How to draw at the centre of a subview - ios

I want to draw an arrow at the center of a SubView which is created by
{let arrowView = ArrowView()
arrowView.frame = CGRect(x: selectButton.frame.minX, y: selectButton.frame.maxY, width: selectButton.frame.width, height: processButton.frame.minY - selectButton.frame.maxY)
arrowView.backgroundColor = UIColor.white
arrowView.viewWithTag(100)
view.addSubview(arrowView)
} //these codes are in the view controller
To draw the arrow in the subview I use the
let arrowPath = UIBezierPath.bezierPathWithArrowFromPoint(startPoint: startPoint, endPoint: endPoint, tailWidth: 4, headWidth: 8, headLength: 6)
// the error occurs here
override func draw(_ rect: CGRect) {
let fillColor = UIColor.white
fillColor.setFill()
arrowPath.lineWidth = 1.0
let strokeColor = UIColor.blue
strokeColor.setStroke()
arrowPath.stroke()
arrowPath.fill()
//these codes are in the subclass of UIView
Since I want to draw the arrow at the center of the subview,
I define the startPoint and the endPoint as
private var startPoint: CGPoint {
return CGPoint(x: bounds.midX, y: bounds.minY)
}
private var endPoint: CGPoint {
return CGPoint(x: bounds.midX, y: bounds.maxY)
}
//try to find the point at the centre of Subview
However, this code does not compile and the error says:
Cannot use instance member 'startPoint' within property initializer; property initializers run before 'self' is available
Edit:
I would like to know how the get the bounds of a subview created by code.
I try the "bounds" variable but get the above error.

arrowPath.center = CGPoint(x:arrowView.frame.size.width/2, y: arrowView.frame.size.height/2)
arrowView.addSubview(arrowPath)

