How to scale a UIImageView proportionally

Question

I have a UIImageView and the objective is to scale it down proportionally by giving it either a height or width    UIImage  image     UIImage alloc  initWithData  NSData dataWithContentsOfURL  NSURL URLWithString   http   farm4 static flickr com 3092 2915896504 a88b69c9de jpg      UIImageView  imageView     UIImageView alloc  initWithImage image       Add image view  self view addSubview imageView         set contentMode to scale aspect to fit imageView contentMode   UIViewContentModeScaleAspectFit     change width of frame CGRect frame   imageView frame  frame size width   100  imageView frame   frame    The image did get resized but the position is not at the top left  What is the best approach to scaling image imageView and how do I correct the position

User · Answer

UIImageView Scale h    import  lt Foundation Foundation h gt    interface UIImageView  Scale   - void  scaleAspectFit  CGFloat  scaleFactor    end   UIImageView Scale m    import  UIImageView Scale h    implementation UIImageView  Scale    - void  scaleAspectFit  CGFloat  scaleFactor       self contentScaleFactor   scaleFactor      self transform   CGAffineTransformMakeScale scaleFactor  scaleFactor        CGRect newRect   self frame      newRect origin x   0      newRect origin y   0      self frame   newRect      end

User · Answer

I just tried this  and UIImage does not support  imageScaledToSize   I ended up adding a method to UIImage using a category - a suggestion I found on the Apple Dev forums   In a project-wide  h -   interface UIImage  Extras  -  UIImage   imageByScalingProportionallyToSize  CGSize targetSize   end    Implementation    implementation UIImage  Extras   -  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       end

User · Answer

imageView contentMode   UIViewContentModeScaleAspectFill  imageView clipsToBounds   YES

User · Answer

You could try making the imageView size match the image  The following code is not tested   CGSize kMaxImageViewSize     width   100   height   100   CGSize imageSize   image size  CGFloat aspectRatio   imageSize width   imageSize height  CGRect frame   imageView frame  if  kMaxImageViewSize width   aspectRatio  lt   kMaxImageViewSize height         frame size width   kMaxImageViewSize width      frame size height   frame size width   aspectRatio     else        frame size height   kMaxImageViewSize height      frame size width   frame size height   aspectRatio    imageView frame   frame

User · Answer

Usually I use this method for my apps  Swift 2 x compatible       Resize UIImage func resizeImage image UIImage  scaleX CGFloat scaleY CGFloat  - gt UIImage       let size   CGSizeApplyAffineTransform image size  CGAffineTransformMakeScale scaleX  scaleY       let hasAlpha   true     let scale  CGFloat   0 0    Automatically use scale factor of main screen      UIGraphicsBeginImageContextWithOptions size   hasAlpha  scale      image drawInRect CGRect origin  CGPointZero  size  size        let scaledImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext       return scaledImage

User · Answer

Here is how you can scale it easily   This works in 2 x with the Simulator and the iPhone   UIImage  thumbnail    originalImage  imageScaledToSize CGSizeMake 40 0  40 0  interpolationQuality 1

User · Answer

Set your UIimageview by scale

User · Answer

For Swift    self imageViews contentMode   UIViewContentMode ScaleToFill

User · Answer

You could try making the imageView size match the image  The following code is not tested   CGSize kMaxImageViewSize     width   100   height   100   CGSize imageSize   image size  CGFloat aspectRatio   imageSize width   imageSize height  CGRect frame   imageView frame  if  kMaxImageViewSize width   aspectRatio  lt   kMaxImageViewSize height         frame size width   kMaxImageViewSize width      frame size height   frame size width   aspectRatio     else        frame size height   kMaxImageViewSize height      frame size width   frame size height   aspectRatio    imageView frame   frame

User · Answer

I ve seen a bit of conversation about scale types so I decided to put together an article regarding some of the most popular content mode scaling types   The associated image is here

