blocks|key|1121854|text|CGImageRef+UIGetScreenImage();|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1121855|Apple现在允许我们在公共应用程序中使用它，即使它是一个私有API|unstyled|1121856|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>CGImageRef UIGetScreenImage();
</code></pre>

Apple now allows us to use it in a public application, even though it's a private API

blocks|key|1121909|text|我想你可能想要renderInContext，而不是drawInContext。drawInContext更像是一种你会重写的方法...|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1121910|请注意，它可能不是在所有视图中都有效，特别是一年前左右，当我尝试在实时摄像机视图中使用它时，它不起作用。|1121911|entityMap^0|7|F|Q|D|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

I think you may want <code>renderInContext</code>, not <code>drawInContext</code>. drawInContext is more a method you would override...

Note that it may not work in all views, specifically a year or so ago when I tried to use this with the live camera view it did not work.

blocks|key|1121954|text|-+(void)drawRect:(CGRect)rect+{
++UIGraphicsBeginImageContext(self.bounds.size);++++
++[self.view.layer+renderInContext:UIGraphicsGetCurrentContext()];
++UIImage+*viewImage+=+UIGraphicsGetImageFromCurrentImageContext();
++UIGraphicsEndImageContext();
++UIImageWriteToSavedPhotosAlbum(viewImage,+nil,+nil,+nil);++
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1121955|这个方法可以放在你的Controller类中。|unstyled|1121956|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>- (void)drawRect:(CGRect)rect {
 UIGraphicsBeginImageContext(self.bounds.size); 
 [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
 UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
 UIGraphicsEndImageContext();
 UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil); 
}
</code></pre>

This method may put in your Controller class.

blocks|key|1122022|text|从iOS7开始，我们有以下默认方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1122023|-+(UIView+*)snapshotViewAfterScreenUpdates:(BOOL)afterUpdates|code-block|syntax|javascript|1122024|调用上述方法比自己尝试将当前视图的内容渲染为位图图像更快。|1122025|如果要对快照应用图形效果，请改用drawViewHierarchyInRect:afterScreenUpdates:方法。|offset|length|style|CODE|1122026|https://developer.apple.com/library/ios/documentation/uikit/reference/uiview_class/uiview/uiview.html|1122027|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|G|17|0|0|2T|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Z|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|10|8|@$K|11|L|12|M|N]]|9|@]|A|$]]|$1|O|3|P|5|6|7|13|8|@]|9|@$K|14|L|15|1|16]]|A|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|P]]]]

iOS7 onwards, we have below default methods :

<pre><code>- (UIView *)snapshotViewAfterScreenUpdates:(BOOL)afterUpdates
</code></pre>

Calling above method is faster than trying to render the contents of the current view into a bitmap image yourself.

If you want to apply a graphical effect, such as blur, to a snapshot, use the <code>drawViewHierarchyInRect:afterScreenUpdates:</code> method instead.

<a href="https://developer.apple.com/library/ios/documentation/uikit/reference/uiview_class/uiview/uiview.html" rel="noreferrer">https://developer.apple.com/library/ios/documentation/uikit/reference/uiview_class/uiview/uiview.html</a>

blocks|key|1337037|text|-(UIImage+*)convertViewToImage
{
++++UIGraphicsBeginImageContext(self.bounds.size);
++++[self+drawViewHierarchyInRect:self.bounds+afterScreenUpdates:YES];
++++UIImage+*image+=+UIGraphicsGetImageFromCurrentImageContext();
++++UIGraphicsEndImageContext();

++return+image;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1337038|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>-(UIImage *)convertViewToImage
{
 UIGraphicsBeginImageContext(self.bounds.size);
 [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
 UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
 UIGraphicsEndImageContext();

 return image;
}
</code></pre>

blocks|key|1122091|text|我已经为UIView创建了可用的扩展，以便在Swift中截图：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1122092|extension+UIView{

var+screenshot:+UIImage{

++++UIGraphicsBeginImageContext(self.bounds.size);
++++let+context+=+UIGraphicsGetCurrentContext();
++++self.layer.renderInContext(context)
++++let+screenShot+=+UIGraphicsGetImageFromCurrentImageContext();
++++UIGraphicsEndImageContext();
++++return+screenShot
}
}|code-block|syntax|javascript|1122093|要使用它，只需键入：|1122094|let+screenshot+=+view.screenshot|1122095|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I have created usable extension for UIView to take screenshot in Swift:

<pre><code>extension UIView{

var screenshot: UIImage{

 UIGraphicsBeginImageContext(self.bounds.size);
 let context = UIGraphicsGetCurrentContext();
 self.layer.renderInContext(context)
 let screenShot = UIGraphicsGetImageFromCurrentImageContext();
 UIGraphicsEndImageContext();
 return screenShot
}
}
</code></pre>

To use it just type:

<pre><code>let screenshot = view.screenshot
</code></pre>

blocks|key|1337099|text|您可以使用以下UIView类别-|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1337100|@implementation+UIView+(SnapShot)

+-+(UIImage+*)snapshotImage
{
++++UIGraphicsBeginImageContextWithOptions(self.bounds.size,+NO,+[UIScreen+mainScreen].scale);++++++++
++++[self+drawViewHierarchyInRect:self.bounds+afterScreenUpdates:NO];++++++++
++++//+old+style+[self.layer+renderInContext:UIGraphicsGetCurrentContext()];++++++++
++++UIImage+*image+=+UIGraphicsGetImageFromCurrentImageContext();++++++++
++++UIGraphicsEndImageContext();++++++++
++++return+image;
}++++
@end|code-block|syntax|javascript|1337101|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

you can use following UIView category - 

<pre><code>@implementation UIView (SnapShot)