Related

Add subview on a parent drawn through UIBezierPath

I've a custom UITabBar. Its bar has a simple but customised shape: its height is bigger then default one, has rounded corners and (important) a shadow layer on the top.
The result is this:
Now I've to add an element that shows the selected section on the top of the bar, to achieve this:
The problem is that no matter the way I choose to add this element (add a subview to the bar or add a new sublayer) but the new element will always be drawn outside the corners. I suppose this is because I can't enable the clipping mask (if I enable the clipping mask I'll kill the shadow and also, more important, the bezierpath)
Do you have any tips for this?
Basically, the goal should be:
have an element that moves horizontally (animated) but cannot be drawn outside the parent (the tabbar)
Actually, the code to draw the custom tabBar is:
class CustomTabBar: UITabBar {
/// The layer that defines the custom shape
private var shapeLayer: CALayer?
/// The radius for the border of the bar
var borderRadius: CGFloat = 0
override func layoutSubviews() {
super.layoutSubviews()
// aspect and shadow
isTranslucent = false
backgroundColor = UIColor.white
tintColor = AZTheme.PaletteColor.primaryColor
shadowImage = nil
layer.masksToBounds = false
layer.shadowColor = UIColor.black.cgColor
layer.shadowOpacity = 0.1
layer.shadowOffset = CGSize(width: 0, height: -1)
layer.shadowRadius = 10
}
override func draw(_ rect: CGRect) {
drawShape()
}
/// Draw and apply the custom shape to the bar
func drawShape() {
let shapeLayer = CAShapeLayer()
shapeLayer.path = createPath()
shapeLayer.fillColor = AZTheme.tabBarControllerBackgroundColor.cgColor
if let oldShapeLayer = self.shapeLayer {
self.layer.replaceSublayer(oldShapeLayer, with: shapeLayer)
} else {
self.layer.insertSublayer(shapeLayer, at: 0)
}
self.shapeLayer = shapeLayer
}
}
// MARK: - Private functions
extension CustomTabBar {
/// Return the custom shape for the bar
internal func createPath() -> CGPath {
let height: CGFloat = self.frame.height
let path = UIBezierPath()
path.move(to: CGPoint(x: 0, y: 0))
path.addArc(withCenter: CGPoint(x: borderRadius, y: 0), radius: borderRadius, startAngle: CGFloat.pi, endAngle: CGFloat.pi * (3/2), clockwise: true)
path.addLine(to: CGPoint(x: frame.width - borderRadius, y: -borderRadius))
path.addArc(withCenter: CGPoint(x: frame.width - borderRadius, y: 0), radius: borderRadius, startAngle: CGFloat.pi * (3/2), endAngle: 0, clockwise: true)
path.addLine(to: CGPoint(x: frame.width, y: height))
path.addLine(to: CGPoint(x: 0, y: height))
path.close()
return path.cgPath
}
}
I solved splitting the owner of custom shape from the owner of the shadow in 2 different views. So I'm using 3 views achieve the goal.
CustomTabBar: has default size and casts shadow with offset.
|
└ SelectorContainer: is a view with custom shape (BezierPath) that is
positioned on the top of the TabBar to graphically "extend" the view
and have the feeling of a bigger TabBar. It has rounded corners on
the top-right, top-left margin. MaskToBounds enabled.
|
└ Selector: simple view that change the its origin through animation.
See the result here
The code:
class CustomTabBar: UITabBar {
/// The corner radius value for the top-left, top-right corners of the TabBar
var borderRadius: CGFloat = 0
/// Who is containing the selector. Is a subview of the TabBar.
private var selectorParent: UIView?
/// Who moves itself following the current section. Is a subview of ```selectorParent```.
private var selector: UIView?
/// The height of the ```selector```
private var selectorHeight: CGFloat = 5
/// The number of sections handled by the TabBarController.
private var numberOfSections: Int = 0
override func layoutSubviews() {
super.layoutSubviews()
isTranslucent = false
backgroundColor = UIColor.white
tintColor = AZTheme.PaletteColor.primaryColor
shadowImage = nil
layer.masksToBounds = false
layer.shadowColor = UIColor.black.cgColor
layer.shadowOpacity = 0.1
layer.shadowOffset = CGSize(width: 0, height: -1)
layer.shadowRadius = 10
}
}
// MARK: - Private functions
extension CustomTabBar {
/// Create the selector element on the top of the TabBar
func setupSelectorView(numberOfSections: Int) {
self.numberOfSections = numberOfSections
// delete previous subviews (if exist)
if let selectorContainer = self.selectorParent {
selectorContainer.removeFromSuperview()
self.selector?.removeFromSuperview()
self.selectorParent = nil
self.selector = nil
}
// SELECTOR CONTAINER
let selectorContainerRect: CGRect = CGRect(x: 0,
y: -borderRadius,
width: frame.width,
height: borderRadius)
let selectorContainer = UIView(frame: selectorContainerRect)
selectorContainer.backgroundColor = UIColor.white
selectorContainer.AZ_roundCorners([.topLeft, .topRight], radius: borderRadius)
selectorContainer.layer.masksToBounds = true
self.addSubview(selectorContainer)
// SELECTOR
let selectorRect: CGRect = CGRect(x: 0,
y: 0,
width: selectorContainer.frame.width / CGFloat(numberOfSections),
height: selectorHeight)
let selector = UIView(frame: selectorRect)
selector.backgroundColor = AZTheme.PaletteColor.primaryColor
selectorContainer.addSubview(selector)
// add views to hierarchy
self.selectorParent = selectorContainer
self.selector = selector
}
/// Animate the position of the selector passing the index of the new section
func animateSelectorTo(sectionIndex: Int) {
guard let selectorContainer = self.selectorParent, let selector = self.selector else { return }
selector.layer.removeAllAnimations()
let sectionWidth: CGFloat = selectorContainer.frame.width / CGFloat(numberOfSections)
let newCoord = CGPoint(x: sectionWidth * CGFloat(sectionIndex), y: selector.frame.origin.y)
UIView.animate(withDuration: 0.25, delay: 0, options: UIView.AnimationOptions.curveEaseOut, animations: { [weak self] in
self?.selector?.frame.origin = newCoord
}, completion: nil)
}
}

