How to Rotate a UIImage 90 degrees

Question

I have a UIImage that is UIImageOrientationUp  portrait  that I would like to rotate counter-clockwise by 90 degrees  to landscape   I don t want to use a CGAffineTransform  I want the pixels of the UIImage to actually shift position  I am using a block of code  shown below  originally intended to resize a UIImage to do this  I set a target size as the current size of the UIImage but I get an error       Error   CGBitmapContextCreate  invalid data bytes row  should be at least 1708 for 8 integer bits component  3 components  kCGImageAlphaPremultipliedLast     I don t get an error whenever I provide a SMALLER size as the target size BTW   How can I ROTATE my UIImage 90 degrees CCW using just core graphics functions while preserving the current size   - UIImage  reverseImageByScalingToSize  CGSize targetSize  UIImage  anImage       UIImage  sourceImage   anImage       CGFloat targetWidth   targetSize height      CGFloat targetHeight   targetSize width       CGImageRef imageRef    sourceImage CGImage       CGBitmapInfo bitmapInfo   CGImageGetBitmapInfo imageRef       CGColorSpaceRef colorSpaceInfo   CGImageGetColorSpace imageRef        if  bitmapInfo    kCGImageAlphaNone            bitmapInfo   kCGImageAlphaNoneSkipLast             CGContextRef bitmap       if  sourceImage imageOrientation    UIImageOrientationUp    sourceImage imageOrientation    UIImageOrientationDown            bitmap   CGBitmapContextCreate NULL  targetHeight  targetWidth  CGImageGetBitsPerComponent imageRef   CGImageGetBytesPerRow imageRef   colorSpaceInfo  bitmapInfo          else             bitmap   CGBitmapContextCreate NULL  targetWidth  targetHeight  CGImageGetBitsPerComponent imageRef   CGImageGetBytesPerRow imageRef   colorSpaceInfo  bitmapInfo                       if  sourceImage imageOrientation    UIImageOrientationRight            CGContextRotateCTM  bitmap  radians 90            CGContextTranslateCTM  bitmap  0  -targetHeight          else if  sourceImage imageOrientation    UIImageOrientationLeft            CGContextRotateCTM  bitmap  radians -90            CGContextTranslateCTM  bitmap  -targetWidth  0          else if  sourceImage imageOrientation    UIImageOrientationDown               NOTHING       else if  sourceImage imageOrientation    UIImageOrientationUp            CGContextRotateCTM  bitmap  radians 90            CGContextTranslateCTM  bitmap  0  -targetHeight              CGContextDrawImage bitmap  CGRectMake 0  0  targetWidth  targetHeight   imageRef       CGImageRef ref   CGBitmapContextCreateImage bitmap       UIImage  newImage    UIImage imageWithCGImage ref        CGContextRelease bitmap       CGImageRelease ref        return newImage

User · Answer

Simple   Just change the image orientation flag   UIImage  oldImage    UIImage imageNamed   whatever jpg    UIImageOrientation newOrientation  switch  oldImage imageOrientation        case UIImageOrientationUp          newOrientation   UIImageOrientationLandscapeLeft          break      case UIImageOrientationLandscapeLeft          newOrientation   UIImageOrientationDown          break      case UIImageOrientationDown          newOrientation   UIImageOrientationLandscapeRight          break      case UIImageOrientationLandscapeRight          newOrientation   UIImageOrientationUp          break         you can also handle mirrored orientations similarly       UIImage  rotatedImage    UIImage imageWithCGImage oldImage CGImage scale 1 0f orientation newOrientation

