swift 快速奔跑的兔几 本节的内容是：绘画

当一个应用程序绘制图形时，它首先创建一个用于在其中绘制内容的画布，cocoa称之为图形上下文。
在创建一个图形上下文的时候，会指出上下文的大小。在此画布之外所有的绘画操作都将被忽略，不会出现在画布上。

框架矩形：用于定义视图的大小和位置的矩形。
视图可以包含多个子视图，如果一个视图位于另一个视图内部，那么当超视图移动时，它也会移动。框架矩形是相对于其超视图定义的。而边界矩形则是相对于自己的坐标空间的位置和大小。
尽管边界矩形的尺寸通常与框架矩形相同，但是也并不是必须如此。例如，如果视图被旋转，框架矩形将改变大小和位置，而边界则保持不变。

如下代码为绘制纯色矩形的栗子：

// 绘制图像
class RabbitsView: UIView {
override func drawRect(rect: CGRect) {
UIColor.grayColor().setFill()
let pathNew = UIBezierPath(rect: self.bounds)
pathNew.fill()
}
}

let viewRect = CGRect(x: 0, y: 0, width: 100, height: 100)
let newVIew = RabbitsView(frame: viewRect)

下面的栗子是圆角矩形的代码：

// 绘制图像
class RabbitsView: UIView {
override func drawRect(rect: CGRect) {
// 收缩边缘
let pathRect = CGRectInset(self.bounds, 1, 1)
let path = UIBezierPath(roundedRect: pathRect, cornerRadius: 10)
//let path = UIBezierPath(rect: self.bounds)
path.lineWidth = 4

UIColor.grayColor().setFill()

UIColor.blackColor().setStroke()

path.fill()
path.stroke()
}
}

let viewRect = CGRect(x: 0, y: 0, width: 100, height: 100)
let newVIew = RabbitsView(frame: viewRect)

下面是创建自定义路径的栗子：

// 绘制图像
class RabbitsView: UIView {
override func drawRect(rect: CGRect) {
let bezierPathNew = UIBezierPath()
let drawingRect = CGRectInset(self.bounds, self.bounds.size.width*0.05,  self.bounds.size.height*0.05)

let topLeft = CGPointMake(CGRectGetMinX(drawingRect), CGRectGetMaxY(drawingRect))
let topRight = CGPointMake(CGRectGetMaxX(drawingRect), CGRectGetMaxY(drawingRect))
let bottomRight = CGPointMake(CGRectGetMaxX(drawingRect), CGRectGetMinY(drawingRect))
let bottomLeft = CGPointMake(CGRectGetMinX(drawingRect), CGRectGetMinY(drawingRect))
let center1 = CGPointMake(CGRectGetMidX(drawingRect), CGRectGetMidY(drawingRect))

bezierPathNew.moveToPoint(topLeft)
bezierPathNew.addLineToPoint(topRight)
bezierPathNew.addLineToPoint(bottomLeft)
bezierPathNew.addCurveToPoint(bottomRight, controlPoint1: center1, controlPoint2: center1)

bezierPathNew.closePath()

UIColor.grayColor().setFill()
UIColor.magentaColor().setStroke()

bezierPathNew.fill()
bezierPathNew.stroke()
}
}

let viewRect = CGRect(x: 0, y: 0, width: 100, height: 100)
let newVIew = RabbitsView(frame: viewRect)

绘制多条子路径的栗子如下：

// 绘制图像
class RabbitsView: UIView {
override func drawRect(rect: CGRect) {
let bezierPathNew = UIBezierPath()
let drawingRect = CGRectInset(self.bounds, self.bounds.size.width*0.05,  self.bounds.size.height*0.05)

let topLeft = CGPointMake(CGRectGetMinX(drawingRect), CGRectGetMaxY(drawingRect))
let topRight = CGPointMake(CGRectGetMaxX(drawingRect), CGRectGetMaxY(drawingRect))
let bottomRight = CGPointMake(CGRectGetMaxX(drawingRect), CGRectGetMinY(drawingRect))
let bottomLeft = CGPointMake(CGRectGetMinX(drawingRect), CGRectGetMinY(drawingRect))
let center1 = CGPointMake(CGRectGetMidX(drawingRect), CGRectGetMidY(drawingRect))

bezierPathNew.moveToPoint(topLeft)
bezierPathNew.addLineToPoint(topRight)
bezierPathNew.addLineToPoint(bottomLeft)
bezierPathNew.addCurveToPoint(bottomRight, controlPoint1: center1, controlPoint2: center1)

bezierPathNew.closePath()

let circleRect = CGRectInset(rect, rect.size.width*0.3, rect.size.height*0.3)
let bezierPathSecond = UIBezierPath(ovalInRect: circleRect)

let bezierPathF = UIBezierPath()

bezierPathNew.appendPath(bezierPathSecond)
bezierPathF.appendPath(bezierPathNew)

UIColor.grayColor().setFill()
UIColor.magentaColor().setStroke()

bezierPathF.fill()
bezierPathF.stroke()
}
}

let viewRect = CGRect(x: 0, y: 0, width: 100, height: 100)
let newVIew = RabbitsView(frame: viewRect)

呼～好多代码啊～～作为一只兔子要去蹦哒一会儿了喔～～～