UIImage resize Scale proportion

Question

Possible Duplicate    Resize UIImage with aspect ratio        The following piece of code is resizing the image perfectly  but the problem is that it messes up the aspect ratio  resulting in a skewed image   Any pointers      Change image resolution  auto-resize to fit     UIImage   scaleImage  UIImage  image toResolution  int resolution       CGImageRef imgRef    image CGImage       CGFloat width   CGImageGetWidth imgRef       CGFloat height   CGImageGetHeight imgRef       CGRect bounds   CGRectMake 0  0  width  height          if already at the minimum resolution  return the orginal image  otherwise scale     if  width  lt   resolution  amp  amp  height  lt   resolution            return image         else           CGFloat ratio   width height           if  ratio  gt  1                bounds size width   resolution              bounds size height   bounds size width   ratio            else               bounds size height   resolution              bounds size width   bounds size height   ratio                       UIGraphicsBeginImageContext bounds size        image drawInRect CGRectMake 0 0  0 0  bounds size width  bounds size height        UIImage  imageCopy   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext         return imageCopy

User · Accepted Answer

This change worked for me      The size returned by CGImageGetWidth imgRef   amp  CGImageGetHeight imgRef  is incorrect as it doesn t respect the image orientation     CGImageRef imgRef    image CGImage      CGFloat width   CGImageGetWidth imgRef      CGFloat height   CGImageGetHeight imgRef         This returns the actual width and height of the photo  and hence solves the problem CGFloat width   image size width   CGFloat height   image size height  CGRect bounds   CGRectMake 0  0  width  height

User · Answer

Try to make the bounds s size integer    include  lt math h gt            if  ratio  gt  1            bounds size width   resolution          bounds size height   round bounds size width   ratio         else           bounds size height   resolution          bounds size width   round bounds size height   ratio

User · Answer

This fixes the math to scale to the max size in both width and height rather than just one depending on the width and height of the original   -  UIImage    scaleProportionalToSize   CGSize size       float widthRatio   size width self size width      float heightRatio   size height self size height       if widthRatio  gt  heightRatio                size CGSizeMake self size width heightRatio self size height heightRatio         else           size CGSizeMake self size width widthRatio self size height widthRatio              return  self scaleToSize size

User · Answer

That s ok not a big problem   thing is u got to find the proportional width and height  like if size is  2048 0 x 1360 0 which has to be resized to 320 x 480 resolution then the resulting image size should be  722 0 x 480 0  here is the formulae to do that   if w h is original and x y are resulting image  w h x y    gt   x  w h  y     submitting w 2048 h 1360 y 480   gt  x 722 0   here width gt height  if height gt width then consider x to be 320 and calculate y    U can submit in this web page   ARC  Confused   alright    here is category for UIImage which will do the thing for you    interface UIImage  UIImageFunctions      -  UIImage    scaleToSize   CGSize size      -  UIImage    scaleProportionalToSize   CGSize size   end  implementation UIImage  UIImageFunctions   -  UIImage    scaleToSize   CGSize size          Scalling selected image to targeted size     CGColorSpaceRef colorSpace   CGColorSpaceCreateDeviceRGB        CGContextRef context   CGBitmapContextCreate NULL  size width  size height  8  0  colorSpace  kCGImageAlphaPremultipliedLast       CGContextClearRect context  CGRectMake 0  0  size width  size height         if self imageOrientation    UIImageOrientationRight                CGContextRotateCTM context  -M PI 2           CGContextTranslateCTM context  -size height  0 0f           CGContextDrawImage context  CGRectMake 0  0  size height  size width   self CGImage             else         CGContextDrawImage context  CGRectMake 0  0  size width  size height   self CGImage        CGImageRef scaledImage CGBitmapContextCreateImage context        CGColorSpaceRelease colorSpace       CGContextRelease context        UIImage  image    UIImage imageWithCGImage  scaledImage        CGImageRelease scaledImage        return image     -  UIImage    scaleProportionalToSize   CGSize size1       if self size width gt self size height                NSLog   LandScape            size1 CGSizeMake  self size width self size height  size1 height size1 height             else               NSLog   Potrait            size1 CGSizeMake size1 width  self size height self size width  size1 width              return  self scaleToSize size1       end   -- the following is appropriate call to do this if img is the UIImage instance   img  img scaleProportionalToSize CGSizeMake 320  480

User · Answer

I used this single line of code to create a new UIImage which is scaled  Set the scale and orientation params to achieve what you want  The first line of code just grabs the image           grab the original image     UIImage  originalImage    UIImage imageNamed   myImage png           scaling set to 2 0 makes the image 1 2 the size       UIImage  scaledImage                     UIImage imageWithCGImage  originalImage CGImage                                 scale  originalImage scale   2 0                                   orientation  originalImage imageOrientation

[iphone] UIImage resize (Scale proportion)

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