ran this myself, with these circumstances:
the window has a [UIColor greenColor] background
the fillColor is white
the punchedOutPath is a oval that's inset 10 points from the edges of the view.
the view has an alpha of 0.75
With the code above, I get this:
The interior is pure green, and the outside has the semi-transparent overlay.
Update
If your covering is an image, then you'll need to create a new image. But the principle is the same:
UIImage* ImageByPunchingPathOutOfImage(UIImage *image, UIBezierPath *path) {
UIGraphicsBeginImageContextWithOptions([image size], YES, [image scale]);
[image drawAtPoint:CGPointZero];
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSetBlendMode(ctx, kCGBlendModeDestinationOut);
[path fill];
UIImage *final = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return final;
}
You would then take the result of this function and put it into a UIImageView.
You can put this into a single screen app into the view controller: It will make a yellow background view and a blue layer on top of it that has an oval region cut out by a mask.
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
// create a yellow background
UIView *bg = [[UIView alloc] initWithFrame:self.view.bounds];
bg.backgroundColor = [UIColor yellowColor];
[self.view addSubview:bg];
// create the mask that will be applied to the layer on top of the
// yellow background
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.fillRule = kCAFillRuleEvenOdd;
maskLayer.frame = self.view.frame;
// create the paths that define the mask
UIBezierPath *maskLayerPath = [UIBezierPath bezierPath];
[maskLayerPath appendPath:[UIBezierPath bezierPathWithRect:CGRectInset(self.view.bounds, 20, 20)]];
// here you can play around with paths :)
// [maskLayerPath appendPath:[UIBezierPath bezierPathWithOvalInRect:(CGRect){{80, 80}, {140, 190}}]];
[maskLayerPath appendPath:[UIBezierPath bezierPathWithOvalInRect:(CGRect){{100, 100}, {100, 150}}]];
maskLayer.path = maskLayerPath.CGPath;
// create the layer on top of the yellow background
CALayer *imageLayer = [CALayer layer];
imageLayer.frame = self.view.layer.bounds;
imageLayer.backgroundColor = [[UIColor blueColor] CGColor];
// apply the mask to the layer
imageLayer.mask = maskLayer;
[self.view.layer addSublayer:imageLayer];
}
this might answer this question as well: UIBezierPath Subtract Path
I have two solution for you.
Draw this path on a CALayer. And use that CALayer as a mask layer for you actual CALayer.
Draw a rectangle with the sizes of you frame before adding arc.
UIBezierPath *path = [UIBezierPath bezierPathWithRect:view.frame];
[path addArcWithCenter:center
radius:200
startAngle:0
endAngle:2*M_PI
clockwise:YES];
I would use second solution. :)