[iOS]渐变毛玻璃效果_uiblureffectstyle

如示意图这种需求，对背景图片添加毛玻璃效果，再添加渐变颜色。
如图

实现

#import "ViewController.h"
 
@interface ViewController ()
 
@property (weak, nonatomic) IBOutlet UIImageView *backImageView;
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
 
    [self frostedGlassViewStyle];
}
 
/* NS_ENUM_AVAILABLE_IOS(8_0)
 * UIBlurEffectStyleExtraLight, // 额外亮度，（高亮风格）
 * UIBlurEffectStyleLight, // 亮风格
 * UIBlurEffectStyleDark,  // 暗风格
 * UIBlurEffectStyleExtraDark __TVOS_AVAILABLE(10_0) __IOS_PROHIBITED __WATCHOS_PROHIBITED,
 * UIBlurEffectStyleRegular NS_ENUM_AVAILABLE_IOS(10_0), // Adapts to user interface style
 * UIBlurEffectStyleProminent NS_ENUM_AVAILABLE_IOS(10_0), // Adapts to user interface style
 */
- (void)frostedGlassViewStyle {
    // 实现模糊效果
    UIBlurEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
    // 毛玻璃视图
    UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:effect];;
    effectView.frame = CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, 200);
    [self.backImageView addSubview:effectView];
    [self gradientView:effectView];
}
 
- (void)gradientView:(UIView *)theView {
    CAGradientLayer *gradient = [CAGradientLayer layer];
    gradient.frame = theView.bounds;
    gradient.colors = [NSMutableArray arrayWithObjects:
                       (id)[UIColor clearColor].CGColor,
                       (id)[UIColor whiteColor].CGColor,
                       (id)[UIColor whiteColor].CGColor,
                       (id)[UIColor whiteColor].CGColor,
                       (id)[UIColor whiteColor].CGColor,
                       nil];
    //（0，0）表示从左上角开始变化。默认值是(0.5,0.0)表示从x轴为中间，y为顶端的开始变化
    gradient.startPoint = CGPointMake(0.5, 0.5);
    //（1，1）表示到右下角变化结束。默认值是(0.5,1.0)表示从x轴为中间，y为低端的结束变化
    gradient.endPoint = CGPointMake(0.5, 1.0);
    [theView.layer insertSublayer:gradient atIndex:0];
}
 
@end