其他
CAGradientLayer (蒙版)初步使用
一.静态使用
1.创建一个 UIImageView *baseImageView, 2.创建一个 CAradientLayer
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = _baseImageView.bounds;
gradientLayer.colors = @[(__bridge id)[UIColor clearColor].CGColor,(__bridge id)[UIColor blackColor].CGColor,(__bridge id)[UIColor clearColor].CGColor];
gradientLayer.locations = @[@(0.25),@(0.5),@(0.75)];
gradientLayer.startPoint = CGPointMake(0, 0);
gradientLayer.endPoint = CGPointMake(1, 1);3.创建一个接受 gradientLayer 的 View
UIView *containtView = [[UIView alloc] initWithFrame:_baseImageView.bounds];
[containtView.layer addSublayer:gradientLayer];4.将 _baseImageView 的 maskView 设置为 containtView
_baseImageView.maskView = containtView;5.运行效果:
6.总结:
使用 CAGradientLayer 实现渐变效果,要设置4个基本属性:
1) colors:渐变过度的图层颜色数组 2)locations: 数组中颜色过度的分割位置 3)startPoint: 渐变的起点 4)endPoint: 渐变的终点
二.动画使用
1.在原有代码基础上添加定时器
- (void)viewDidLoad {
[super viewDidLoad]; CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = _baseImageView.bounds;
gradientLayer.colors = @[(__bridge id)[UIColor clearColor].CGColor,(__bridge id)[UIColor redColor].CGColor,(__bridge id)[UIColor clearColor].CGColor];
gradientLayer.locations = @[@(0.25),@(0.5),@(0.75)];
gradientLayer.startPoint = CGPointMake(0, 0);
gradientLayer.endPoint = CGPointMake(1, 1);
view = [[UIView alloc] initWithFrame:_baseImageView.bounds];
[view.layer addSublayer:gradientLayer];
_baseImageView.maskView = view;
[NSTimer scheduledTimerWithTimeInterval:2.0f target:self selector:@selector(repeat) userInfo:nil repeats:YES];
}
- (void)repeat{ dispatch_async(dispatch_get_main_queue(), ^{
__block CGRect rect = CGRectMake(-_baseImageView.bounds.size.width, 0, _baseImageView.bounds.size.width * 2, _baseImageView.bounds.size.height * 2);
view.frame = rect;
[UIView animateWithDuration:1.0f animations:^{
rect.origin.x = _baseImageView.bounds.size.width;
view.frame = rect;
}];
});
}2.运行效果
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