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
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
}
}
其他回答
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。
- (UIImage*)screenshotForView:(UIView *)view
{
UIGraphicsBeginImageContext(view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// hack, helps w/ our colors when blurring
NSData *imageData = UIImageJPEGRepresentation(image, 1); // convert to jpeg
image = [UIImage imageWithData:imageData];
return image;
}
使用现代的uigraphicsimagerender
public extension UIView {
@available(iOS 10.0, *)
public func renderToImage(afterScreenUpdates: Bool = false) -> UIImage {
let rendererFormat = UIGraphicsImageRendererFormat.default()
rendererFormat.opaque = isOpaque
let renderer = UIGraphicsImageRenderer(size: bounds.size, format: rendererFormat)
let snapshotImage = renderer.image { _ in
drawHierarchy(in: bounds, afterScreenUpdates: afterScreenUpdates)
}
return snapshotImage
}
}
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)
}
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
}
}