 - (UIImage *)snapshotImage
{
 UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, [UIScreen mainScreen].scale); 
 [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:NO]; 
 // old style [self.layer renderInContext:UIGraphicsGetCurrentContext()]; 
 UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); 
 UIGraphicsEndImageContext(); 
 return image;
} 
@end
</code></pre>

blocks|key|1122153|text|iOS+10提供了新的应用编程接口|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1122154|extension+UIView+{
++++func+makeScreenshot()+->+UIImage+{
++++++++let+renderer+=+UIGraphicsImageRenderer(bounds:+self.bounds)
++++++++return+renderer.image+{+(context)+in
++++++++++++self.layer.render(in:+context.cgContext)
++++++++}
++++}
}|code-block|syntax|javascript|1122155|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

There is new API from iOS 10

<pre><code>extension UIView {
 func makeScreenshot() -&gt; UIImage {
 let renderer = UIGraphicsImageRenderer(bounds: self.bounds)
 return renderer.image { (context) in
 self.layer.render(in: context.cgContext)
 }
 }
}
</code></pre>

blocks|key|1337164|text|Swift+4更新：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1337165|extension+UIView+{
+++var+screenShot:+UIImage?++{
++++++++if+#available(iOS+10,+*)+{
++++++++++++let+renderer+=+UIGraphicsImageRenderer(bounds:+self.bounds)
++++++++++++return+renderer.image+{+(context)+in
++++++++++++++++self.layer.render(in:+context.cgContext)
++++++++++++}
++++++++}+else+{
++++++++++++UIGraphicsBeginImageContextWithOptions(bounds.size,+false,+5);
++++++++++++if+let+_+=+UIGraphicsGetCurrentContext()+{
++++++++++++++++drawHierarchy(in:+bounds,+afterScreenUpdates:+true)
++++++++++++++++let+screenshot+=+UIGraphicsGetImageFromCurrentImageContext()
++++++++++++++++UIGraphicsEndImageContext()
++++++++++++++++return+screenshot
++++++++++++}
++++++++++++return+nil
++++++++}
++++}
}|code-block|syntax|javascript|1337166|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Swift 4 updated :

<pre><code>extension UIView {
 var screenShot: UIImage? {
 if #available(iOS 10, *) {
 let renderer = UIGraphicsImageRenderer(bounds: self.bounds)
 return renderer.image { (context) in
 self.layer.render(in: context.cgContext)
 }
 } else {
 UIGraphicsBeginImageContextWithOptions(bounds.size, false, 5);
 if let _ = UIGraphicsGetCurrentContext() {
 drawHierarchy(in: bounds, afterScreenUpdates: true)
 let screenshot = UIGraphicsGetImageFromCurrentImageContext()
 UIGraphicsEndImageContext()
 return screenshot
 }
 return nil
 }
 }
}
</code></pre>

blocks|key|1337179|text|+//+MARK:+-+Actions
+@objc+func+imageWasSaved(_+image:+UIImage,+error:+Error?,+context:+UnsafeMutableRawPointer)+{
+++++if+let+error+=+error+{
+++++++++print(error.localizedDescription)
+++++++++return
+++++}

+++++print("Image+was+saved+in+the+photo+gallery")
+++++UIApplication.shared.open(URL(string:"photos-redirect://")!)
+}
+++
+func+takeScreenshot(of+view:+UIView)+{
+++++
+++++let+bounds+=+UIScreen.main.bounds
+++++UIGraphicsBeginImageContextWithOptions(bounds.size,+false,+UIScreen.main.scale)

+++++self.view.drawHierarchy(in:+self.view.bounds,+afterScreenUpdates:+true)

++++++++let+screenshot+=+UIGraphicsGetImageFromCurrentImageContext()!
++++++++UIGraphicsEndImageContext()
+++++UIImageWriteToSavedPhotosAlbum(screenshot,+self,+#selector(imageWasSaved),+nil)
+}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1337180|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> // MARK: - Actions
 @objc func imageWasSaved(_ image: UIImage, error: Error?, context: UnsafeMutableRawPointer) {
 if let error = error {
 print(error.localizedDescription)
 return
 }

 print(&quot;Image was saved in the photo gallery&quot;)
 UIApplication.shared.open(URL(string:&quot;photos-redirect://&quot;)!)
 }
 
 func takeScreenshot(of view: UIView) {
 
 let bounds = UIScreen.main.bounds
 UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.main.scale)

 self.view.drawHierarchy(in: self.view.bounds, afterScreenUpdates: true)

 let screenshot = UIGraphicsGetImageFromCurrentImageContext()!
 UIGraphicsEndImageContext()
 UIImageWriteToSavedPhotosAlbum(screenshot, self, #selector(imageWasSaved), nil)
 }
 
</code></pre>

I am wondering how my iPhone app can take a screen shot of a specific <code>UIView</code> as a <code>UIImage</code>.

I tried this code but all I get is a blank image.

<pre><code>UIGraphicsBeginImageContext(CGSizeMake(320,480));
CGContextRef context = UIGraphicsGetCurrentContext();
[myUIView.layer drawInContext:context];
UIImage *screenShot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
</code></pre>

<code>myUIView</code> has dimensions 320x480 an it has some sub-views.
What is the correct way to do this?

How Do I Take a Screen Shot of a UIView?

Swift

我想知道我的iPhone应用程序如何将特定UIView的屏幕截图作为UIImage。我试过这个代码，但我得到的只是一个空白图像。UIGraphicsBeginImageContext(CGSizeMake(320,480));CGContextRef context = UIGraphicsGetCurrentCont...

问如何拍摄UIView的屏幕截图？
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