iOS 使用贝塞尔曲线绘制蒙层上部分区域透明

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核心代码

UIBezierPath *tempPath = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(120, 150, 100, 50) byRoundingCorners:(UIRectCornerTopLeft |UIRectCornerTopRight |UIRectCornerBottomRight|UIRectCornerBottomLeft) cornerRadii:CGSizeMake(4, 4)];
    UIView *guideView = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];
    guideView.backgroundColor = [UIColor blackColor];
    guideView.alpha = 0.6;
    guideView.layer.mask = [self addTransparencyViewWith:tempPath];
    [[UIApplication sharedApplication].keyWindow addSubview:guideView];

- (CAShapeLayer *)addTransparencyViewWith:(UIBezierPath *)tempPath{
    UIBezierPath *path = [UIBezierPath bezierPathWithRect:[UIScreen mainScreen].bounds];
    [path appendPath:tempPath];
    path.usesEvenOddFillRule = YES;
 
    CAShapeLayer *shapeLayer = [CAShapeLayer layer];
    shapeLayer.path = path.CGPath;
    shapeLayer.fillColor= [UIColor blackColor].CGColor;  //其他颜色都可以，只要不是透明的
    shapeLayer.fillRule=kCAFillRuleEvenOdd;
    return shapeLayer;
}

参考