Adding the same layer in a subview changes its visual position

I added a subview (with a black border) in a view and centered it.
Then I generate 2 identical triangles with CAShapeLayer and add one to the subview and the other to the main view.
Here is the visual result in Playground where we can see that the green triangle is totally off and should have been centered.
And here is the code:
let view = UIView()
let borderedView = UIView()
var containedFrame = CGRect(x: 0, y: 0, width: 100, height: 100)
func setupUI() {
view.frame = CGRect(x: 0, y: 0, width: 300, height: 600)
view.backgroundColor = .white
borderedView.frame = containedFrame
borderedView.center = view.center
borderedView.backgroundColor = .clear
borderedView.layer.borderColor = UIColor.black.cgColor
borderedView.layer.borderWidth = 1
view.addSubview(borderedView)
setupTriangles()
}
private func setupTriangles() {
view.layer.addSublayer(createTriangle(color: .red)) // RED triangle
borderedView.layer.addSublayer(createTriangle(color: .green)) // GREEN triangle
}
private func createTriangle(color: UIColor) -> CAShapeLayer {
let layer = CAShapeLayer()
let bezierPath = UIBezierPath()
bezierPath.move(to: CGPoint(x: 0, y: 0))
bezierPath.addLine(to: CGPoint(x: -containedFrame.width, y: 0))
bezierPath.addLine(to: CGPoint(x: 0, y: -containedFrame.height))
bezierPath.close()
layer.position = borderedView.center
layer.path = bezierPath.cgPath
layer.fillColor = color.cgColor
return layer
}
Note: All position (of view, the borderedView and both triangles) are the same (150.0, 300.0)
Question: Why is the green layer not in the right position?
#DuncanC is right that each view has its own coordinate system. Your problem is this line:
layer.position = borderedView.center
That sets the layer's position to the center of the frame for the borderedView which is in the coordinate system of view. When you create the green triangle, it needs to use the coordinate system of borderedView.
You can fix this by passing the view to your createTriangle function, and then use the center of the bounds of that view as the layer position:
private func setupTriangles() {
view.layer.addSublayer(createTriangle(color: .red, for: view)) // RED triangle
borderedView.layer.addSublayer(createTriangle(color: .green, for: borderedView)) // GREEN triangle
}
private func createTriangle(color: UIColor, for view: UIView) -> CAShapeLayer {
let layer = CAShapeLayer()
let bezierPath = UIBezierPath()
bezierPath.move(to: CGPoint(x: 0, y: 0))
bezierPath.addLine(to: CGPoint(x: -containedFrame.width, y: 0))
bezierPath.addLine(to: CGPoint(x: 0, y: -containedFrame.height))
bezierPath.close()
layer.position = CGPoint(x: view.bounds.midX, y: view.bounds.midY)
layer.path = bezierPath.cgPath
layer.fillColor = color.cgColor
return layer
}
Note: When you do this, the green triangle appears directly below the red one, so it isn't visible.
Every view/layer uses the coordinate system of it's superview/superlayer. If you add a layer to self.view.layer, it will be positioned in self.view.layer's coordinate system. If you add a layer to borderedView.layer, it will be in borderedView.layer's coordinate system.
Think of the view/layer hierarchy as stacks of pieces of graph paper. You place a new piece of paper on the current piece (the superview/layer) in the current piece's coordinates system, but then if you draw on the new view/layer, or add new views/layer inside that one, you use the new view/layer's coordinate system.

