我的代码在普通设备上工作正常，但在视网膜设备上产生模糊的图像。
有人知道我的问题的解决方案吗?
+ (UIImage *) imageWithView:(UIView *)view
{
UIGraphicsBeginImageContext(view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
当前回答
我已经创建了一个基于@Dima解决方案的Swift扩展:
extension UIImage {
class func imageWithView(view: UIView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0)
view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)
let img = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img
}
}
编辑:Swift 4改进版本
extension UIImage {
class func imageWithView(_ view: UIView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.isOpaque, 0)
defer { UIGraphicsEndImageContext() }
view.drawHierarchy(in: view.bounds, afterScreenUpdates: true)
return UIGraphicsGetImageFromCurrentImageContext() ?? UIImage()
}
}
用法:
let view = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
let image = UIImage.imageWithView(view)
其他回答
我已经创建了一个基于@Dima解决方案的Swift扩展:
extension UIImage {
class func imageWithView(view: UIView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0)
view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)
let img = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img
}
}
编辑:Swift 4改进版本
extension UIImage {
class func imageWithView(_ view: UIView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.isOpaque, 0)
defer { UIGraphicsEndImageContext() }
view.drawHierarchy(in: view.bounds, afterScreenUpdates: true)
return UIGraphicsGetImageFromCurrentImageContext() ?? UIImage()
}
}
用法:
let view = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
let image = UIImage.imageWithView(view)
所有Swift 3的答案都不适合我，所以我翻译了最受欢迎的答案:
extension UIImage {
class func imageWithView(view: UIView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.isOpaque, 0.0)
view.layer.render(in: UIGraphicsGetCurrentContext()!)
let img: UIImage? = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img!
}
}
目前接受的答案已经过时了，至少如果你支持iOS 7的话。
如果你只支持iOS7+，下面是你应该使用的:
+ (UIImage *) imageWithView:(UIView *)view
{
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0f);
[view drawViewHierarchyInRect:view.bounds afterScreenUpdates:NO];
UIImage * snapshotImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return snapshotImage;
}
斯威夫特4:
func imageWithView(view: UIView) -> UIImage? {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.isOpaque, 0.0)
defer { UIGraphicsEndImageContext() }
view.drawHierarchy(in: view.bounds, afterScreenUpdates: true)
return UIGraphicsGetImageFromCurrentImageContext()
}
根据这篇文章，你可以看到新的iOS7方法drawviewherarchyinrect:afterScreenUpdates:比renderInContext:快很多倍。
Swift 3.0实现
extension UIView {
func getSnapshotImage() -> UIImage {
UIGraphicsBeginImageContextWithOptions(bounds.size, isOpaque, 0)
drawHierarchy(in: bounds, afterScreenUpdates: false)
let snapshotImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return snapshotImage
}
}
下面是一个基于@Dima的答案的Swift 4 UIView扩展。
extension UIView {
func snapshotImage() -> UIImage? {
UIGraphicsBeginImageContextWithOptions(bounds.size, isOpaque, 0)
drawHierarchy(in: bounds, afterScreenUpdates: false)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
}
