How Do I Take a Screen Shot of a UIView

Question

I am wondering how my iPhone app can take a screen shot of a specific UIView as a UIImage   I tried this code but all I get is a blank image   UIGraphicsBeginImageContext CGSizeMake 320 480    CGContextRef context   UIGraphicsGetCurrentContext     myUIView layer drawInContext context   UIImage  screenShot   UIGraphicsGetImageFromCurrentImageContext    UIGraphicsEndImageContext      myUIView has dimensions 320x480 an it has some sub-views  What is the correct way to do this

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

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The following snippet is used to take screenshot    UIGraphicsBeginImageContext self muUIView bounds size     myUIView layer renderInContext UIGraphicsGetCurrentContext      UIImage  screenShot   UIGraphicsGetImageFromCurrentImageContext    UIGraphicsEndImageContext      Use  renderInContext  method instead of drawInContext  method  renderInContext  method renders the receiver and its sublayers into current context  This method renders directly from the layer tree

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You need to capture the key window for a screenshot or a UIView  You can do it in Retina Resolution using UIGraphicsBeginImageContextWithOptions and set its scale parameter 0 0f  It always captures in native resolution  retina for iPhone 4 and later    This one does a full screen screenshot  key window   UIWindow  keyWindow     UIApplication sharedApplication  keyWindow   CGRect rect    keyWindow bounds   UIGraphicsBeginImageContextWithOptions rect size YES 0 0f   CGContextRef context   UIGraphicsGetCurrentContext     keyWindow layer renderInContext context      UIImage  capturedScreen   UIGraphicsGetImageFromCurrentImageContext    UIGraphicsEndImageContext      This code capture a UIView in native resolution  CGRect rect    captureView bounds   UIGraphicsBeginImageContextWithOptions rect size YES 0 0f   CGContextRef context   UIGraphicsGetCurrentContext     captureView layer renderInContext context      UIImage  capturedImage   UIGraphicsGetImageFromCurrentImageContext    UIGraphicsEndImageContext      This saves the UIImage in jpg format with 95  quality in the app s document folder if you need to do that   NSString   imagePath    NSHomeDirectory   stringByAppendingPathComponent  NSString stringWithFormat   Documents capturedImage jpg          UIImageJPEGRepresentation capturedImage  0 95  writeToFile imagePath atomically YES

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- UIImage   convertViewToImage       UIGraphicsBeginImageContext self bounds size        self drawViewHierarchyInRect self bounds afterScreenUpdates YES       UIImage  image   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext       return image

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Apple does not allow      CGImageRef UIGetScreenImage      Applications should take a screenshot using the drawRect method as specified in  http   developer apple com library ios  qa qa2010 qa1703 html

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you can use following UIView category -    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

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I have created usable extension for UIView to take screenshot in Swift   extension UIView   var screenshot  UIImage       UIGraphicsBeginImageContext self bounds size       let context   UIGraphicsGetCurrentContext        self layer renderInContext context      let screenShot   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return screenShot       To use it just type   let screenshot   view screenshot

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Swift 4 updated    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

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I think you may want renderInContext  not drawInContext   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

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I created this extension for save a screen shot from UIView  extension UIView   func saveImageFromView path path String        UIGraphicsBeginImageContextWithOptions bounds size  false  UIScreen mainScreen   scale      drawViewHierarchyInRect bounds  afterScreenUpdates  true      let image   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext       UIImageJPEGRepresentation image  0 4   writeToFile path  atomically  true        call   let pathDocuments   NSSearchPathForDirectoriesInDomains NSSearchPathDirectory DocumentDirectory  NSSearchPathDomainMask UserDomainMask  true  first  let pathImage      pathDocuments    user  usuarioID integerValue  jpg  reportView saveImageFromView path  pathImage    If you want to create a png must change   UIImageJPEGRepresentation image  0 4   writeToFile path  atomically  true    by  UIImagePNGRepresentation image   writeToFile path  atomically  true