How to reference BezierPath in a UIView

I am trying to detect Taps inside BezierPaths in a UIView and have found many references to the containsPoint method. However I cannot seem to find how to actually reference the BezierPaths from my ViewController.
I have set up:
class func drawSA(frame targetFrame: CGRect = CGRect(x: 0, y: 0, width: 69, height: 107), resizing: ResizingBehavior = .aspectFit, SACountries: [String: ViewController.CountryStruct])
{
let myPath = UIBezierPath()
myPath.move(to: CGPoint(x: 32.24, y: 8.61))
myPath.addLine(to: CGPoint(x: 31.99, y: 8.29))
myPath.addLine(to: CGPoint(x: 31.78, y: 8.19))
myPath.close()
}
The Beziers are drawn in this function, called by:
override func draw(_ rect: CGRect)
In the main ViewController, I have the following function for detecting a Tap on the UIView:
#objc func SATap(sender: UITapGestureRecognizer)
{
let location = sender.location(in: self.SAView)
// how do I call containsPoint from here?
}
How do I call containsPoint from here?
The bezierPaths are drawn correctly at runtime.
As the Paths are created in a Class Function within a separate Class, I cannot save them to the View directly.
I solved this by putting the UIBezierPaths into a Dictionary and then return the Dictionary. An Array would work too, but this way I can access specific Paths easily.
class func drawSA(frame targetFrame: CGRect = CGRect(x: 0, y: 0, width: 71, height: 120), resizing: ResizingBehavior = .aspectFit, SACountries: [String: ViewController.CountryStruct]) -> ([String: UIBezierPath])
{
var Paths = [String: UIBezierPath]()
let myPath = UIBezierPath()
myPath.move(to: CGPoint(x: 32.24, y: 8.61))
myPath.addLine(to: CGPoint(x: 31.99, y: 8.29))
myPath.addLine(to: CGPoint(x: 31.78, y: 8.19))
myPath.close()
Paths["mP"] = myPath
let myPath2 = UIBezierPath()
myPath2.move(to: CGPoint(x: 32.24, y: 8.61))
myPath2.addLine(to: CGPoint(x: 31.99, y: 8.29))
myPath2.addLine(to: CGPoint(x: 31.78, y: 8.19))
myPath2.close()
Paths["mP2"] = myPath2
return Paths
}
I then used View.addLayer to create Layers in the View and added the Layer.name property to each Layer when creating them with a For In Loop on the Dictionary:
for path in Paths.keys.sorted()
{
self.layer.addSublayer(CreateLayer(path)) // The Function simply creates a CAShapeLayer
}
I then used the Dictionary in the Gesture Function:
#objc func ATap(sender: UITapGestureRecognizer)
{
let location = sender.location(in: self.SAView)
// You need to Scale Location if your CAShapeLayers are Scaled
for path in SAView.Paths
{
let value = path.value
value.contains(location)
if value.contains(location)
{
for (index, layer) in SAView.layer.sublayers!.enumerated()
{
if layer.name == path.key
{
// Do something when specific layer is Tapped
}
}
}
}
}
There may well be better ways of doing this, but it's all working and performs well.

Swift textfields without border

I am new to swift. Your help will be really appreciated.
I have two textfields in my application. How would I create same UI as given in the pic below.
I want to create textfields with only one below border as given in the screenshot.
https://www.dropbox.com/s/wlizis5zybsvnfz/File%202017-04-04%2C%201%2052%2024%20PM.jpeg?dl=0
#IBOutlet var textField: UITextField! {
didSet {
let border = CALayer()
let width: CGFloat = 1 // this manipulates the border's width
border.borderColor = UIColor.darkGray.cgColor
border.frame = CGRect(x: 0, y: textField.frame.size.height - width,
width: textField.frame.size.width, height: textField.frame.size.height)
border.borderWidth = width
textField.layer.addSublayer(border)
textField.layer.masksToBounds = true
}
}
Create a subclass of UITextField so you can reuse this component across multiple views without have to re implement the drawing code. Expose various properties via #IBDesignable and #IBInspectable and you can have control over color and thickness in the story board. Also - implement a "redraw" on by overriding layoutSubviews so the border will adjust if you are using auto layout and there is an orientation or perhaps constraint based animation. That all said - effectively your subclass could look like this:
import UIKit
class Field: UITextField {
private let border = CAShapeLayer()
#IBInspectable var color: UIColor = UIColor.blue {
didSet {
border.strokeColor = color.cgColor
}
}
#IBInspectable var thickness: CGFloat = 1.0 {
didSet {
border.lineWidth = thickness
}
}
override func draw(_ rect: CGRect) {
self.borderStyle = .none
let from = CGPoint(x: 0, y: rect.height)
let here = CGPoint(x: rect.width, y: rect.height)
let path = borderPath(start: from, end: here).cgPath
border.path = path
border.strokeColor = color.cgColor
border.lineWidth = thickness
border.fillColor = nil
layer.addSublayer(border)
}
override func layoutSubviews() {
super.layoutSubviews()
let from = CGPoint(x: 0, y: bounds.height)
let here = CGPoint(x: bounds.width, y: bounds.height)
border.path = borderPath(start: from, end: here).cgPath
}
private func borderPath(start: CGPoint, end: CGPoint) -> UIBezierPath {
let path = UIBezierPath()
path.move(to: start)
path.addLine(to: end)
return path
}
}
Then when you add a text field view to your story board - update the class in the Identity Inspector to use this subclass, Field - and then in the attributes inspector, you can set color and thickness.
Add border at Bottom in UITextField call below function:
func setTextFieldBorder(_ dimension: CGRect) -> CALayer {
let border = CALayer()
let width = CGFloat(2.0)
border.borderColor = UIColor.darkGray.cgColor
border.frame = CGRect(x: 0, y: dimension.size.height - width, width: dimension.size.width, height: dimension.size.height)
border.borderWidth = width
return border
}
How to set UITextField border in textField below sample code for that:
txtDemo.layer.addSublayer(setTextFieldBorder(txtDemo.frame))
txtDemo.layer.masksToBounds = true
Where txtDemo is IBOutlet of UITextField.