User · Answer

I had trouble with ll of the above  including the approved answer  I converted Hardy s category back into a method since all i wanted was to rotate an image  Here s the code and usage   -  UIImage   imageRotatedByDegrees  UIImage  oldImage deg  CGFloat degrees     calculate the size of the rotated view s containing box for our drawing space UIView  rotatedViewBox     UIView alloc  initWithFrame CGRectMake 0 0 oldImage size width  oldImage size height    CGAffineTransform t   CGAffineTransformMakeRotation degrees   M PI   180   rotatedViewBox transform   t  CGSize rotatedSize   rotatedViewBox frame size     Create the bitmap context UIGraphicsBeginImageContext rotatedSize   CGContextRef bitmap   UIGraphicsGetCurrentContext        Move the origin to the middle of the image so we will rotate and scale around the center  CGContextTranslateCTM bitmap  rotatedSize width 2  rotatedSize height 2            Rotate the image context CGContextRotateCTM bitmap   degrees   M PI   180        Now  draw the rotated scaled image into the context CGContextScaleCTM bitmap  1 0  -1 0   CGContextDrawImage bitmap  CGRectMake -oldImage size width   2  -oldImage size height   2  oldImage size width  oldImage size height    oldImage CGImage     UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext    UIGraphicsEndImageContext    return newImage      And the usage   UIImage  image2    self imageRotatedByDegrees image deg 90     Thanks Hardy

User · Answer

tint uiimage grayscale  appears to be the appropriate Google-Fu for this one  straight away I get   https   discussions apple com message 8104516 messageID 8104516 amp  8104516  https   discussions apple com thread 2751445 start 0 amp tstart 0  How would I tint an image programmatically on the iPhone

User · Answer

As strange as this seems  the following code solved the problem for me      UIImage  unrotateImage  UIImage  image       CGSize size   image size      UIGraphicsBeginImageContext size        image drawInRect CGRectMake 0 0 size width  size height        UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext         return newImage

User · Answer

Minor change to the other answers that are based on Hardy Macia s code  There is no need to create a whole UIView object simply to calculate the bounding rectangle of the rotated image  Just apply a rotate transform to the image rectangle using CGRectApplyAffineTransform   static CGFloat DegreesToRadians CGFloat degrees   return degrees   M PI   180   static CGFloat RadiansToDegrees CGFloat radians   return radians   180 M PI     -  CGSize rotatedImageSize  CGFloat degrees       CGAffineTransform t   CGAffineTransformMakeRotation DegreesToRadians degrees        CGRect originalImageRect   CGRectMake 0  0  self size width  self size height       CGRect rotatedImageRect   CGRectApplyAffineTransform originalImageRect  t       CGSize rotatedSize   rotatedImageRect size       return rotatedSize     -  UIImage  imageRotatedByDegrees  CGFloat degrees          calculate the size of the rotated view s containing box for our drawing space     CGSize rotatedSize    self rotatedImageSize degrees           Create the bitmap context     UIGraphicsBeginImageContext rotatedSize       CGContextRef bitmap   UIGraphicsGetCurrentContext            Move the origin to the middle of the image so we will rotate and scale around the center      CGContextTranslateCTM bitmap  rotatedSize width 2  rotatedSize height 2                Rotate the image context     CGContextRotateCTM bitmap  DegreesToRadians degrees            Now  draw the rotated scaled image into the context     CGContextScaleCTM bitmap  1 0  -1 0       CGContextDrawImage bitmap  CGRectMake -self size width   2  -self size height   2  self size width  self size height    self CGImage         UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return newImage

