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
在这个方法中，只需要传递一个view对象它就会返回一个UIImage对象。
-(UIImage*)getUIImageFromView:(UIView*)yourView
{
UIGraphicsBeginImageContext(yourView.bounds.size);
[yourView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
其他回答
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。
有时drawRect方法使问题，所以我得到这些答案更合适。你也可以看看 在DrawRect方法中捕获UIView的UIImage
对于Swift 5.1，你可以使用这个扩展:
extension UIView {
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { layer.render(in: $0.cgContext) }
}
}
斯威夫特2.0:
使用扩展方法:
extension UIImage{
class func renderUIViewToImage(viewToBeRendered:UIView?) -> UIImage
{
UIGraphicsBeginImageContextWithOptions((viewToBeRendered?.bounds.size)!, false, 0.0)
viewToBeRendered!.drawViewHierarchyInRect(viewToBeRendered!.bounds, afterScreenUpdates: true)
viewToBeRendered!.layer.renderInContext(UIGraphicsGetCurrentContext()!)
let finalImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return finalImage
}
}
用法:
override func viewDidLoad() {
super.viewDidLoad()
//Sample View To Self.view
let sampleView = UIView(frame: CGRectMake(100,100,200,200))
sampleView.backgroundColor = UIColor(patternImage: UIImage(named: "ic_120x120")!)
self.view.addSubview(sampleView)
//ImageView With Image
let sampleImageView = UIImageView(frame: CGRectMake(100,400,200,200))
//sampleView is rendered to sampleImage
var sampleImage = UIImage.renderUIViewToImage(sampleView)
sampleImageView.image = sampleImage
self.view.addSubview(sampleImageView)
}
