iOS-为视图添加阴影

朴灿烈づ我的快乐病毒、 2022-08-03 13:38 190阅读 0赞

## 情况一：视图添加圆角，在添加阴影 ##

//阴影视图
        self.viewShadow = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
        self.viewShadow.backgroundColor = [UIColor redColor];
        self.viewShadow.layer.shadowOpacity = 1;
        self.viewShadow.layer.cornerRadius = 5;
        self.viewShadow.layer.borderWidth = 1;
        self.viewShadow.layer.masksToBounds = YES;
        //阴影视图背景
        self.viewShadowBg = [[UIView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];
        self.viewShadowBg.layer.shadowOpacity = 1;
        self.viewShadowBg.layer.shadowOffset = CGSizeZero;
        self.viewShadowBg.layer.shadowColor = [UIColor greenColor].CGColor;
        self.viewShadowBg.layer.shadowRadius = 10;
        self.viewShadowBg.layer.borderWidth = 1;
        self.viewShadowBg.layer.borderColor = [UIColor grayColor].CGColor;
        self.viewShadowBg.layer.cornerRadius = 5;

## 情况二：自定义视图阴影效果 ##

自定义视图阴影，我们用到的是这个属性：`view.layer.shadowPath`，我们通过这个属性来自定义视图阴影。

### 贝塞尔曲线 ###

这里我们还用到了贝塞尔曲线，通过数学方式来描述图形效果，常见于计算机中图像的描述。objective-c中通过UIBezierPath来描述贝塞尔曲线。贝塞尔曲线知识点补充：  
[Bezier曲线简介][Bezier]  
[贝塞尔曲线-维基百科][-]

### 实现正常矩形效果： ###

### 实现自定义画梯形： ###

UIView *view = [[UIView alloc] init];
        view.frame = CGRectMake(100, 100, 100, 100);
        view.center = self.view.center;
        view.backgroundColor = [UIColor clearColor];
        view.layer.shadowColor = [UIColor blackColor].CGColor;
        view.layer.shadowOpacity = 0.7f;
        view.layer.shadowOffset = CGSizeMake(30.0f, 10.0f);
        view.layer.shadowRadius = 2.0f;
        view.layer.masksToBounds = NO;
        //自定义画梯形
        CGSize size = view.bounds.size;
        UIBezierPath *path = [UIBezierPath bezierPath];
        [path moveToPoint:CGPointMake(size.width * 0.33f, size.height * 0.66f)];
        [path addLineToPoint:CGPointMake(size.width * 0.66f, size.height * 0.66f)];
        [path addLineToPoint:CGPointMake(size.width * 1.15f, size.height * 1.15f)];
        [path addLineToPoint:CGPointMake(size.width * -0.15f, size.height * 1.15f)];
        view.layer.shadowPath = path.CGPath;
        [self.view addSubview:view];

#### 实现自定义大小椭圆形： ####

[Bezier]: http://blog.csdn.net/johnny710vip/article/details/6859853
[-]: https://zh.wikipedia.org/wiki/%E8%B2%9D%E8%8C%B2%E6%9B%B2%E7%B7%9A#column-one