面向接口编程，多个类的共同点提出来，当做接口，充分利用多态的特性减少判断，利用封装，继承，能使得代码更加清晰易读，添加功能也不需要改太多东西。可扩展性高
将需要画的线，矩形，椭圆等都写成类
import UIKit
class ViewController: UIViewController {
@IBAction func didClicked(sender: UIButton) {
let cv = self.view as! CustomView
// let array = cv.array
let path = NSHomeDirectory() + "/Documents/1.jpg"
//
// NSKeyedArchiver.archiveRootObject(array, toFile: path)
//1. 开始一个image上下文，绘制在内存的一个区域，保存为JPG
UIGraphicsBeginImageContext(self.view.bounds.size)
//2. 获取image context
//a.
// let context = UIGraphicsGetCurrentContext()
//
// for line in array {
// line.draw(context!)
// }
//
// CGContextDrawPath(context, .Stroke)
//b. 将视图上的所有内容绘制到当前的context中
//截屏
cv.drawViewHierarchyInRect(cv.bounds, afterScreenUpdates: true)
//3. 从当前上下文中获取图片(UIImage)
let image = UIGraphicsGetImageFromCurrentImageContext()
// let data = UIImagePNGRepresentation(image) //UIImage -> NSData
let data = UIImageJPEGRepresentation(image, 0.4)
try! data?.writeToFile(path, options: .AtomicWrite)
//4. 结束图形上下文
UIGraphicsEndImageContext()
//1. 可以自动转换
//Int/Float... <-> NSNumber
//String <-> NSString
//2. 容器的转换有条件，元素必须能够自动转换
//Dictionary <-> NSDictionary
//Array <-> NSArray
// var strArray = Array<String>()
// for point in array {
// //CGPoint -> NSString
// strArray.append(NSStringFromCGPoint(point))
// }
// //NSArray是一个不可变类型
// (strArray as NSArray).writeToFile(path, atomically: true)
}
func changeShape(type: Shape.Type) {
let cv = self.view as! CustomView
cv.type = type
}
//meta programming
//meta type: 元类型
@IBAction func didLineClicked(sender: UIButton) {
changeShape(Line.self)
}
@IBAction func didRectClicked(sender: UIButton) {
changeShape(Rectangle.self)
}
@IBAction func didCurveClicked(sender: UIButton) {
changeShape(Curve.self)
}
@IBAction func didCircleClicked(sender: AnyObject) {
changeShape(Circle.self)
}
@IBAction func RedColor(sender: UIButton) {
let cv = self.view as! CustomView
cv.color = UIColor.redColor().self
}
@IBAction func BlueColor(sender: UIButton) {
let cv = self.view as! CustomView
cv.color = UIColor.blueColor().self
}
override func viewDidLoad() {
super.viewDidLoad()
let cv = self.view as! CustomView
let path = NSHomeDirectory() + "/Documents/array.plist"
let array = NSKeyedUnarchiver.unarchiveObjectWithFile(path)
if let a = array as? Array<Line> {
cv.array = a
}
// let strArray = NSArray(contentsOfFile: path)!
// for str in strArray {
// //NSString -> CGPoint
// let point = CGPointFromString(str as! String)
// cv.array.append(point)
// }
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
import UIKit
class CustomView: UIView {
var array = Array<Shape>()
var type: Shape.Type = Line.self //默认为Line类型
var color: UIColor?
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
//1. 视图显示
//2. 大小、位置改变
override func drawRect(rect: CGRect) {
let context = UIGraphicsGetCurrentContext()
for shape in array {
CGContextSetLineWidth(context, 3)
CGContextSaveGState(context)
CGContextSetStrokeColorWithColor(context,shape.color?.CGColor)
//多态
shape.draw(context!)
CGContextStrokePath(context)
}
CGContextDrawPath(context, .Stroke)
}
func pointForTouches(touches: Set<UITouch>) -> CGPoint {
let touch = touches.first! //UITouch
let point = touch.locationInView(self)
return point
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
//获取起点
let point = pointForTouches(touches)
let shape = type.init() //必须有required的构造函数
if color != nil {
shape.color = color!
