** CAGradientlayer可以绘制一个充满整个图层的颜色梯度(包括原型图层等图层)在一个背景颜色上 **
属性
colors
var colors: [AnyObject]?
一个内部是CGColorRef的数组,规定所有的梯度所显示的颜色,默认为nillocations
var locations: [NSNumber]?
一个内部是NSNumber的可选数组,规定所有的颜色梯度的区间范围,选值只能在0到1之间,并且数组的数据必须单增,默认值为nilendPoint
var endPoint: CGPoint
图层颜色绘制的终点坐标,也就是阶梯图层绘制的结束点,默认值是(0.5,1.0)startPoint
var startPoint: CGPoint
与endPoint相互对应,就是绘制阶梯图层的起点坐标,绘制颜色的起点,默认值是(0.5,0.0)type
var type:String
绘制类型,默认值是kCAGradientLayerAxial,也就是线性绘制,各个颜色阶层直接的变化是线性的
实例
通过属性大家都差不多知道该如何使用阶梯图层了,接下来我们看一下普通的例子,然后讨论几种情况
//
// ViewController.swift
// CALayer-CAGradientLayer
//
// Created by 蔡士林 on 6/16/16.
// Copyright © 2016 BZ. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// 创建阶梯图层
let gradientLayer = CAGradientLayer()
// 设置阶梯图层的背景
//gradientLayer.backgroundColor = UIColor.grayColor().CGColor
// 图层的颜色空间(阶梯显示时按照数组的顺序显示渐进色)
gradientLayer.colors = [UIColor.redColor().CGColor,UIColor.blueColor().CGColor,UIColor.greenColor().CGColor]
// 各个阶梯的区间百分比
gradientLayer.locations = [0.1,0.6,1]
gradientLayer.frame = CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.width)
gradientLayer.position = self.view.center
// 绘图的起点(默认是(0.5,0))
gradientLayer.startPoint = CGPointMake(1, 0)
// 绘图的终点(默认是(0.5,1))
![Uploading (0,0.5)(1,0.5)@2x_114834.png . . .]
gradientLayer.endPoint = CGPointMake(0, 1)
self.view.layer.addSublayer(gradientLayer)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
动画
//
// ViewController.swift
// CALayer-CAGradientLayer
//
// Created by 蔡士林 on 6/16/16.
// Copyright © 2016 BZ. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
var graLayer:CAGradientLayer!
var index = 0.1
override func viewDidLoad() {
super.viewDidLoad()
let gradientLayer = CAGradientLayer()
gradientLayer.backgroundColor = UIColor.grayColor().CGColor
gradientLayer.colors = [UIColor.redColor().CGColor,UIColor.blueColor().CGColor,UIColor.greenColor().CGColor]
gradientLayer.locations = [0.1,0.15,1]
gradientLayer.frame = CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.width)
gradientLayer.position = self.view.center
gradientLayer.startPoint = CGPointMake(1, 0)
gradientLayer.endPoint = CGPointMake(0, 1)
self.graLayer = gradientLayer
self.view.layer.addSublayer(gradientLayer)
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
NSTimer.scheduledTimerWithTimeInterval(0.02, target: self, selector: #selector(ViewController.change), userInfo: nil, repeats: true)
}
func change(){
index = index + 0.01
let twoIndex = index + 0.05
graLayer.locations = [index,twoIndex,1]
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
