通过CAGradientLayer制作渐变色效果

最新推荐文章于 2024-08-08 09:19:15 发布

u011010305

最新推荐文章于 2024-08-08 09:19:15 发布

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本文链接：https://blog.youkuaiyun.com/u011010305/article/details/50883628

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Gradient：本身就是梯度的意思,其中CAGradientLayer是Layer的子类.

一般CAGradientLayer可以用于遮罩效果.

用法简介:

首先,实例化:

    //初始化imageView
    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image"]];
    imageView.frame = CGRectMake(0, 0, self.view.bounds.size.width, 200);
    imageView.center = self.view.center;
    [self.view addSubview:imageView];
     
    //初始化渐变层,并添加渐变层
    self.gradientLayer = [CAGradientLayer layer];
    self.gradientLayer.frame = imageView.bounds;
    [imageView.layer addSublayer:self.gradientLayer];
     
    //设置渐变颜色方向,本例是纵向
    self.gradientLayer.startPoint = CGPointMake(0, 0);
    self.gradientLayer.endPoint = CGPointMake(0, 1);
     
    //设定颜色组
    self.gradientLayer.colors = @[(__bridge id)[UIColor clearColor].CGColor,
                                  (__bridge id)[UIColor purpleColor].CGColor];
     
    //设定颜色分割点,是以0~1来计算分割点的.该属性必须是单调上升的
    self.gradientLayer.locations = @[@(0.5f) ,@(1.0f)];