I'm drawing a UIBezierPath into a CAShapeLayer, because I want to use strokeStart and strokeEnd to control which sections of the path are drawn. Everything works fine except lineDashPattern is being ignored. What am I doing wrong?
I have tried using setLineDash on the UIBezierPath itself. It works if I stroke the path directly into the context (using [path stroke]), but doesn't help if I assign the CGPath to the shapeLayer, which is what I need.
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)context
{
UIGraphicsPushContext(context);
CAShapeLayer *shapeLayer = (CAShapeLayer *)layer;
UIBezierPath *path = [MyMapPath pathForMap:nil];
shapeLayer.path = path.CGPath;
shapeLayer.fillColor = [[UIColor clearColor] CGColor];
shapeLayer.strokeColor = [[UIColor redColor] CGColor];
shapeLayer.lineWidth = 6.0f;
shapeLayer.lineDashPattern = #[#2,#2];
shapeLayer.strokeStart = 0.0f;
shapeLayer.strokeEnd = 0.7f;
UIGraphicsPopContext();
}
Related
I need to draw a separator line with some dots on it. I have decided I will do this using the draw method, as opposed to including images of the separator. I will do this for performance and for customisability, as the separator changes sometimes.
Now I have looked into the draw() method on UIView and I have noticed that Apple suggests using GLKView when drawing using OpenGL.
For a simple separator, won't it be too much of a hassle to call OpenGL? Or is the OpenGL overhead negligible? When would I want to use the native UIKit draw() then?
FYI I don't know either method, but want to learn both methods, so don't reply "what you know best". I am simply asking about performance.
OpenGL uses GPU instead of CPU for computation. If you are making something like a gaming app, then you can think of using OpenGL. I believe you want to draw a line in an iOS App. For that you can either use drawRect method in UIView or create a shapeLayer and add it as a sublayer.
The following examples will show you:
CAShapeLayer *simpleLine = [CAShapeLayer layer];
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(0, 80)];
[path addLineToPoint:CGPointMake(300, 80)];
simpleLine.lineWidth = 1.0;
simpleLine.path = path.CGPath;
simpleLine.strokeColor = [[UIColor blackColor] CGColor];
[[self.view layer] addSublayer:simpleLine];
For using drawRect, you are supposed to do this inside a Custom UIView as opposed to the above method.
- (void)drawRect:(CGRect)rect {
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(0, 80)];
[path addLineToPoint:CGPointMake(300, 80)];
path.lineWidth = 1.0;
[[UIColor blueColor] setStroke];
[path stroke];
}
If your separator parameters changes and if you are making an app, it's better to use drawRect method. You can call this method anytime by using [CustomUIView setNeedsDisplay:YES]
Edit
What you're asking for is circle over line. You can do that by drawing UIBezierPath for line first and then add UIBezierPath for circle later.
Normal Line
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(10.0, 10.0)];
[path addLineToPoint:CGPointMake(100.0, 100.0)];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = [path CGPath];
shapeLayer.strokeColor = [[UIColor redColor] CGColor];
shapeLayer.lineWidth = 3.0;
shapeLayer.fillColor = [[UIColor clearColor] CGColor];
[self.view.layer addSublayer:shapeLayer];
Dotted Line
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(10.0, 10.0)];
[path addLineToPoint:CGPointMake(100.0, 100.0)];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = [path CGPath];
shapeLayer.strokeColor = [[UIColor redColor] CGColor];
shapeLayer.lineWidth = 3.0;
shapeLayer.fillColor = [[UIColor clearColor] CGColor];
shapeLayer.lineDashPattern = #[#4, #2];
[self.view.layer addSublayer:shapeLayer];
I read this post Draw dotted (not dashed!) line, with IBDesignable in 2017 about drawing a dotted line (rather than a dashed line). However, I am not too familiar with graphics generally and I'm wondering how I can do this with a CALayer (so I don't have to do the whole get current graphics context thing).
I am trying to produce a dotted line that looks like this (the white part, ignore the background):
Here's the code I have working to produce a dotted line:
CAShapeLayer *shapelayer = [CAShapeLayer layer];
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:startPoint];
[path addLineToPoint:endPoint];
[path setLineCapStyle:kCGLineCapRound];
UIColor *fill = [UIColor whiteColor];
shapelayer.strokeStart = 0.0;
shapelayer.strokeColor = fill.CGColor;
shapelayer.lineWidth = 4.0;
shapelayer.lineJoin = kCALineJoinRound;
shapelayer.lineDashPattern = [NSArray arrayWithObjects:[NSNumber numberWithInt:4],[NSNumber numberWithInt:6 ], nil];
shapelayer.path = path.CGPath;
return shapelayer;
How can I mirror the code in the SO post I referenced but continue using a CALayer?
