High Quality Image Scaling Library

Question

I want to scale an image in C  with quality level as good as Photoshop does  Is there any C  image processing library available to do this thing

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CodeProject articles discussing and sharing source code for scaling images    Two Pass Scaling using Filters Matrix Transformation of Images in C   using  NET GDI  Resizing a Photographic image with GDI  for  NET Fast Dyadic Image Scaling with Haar Transform

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When you draw the image using GDI  it scales quite well in my opinion  You can use this to create a scaled image   If you want to scale your image with GDI  you can do something like this   Bitmap original       Bitmap scaled   new Bitmap new Size original Width   4  original Height   4    using  Graphics graphics   Graphics FromImage scaled       graphics DrawImage original  new Rectangle 0  0  scaled Width  scaled Height

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Try This basic code snippet   private static Bitmap ResizeBitmap Bitmap srcbmp  int width  int height         Bitmap newimage   new Bitmap width  height       using  Graphics g   Graphics FromImage newimage              g DrawImage srcbmp  0  0  width  height       return newimage

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Try This basic code snippet   private static Bitmap ResizeBitmap Bitmap srcbmp  int width  int height         Bitmap newimage   new Bitmap width  height       using  Graphics g   Graphics FromImage newimage              g DrawImage srcbmp  0  0  width  height       return newimage

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You can try dotImage  one of my company s products  which includes an object for resampling images that has 18 filter types for various levels of quality   Typical usage is      BiCubic is one technique available in PhotoShop ResampleCommand resampler   new ResampleCommand newSize  ResampleMethod BiCubic   AtalaImage newImage   resampler Apply oldImage  Image    in addition  dotImage includes 140 some odd image processing commands including many filters similar to those in PhotoShop  if that s what you re looking for

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This might help      public Image ResizeImage Image source  RectangleF destinationBounds                RectangleF sourceBounds   new RectangleF 0 0f 0 0f  float source Width   float source Height           RectangleF scaleBounds   new RectangleF             Image destinationImage   new Bitmap  int destinationBounds Width   int destinationBounds Height           Graphics graph   Graphics FromImage destinationImage           graph InterpolationMode               System Drawing Drawing2D InterpolationMode HighQualityBicubic              Fill with background color         graph FillRectangle new SolidBrush System Drawing Color White   destinationBounds            float resizeRatio  sourceRatio          float scaleWidth  scaleHeight           sourceRatio    float source Width    float source Height           if  sourceRatio  gt   1 0f                          landscape             resizeRatio   destinationBounds Width   sourceBounds Width              scaleWidth   destinationBounds Width              scaleHeight   sourceBounds Height   resizeRatio              float trimValue   destinationBounds Height - scaleHeight              graph DrawImage source  0   trimValue   2   destinationBounds Width  scaleHeight                     else                         portrait             resizeRatio   destinationBounds Height sourceBounds Height              scaleWidth   sourceBounds Width   resizeRatio              scaleHeight   destinationBounds Height              float trimValue   destinationBounds Width - scaleWidth              graph DrawImage source   trimValue   2   0  scaleWidth  destinationBounds Height                      return destinationImage           Note the InterpolationMode HighQualityBicubic -  this is generally a good tradeoff between performance and results

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I have some improve for Doctor Jones s answer   It works for who wanted to how to proportional resize the image  It tested and worked for me   The methods of class I added   public static System Drawing Bitmap ResizeImage System Drawing Image image  Size size        return ResizeImage image  size Width  size Height       public static Size GetProportionedSize Image image  int maxWidth  int maxHeight  bool withProportion        if  withProportion                double sourceWidth   image Width          double sourceHeight   image Height           if  sourceWidth  lt  maxWidth  amp  amp  sourceHeight  lt  maxHeight                        maxWidth    int sourceWidth              maxHeight    int sourceHeight                    else                       double aspect   sourceHeight   sourceWidth               if  sourceWidth  lt  sourceHeight                                maxWidth   Convert ToInt32 Math Round  maxHeight   aspect   0                              else                               maxHeight   Convert ToInt32 Math Round  maxWidth   aspect   0                                       return new Size maxWidth  maxHeight       and new available using according to this codes   using  var resized   ImageUtilities ResizeImage image  ImageUtilities GetProportionedSize image  50  100          ImageUtilities SaveJpeg   C  myimage jpeg   resized  90

