Resize UIImage by keeping Aspect ratio and width

Question

I seen in many posts for resizing the image by keeping aspect ratio  These functions uses the fixed points Width and Height  for RECT while resizing  But in my project  I need to resize the view based on the Width alone  Height should be taken automatically based on the aspect ratio  anyone help me to achieve this

User · Answer

This method is a category on UIImage  Does scale to fit in few lines of code using AVFoundation  Don t forget to import  import  lt AVFoundation AVFoundation h gt     implementation UIImage  Helper   -  UIImage   imageScaledToFitToSize  CGSize size       CGRect scaledRect   AVMakeRectWithAspectRatioInsideRect self size  CGRectMake 0  0  size width  size height        UIGraphicsBeginImageContextWithOptions size  NO  0        self drawInRect scaledRect       UIImage  scaledImage   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return scaledImage      end

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Well  we have few good answers here for resizing image  but I just modify as per my need  hope this help someone like me   My Requirement was   If image width is more than 1920  resize it with 1920 width and maintaining height with original aspect ratio  If image height is more than 1080  resize it with 1080 height and maintaining width with original aspect ratio       if  originalImage size width  gt  1920             CGSize newSize          newSize width   1920          newSize height    1920   originalImage size height    originalImage size width          originalImage    ProfileEditExperienceViewController imageWithImage originalImage scaledToSize newSize                if  originalImage size height  gt  1080                 CGSize newSize              newSize width    1080   originalImage size width    originalImage size height              newSize height   1080              originalImage    ProfileEditExperienceViewController imageWithImage originalImage scaledToSize newSize           UIImage   imageWithImage  UIImage   image scaledToSize  CGSize newSize           UIGraphicsBeginImageContext newSize            image drawInRect CGRectMake 0  0  newSize width  newSize height            UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext            UIGraphicsEndImageContext            return newImage         Thanks to  Srikar Appal   for resizing I have used his method    You may like to check this as well for resize calculation

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This one was perfect for me  Keeps aspect ratio and takes a maxLength  Width or Height will not be more than maxLength  - UIImage  imageWithImage   UIImage   sourceImage maxLength   float  maxLength       CGFloat scaleFactor   maxLength   MAX sourceImage size width  sourceImage size height        float newHeight   sourceImage size height   scaleFactor      float newWidth   sourceImage size width   scaleFactor       UIGraphicsBeginImageContext CGSizeMake newWidth  newHeight         sourceImage drawInRect CGRectMake 0  0  newWidth  newHeight        UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return newImage

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Programmatically   imageView contentMode   UIViewContentModeScaleAspectFit    Storyboard

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If you don t happen to know if the image will be portrait or landscape  e g user takes pic with camera   I created another method that takes max width and height parameters   Lets say you have a UIImage  myLargeImage which is a 4 3 ratio   UIImage  myResizedImage    ImageUtilities imageWithImage myLargeImage                                          scaledToMaxWidth 1024                                                 maxHeight 1024     The resized UIImage will be 1024x768 if landscape  768x1024 if portrait  This method will also generate higher res images for retina display      UIImage   imageWithImage  UIImage   image scaledToSize  CGSize size       if    UIScreen mainScreen  respondsToSelector  selector scale              UIGraphicsBeginImageContextWithOptions size  NO    UIScreen mainScreen  scale          else           UIGraphicsBeginImageContext size              image drawInRect CGRectMake 0  0  size width  size height        UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext            UIGraphicsEndImageContext         return newImage        UIImage   imageWithImage  UIImage   image scaledToMaxWidth  CGFloat width maxHeight  CGFloat height       CGFloat oldWidth   image size width      CGFloat oldHeight   image size height       CGFloat scaleFactor    oldWidth  gt  oldHeight    width   oldWidth   height   oldHeight       CGFloat newHeight   oldHeight   scaleFactor      CGFloat newWidth   oldWidth   scaleFactor      CGSize newSize   CGSizeMake newWidth  newHeight        return  ImageUtilities imageWithImage image scaledToSize newSize