User · Answer

A thread safe rotation function is the following  it works much better    - UIImage  imageByRotatingImage  UIImage  initImage fromImageOrientation  UIImageOrientation orientation   CGImageRef imgRef   initImage CGImage   CGFloat width   CGImageGetWidth imgRef   CGFloat height   CGImageGetHeight imgRef    CGAffineTransform transform   CGAffineTransformIdentity  CGRect bounds   CGRectMake 0  0  width  height   CGSize imageSize   CGSizeMake CGImageGetWidth imgRef   CGImageGetHeight imgRef    CGFloat boundHeight  UIImageOrientation orient   orientation  switch orient         case UIImageOrientationUp    EXIF   1         return initImage          break       case UIImageOrientationUpMirrored    EXIF   2         transform   CGAffineTransformMakeTranslation imageSize width  0 0           transform   CGAffineTransformScale transform  -1 0  1 0           break       case UIImageOrientationDown    EXIF   3         transform   CGAffineTransformMakeTranslation imageSize width  imageSize height           transform   CGAffineTransformRotate transform  M PI           break       case UIImageOrientationDownMirrored    EXIF   4         transform   CGAffineTransformMakeTranslation 0 0  imageSize height           transform   CGAffineTransformScale transform  1 0  -1 0           break       case UIImageOrientationLeftMirrored    EXIF   5         boundHeight   bounds size height          bounds size height   bounds size width          bounds size width   boundHeight          transform   CGAffineTransformMakeTranslation imageSize height  imageSize width           transform   CGAffineTransformScale transform  -1 0  1 0           transform   CGAffineTransformRotate transform  3 0   M PI   2 0           break       case UIImageOrientationLeft    EXIF   6         boundHeight   bounds size height          bounds size height   bounds size width          bounds size width   boundHeight          transform   CGAffineTransformMakeTranslation 0 0  imageSize width           transform   CGAffineTransformRotate transform  3 0   M PI   2 0           break       case UIImageOrientationRightMirrored    EXIF   7         boundHeight   bounds size height          bounds size height   bounds size width          bounds size width   boundHeight          transform   CGAffineTransformMakeScale -1 0  1 0           transform   CGAffineTransformRotate transform  M PI   2 0           break       case UIImageOrientationRight    EXIF   8         boundHeight   bounds size height          bounds size height   bounds size width          bounds size width   boundHeight          transform   CGAffineTransformMakeTranslation imageSize height  0 0           transform   CGAffineTransformRotate transform  M PI   2 0           break       default           NSException raise NSInternalInconsistencyException format   Invalid image orientation          Create the bitmap context CGContextRef    context   NULL  void            bitmapData  int             bitmapByteCount  int             bitmapBytesPerRow      Declare the number of bytes per row  Each pixel in the bitmap in this    example is represented by 4 bytes  8 bits each of red  green  blue  and    alpha  bitmapBytesPerRow      bounds size width   4   bitmapByteCount        bitmapBytesPerRow   bounds size height   bitmapData   malloc  bitmapByteCount    if  bitmapData    NULL        return nil        Create the bitmap context  We want pre-multiplied ARGB  8-bits    per component  Regardless of what the source image format is     CMYK  Grayscale  and so on  it will be converted over to the format    specified here by CGBitmapContextCreate  CGColorSpaceRef colorspace   CGImageGetColorSpace imgRef   context   CGBitmapContextCreate  bitmapData bounds size width bounds size height 8 bitmapBytesPerRow                                   colorspace  kCGBitmapAlphaInfoMask  amp  kCGImageAlphaPremultipliedLast    if  context    NULL         error creating context     return nil   CGContextScaleCTM context  -1 0  -1 0   CGContextTranslateCTM context  -bounds size width  -bounds size height    CGContextConcatCTM context  transform       Draw the image to the bitmap context  Once we draw  the memory    allocated for the context for rendering will then contain the    raw image data in the specified color space  CGContextDrawImage context  CGRectMake 0 0 width  height   imgRef    CGImageRef imgRef2   CGBitmapContextCreateImage context   CGContextRelease context   free bitmapData   UIImage   image    UIImage imageWithCGImage imgRef2 scale initImage scale orientation UIImageOrientationUp   CGImageRelease imgRef2   return image

User · Answer

Rotate Image by 90 degree  clockwise anti-clockwise direction   Function call -    UIImage  rotatedImage    self rotateImage originalImage clockwise YES     Implementation   -  UIImage  rotateImage  UIImage  sourceImage clockwise  BOOL clockwise         CGSize size   sourceImage size      UIGraphicsBeginImageContext CGSizeMake size height  size width          UIImage imageWithCGImage  sourceImage CGImage                           scale 1 0                    orientation clockwise   UIImageOrientationRight   UIImageOrientationLeft                     drawInRect CGRectMake 0 0 size height  size width        UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext        return newImage