User · Answer

Here is how you can scale it easily   This works in 2 x with the Simulator and the iPhone   UIImage  thumbnail    originalImage  imageScaledToSize CGSizeMake 40 0  40 0  interpolationQuality 1

User · Answer

Fixed easily  once I found the documentation   imageView contentMode    scaleAspectFit

User · Answer

If the solutions proposed here aren t working for you  and your image asset is actually a PDF  note that XCode actually treats PDFs differently than image files  In particular  it doesn t seem able to scale to fill properly with a PDF  it ends up tiled instead  This drove me crazy until I figured out that the issue was the PDF format  Convert to JPG and you should be good to go

User · Answer

Set your UIimageview by scale

User · Answer

This works fine for me Swift 2 x   imageView contentMode    ScaleAspectFill imageView clipsToBounds   true

User · Answer

one can resize an UIImage this way  image    UIImage imageWithCGImage  image CGImage  scale 2 0 orientation UIImageOrientationUp

User · Answer

UIImage  image     UIImage alloc  initWithData  NSData dataWithContentsOfURL  NSURL URLWithString   http   farm4 static flickr com 3092 2915896504 a88b69c9de jpg      UIImageView  imageView     UIImageView alloc  initWithImage image        set contentMode to scale aspect to fit imageView contentMode   UIViewContentModeScaleAspectFit     change width of frame   CGRect frame   imageView frame    frame size width   100    imageView frame   frame     original lines that deal with frame commented out  yo  imageView frame   CGRectMake 10  20  60  60           Add image view  myView addSubview imageView      The original code posted at the top worked well for me in iOS 4 2    I found that creating a CGRect and specifying all the top  left  width  and height values was the easiest way to adjust the position in my case  which was using a UIImageView inside a table cell   Still need to add code to release objects

User · Answer

Usually I use this method for my apps  Swift 2 x compatible       Resize UIImage func resizeImage image UIImage  scaleX CGFloat scaleY CGFloat  - gt UIImage       let size   CGSizeApplyAffineTransform image size  CGAffineTransformMakeScale scaleX  scaleY       let hasAlpha   true     let scale  CGFloat   0 0    Automatically use scale factor of main screen      UIGraphicsBeginImageContextWithOptions size   hasAlpha  scale      image drawInRect CGRect origin  CGPointZero  size  size        let scaledImage   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext       return scaledImage

User · Answer

I think you can do something like  image center     imageView window  center

User · Answer

Here is how you can scale it easily   This works in 2 x with the Simulator and the iPhone   UIImage  thumbnail    originalImage  imageScaledToSize CGSizeMake 40 0  40 0  interpolationQuality 1

User · Answer

imageView contentMode   UIViewContentModeScaleAspectFill  imageView clipsToBounds   YES

User · Answer

You could try making the imageView size match the image  The following code is not tested   CGSize kMaxImageViewSize     width   100   height   100   CGSize imageSize   image size  CGFloat aspectRatio   imageSize width   imageSize height  CGRect frame   imageView frame  if  kMaxImageViewSize width   aspectRatio  lt   kMaxImageViewSize height         frame size width   kMaxImageViewSize width      frame size height   frame size width   aspectRatio     else        frame size height   kMaxImageViewSize height      frame size width   frame size height   aspectRatio    imageView frame   frame

User · Answer

Here is how you can scale it easily   This works in 2 x with the Simulator and the iPhone   UIImage  thumbnail    originalImage  imageScaledToSize CGSizeMake 40 0  40 0  interpolationQuality 1

User · Answer

Fixed easily  once I found the documentation   imageView contentMode    scaleAspectFit

User · Answer

If the solutions proposed here aren t working for you  and your image asset is actually a PDF  note that XCode actually treats PDFs differently than image files  In particular  it doesn t seem able to scale to fill properly with a PDF  it ends up tiled instead  This drove me crazy until I figured out that the issue was the PDF format  Convert to JPG and you should be good to go

