Ios 如何将视图另存为图像

我正在使用Rubymotion构建一个iOS应用程序。在这个应用程序中，我让用户通过在视图上绘图来“签名”。我想保存这个“签名”到一个真实的图像，以便我可以上传到服务器

我想我在这里找到了一个Objective-C解决方案：

其代码如下所示：

UIGraphicsBeginImageContext(view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

UIGraphicsBeginImageContext(signature.bounds.size)
signature.layer.renderInContext(UIGraphicsGetCurrentContext)
image = UIImage.UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

UIGraphicsBeginImageContext(signature.bounds.size)
signature.layer.renderInContext(UIGraphicsGetCurrentContext())
image = UIImage.UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
image = UIImagePNGRepresentation(image)

我曾尝试将此代码“翻译”为Ruby，如下所示：

UIGraphicsBeginImageContext(view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

UIGraphicsBeginImageContext(signature.bounds.size)
signature.layer.renderInContext(UIGraphicsGetCurrentContext)
image = UIImage.UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

UIGraphicsBeginImageContext(signature.bounds.size)
signature.layer.renderInContext(UIGraphicsGetCurrentContext())
image = UIImage.UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
image = UIImagePNGRepresentation(image)

但我在运行它时遇到了以下错误：

uninitialized constant SignatureController::UIGraphicsGetCurrentContext (NameError)
2013-01-27 14:20:29.943 buy_app[18384:13d03] *** Terminating app due to uncaught exception 'NameError', reason: 'signature_controller.rb:88:in `save': uninitialized constant SignatureController::UIGraphicsGetCurrentContext (NameError)

我做错了什么？将普通视图保存到图像中的最佳方法是什么

谢谢

更新

我是这样解决的：

UIGraphicsBeginImageContext(view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

UIGraphicsBeginImageContext(signature.bounds.size)
signature.layer.renderInContext(UIGraphicsGetCurrentContext)
image = UIImage.UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

UIGraphicsBeginImageContext(signature.bounds.size)
signature.layer.renderInContext(UIGraphicsGetCurrentContext())
image = UIImage.UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
image = UIImagePNGRepresentation(image)

我是这样解决的

UIGraphicsBeginImageContext(signature.bounds.size)
signature.layer.renderInContext(UIGraphicsGetCurrentContext())
image = UIImage.UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
image = UIImagePNGRepresentation(image)

我是这样解决的

UIGraphicsBeginImageContext(signature.bounds.size)
signature.layer.renderInContext(UIGraphicsGetCurrentContext())
image = UIImage.UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
image = UIImagePNGRepresentation(image)

---

对于视网膜显示，您需要使用

UIGraphicsBeginImageContextWithOptions（bounds.size，false，UIScreen.mainScreen.scale）

否则会将图像缩小到1/4分辨率。对于视网膜显示，您需要使用

UIGraphicsBeginImageContextWithOptions（bounds.size，false，UIScreen.mainScreen.scale）

否则会将图像缩小到1/4分辨率。