User · Answer

I like the simple elegance of Peter Sarnowski s answer  but it can cause problems when you can t rely on EXIF metadata and the like  In situations where you need to rotate the actual image data I would recommend something like this   -  UIImage   rotateImage  UIImage    img       CGSize imgSize    img size       UIGraphicsBeginImageContext imgSize       CGContextRef context   UIGraphicsGetCurrentContext        CGContextRotateCTM context  M PI 2       CGContextTranslateCTM context  0  -640        img drawInRect CGRectMake 0  0  imgSize height  imgSize width        UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return newImage      The above code takes an image whose orientation is Landscape  can t remember if it s Landscape Left or Landscape Right  and rotates it into Portrait  It is an example which can be modified for your needs   The key arguments you would have to play with are CGContextRotateCTM context  M PI 2  where you decide how much you want to rotate by  but then you have to make sure the picture still draws on the screen using CGContextTranslateCTM context  0  -640   This last part is quite important to make sure you see the image and not a blank screen     For more info check out the source

User · Answer

Check out the simple and awesome code of Hardy Macia at  cutting-scaling-and-rotating-uiimages  Just call  UIImage  rotatedImage    originalImage imageRotatedByDegrees 90 0     Thanks Hardy Macia   Header     UIImage   imageAtRect  CGRect rect   UIImage   imageByScalingProportionallyToMinimumSize  CGSize targetSize   UIImage   imageByScalingProportionallyToSize  CGSize targetSize   UIImage   imageByScalingToSize  CGSize targetSize   UIImage   imageRotatedByRadians  CGFloat radians   UIImage   imageRotatedByDegrees  CGFloat degrees    Since the link may die  here s the complete code         UIImage-Extensions h        Created by Hardy Macia on 7 1 09      Copyright 2009 Catamount Software  All rights reserved      import  lt Foundation Foundation h gt   import  lt UIKit UIKit h gt    interface UIImage  CS Extensions  -  UIImage   imageAtRect  CGRect rect  -  UIImage   imageByScalingProportionallyToMinimumSize  CGSize targetSize  -  UIImage   imageByScalingProportionallyToSize  CGSize targetSize  -  UIImage   imageByScalingToSize  CGSize targetSize  -  UIImage   imageRotatedByRadians  CGFloat radians  -  UIImage   imageRotatedByDegrees  CGFloat degrees    end          UIImage-Extensions m        Created by Hardy Macia on 7 1 09      Copyright 2009 Catamount Software  All rights reserved       import  UIImage-Extensions h   CGFloat DegreesToRadians CGFloat degrees   return degrees   M PI   180    CGFloat RadiansToDegrees CGFloat radians   return radians   180 M PI      implementation UIImage  CS Extensions   - UIImage   imageAtRect  CGRect rect       CGImageRef imageRef   CGImageCreateWithImageInRect  self CGImage   rect      UIImage  subImage    UIImage imageWithCGImage  imageRef      CGImageRelease imageRef       return subImage      -  UIImage   imageByScalingProportionallyToMinimumSize  CGSize targetSize       UIImage  sourceImage   self     UIImage  newImage   nil      CGSize imageSize   sourceImage size     CGFloat width   imageSize width     CGFloat height   imageSize height      CGFloat targetWidth   targetSize width     CGFloat targetHeight   targetSize height      CGFloat scaleFactor   0 0     CGFloat scaledWidth   targetWidth     CGFloat scaledHeight   targetHeight      CGPoint thumbnailPoint   CGPointMake 0 0 0 0       if  CGSizeEqualToSize imageSize  targetSize     NO           CGFloat widthFactor   targetWidth   width        CGFloat heightFactor   targetHeight   height         if  widthFactor  gt  heightFactor            scaleFactor   widthFactor        else          scaleFactor   heightFactor         scaledWidth    width   scaleFactor        scaledHeight   height   scaleFactor            center the image        if  widthFactor  gt  heightFactor             thumbnailPoint y    targetHeight - scaledHeight    0 5           else if  widthFactor  lt  heightFactor             thumbnailPoint x    targetWidth - scaledWidth    0 5                       this is actually the interesting part      UIGraphicsBeginImageContext