}
shape.addPoint(point)
array.append(shape)
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
//获取动态点
let point = pointForTouches(touches)
let shape = array.last
shape?.addPoint(point)
self.setNeedsDisplay() //强制刷新(重绘)
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
//获取终点
let point = pointForTouches(touches)
let shape = array.last
shape?.addPoint(point)
self.setNeedsDisplay() //强制刷新(重绘)
}
}
import UIKit
//enum ShapeType {
// case Line
// case Rect
// case Ellipse
//}
//定义接口协议，方便其他类调用
protocol ShapeProtocol {
func draw(context: CGContextRef)
func addPoint(point: CGPoint)
}
class Shape: NSObject, NSCoding, ShapeProtocol {
// var begin: CGPoint!
// var end: CGPoint!
// var cgcolor: CGColor!
//NSArray中只能存放对象
var points = Array<Point>()
var color:UIColor!
required override init() {
super.init()
}
required init?(coder aDecoder: NSCoder) {
// begin = aDecoder.decodeCGPointForKey("begin")
// end = aDecoder.decodeCGPointForKey("end")
// 取数据
if let array = aDecoder.decodeObjectForKey("points") as? Array<Point> {
points = array
}
if let m = aDecoder.decodeObjectForKey("color") as? UIColor{
color = m
}
}
// 存数据
func encodeWithCoder(aCoder: NSCoder) {
// aCoder.encodeCGPoint(begin, forKey: "begin")
// aCoder.encodeCGPoint(end, forKey: "end")
aCoder.encodeObject(points, forKey: "points")
aCoder.encodeObject(color, forKey: "color")
}
func draw(context: CGContextRef) {
}
func addPoint(point: CGPoint) {
}
}
import UIKit
//两个点之间的画图，如线，矩形，定义为SimpleShape简单图形类，继承Shape图形类
class SimpleShape: Shape {
override func addPoint(point: CGPoint) {
let p = Point(point: point)
if points.count < 2 {
points.append(p)
}
else {
points[1] = p
}
}
}
import UIKit
//线
class Line: SimpleShape {
override func draw(context: CGContextRef) {
// 安全检查，如果少于两个点，就不画了
if points.count < 2 {
return
}
CGContextMoveToPoint(context, points[0].x, points[0].y)
CGContextAddLineToPoint(context, points[1].x, points[1].y)
}
}
import UIKit
//矩形
class Rectangle: SimpleShape {
override func draw(context: CGContextRef) {
// 安全检查，必须大于等于两个点才画
guard points.count >= 2 else {
return
}
CGContextAddRect(context, CGRect(x: points[0].x, y: points[0].y, width: points[1].x - points[0].x, height: points[1].y - points[0].y))
}
}
---------------------------
```bash
import UIKit
任意线
class Curve: Shape {
override func addPoint(point: CGPoint) {
let p = Point(point: point)
points.append(p)
}
override func draw(context: CGContextRef) {
if points.count < 2 {
return
}
CGContextMoveToPoint(context, points[0].x, points[0].y)
for p in points {
CGContextAddLineToPoint(context, p.x, p.y)
}
}
}
import UIKit
//椭圆
class Circle: SimpleShape {
override func draw(context: CGContextRef) {
let begin = points[0] //圆心
let end = points[1]
// 求半径
//r = ((x1-x0)**2 + (y1-y0)**2)^2
let radius = sqrt(pow((end.x - begin.x), 2) + pow((end.y - begin.y), 2))
CGContextAddEllipseInRect(context, CGRect(x: begin.x - radius, y: begin.y - radius, width: radius + radius, height: radius + radius))
}
}
import UIKit
class Point: NSObject, NSCoding {
var x: CGFloat = 0
var y: CGFloat = 0
init(point: CGPoint) {
super.init()
x = point.x
y = point.y
}
// 取数据
required init?(coder aDecoder: NSCoder) {
x = CGFloat(aDecoder.decodeDoubleForKey("x"))
y = CGFloat(aDecoder.decodeDoubleForKey("y"))
}
// 存数据
func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeDouble(Double(x), forKey: "x")
aCoder.encodeDouble(Double(y), forKey: "y")
}
}
编译运行结果如下：
Paste_Image.png
真彩色，类似取色工具 pod search colorpick
协议和扩展都要实现属性，实际上是计算属性 {set get}
为防止重构，写程序前要留后路
