a、利用UIBezierPath在DrawRect：中绘制一个给定颜色的三角位图，代码如下：

- (void)drawRect:(CGRect)rect

{ // Drawing code

    UIBezierPath *path = [UIBezierPath bezierPath];

    [path moveToPoint:CGPointMake(rect.size.width/2, 0)];

    [path addLineToPoint:CGPointMake(rect.size.width, rect.size.height)];

    [path addCurveToPoint:CGPointMake(0, rect.size.height) controlPoint1:CGPointMake(rect.size.width/2, rect.size.height) controlPoint2:CGPointMake(rect.size.width/2, rect.size.height)];

    [path closePath];

    [[UIColor colorWithRed:25.0/255 green:141.0/225 blue:200.0/255 alpha:1] setStroke];

    [[UIColor colorWithRed:25.0/255 green:141.0/225 blue:200.0/255 alpha:1] setFill];

    [path stroke];

    [path fill];

    self.layer.shadowColor = [UIColor blackColor].CGColor;

    self.layer.shadowRadius = 3;

    self.layer.shadowOpacity = 0.4;

//    self.layer.shadowPath = [];

}

b、UIBezierPath和CAShapelayer的组合使用，其实是CAShaperLayer可以拥有一个自己的贝塞尔路径，绘制一左右两半颜色不同的图层视图，代码如下：

#import "BezierView.h"

@interface BezierView()

{

    CAShapeLayer *_leftLayer;

    UIBezierPath *_leftPath;

    CAShapeLayer *_rightLayer;

    UIBezierPath *_rightPath;

}

@end

@implementation BezierView

- (id)initWithFrame:(CGRect)frame

{

    self = [super initWithFrame:frame];

    if (self) {

        // Initialization code

        _leftSpan = self.frame.size.width/4;

        _leftLayer = [[CAShapeLayer alloc] init];

        [self.layer addSublayer:_leftLayer];//将图层添加添加上去。

        _leftLayer.fillColor = nil;

        _leftLayer.frame = self.bounds;

        _rightLayer = [[CAShapeLayer alloc] init];

        [self.layer addSublayer:_rightLayer];//图层的添加

        _rightLayer.fillColor = nil;

        _rightLayer.frame = self.bounds;

        self.backgroundColor = [UIColor blueColor];        

    }

    return self;

}

-(void)setLeftOne

{

    _leftPath = [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, _leftSpan, self.frame.size.height)];

    _leftLayer.path = _leftPath.CGPath;

}

-(void)setRightOne

{

    _rightPath = [UIBezierPath bezierPathWithRect:CGRectMake(_leftSpan, 0, self.frame.size.width-_leftSpan, self.frame.size.height)];

    _rightLayer.path = _rightPath.CGPath;

}

-(void)setRightColor:(UIColor *)rightColor

{

    _rightLayer.fillColor = rightColor.CGColor;

    [self setRightOne];

}

-(void)setLeftColor:(UIColor *)leftColor

{

    _leftLayer.fillColor = leftColor.CGColor;

    [self setLeftOne];

}

-(void)setLeftSpan:(CGFloat)leftSpan

{

    _leftSpan = leftSpan;

    [self setLeftOne];

    [self setRightOne];

}

/*

// Only override drawRect: if you perform custom drawing.

// An empty implementation adversely affects performance during animation.

- (void)drawRect:(CGRect)rect

{

    // Drawing code

}

*/

@end