I tried modifying the code from that post like so:
UIBezierPath * path = [[UIBezierPath alloc] init];
[path moveToPoint:startPoint];
[path addLineToPoint:endPoint];
[path setLineWidth:8.0];
CGFloat dashes[] = { path.lineWidth, path.lineWidth * 2 };
[path setLineDash:dashes count:2 phase:0];
[path setLineCapStyle:kCGLineCapRound];
[path stroke];
CAShapeLayer *returnLayer = [CAShapeLayer layer];
returnLayer.path = path.CGPath;
return returnLayer;
However, this ends up drawing nothing.
I hope this will help you.
CAShapeLayer *circleLayer = [CAShapeLayer layer];
[circleLayer setPath:[[UIBezierPath bezierPathWithOvalInRect:CGRectMake(50, 50, 100, 100)] CGPath]];
circleLayer.lineWidth = 2.0;
[circleLayer setStrokeColor:[[UIColor redColor] CGColor]];
[circleLayer setFillColor:[[UIColor clearColor] CGColor]];
circleLayer.lineJoin = kCALineJoinRound;
circleLayer.lineDashPattern = [NSArray arrayWithObjects:[NSNumber numberWithInt:2],[NSNumber numberWithInt:3 ], nil];
// self.bgImage is parentView
[[self.bgImage layer] addSublayer:circleLayer];
self.bgImage.layer.borderWidth = 1.0f;
self.bgImage.layer.borderColor = [[UIColor blueColor]CGColor];
I have attached the output of the image
In my case I had to set the lineCapStyle rather than the lineJoinStyle.
I am new to painting app ,so please suggest me is there any way to remove.
i was googled i am only getting
CGContextSetBlendMode(_context, kCGBlendModeClear);
but not for CAShape layer
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(touchPoint.x,touchPoint.y)];
[path addLineToPoint:CGPointMake(startingPoint.x,startingPoint.y)];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = [path CGPath];
// shapeLayer.strokeColor =kCGBlendModeClear;
if([UIDevice currentDevice].userInterfaceIdiom ==UIUserInterfaceIdiomPad)
{
shapeLayer.lineWidth = 7.0;
}
else
{
shapeLayer.lineWidth = 5.0;
}
shapeLayer.fillColor = [[UIColor clearColor] CGColor];
[self.layer addSublayer:shapeLayer];
[clearBeizer addObject:shapeLayer];
please help me to remove that layer thanks.
I am having an app in which I am doing some calculations and based on that I want to draw a traverse like shown below.
Here is an image of the traverse.
I have distance of AB, BC and so on.
Based on this values I need to draw an image shown above.
I know how to draw a line using UIBezierPath and using the below code.
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(100.0, 100.0)];
[path addLineToPoint:CGPointMake(100.0, 100.0)];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = [path CGPath];
shapeLayer.strokeColor = [[UIColor blueColor] CGColor];
shapeLayer.lineWidth = 3.0;
shapeLayer.fillColor = [[UIColor clearColor] CGColor];
But how to draw this with this calculations. I am confused with it. I just want some guidance on it.
My main aim is to draw image with the design pattern shown below.
EDIT
I have a distance of 50.0 and an angle of 37 for line AB. How to draw a line AB from that?
Please help.
Any help will be appreciated. Thanks.
Example:
- (void)drawTraverseWithFirstPoint:(CGPoint)firstPoint secondPoint:(CGPoint)point thirdPoint:(CGPoint)thirdPoint fourthPoint:(CGPoint)fourthPoint andLastPoint:(CGPointLastPoint) {
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:your_start_point];
[path addLineToPoint:firstPoint];
[path addLineToPoint:secondPoint];
[path addLineToPoint:thirdPoint];
[path addLineToPoint:fourthPoint];
[path addLineToPoint:lastPoint];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = [path CGPath];
shapeLayer.strokeColor = [[UIColor blueColor] CGColor];
shapeLayer.lineWidth = 3.0;
shapeLayer.fillColor = [[UIColor clearColor] CGColor];
}
Just do the calculations first and pass it as paramethers or pass an Array with points however it is easier for you, i hope you will understand my example good day.
I am drawing a line using UIBezierPath
[path moveToPoint:CGPointMake(xco2, yco2)];
[path addLineToPoint:CGPointMake(xco, yco)];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = [path CGPath];
shapeLayer.strokeColor = [[UIColor whiteColor] CGColor];
shapeLayer.lineWidth = 3.0;
shapeLayer.fillColor = [[UIColor clearColor] CGColor];
[self.view.layer addSublayer:shapeLayer];
this is the code snippet by which I am drawing lines , but using this code I can only able to draw solid lines , but my client need many customized line like dotted lines , dashed lines etc and other customized lines . I am new in Xcode and I need help to do this
You can use following method's to change line pattern
[shapeLayer setLineDashPattern:[NSArray arrayWithObjects:[NSNumber numberWithInt:10],
[NSNumber numberWithInt:5],nil]];
shapelayer.lineJoin = kCALineJoinMiter;
shapelayer.lineDashPhase = 3.0f;