UIBezierPath

UIBezierPath是对CGContextRef的封装, 方法名称有相识的地方
基本

//画笔
UIBezierPath * path = [UIBezierPath bezierPath];
  //把路径添加到上下文
CGContextAddPath(ctx, bezierPath.CGPath);
 //渲染上下文(layer)
CGContextStrokePath(ctx);

设置

 [path1 setLineWidth:5];//框
 [path1 stroke];//填充

画线

 [path moveToPoint:CGPointMake(45,45)];
[path addLineToPoint:CGPointMake(20, 45)];
 [path addLineToPoint:CGPointMake(45, 20)];

画圆

 [path addArcWithCenter:CGPointMake(45, 45) radius:5 startAngle:0 endAngle:M_PI*1.5 clockwise:YES];

弧度:通过控制点（ControlPoint来改变直线的弧度)

 [bezierPath addQuadCurveToPoint:CGPointMake(100, 250) controlPoint:CGPointMake(50, 250)];

画一条线

    UIBezierPath *bezierPath = [UIBezierPath bezierPath];
    [bezierPath moveToPoint:CGPointMake( x1+width*1.0, y)];
    [bezierPath addLineToPoint:CGPointMake(x2-width*1.0, y)];
    CGContextSetLineWidth(context, 1);
    [color setStroke];
    
    CGContextAddPath(context, bezierPath.CGPath);
    CGContextStrokePath(context);

[UIBezierPath bezierPathWithArcCenter:center radius:100 startAngle:0 endAngle:M_PI_2 clockwise:YES];