targetSize       CGRect thumbnailRect   CGRectZero     thumbnailRect origin   thumbnailPoint     thumbnailRect size width    scaledWidth     thumbnailRect size height   scaledHeight       sourceImage drawInRect thumbnailRect       newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext        if newImage    nil  NSLog   could not scale image         return newImage       -  UIImage   imageByScalingProportionallyToSize  CGSize targetSize       UIImage  sourceImage   self     UIImage  newImage   nil      CGSize imageSize   sourceImage size     CGFloat width   imageSize width     CGFloat height   imageSize height      CGFloat targetWidth   targetSize width     CGFloat targetHeight   targetSize height      CGFloat scaleFactor   0 0     CGFloat scaledWidth   targetWidth     CGFloat scaledHeight   targetHeight      CGPoint thumbnailPoint   CGPointMake 0 0 0 0       if  CGSizeEqualToSize imageSize  targetSize     NO           CGFloat widthFactor   targetWidth   width        CGFloat heightFactor   targetHeight   height         if  widthFactor  lt  heightFactor            scaleFactor   widthFactor        else          scaleFactor   heightFactor         scaledWidth    width   scaleFactor        scaledHeight   height   scaleFactor            center the image        if  widthFactor  lt  heightFactor             thumbnailPoint y    targetHeight - scaledHeight    0 5           else if  widthFactor  gt  heightFactor             thumbnailPoint x    targetWidth - scaledWidth    0 5                       this is actually the interesting part      UIGraphicsBeginImageContext targetSize       CGRect thumbnailRect   CGRectZero     thumbnailRect origin   thumbnailPoint     thumbnailRect size width    scaledWidth     thumbnailRect size height   scaledHeight       sourceImage drawInRect thumbnailRect       newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext        if newImage    nil  NSLog   could not scale image         return newImage       -  UIImage   imageByScalingToSize  CGSize targetSize       UIImage  sourceImage   self     UIImage  newImage   nil           CGSize imageSize   sourceImage size          CGFloat width   imageSize width          CGFloat height   imageSize height      CGFloat targetWidth   targetSize width     CGFloat targetHeight   targetSize height           CGFloat scaleFactor   0 0     CGFloat scaledWidth   targetWidth     CGFloat scaledHeight   targetHeight      CGPoint thumbnailPoint   CGPointMake 0 0 0 0          this is actually the interesting part      UIGraphicsBeginImageContext targetSize       CGRect thumbnailRect   CGRectZero     thumbnailRect origin   thumbnailPoint     thumbnailRect size width    scaledWidth     thumbnailRect size height   scaledHeight       sourceImage drawInRect thumbnailRect       newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext        if newImage    nil  NSLog   could not scale image         return newImage       -  UIImage   imageRotatedByRadians  CGFloat radians      return  self imageRotatedByDegrees RadiansToDegrees radians       -  UIImage   imageRotatedByDegrees  CGFloat degrees             calculate the size of the rotated view s containing box for our drawing space    UIView  rotatedViewBox     UIView alloc  initWithFrame CGRectMake 0 0 self size width  self size height       CGAffineTransform t   CGAffineTransformMakeRotation DegreesToRadians degrees       rotatedViewBox transform   t     CGSize rotatedSize   rotatedViewBox frame size      rotatedViewBox release          Create the bitmap context    UIGraphicsBeginImageContext rotatedSize      CGContextRef bitmap   UIGraphicsGetCurrentContext           Move the origin to the middle of the image so we will rotate and scale around the center     CGContextTranslateCTM bitmap  rotatedSize width 2  rotatedSize height 2               Rotate the image context    CGContextRotateCTM bitmap  DegreesToRadians degrees           Now  draw the rotated scaled image into the context    CGContextScaleCTM bitmap  1 0  -1 0      CGContextDrawImage bitmap  CGRectMake -self size width   2  -self size height   2  self size width  self size height    self CGImage        UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext       return newImage       end