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Swift 5 version of aspect-fit-to-height  based on answer by  J  nos  Uses the modern UIGraphicsImageRenderer API  so a valid UIImage is guaranteed to return   extension UIImage           Given a required height  returns a  rasterised  copy         of the image  aspect-fitted to that height       func aspectFittedToHeight   newHeight  CGFloat  - gt  UIImage               let scale   newHeight   self size height         let newWidth   self size width   scale         let newSize   CGSize width  newWidth  height  newHeight          let renderer   UIGraphicsImageRenderer size  newSize           return renderer image     in             self draw in  CGRect origin   zero  size  newSize                       You can use this in conjunction with a  vector-based  PDF image asset  to preserve quality at any render size

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In Swift 3 there are some changes   Here is an extension to UIImage   public extension UIImage       public func resize height  CGFloat  - gt  UIImage            let scale   height   self size height         let width   self size width   scale         UIGraphicsBeginImageContext CGSize width  width  height  height           self draw in  CGRect x 0  y 0  width width  height height           let resultImage   UIGraphicsGetImageFromCurrentImageContext           UIGraphicsEndImageContext           return resultImage

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Zeeshan Tufail  and Womble answers in Swift 5 with small improvements   Here we have extension with 2 functions to scale image to maxLength of any dimension and jpeg compression   extension UIImage       func aspectFittedToMaxLengthData maxLength  CGFloat  compressionQuality  CGFloat  - gt  Data           let scale   maxLength   max self size height  self size width          let format   UIGraphicsImageRendererFormat           format scale   scale         let renderer   UIGraphicsImageRenderer size  self size  format  format          return renderer jpegData withCompressionQuality  compressionQuality    context in             self draw in  CGRect origin   zero  size  self size                       func aspectFittedToMaxLengthImage maxLength  CGFloat  compressionQuality  CGFloat  - gt  UIImage            let newImageData   aspectFittedToMaxLengthData maxLength  maxLength  compressionQuality  compressionQuality          return UIImage data  newImageData

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I have solved it in a much simpler way  UIImage  placeholder    UIImage imageNamed   OriginalImage png    self yourImageview image    UIImage imageWithCGImage  placeholder CGImage  scale  placeholder scale   1 5                                    orientation  placeholder imageOrientation      multiplier of the scale will define the scalling of the image more the multiplier smaller the image  so You can check what fits your screen   Or you can also get the multiplire by dividing imagewidth screenwidth

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The method of Srikar works very well  if you know both height and width of your new Size  If you for example know only the width you want to scale to and don t care about the height you first have to calculate the scale factor of the height     UIImage  imageWithImage   UIImage   sourceImage scaledToWidth   float  i width       float oldWidth   sourceImage size width      float scaleFactor   i width   oldWidth       float newHeight   sourceImage size height   scaleFactor      float newWidth   oldWidth   scaleFactor       UIGraphicsBeginImageContext CGSizeMake newWidth  newHeight         sourceImage drawInRect CGRectMake 0  0  newWidth  newHeight        UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext            UIGraphicsEndImageContext        return newImage

User · Answer

Just import AVFoundation and use AVMakeRectWithAspectRatioInsideRect CGRectCurrentSize  CGRectMake 0  0  YOUR WIDTH  CGFLOAT MAX

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To improve on Ryan s answer         UIImage   imageWithImage  UIImage   image scaledToSize  CGSize size   CGFloat oldWidth   image size width          CGFloat oldHeight   image size height     You may need to take some retina adjustments into consideration here         CGFloat scaleFactor    oldWidth  gt  oldHeight    width   oldWidth   height   oldHeight   return  UIImage imageWithCGImage image CGImage scale scaleFactor orientation UIImageOrientationUp

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thanks  Maverick1st the algorithm  I implemented it to Swift  in my case height is the input parameter  class func resizeImage image  UIImage  newHeight  CGFloat  - gt  UIImage        let scale   newHeight   image size height     let newWidth   image size width   scale     UIGraphicsBeginImageContext CGSizeMake newWidth  newHeight       image drawInRect CGRectMake 0  0  newWidth  newHeight       let newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext        return newImage

