Resize UIImage and change the size of UIImageView

Question

I have this UIImageView and I have the values of its max height and max width  What I want to achieve is that I want to take the image  with any aspect ratio and any resolution  and I want it to fit in the borders  so the picture does not exceed them  but it can shrink them as it wants   marked red in the picture      Right now the image fits the necessary size properly  but I have 2 worries  1  The UIImageView is not equal the size of the resized image  thus leaving red background  and I don t want that  2  If the image is smaller that the height of my UIImageView it is not resized to be smaller  it stays the same height   Here s my code and I know its wrong   UIImage  actualImage    attachmentsArray lastObject   UIImageView  attachmentImageNew     UIImageView alloc  initWithFrame CGRectMake 5 5  6 5  245  134    attachmentImageNew image   actualImage  attachmentImageNew backgroundColor    UIColor redColor   attachmentImageNew contentMode   UIViewContentModeScaleAspectFit    So how do I dynamically change the size not only of the UIImageView image  but of the whole UIImageView  thus making its size totally adjustable to its content  Any help would be much appreciated  thanks

User · Answer

if   SDWebImageManager sharedManager  diskImageExistsForURL  NSURL URLWithString   URL STRING1                 NSString  key     SDWebImageManager sharedManager  cacheKeyForURL  NSURL URLWithString   URL STRING1             UIImage  tempImage  self imageWithImage   SDImageCache sharedImageCache  imageFromDiskCacheForKey key  scaledToWidth cell imgview bounds size width          cell imgview image tempImage           else              cell imgview sd setImageWithURL  NSURL URLWithString   URL STRING1   placeholderImage nil completed   UIImage  image  NSError  error  SDImageCacheType cacheType  NSURL  imageURL                        UIImage  tempImage  self imageWithImage image scaledToWidth cell imgview bounds size width               cell imgview image tempImage                     tableView beginUpdates                      tableView endUpdates

User · Answer

-  UIImage   image  UIImage  originalImage scaledToSize  CGSize size         avoid redundant drawing     if  CGSizeEqualToSize originalImage size  size                 return originalImage               create drawing context     UIGraphicsBeginImageContextWithOptions size  NO  0 0f          draw      originalImage drawInRect CGRectMake 0 0f  0 0f  size width  size height           capture resultant image     UIImage  image   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext           return image     return image

User · Answer

If you have the size of the image  why don t you set the frame size of the image view to be of this size   EDIT----  Ok  so seeing your comment I propose this   UIImageView  imageView    so let s say you re image view size is set to the maximum size you want  CGFloat maxWidth   imageView frame size width  CGFloat maxHeight   imageView frame size height   CGFloat viewRatio   maxWidth   maxHeight  CGFloat imageRatio   image size height   image size width   if  imageRatio  gt  viewRatio        CGFloat imageViewHeight   round maxWidth   imageRatio       imageView frame   CGRectMake 0  ceil  self bounds size height - imageViewHeight    2 f   maxWidth  imageViewHeight     else if  imageRatio  lt  viewRatio        CGFloat imageViewWidth   roundf maxHeight   imageRatio       imageView frame   CGRectMake ceil  maxWidth - imageViewWidth    2 f   0  imageViewWidth  maxHeight     else         your image view is already at the good size     This code will resize your image view to its image ratio  and also position the image view to the same centre as your  default  position   PS  I hope you re setting imageView layer shouldRasterise   YES and imageView layer rasterizationScale    UIScreen mainScreen  scale   if you re using CALayer shadow effect    It will greatly improve the performance of your UI

User · Answer

When you get the width and height of a resized image Get width of a resized image after UIViewContentModeScaleAspectFit  you can resize your imageView   imageView frame   CGRectMake 0  0  resizedWidth  resizedHeight   imageView center   imageView superview center    I haven t checked if it works  but I think all should be OK

User · Answer

I think what you want is a different content mode  Try using UIViewContentModeScaleToFill  This will scale the content to fit the size of ur UIImageView by changing the aspect ratio of the content if necessary   Have a look to the content mode section on the official doc to get a better idea of the different content mode available  it is illustrated with images

User · Answer

Use the category below and then apply border from Quartz into your image    yourimage layer setBorderColor   UIColor whiteColor  CGColor     yourimage layer setBorderWidth 2     The category  UIImage AutoScaleResize h   import  lt Foundation Foundation h gt    interface UIImage  AutoScaleResize   -  UIImage   imageByScalingAndCroppingForSize  CGSize targetSize    end   UIImage AutoScaleResize m   import  UIImage AutoScaleResize h    implementation UIImage  AutoScaleResize   -  UIImage   imageByScalingAndCroppingForSize  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     scale to fit height                   else                       scaleFactor   heightFactor     scale to fit width                    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                                     UIGraphicsBeginImageContext targetSize      this will crop      CGRect thumbnailRect   CGRectZero      thumbnailRect origin   thumbnailPoint      thumbnailRect size width    scaledWidth      thumbnailRect size height   scaledHeight        sourceImage drawInRect thumbnailRect        newImage   UIGraphicsGetImageFromCurrentImageContext         if newImage    nil                NSLog   could not scale image                 pop the context to get back to the default     UIGraphicsEndImageContext         return newImage      end

User · Answer

This is the Swift equivalent for Rajneesh071 s answer  using extensions       UIImage     func scaleToSize aSize  CGSize  - gt  UIImage       if  CGSizeEqualToSize self size  aSize           return self            UIGraphicsBeginImageContextWithOptions aSize  false  0 0      self drawInRect CGRectMake 0 0  0 0  aSize width  aSize height       let image   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext       return image         Usage   let image   UIImage named   Icon   item icon   image  scaleToSize CGSize width  30 0  height  30 0

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