User · Answer

There is a extremely efficient UIImage category named NYXImagesKit  It uses vDSP  CoreImage and vImage to be as fast as possible  It has a UIImage Rotating category that saved my day     https   github com Nyx0uf NYXImagesKit

User · Answer

I try this code  it works  and took from  http   www catamount com blog 1015 uiimage-extensions-for-cutting-scaling-and-rotating-uiimages      UIImage   rotateImage  UIImage  src byRadian  CGFloat radian          calculate the size of the rotated view s containing box for our drawing space     UIView  rotatedViewBox     UIView alloc  initWithFrame CGRectMake 0 0  src size width  src size height        CGAffineTransform t   CGAffineTransformMakeRotation radian       rotatedViewBox transform   t      CGSize rotatedSize   rotatedViewBox frame size          Create the bitmap context     UIGraphicsBeginImageContext rotatedSize       CGContextRef bitmap   UIGraphicsGetCurrentContext            Move the origin to the middle of the image so we will rotate and scale around the center      CGContextTranslateCTM bitmap  rotatedSize width 2  rotatedSize height 2                Rotate the image context     CGContextRotateCTM bitmap  radian           Now  draw the rotated scaled image into the context     CGContextScaleCTM bitmap  1 0  -1 0       CGContextDrawImage bitmap  CGRectMake -src size width   2  -src size height   2  src size width  src size height    src CGImage         UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return newImage

User · Answer

I believe the easiest way  and thread safe too  is to do     assume that the image is loaded in landscape mode from disk UIImage   landscapeImage    UIImage imageNamed imgname   UIImage   portraitImage     UIImage alloc  initWithCGImage  landscapeImage CGImage                                                      scale  1 0                                                orientation  UIImageOrientationRight     Note  As Brainware said this only modifies the orientation data of the image - the pixel data is untouched  For some applications  this may not be enough   Or in Swift   guard     let landscapeImage   UIImage named   imgname        let landscapeCGImage   landscapeImage cgImage else   return   let portraitImage   UIImage cgImage  landscapeCGImage  scale  landscapeImage scale  orientation   right

User · Answer

Swift 3 UIImage extension   func fixOrientation   - gt  UIImage           No-op if the orientation is already correct     if   self imageOrientation     up             return self                We need to calculate the proper transformation to make the image upright         We do it in 2 steps  Rotate if Left Right Down  and then flip if Mirrored      var transform  CGAffineTransform    identity      if   self imageOrientation     down    self imageOrientation     downMirrored             transform   transform translatedBy x  self size width  y  self size height          transform   transform rotated by   pi             if   self imageOrientation     left    self imageOrientation     leftMirrored             transform   transform translatedBy x  self size width  y  0          transform   transform rotated by   pi 2             if   self imageOrientation     right    self imageOrientation     rightMirrored             transform   transform translatedBy x  0  y  self size height           transform   transform rotated by  - pi 2              if   self imageOrientation     upMirrored    self imageOrientation     downMirrored             transform   transform translatedBy x  self size width  y  0          transform   transform scaledBy x  -1  y  1             if   self imageOrientation     leftMirrored    self imageOrientation     rightMirrored             transform   transform translatedBy x  self size height  y  0           transform   transform scaledBy x  -1  y  1                 Now we draw the underlying CGImage into a new context  applying the transform        calculated above      let ctx  CGContext   CGContext data  nil  width  Int self size width   height  Int self size height                                      bitsPerComponent  self cgImage  bitsPerComponent  bytesPerRow  0                                     space  self cgImage  colorSpace                                      bitmapInfo  self cgImage  bitmapInfo rawValue         ctx concatenate transform       if   self imageOrientation     left            self imageOrientation     leftMirrored            self imageOrientation     right            self imageOrientation     rightMirrored             ctx draw self cgImage   in  CGRect x  0 0 y  0 0 width  self size height height  self size width         else           ctx draw self cgImage   in  CGRect x  0 0 y  0 0 width  self size width height  self size height                 And now we just create a new UIImage from the drawing context and return it     return UIImage cgImage  ctx makeImage