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Details   Xcode Version 10 3  10G8   Swift 5   Solution  import UIKit  extension CALayer       func makeSnapshot   - gt  UIImage            let scale   UIScreen main scale         UIGraphicsBeginImageContextWithOptions frame size  false  scale          defer   UIGraphicsEndImageContext             guard let context   UIGraphicsGetCurrentContext   else   return nil           render in  context          let screenshot   UIGraphicsGetImageFromCurrentImageContext           return screenshot          extension UIView       func makeSnapshot   - gt  UIImage            if  available iOS 10 0                   let renderer   UIGraphicsImageRenderer size  frame size              return renderer image     in drawHierarchy in  bounds  afterScreenUpdates  true              else               return layer makeSnapshot                       Usage  let image   view makeSnapshot     Full sample     Do not forget to add the solution code here   import UIKit  class ViewController  UIViewController         IBOutlet var viewForScreenShot  UIView       IBOutlet var screenShotRenderer  UIImageView        IBAction func makeViewScreenShotButtonTapped2   sender  UIButton            screenShotRenderer image   viewForScreenShot makeSnapshot                Main storyboard    lt  xml version  1 0  encoding  UTF-8   gt   lt document type  com apple InterfaceBuilder3 CocoaTouch Storyboard XIB  version  3 0  toolsVersion  11762  systemVersion  16C67  targetRuntime  iOS CocoaTouch  propertyAccessControl  none  useAutolayout  YES  useTraitCollections  YES  colorMatched  YES  initialViewController  BYZ-38-t0r  gt       lt device id  retina4 7  orientation  portrait  gt           lt adaptation id  fullscreen   gt       lt  device gt       lt dependencies gt           lt deployment identifier  iOS   gt           lt plugIn identifier  com apple InterfaceBuilder IBCocoaTouchPlugin  version  11757   gt           lt capability name  documents saved in the Xcode 8 format  minToolsVersion  8 0   gt       lt  dependencies gt       lt scenes gt           lt  --View Controller-- gt           lt scene sceneID  tne-QT-ifu  gt               lt objects gt                   lt viewController id  BYZ-38-t0r  customClass  ViewController  customModule  stackoverflow 2214957  customModuleProvider  target  sceneMemberID  viewController  gt                       lt layoutGuides gt                           lt viewControllerLayoutGuide type  top  id  y3c-jy-aDJ   gt                           lt viewControllerLayoutGuide type  bottom  id  wfy-db-euE   gt                       lt  layoutGuides gt                       lt view key  view  contentMode  scaleToFill  id  8bC-Xf-vdC  gt                           lt rect key  frame  x  0 0  y  0 0  width  375  height  667   gt                           lt autoresizingMask key  autoresizingMask  widthSizable  YES  heightSizable  YES   gt                           lt subviews gt                               lt view contentMode  scaleToFill  translatesAutoresizingMaskIntoConstraints  NO  id  Acg-GO-mMN  gt                                   lt rect key  frame  x  67  y  28  width  240  height  128   gt                                   lt subviews gt                                       lt textField opaque  NO  clipsSubviews  YES  contentMode  scaleToFill  contentHorizontalAlignment  left  contentVerticalAlignment  center  borderStyle  roundedRect  textAlignment  natural  minimumFontSize  17  translatesAutoresizingMaskIntoConstraints  NO  id  4Fr-O3-56t  gt                                           lt rect key  frame  x  72  y  49  width  96  height  30   gt                                           lt constraints gt                                               lt constraint firstAttribute  height  constant  30  id  cLv-es-h7Q   gt                                               lt constraint firstAttribute  width  constant  96  id  ytF-FH-gdm   gt                                           lt  constraints gt                                           lt nil key  textColor   gt                                           lt fontDescription key  fontDescription  type  system  pointSize  14   gt                                           lt textInputTraits key  textInputTraits   gt                                       lt  textField gt                                   lt  subviews gt                                   lt color key  backgroundColor  red  0 0  green  0 47843137250000001  blue  1  alpha  0 49277611300000002  colorSpace  custom  customColorSpace  sRGB   gt                                   lt color key  tintColor  white  0 66666666666666663  alpha  1  colorSpace  calibratedWhite   gt                                   lt constraints gt                                       lt constraint firstItem  4Fr-O3-56t  firstAttribute  centerX  secondItem  Acg-GO-mMN  secondAttribute  centerX  id  egj-rT-Gz5   gt                                       lt constraint firstItem  4Fr-O3-56t  firstAttribute  centerY  secondItem  Acg-GO-mMN  secondAttribute  centerY  id  ymi-Ll-WIV   gt                                   lt  constraints gt                               lt  view gt                               lt button opaque  NO  contentMode  scaleToFill  contentHorizontalAlignment  center  contentVerticalAlignment  center  buttonType  roundedRect  lineBreakMode  middleTruncation  translatesAutoresizingMaskIntoConstraints  NO  id  SQq-IE-pvj  gt                                   lt rect key  frame  x  109  y  214  width  157  height  30   gt                                   lt state key  normal  title  make view screen shot   gt                                   lt connections gt                                       lt action selector  makeViewScreenShotButtonTapped2   destination  BYZ-38-t0r  eventType  touchUpInside  id  KSY-ec-uvA   gt                                   lt  connections gt                               lt  button gt                               lt imageView userInteractionEnabled  NO  contentMode  scaleAspectFit  horizontalHuggingPriority  251  verticalHuggingPriority  251  translatesAutoresizingMaskIntoConstraints  NO  id  CEZ-Ju-Tpq  gt                                   lt rect key  frame  x  67  y  269  width  240  height  128   gt                                   lt constraints gt                                       lt constraint firstAttribute  width  constant  240  id  STo-iJ-rM4   gt                                       lt constraint firstAttribute  height  constant  128  id  tfi-zF-zdn   gt                                   lt  constraints gt                               lt  imageView gt                           lt  subviews gt                           lt color key  backgroundColor  red  0 95941069162436543  green  0 95941069162436543  blue  0 95941069162436543  alpha  1  colorSpace  custom  customColorSpace  sRGB   gt                           lt constraints gt                               lt constraint firstItem  CEZ-Ju-Tpq  firstAttribute  top  secondItem  SQq-IE-pvj  secondAttribute  bottom  constant  25  id  6x1-iB-gKF   gt                               lt constraint firstItem  Acg-GO-mMN  firstAttribute  leading  secondItem  CEZ-Ju-Tpq  secondAttribute  leading  id  LUp-Be-FiC   gt                               lt constraint firstItem  SQq-IE-pvj  firstAttribute  top  secondItem  Acg-GO-mMN  secondAttribute  bottom  constant  58  id  Qu0-YT-k9O   gt                               lt constraint firstItem  Acg-GO-mMN  firstAttribute  centerX  secondItem  8bC-Xf-vdC  secondAttribute  centerX  id  Qze-zd-ajY   gt                               lt constraint firstItem  Acg-GO-mMN  firstAttribute  trailing  secondItem  CEZ-Ju-Tpq  secondAttribute  trailing  id  b1d-sp-GHD   gt                               lt constraint firstItem  SQq-IE-pvj  firstAttribute  centerX  secondItem  CEZ-Ju-Tpq  secondAttribute  centerX  id  qCL-AF-Cro   gt                               lt constraint firstItem  Acg-GO-mMN  firstAttribute  top  secondItem  y3c-jy-aDJ  secondAttribute  bottom  constant  8  symbolic  YES  id  u5Y-eh-oSG   gt                               lt constraint firstItem  CEZ-Ju-Tpq  firstAttribute  centerY  secondItem  8bC-Xf-vdC  secondAttribute  centerY  id  vkx-JQ-pOF   gt                           lt  constraints gt                       lt  view gt                       lt connections gt                           lt outlet property  screenShotRenderer  destination  CEZ-Ju-Tpq  id  8QB-OE-ib6   gt                           lt outlet property  viewForScreenShot  destination  Acg-GO-mMN  id  jgL-yn-8kk   gt                       lt  connections gt                   lt  viewController gt                   lt placeholder placeholderIdentifier  IBFirstResponder  id  dkx-z0-nzr  sceneMemberID  firstResponder   gt               lt  objects gt               lt point key  canvasLocation  x  32 799999999999997  y  37 331334332833585   gt           lt  scene gt       lt  scenes gt   lt  document gt    Result