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If somebody needs this solution in Swift 5  private func resizeImage image  UIImage  newHeight  CGFloat  - gt  UIImage            let scale   newHeight   image size height     let newWidth   image size width   scale     UIGraphicsBeginImageContext CGSize width newWidth  height newHeight       image draw in CGRect x 0  y 0  width newWidth  height newHeight       let newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext        return newImage

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Best answer Maverick 1st s correctly translated to Swift  working with latest swift 3     func imageWithImage  sourceImage UIImage  scaledToWidth  CGFloat  - gt  UIImage       let oldWidth   sourceImage size width     let scaleFactor   scaledToWidth   oldWidth      let newHeight   sourceImage size height   scaleFactor     let newWidth   oldWidth   scaleFactor      UIGraphicsBeginImageContext CGSize width newWidth  height newHeight       sourceImage draw in  CGRect x 0  y 0  width newWidth  height newHeight       let newImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext       return newImage

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The simplest way is to set the frame of your UIImageView and set the contentMode to one of the resizing options   The code goes like this - This can be used as an utility method -     UIImage   imageWithImage  UIImage   image scaledToSize  CGSize newSize       UIGraphicsBeginImageContext newSize        image drawInRect CGRectMake 0  0  newSize width  newSize height        UIImage  newImage   UIGraphicsGetImageFromCurrentImageContext            UIGraphicsEndImageContext        return newImage

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extension UIImage            Returns a image that fills in newSize     func resizedImage newSize  CGSize  - gt  UIImage            guard size    newSize else   return self        let hasAlpha   false     let scale  CGFloat   0 0     UIGraphicsBeginImageContextWithOptions newSize   hasAlpha  scale          UIGraphicsBeginImageContextWithOptions newSize  false  0 0           draw in  CGRect x  0  y  0  width  newSize width  height  newSize height           let newImage  UIImage    UIGraphicsGetImageFromCurrentImageContext           UIGraphicsEndImageContext           return newImage                Returns a resized image that fits in rectSize  keeping it s aspect ratio         Note that the new image size is not rectSize  but within it      func resizedImageWithinRect rectSize  CGSize  - gt  UIImage            let widthFactor   size width   rectSize width         let heightFactor   size height   rectSize height          var resizeFactor   widthFactor         if size height  gt  size width               resizeFactor   heightFactor                    let newSize   CGSize width  size width   resizeFactor  height  size height   resizeFactor          let resized   resizedImage newSize  newSize           return resized           When scale is set to 0 0  the scale factor of the main screen is used  which for Retina displays is 2 0 or higher  3 0 on the iPhone 6 Plus

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Ryan s Solution  Ryan in swift code  use    func imageWithSize image  UIImage size  CGSize - gt UIImage      if UIScreen mainScreen   respondsToSelector  scale            UIGraphicsBeginImageContextWithOptions size false UIScreen mainScreen   scale             else                UIGraphicsBeginImageContext size              image drawInRect CGRectMake 0  0  size width  size height        var newImage   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext         return newImage       Summon this function VVV func resizeImageWithAspect image  UIImage scaledToMaxWidth width CGFloat maxHeight height  CGFloat - gt UIImage       let oldWidth   image size width      let oldHeight   image size height       let scaleFactor    oldWidth  gt  oldHeight    width   oldWidth   height   oldHeight       let newHeight   oldHeight   scaleFactor      let newWidth   oldWidth   scaleFactor      let newSize   CGSizeMake newWidth  newHeight        return imageWithSize image  size  newSize

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Calculates the best height of the image for available width   import Foundation  public extension UIImage       public func height forWidth width  CGFloat  - gt  CGFloat           let boundingRect   CGRect              x  0              y  0              width  width              height  CGFloat MAXFLOAT                    let rect   AVMakeRect              aspectRatio  size              insideRect  boundingRect                   return rect size height

[iphone] Resize UIImage by keeping Aspect ratio and width

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