在 iOS7 中半透明的 UIToolbar 上挖一个洞

Question

我需要实现带有圆孔的模糊视图，这将在 iOS7+ 中工作

我尝试使用本机 UIToolbar，但在 iOS7 中出现一些奇怪的行为，当我将工具栏半透明设置为 YES 并应用蒙版时，它会消失。当我尝试在 iOS8 中做同样的事情时，它工作正常。

叠加视图的init方法代码：

- (instancetype)initWithFrame:(CGRect)frame withTransparentCircleInCenet:(CGPoint)center radius:(CGFloat)radius withStrokeSize:(CGFloat)strokeSize andColor:(CGColorRef)strokeColor
{
    self = [super initWithFrame:frame];
    if (self) {
        self.opaque = NO;
        //Use UIToolbar for Blur
        _nativeBlurView = [[UIToolbar alloc] initWithFrame:self.bounds];
        _nativeBlurView.barStyle = UIBarStyleBlack;
        _nativeBlurView.translucent = YES;
        [self.layer insertSublayer:_nativeBlurView.layer atIndex:0];

        //Create mask with hole
        CAShapeLayer *mask = [[CAShapeLayer alloc] init];
        mask.frame = _nativeBlurView.layer.bounds;
        UIBezierPath *maskPath = [UIBezierPath bezierPathWithRect:mask.frame];
        UIBezierPath *circlePath = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:0 endAngle:2*M_PI clockwise:NO];
        [maskPath appendPath:circlePath];
        [maskPath setUsesEvenOddFillRule:YES];
        mask.path = maskPath.CGPath;
        [mask setFillRule:kCAFillRuleEvenOdd];
        mask.fillColor = [[UIColor blackColor] CGColor];
        _nativeBlurView.layer.mask = mask;

        //draw circle over the hole
        UIBezierPath *strokeCirclePath  = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:0 endAngle:2*M_PI clockwise:NO];
        CAShapeLayer *circle = [CAShapeLayer layer];
        circle.path = [strokeCirclePath CGPath];
        circle.strokeStart = 0;
        circle.strokeEnd = 1;
        circle.lineWidth = strokeSize;
        circle.strokeColor = strokeColor;
        circle.fillColor = [[UIColor clearColor] CGColor];
        circle.shadowOffset = CGSizeMake(0, strokeSize);
        circle.shadowOpacity = 0.5;
        circle.shadowColor = [[UIColor blackColor] CGColor];
        [self.layer insertSublayer:circle atIndex:1];

    }
    return self;
}

截图：

iOS7:

iOS8:

Answer 1

我对 Alex Usbergo 的 UIERealTimeBlurView 中的非原生模糊进行了返工，并将其用于模糊层。这个解决方案的 CPU 利用率很高，但对我来说没问题。