User · Answer

If you want to add a photo rotate button that ll keep rotating the photo in 90 degree increments  here you go   finalImage is a UIImage that s already been created elsewhere    -  void rotatePhoto       UIImage  rotatedImage       if  finalImage imageOrientation    UIImageOrientationRight          rotatedImage     UIImage alloc  initWithCGImage  finalImage CGImage                                               scale  1 0                                         orientation  UIImageOrientationDown       else if  finalImage imageOrientation    UIImageOrientationDown          rotatedImage     UIImage alloc  initWithCGImage  finalImage CGImage                                               scale  1 0                                         orientation  UIImageOrientationLeft       else if  finalImage imageOrientation    UIImageOrientationLeft          rotatedImage     UIImage alloc  initWithCGImage  finalImage CGImage                                               scale  1 0                                         orientation  UIImageOrientationUp       else         rotatedImage     UIImage alloc  initWithCGImage  finalImage CGImage                                                      scale  1 0                                                orientation  UIImageOrientationRight       finalImage   rotatedImage

User · Answer

What about something like   static inline double radians  double degrees   return degrees   M PI 180   UIImage  rotate UIImage  src  UIImageOrientation orientation        UIGraphicsBeginImageContext src size        CGContextRef context   UIGraphicsGetCurrentContext         if  orientation    UIImageOrientationRight            CGContextRotateCTM  context  radians 90          else if  orientation    UIImageOrientationLeft            CGContextRotateCTM  context  radians -90          else if  orientation    UIImageOrientationDown               NOTHING       else if  orientation    UIImageOrientationUp            CGContextRotateCTM  context  radians 90                src drawAtPoint CGPointMake 0  0         UIImage  image   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return image

User · Answer

For Swift  Here is a simple extension to UIImage      ImageRotation swift  import UIKit  extension UIImage         public func imageRotatedByDegrees degrees  CGFloat  flip  Bool  - gt  UIImage           let radiansToDegrees   CGFloat  - gt  CGFloat                 return  0    180 0   CGFloat M PI                     let degreesToRadians   CGFloat  - gt  CGFloat                 return  0   180 0   CGFloat M PI                        calculate the size of the rotated view s containing box for our drawing space         let rotatedViewBox   UIView frame  CGRect origin  CGPointZero  size  size           let t   CGAffineTransformMakeRotation degreesToRadians degrees            rotatedViewBox transform   t         let rotatedSize   rotatedViewBox frame size             Create the bitmap context         UIGraphicsBeginImageContext rotatedSize          let bitmap   UIGraphicsGetCurrentContext               Move the origin to the middle of the image so we will rotate and scale around the center          CGContextTranslateCTM bitmap  rotatedSize width   2 0  rotatedSize height   2 0                    Rotate the image context         CGContextRotateCTM bitmap  degreesToRadians degrees                Now  draw the rotated scaled image into the context         var yFlip  CGFloat          if flip               yFlip   CGFloat -1 0            else               yFlip   CGFloat 1 0                     CGContextScaleCTM bitmap  yFlip  -1 0          CGContextDrawImage bitmap  CGRectMake -size width   2  -size height   2  size width  size height   CGImage           let newImage   UIGraphicsGetImageFromCurrentImageContext           UIGraphicsEndImageContext            return newImage            Source   Use it with   rotatedPhoto   rotatedPhoto  imageRotatedByDegrees 90  flip  false     The former will rotate an image and flip it if flip is set to true