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iOS 7 has a new method that allows you to draw a view hierarchy into the current graphics context  This can be used to get an UIImage very fast    I implemented a category method on UIView to get the view as an UIImage   -  UIImage   pb takeSnapshot       UIGraphicsBeginImageContextWithOptions self bounds size  NO   UIScreen mainScreen  scale         self drawViewHierarchyInRect self bounds afterScreenUpdates YES           old style  self layer renderInContext UIGraphicsGetCurrentContext          UIImage  image   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return image      It is considerably faster then the existing renderInContext  method   Reference  https   developer apple com library content qa qa1817  index html  UPDATE FOR SWIFT  An extension that does the same   extension UIView        func pb takeSnapshot   - gt  UIImage           UIGraphicsBeginImageContextWithOptions bounds size  false  UIScreen mainScreen   scale           drawViewHierarchyInRect self bounds  afterScreenUpdates  true              old style  layer renderInContext UIGraphicsGetCurrentContext             let image   UIGraphicsGetImageFromCurrentImageContext           UIGraphicsEndImageContext           return image           UPDATE FOR SWIFT 3      UIGraphicsBeginImageContextWithOptions bounds size  false  UIScreen main scale       drawHierarchy in  self bounds  afterScreenUpdates  true       let image   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext       return image

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There is new API from iOS 10  extension UIView       func makeScreenshot   - gt  UIImage           let renderer   UIGraphicsImageRenderer bounds  self bounds          return renderer image    context  in             self layer render in  context cgContext

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-  void drawRect  CGRect rect     UIGraphicsBeginImageContext self bounds size          self view layer renderInContext UIGraphicsGetCurrentContext       UIImage  viewImage   UIGraphicsGetImageFromCurrentImageContext      UIGraphicsEndImageContext      UIImageWriteToSavedPhotosAlbum viewImage  nil  nil  nil         This method may put in your Controller class

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iOS7 onwards  we have below default methods    -  UIView   snapshotViewAfterScreenUpdates  BOOL afterUpdates   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 drawViewHierarchyInRect afterScreenUpdates  method instead   https   developer apple com library ios documentation uikit reference uiview class uiview uiview html

[ios] How Do I Take a Screen Shot of a UIView?

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