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This is an article I spotted being referenced in Paint NET s code for image resampling  Various Simple Image Processing Techniques by Paul Bourke

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Tested libraries like Imagemagick and GD are available for  NET  You could also read up on things like bicubic interpolation and write your own

User · Answer

You can try dotImage  one of my company s products  which includes an object for resampling images that has 18 filter types for various levels of quality   Typical usage is      BiCubic is one technique available in PhotoShop ResampleCommand resampler   new ResampleCommand newSize  ResampleMethod BiCubic   AtalaImage newImage   resampler Apply oldImage  Image    in addition  dotImage includes 140 some odd image processing commands including many filters similar to those in PhotoShop  if that s what you re looking for

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You could try the magic kernel  It produces less pixelation artifacts than bicubic resample when upscaling and it also gives very good results when downscaling  The source code is available in c  from the web site

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Use this library  http   imageresizing net  Have a read of this article by the library author  20 Image Sizing Pitfalls with  NET

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When you draw the image using GDI  it scales quite well in my opinion  You can use this to create a scaled image   If you want to scale your image with GDI  you can do something like this   Bitmap original       Bitmap scaled   new Bitmap new Size original Width   4  original Height   4    using  Graphics graphics   Graphics FromImage scaled       graphics DrawImage original  new Rectangle 0  0  scaled Width  scaled Height

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There s an article on Code Project about using GDI  for  NET to do photo resizing using  say  Bicubic interpolation   There was also another article about this topic on another blog  MS employee  I think   but I can t find the link anywhere     Perhaps someone else can find it

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Use this library  http   imageresizing net  Have a read of this article by the library author  20 Image Sizing Pitfalls with  NET

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There s an article on Code Project about using GDI  for  NET to do photo resizing using  say  Bicubic interpolation   There was also another article about this topic on another blog  MS employee  I think   but I can t find the link anywhere     Perhaps someone else can find it

User · Answer

you could try this one if it s a lowres cgi 2D Image Filter

User · Answer

Tested libraries like Imagemagick and GD are available for  NET  You could also read up on things like bicubic interpolation and write your own

User · Answer

CodeProject articles discussing and sharing source code for scaling images    Two Pass Scaling using Filters Matrix Transformation of Images in C   using  NET GDI  Resizing a Photographic image with GDI  for  NET Fast Dyadic Image Scaling with Haar Transform

User · Answer

Try the different values for Graphics InterpolationMode  There are several typical scaling algorithms available in GDI   If one of these is sufficient for your need  you can go this route instead of relying on an external library

User · Answer

Try the different values for Graphics InterpolationMode  There are several typical scaling algorithms available in GDI   If one of these is sufficient for your need  you can go this route instead of relying on an external library

User · Answer

When you draw the image using GDI  it scales quite well in my opinion  You can use this to create a scaled image   If you want to scale your image with GDI  you can do something like this   Bitmap original       Bitmap scaled   new Bitmap new Size original Width   4  original Height   4    using  Graphics graphics   Graphics FromImage scaled       graphics DrawImage original  new Rectangle 0  0  scaled Width  scaled Height

User · Answer

There s an article on Code Project about using GDI  for  NET to do photo resizing using  say  Bicubic interpolation   There was also another article about this topic on another blog  MS employee  I think   but I can t find the link anywhere     Perhaps someone else can find it

