iOS：绘图

1、UIBezierPath（贝塞尔曲线）

　　1-1）、在重写 drawRect: 方法里使用

　　　　使用不难，看 UIBezierPath.h 基本都会用，值得注意的是，颜色设置如下：

[[UIColor redColor]set];

　　　　下面是学习过程中的代码

- (void)drawRect:(CGRect)rect
{
    //矩形
    UIBezierPath *path1 = [UIBezierPath bezierPathWithRect:CGRectMake(20, 20, 50, 50)];
    [[UIColor grayColor]set];
    [path1 stroke];
    //内切圆
    UIBezierPath *path2 = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(100, 20, 50, 50)];
    [[UIColor blueColor]set];
    [path2 fill];
    [path2 stroke];
    //切4个圆角
    UIBezierPath *path3 = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(200, 20, 50, 50) cornerRadius:15.0];
    [[UIColor greenColor]set];
    [path3 stroke];
    //切1-4个圆角(最后一个参数cornerRadii，好像就size.width有效果？)
    UIBezierPath *path4 = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(300, 20, 50, 50) byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomRight  cornerRadii:CGSizeMake(15.0, 35.0)];
    [[UIColor whiteColor]set];
    [path4 stroke];
    //弧形
    UIBezierPath *path5 = [UIBezierPath bezierPathWithArcCenter:CGPointMake(50, 120) radius:25.0 startAngle:M_PI endAngle:M_PI/4 clockwise:YES];
    [[UIColor yellowColor]set];
    [path5 stroke];

    //画直线
    UIBezierPath *path6 = [UIBezierPath bezierPath];
    [path6 setLineWidth:3.0];
    [[UIColor redColor]set];
    [path6 moveToPoint:CGPointMake(100, 100)];
    [path6 addLineToPoint:CGPointMake(150, 100)];
    [path6 addLineToPoint:CGPointMake(150, 150)];
    [path6 addLineToPoint:CGPointMake(100, 150)];
    [path6 addLineToPoint:CGPointMake(100, 100)];
    [path6 addLineToPoint:CGPointMake(200, 125)];
    [path6 addLineToPoint:CGPointMake(150, 150)];
    [path6 closePath];
    path6.usesEvenOddFillRule = YES;
    [path6 fill];
    [path6 stroke];

    //贝塞尔曲线
    UIBezierPath *path7 = [UIBezierPath bezierPath];
    [path7 setLineWidth:5.0];
    [[UIColor orangeColor]set];
    [path7 moveToPoint:CGPointMake(200, 100)];
    [path7 addCurveToPoint:CGPointMake(300, 100) controlPoint1:CGPointMake(250, 150) controlPoint2:CGPointMake(275, 50)];
    [path7 stroke];

    //贝塞尔曲线
    UIBezierPath *path8 = [UIBezierPath bezierPath];
    [path8 setLineWidth:5.0];
    [[UIColor purpleColor]set];
    [path8 moveToPoint:CGPointMake(200, 150)];
    [path8 addQuadCurveToPoint:CGPointMake(300, 150) controlPoint:CGPointMake(250, 200)];
    [path8 stroke];

    //带圆心到起始角度线段的弧形
    UIBezierPath *path9 = [UIBezierPath bezierPath];
    [path9 setLineWidth:5.0];
    [[UIColor brownColor]set];
    [path9 moveToPoint:CGPointMake(50, 200)];
    [path9 addArcWithCenter:CGPointMake(50, 200) radius:25.0 startAngle:0.0 endAngle:M_PI clockwise:YES];
    [path9 stroke];

    //虚线
    UIBezierPath *path10 = [UIBezierPath bezierPath];
    [path10 setLineWidth:5.0];
    [[UIColor whiteColor]set];
    [path10 moveToPoint:CGPointMake(10, 300)];
    [path10 addLineToPoint:CGPointMake(SCREEN_WIDTH - 10, 300)];
    CGFloat lineDash[] = {10.0,2.0,5.0,5.0};
    //奇数实线，偶数虚线，phase起始偏移
    [path10 setLineDash:lineDash count:4 phase:0];
    [path10 stroke];
}

　　1-2）、在普通方法里使用，需要画布。配合 CAShapeLayer 。

　　　　注意：1、设置线宽、颜色、填充等，都由 CAShapeLayer 完成，UIBezierPath 只完成路径的绘画。

　　　　　　　2、CAShapeLayer的大小，可以设成屏幕的大小 SCREEN.BOUNDS。UIBezierPath画完线条后，自动剪裁，如果没闭合，会自动连接起点、终点剪裁。

　　　　下面是学习过程中的代码

- (void)drawTest
{
    //矩形
    CGRect rect1 = {20, 20, 50, 50};
    UIBezierPath *path1 = [UIBezierPath bezierPathWithRect:rect1];

    CAShapeLayer *shapeLayer1 = [[CAShapeLayer alloc]init];
    shapeLayer1.position = self.layer.position;
    shapeLayer1.bounds = self.layer.bounds;
    shapeLayer1.path = path1.CGPath;
    shapeLayer1.fillColor = [UIColor grayColor].CGColor;
    [self.layer addSublayer:shapeLayer1];

    //内切圆
    CGRect rect2 = {100, 20, 50, 50};
    UIBezierPath *path2 = [UIBezierPath bezierPathWithOvalInRect:rect2];

    CAShapeLayer *shapeLayer2 = [[CAShapeLayer alloc]init];
    shapeLayer2.position = self.layer.position;
    shapeLayer2.bounds = self.layer.bounds;
    shapeLayer2.path = path2.CGPath;
    shapeLayer2.fillColor = [UIColor blueColor].CGColor;
    shapeLayer2.strokeColor = [UIColor orangeColor].CGColor;
    shapeLayer2.strokeStart = 0.0;
    shapeLayer2.strokeEnd = 0.7;
    shapeLayer2.lineWidth = 3.0;
    [self.layer addSublayer:shapeLayer2];

    //画线
    UIBezierPath *path3 = [UIBezierPath bezierPath];
    [path3 moveToPoint:CGPointMake(100, 100)];
    [path3 addLineToPoint:CGPointMake(150, 100)];
    [path3 addLineToPoint:CGPointMake(150, 150)];
    [path3 addLineToPoint:CGPointMake(100, 150)];
    [path3 addLineToPoint:CGPointMake(100, 100)];
    [path3 addLineToPoint:CGPointMake(200, 125)];
    [path3 addLineToPoint:CGPointMake(150, 150)];

    CAShapeLayer *shapeLayer3 = [[CAShapeLayer alloc]init];
    shapeLayer3.position = self.layer.position;
    shapeLayer3.bounds = self.layer.bounds;
    shapeLayer3.path = path3.CGPath;
    shapeLayer3.fillColor = [UIColor redColor].CGColor;
    shapeLayer3.strokeColor = [UIColor orangeColor].CGColor;
    shapeLayer3.lineWidth = 3.0;
    shapeLayer3.fillRule = kCAFillRuleEvenOdd;
    [self.layer addSublayer:shapeLayer3];
}