User · Answer

I think you can do something like  image center     imageView window  center

User · Answer

You could try making the imageView size match the image  The following code is not tested   CGSize kMaxImageViewSize     width   100   height   100   CGSize imageSize   image size  CGFloat aspectRatio   imageSize width   imageSize height  CGRect frame   imageView frame  if  kMaxImageViewSize width   aspectRatio  lt   kMaxImageViewSize height         frame size width   kMaxImageViewSize width      frame size height   frame size width   aspectRatio     else        frame size height   kMaxImageViewSize height      frame size width   frame size height   aspectRatio    imageView frame   frame

User · Answer

one can resize an UIImage this way  image    UIImage imageWithCGImage  image CGImage  scale 2 0 orientation UIImageOrientationUp

User · Answer

Set your ImageView by selecting Mode to Aspect Fill and check the Clip Subviews box

User · Answer

For Swift    self imageViews contentMode   UIViewContentMode ScaleToFill

User · Answer

UIImage  image     UIImage alloc  initWithData  NSData dataWithContentsOfURL  NSURL URLWithString   http   farm4 static flickr com 3092 2915896504 a88b69c9de jpg      UIImageView  imageView     UIImageView alloc  initWithImage image        set contentMode to scale aspect to fit imageView contentMode   UIViewContentModeScaleAspectFit     change width of frame   CGRect frame   imageView frame    frame size width   100    imageView frame   frame     original lines that deal with frame commented out  yo  imageView frame   CGRectMake 10  20  60  60           Add image view  myView addSubview imageView      The original code posted at the top worked well for me in iOS 4 2    I found that creating a CGRect and specifying all the top  left  width  and height values was the easiest way to adjust the position in my case  which was using a UIImageView inside a table cell   Still need to add code to release objects

User · Answer

I used following code where imageCoverView is UIView holds UIImageView  if  image size height lt self imageCoverView bounds size height  amp  amp  image size width lt self imageCoverView bounds size width         self profileImageView sizeToFit       self profileImageView contentMode  UIViewContentModeCenter   else       self profileImageView contentMode  UIViewContentModeScaleAspectFit

User · Answer

I just tried this  and UIImage does not support  imageScaledToSize   I ended up adding a method to UIImage using a category - a suggestion I found on the Apple Dev forums   In a project-wide  h -   interface UIImage  Extras  -  UIImage   imageByScalingProportionallyToSize  CGSize targetSize   end    Implementation    implementation UIImage  Extras   -  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       end

User · Answer

UIImageView Scale h    import  lt Foundation Foundation h gt    interface UIImageView  Scale   - void  scaleAspectFit  CGFloat  scaleFactor    end   UIImageView Scale m    import  UIImageView Scale h    implementation UIImageView  Scale    - void  scaleAspectFit  CGFloat  scaleFactor       self contentScaleFactor   scaleFactor      self transform   CGAffineTransformMakeScale scaleFactor  scaleFactor        CGRect newRect   self frame      newRect origin x   0      newRect origin y   0      self frame   newRect      end

User · Answer

I think you can do something like  image center     imageView window  center

User · Answer

I used following code where imageCoverView is UIView holds UIImageView  if  image size height lt self imageCoverView bounds size height  amp  amp  image size width lt self imageCoverView bounds size width         self profileImageView sizeToFit       self profileImageView contentMode  UIViewContentModeCenter   else       self profileImageView contentMode  UIViewContentModeScaleAspectFit

User · Answer

This works fine for me Swift 2 x   imageView contentMode    ScaleAspectFill imageView clipsToBounds   true

User · Answer

I ve seen a bit of conversation about scale types so I decided to put together an article regarding some of the most popular content mode scaling types   The associated image is here

User · Answer

I think you can do something like  image center     imageView window  center

User · Answer

Set your ImageView by selecting Mode to Aspect Fill and check the Clip Subviews box

[objective-c] How to scale a UIImageView proportionally?

Examples related to objective-c

Examples related to cocoa-touch