Create a Diagonal Custom UIView in Swift

I am working on designing custom UIimageview in swift. I want to create a UIimageview using beizerpath similar to this
The coding should be in swift.
Any help is appreciated. Thanks
Create a CAShapeLayer and supply it a path and a fillColor:
#IBDesignable
public class AngleView: UIView {
#IBInspectable public var fillColor: UIColor = .blue { didSet { setNeedsLayout() } }
var points: [CGPoint] = [
.zero,
CGPoint(x: 1, y: 0),
CGPoint(x: 1, y: 1),
CGPoint(x: 0, y: 0.5)
] { didSet { setNeedsLayout() } }
private lazy var shapeLayer: CAShapeLayer = {
let _shapeLayer = CAShapeLayer()
self.layer.insertSublayer(_shapeLayer, at: 0)
return _shapeLayer
}()
override public func layoutSubviews() {
shapeLayer.fillColor = fillColor.cgColor
guard points.count > 2 else {
shapeLayer.path = nil
return
}
let path = UIBezierPath()
path.move(to: convert(relativePoint: points[0]))
for point in points.dropFirst() {
path.addLine(to: convert(relativePoint: point))
}
path.close()
shapeLayer.path = path.cgPath
}
private func convert(relativePoint point: CGPoint) -> CGPoint {
return CGPoint(x: point.x * bounds.width + bounds.origin.x, y: point.y * bounds.height + bounds.origin.y)
}
}
Now, I made this designable (so if you put it in a separate framework target, you can add this view right in your storyboard and see it rendered there). It still works if you're not using storyboards. It just can be convenient to do so:
I also used relative coordinates (with values ranging from zero to one) and have a method to convert those to actual coordinates, but you can hard code your coordinates if you want. But using this as values from zero to one, you have an angular view that can participate in auto-layout without needing to worry about changing specific coordinate values.
Finally, minor things that might seem trivial, but I construct the path in layoutSubviews: That way, as the view changes size (whether via auto-layout or programmatic changes), the view will be correctly re-rendered. Likewise, by using didSet for fillColor and points, if you change either of those, the view will be re-rendered for you.
Feel free to change this as you see fit, but hopefully this illustrates the basic idea of just having a CAShapeLayer with a custom path.
If you use insertSublayer, you can then combine this with other subviews of the AngleView, e.g.:
I'm using something like this and it worked fine, you can add any thing you want to the view
import UIKit
class CustomView: UIView {
// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
// Drawing code
// Get Height and Width
let layerHeight = layer.frame.height
let layerWidth = layer.frame.width
// Create Path
let bezierPath = UIBezierPath()
// Points
let pointA = CGPoint(x: 0, y: 0)
let pointB = CGPoint(x: layerWidth, y: 0)
let pointC = CGPoint(x: layerWidth, y: layerHeight)
let pointD = CGPoint(x: 0, y: layerHeight*2/3)
// Draw the path
bezierPath.move(to: pointA)
bezierPath.addLine(to: pointB)
bezierPath.addLine(to: pointC)
bezierPath.addLine(to: pointD)
bezierPath.close()
// Mask to Path
let shapeLayer = CAShapeLayer()
shapeLayer.path = bezierPath.cgPath
layer.mask = shapeLayer
}
}

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