目标c有一些答案,但没有找到任何关于swift的答案。
我想创建一个中间有透明圆圈的暗视图,这样用户就可以看到子视图并与之交互。我如何使用swift实现这一点。
更确切地说,我正在寻找一个像whatsapp个人资料图片实现这样的结果。中间有一个透明的圆圈,用户可以看到图片并滚动。
谢谢你们的帮助!
Cyril的答案被翻译成swift以防止额外键入:
func circularOverlayMask() -> UIImage {
let bounds = self.view.bounds
let width = bounds.size.width
let height = bounds.size.height
let diameter = width
let radius = diameter / 2
let center = CGPointMake(width / 2, height / 2)
// Create the image context
UIGraphicsBeginImageContextWithOptions(bounds.size, false, 0)
// Create the bezier paths
let clipPath = UIBezierPath(rect: bounds)
let maskPath = UIBezierPath(ovalInRect: CGRectMake(center.x - radius, center.y - radius, diameter, diameter))
clipPath.appendPath(maskPath)
clipPath.usesEvenOddFillRule = true
clipPath.addClip()
UIColor(white: 0, alpha: 0.5).setFill()
clipPath.fill()
let finalImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()
return finalImage
}
以下是我在项目中创建圆形掩码的方法(这不是Swift中的方法,但很容易翻译):
- (UIImage *)circularOverlayMask
{
// Constants
CGRect bounds = self.navigationController.view.bounds;
CGFloat width = bounds.size.width;
CGFloat height = bounds.size.height;
CGFloat diameter = width - (INNER_EDGE_INSETS * 2);
CGFloat radius = diameter / 2;
CGPoint center = CGPointMake(width / 2, height / 2);
// Create the image context
UIGraphicsBeginImageContextWithOptions(bounds.size, NO, 0);
// Create the bezier paths
UIBezierPath *clipPath = [UIBezierPath bezierPathWithRect:bounds];
UIBezierPath *maskPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(center.x - radius, center.y - radius, diameter, diameter)];
[clipPath appendPath:maskPath];
clipPath.usesEvenOddFillRule = YES;
[clipPath addClip];
[[UIColor colorWithWhite:0 alpha:0.5f] setFill];
[clipPath fill];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return finalImage;
}
我基本上创建了一个子视图,添加到图像滚动视图上方,如下所示:
UIImageView *maskView = [[UIImageView alloc] initWithImage:[self overlayMask]];
maskView.userInteractionEnabled = NO;
[self.view insertSubview:maskView aboveSubview:_scrollView];
希望能有所帮助。
(最初在DZNPhotoPickerController中找到)