User · Answer

Here is a Swift extension to UIImage that rotates the image by any arbitrary angle   Use it like this  let rotatedImage   image rotated byDegrees  degree   I used the Objective-C code in one of the other answers and removed a few lines that we incorrect  rotated box stuff  and turned it into an extension for UIImage   extension UIImage    func rotate byDegrees degree  Double  - gt  UIImage       let radians   CGFloat degree M PI  180 0 as CGFloat     let rotatedSize   self size     let scale   UIScreen mainScreen   scale     UIGraphicsBeginImageContextWithOptions rotatedSize  false  scale      let bitmap   UIGraphicsGetCurrentContext       CGContextTranslateCTM bitmap  rotatedSize width   2  rotatedSize height   2       CGContextRotateCTM bitmap  radians       CGContextScaleCTM bitmap  1 0  -1 0       CGContextDrawImage bitmap  CGRectMake -self size width   2  -self size height   2   self size width  self size height   self CGImage        let newImage   UIGraphicsGetImageFromCurrentImageContext        return newImage

User · Answer

Swift 4 2 version of RawMean s answer   extension UIImage    func rotated byDegrees degree  Double  - gt  UIImage       let radians   CGFloat degree    pi    180 0 as CGFloat     let rotatedSize   self size     let scale   UIScreen main scale     UIGraphicsBeginImageContextWithOptions rotatedSize  false  scale      let bitmap   UIGraphicsGetCurrentContext       bitmap  translateBy x  rotatedSize width   2  y  rotatedSize height   2      bitmap  rotate by  radians      bitmap  scaleBy x  1 0  y  -1 0      bitmap  draw          self cgImage           in  CGRect init x  -self size width   2  y  -self size height   2   width  self size width  height  self size height       let newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext      this is needed     return newImage

User · Answer

resize-a-uiimage-the-right-way explains some of the issues many code samples for doing this have  and has some code snippets to help deal with UIImages - the private helper method in UIImage resize m accepts a transform to allow rotation  so you d just need to expose that as a public interface      Returns a copy of the image that has been transformed using the given affine transform and scaled to the new size    The new image s orientation will be UIImageOrientationUp  regardless of the current image s orientation    If the new size is not integral  it will be rounded up -  UIImage   resizedImage  CGSize newSize                 transform  CGAffineTransform transform            drawTransposed  BOOL transpose      interpolationQuality  CGInterpolationQuality quality       CGRect newRect   CGRectIntegral CGRectMake 0  0  newSize width  newSize height        CGRect transposedRect   CGRectMake 0  0  newRect size height  newRect size width       CGImageRef imageRef   self CGImage          Build a context that s the same dimensions as the new size     CGContextRef bitmap   CGBitmapContextCreate NULL                                                  newRect size width                                                  newRect size height                                                  CGImageGetBitsPerComponent imageRef                                                   0                                                  CGImageGetColorSpace imageRef                                                   CGImageGetBitmapInfo imageRef            Rotate and or flip the image if required by its orientation     CGContextConcatCTM bitmap  transform           Set the quality level to use when rescaling     CGContextSetInterpolationQuality bitmap  quality           Draw into the context  this scales the image     CGContextDrawImage bitmap  transpose   transposedRect   newRect  imageRef           Get the resized image from the context and a UIImage     CGImageRef newImageRef   CGBitmapContextCreateImage bitmap       UIImage  newImage    UIImage imageWithCGImage newImageRef           Clean up     CGContextRelease bitmap       CGImageRelease newImageRef        return newImage      This is the license from that file      Created by Trevor Harmon on 8 5 09     Free for personal or commercial use  with or without modification     No warranty is expressed or implied

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