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|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|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|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|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|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|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|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|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|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 = UIGraphicsGetCurrentContext();[myUIView.layer drawInContext:cont

问如何拍摄UIView的屏幕截图？
EN

回答 10

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何拍摄UIView的屏幕截图？EN

回答 10

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何拍摄UIView的屏幕截图？
EN