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Here s a nicely commented Image Manipulation helper class that you can look at and use   I wrote it as an example of how to perform certain image manipulation tasks in C    You ll be interested in the ResizeImage function that takes a System Drawing Image  the width and the height as the arguments   using System  using System Collections Generic  using System Drawing  using System Drawing Imaging   namespace DoctaJonez Drawing Imaging            lt summary gt          Provides various image untilities  such as high quality resizing and the ability to save a JPEG           lt  summary gt      public static class ImageUtilities                        lt summary gt              A quick lookup for getting image encoders              lt  summary gt          private static Dictionary lt string  ImageCodecInfo gt  encoders   null                lt summary gt              A lock to prevent concurrency issues loading the encoders               lt  summary gt          private static object encodersLock   new object                  lt summary gt              A quick lookup for getting image encoders              lt  summary gt          public static Dictionary lt string  ImageCodecInfo gt  Encoders                         get accessor that creates the dictionary on demand             get                                 if the quick lookup isn t initialised  initialise it                 if  encoders    null                                          protect against concurrency issues                     lock  encodersLock                                                  check again  we might not have been the first person to acquire the lock  see the double checked lock pattern                          if  encoders    null                                                        encoders   new Dictionary lt string  ImageCodecInfo gt                                    get all the codecs                             foreach  ImageCodecInfo codec in ImageCodecInfo GetImageEncoders                                                                    add each codec to the quick lookup                                 encoders Add codec MimeType ToLower    codec                                                                                                                      return the lookup                 return encoders                                        lt summary gt              Resize the image to the specified width and height               lt  summary gt               lt param name  image  gt The image to resize  lt  param gt               lt param name  width  gt The width to resize to  lt  param gt               lt param name  height  gt The height to resize to  lt  param gt               lt returns gt The resized image  lt  returns gt          public static System Drawing Bitmap ResizeImage System Drawing Image image  int width  int height                          a holder for the result             Bitmap result   new Bitmap width  height                 set the resolutions the same to avoid cropping due to resolution differences             result SetResolution image HorizontalResolution  image VerticalResolution                  use a graphics object to draw the resized image into the bitmap             using  Graphics graphics   Graphics FromImage result                                   set the resize quality modes to high quality                 graphics CompositingQuality   System Drawing Drawing2D CompositingQuality HighQuality                  graphics InterpolationMode   System Drawing Drawing2D InterpolationMode HighQualityBicubic                  graphics SmoothingMode   System Drawing Drawing2D SmoothingMode HighQuality                    draw the image into the target bitmap                 graphics DrawImage image  0  0  result Width  result Height                                return the resulting bitmap             return result                          lt summary gt               Saves an image as a jpeg image  with the given quality               lt  summary gt                lt param name  path  gt Path to which the image would be saved  lt  param gt                lt param name  quality  gt An integer from 0 to 100  with 100 being the              highest quality lt  param gt                lt exception cref  ArgumentOutOfRangeException  gt              An invalid value was entered for image quality               lt  exception gt          public static void SaveJpeg string path  Image image  int quality                          ensure the quality is within the correct range             if   quality  lt  0      quality  gt  100                                   create the error message                 string error   string Format  Jpeg image quality must be between 0 and 100  with 100 being the highest quality   A value of  0  was specified    quality                     throw a helpful exception                 throw new ArgumentOutOfRangeException error                                create an encoder parameter for the image quality             EncoderParameter qualityParam   new EncoderParameter System Drawing Imaging Encoder Quality  quality                 get the jpeg codec             ImageCodecInfo jpegCodec   GetEncoderInfo  image jpeg                   create a collection of all parameters that we will pass to the encoder             EncoderParameters encoderParams   new EncoderParameters 1                 set the quality parameter for the codec             encoderParams Param 0    qualityParam                save the image using the codec and the parameters             image Save path  jpegCodec  encoderParams                           lt summary gt               Returns the image codec with the given mime type               lt  summary gt           public static ImageCodecInfo GetEncoderInfo string mimeType                          do a case insensitive search for the mime type             string lookupKey   mimeType ToLower                   the codec to return  default to null             ImageCodecInfo foundCodec   null                 if we have the encoder  get it to return             if  Encoders ContainsKey lookupKey                                   pull the codec from the lookup                 foundCodec   Encoders lookupKey                              return foundCodec                         Update  A few people have been asking in the comments for samples of how to consume the ImageUtilities class  so here you go     resize the image to the specified height and width using  var resized   ImageUtilities ResizeImage image  50  100           save the resized image as a jpeg with a quality of 90     ImageUtilities SaveJpeg   C  myimage jpeg   resized  90       Note  Remember that images are disposable  so you need to assign the result of your resize to a using declaration  or you could use a try finally and make sure you call dispose in your finally

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Here s a nicely commented Image Manipulation helper class that you can look at and use   I wrote it as an example of how to perform certain image manipulation tasks in C    You ll be interested in the ResizeImage function that takes a System Drawing Image  the width and the height as the arguments   using System  using System Collections Generic  using System Drawing  using System Drawing Imaging   namespace DoctaJonez Drawing Imaging            lt summary gt          Provides various image untilities  such as high quality resizing and the ability to save a JPEG           lt  summary gt      public static class ImageUtilities                        lt summary gt              A quick lookup for getting image encoders              lt  summary gt          private static Dictionary lt string  ImageCodecInfo gt  encoders   null                lt summary gt              A lock to prevent concurrency issues loading the encoders               lt  summary gt          private static object encodersLock   new object                  lt summary gt              A quick lookup for getting image encoders              lt  summary gt          public static Dictionary lt string  ImageCodecInfo gt  Encoders                         get accessor that creates the dictionary on demand             get                                 if the quick lookup isn t initialised  initialise it                 if  encoders    null                                          protect against concurrency issues                     lock  encodersLock                                                  check again  we might not have been the first person to acquire the lock  see the double checked lock pattern                          if  encoders    null                                                        encoders   new Dictionary lt string  ImageCodecInfo gt                                    get all the codecs                             foreach  ImageCodecInfo codec in ImageCodecInfo GetImageEncoders                                                                    add each codec to the quick lookup                                 encoders Add codec MimeType ToLower    codec                                                                                                                      return the lookup                 return encoders                                        lt summary gt              Resize the image to the specified width and height               lt  summary gt               lt param name  image  gt The image to resize  lt  param gt               lt param name  width  gt The width to resize to  lt  param gt               lt param name  height  gt The height to resize to  lt  param gt               lt returns gt The resized image  lt  returns gt          public static System Drawing Bitmap ResizeImage System Drawing Image image  int width  int height                          a holder for the result             Bitmap result   new Bitmap width  height                 set the resolutions the same to avoid cropping due to resolution differences             result SetResolution image HorizontalResolution  image VerticalResolution                  use a graphics object to draw the resized image into the bitmap             using  Graphics graphics   Graphics FromImage result                                   set the resize quality modes to high quality                 graphics CompositingQuality   System Drawing Drawing2D CompositingQuality HighQuality                  graphics InterpolationMode   System Drawing Drawing2D InterpolationMode HighQualityBicubic                  graphics SmoothingMode   System Drawing Drawing2D SmoothingMode HighQuality                    draw the image into the target bitmap                 graphics DrawImage image  0  0  result Width  result Height                                return the resulting bitmap             return result                          lt summary gt               Saves an image as a jpeg image  with the given quality               lt  summary gt                lt param name  path  gt Path to which the image would be saved  lt  param gt                lt param name  quality  gt An integer from 0 to 100  with 100 being the              highest quality lt  param gt                lt exception cref  ArgumentOutOfRangeException  gt              An invalid value was entered for image quality               lt  exception gt          public static void SaveJpeg string path  Image image  int quality                          ensure the quality is within the correct range             if   quality  lt  0      quality  gt  100                                   create the error message                 string error   string Format  Jpeg image quality must be between 0 and 100  with 100 being the highest quality   A value of  0  was specified    quality                     throw a helpful exception                 throw new ArgumentOutOfRangeException error                                create an encoder parameter for the image quality             EncoderParameter qualityParam   new EncoderParameter System Drawing Imaging Encoder Quality  quality                 get the jpeg codec             ImageCodecInfo jpegCodec   GetEncoderInfo  image jpeg                   create a collection of all parameters that we will pass to the encoder             EncoderParameters encoderParams   new EncoderParameters 1                 set the quality parameter for the codec             encoderParams Param 0    qualityParam                save the image using the codec and the parameters             image Save path  jpegCodec  encoderParams                           lt summary gt               Returns the image codec with the given mime type               lt  summary gt           public static ImageCodecInfo GetEncoderInfo string mimeType                          do a case insensitive search for the mime type             string lookupKey   mimeType ToLower                   the codec to return  default to null             ImageCodecInfo foundCodec   null                 if we have the encoder  get it to return             if  Encoders ContainsKey lookupKey                                   pull the codec from the lookup                 foundCodec   Encoders lookupKey                              return foundCodec                         Update  A few people have been asking in the comments for samples of how to consume the ImageUtilities class  so here you go     resize the image to the specified height and width using  var resized   ImageUtilities ResizeImage image  50  100           save the resized image as a jpeg with a quality of 90     ImageUtilities SaveJpeg   C  myimage jpeg   resized  90       Note  Remember that images are disposable  so you need to assign the result of your resize to a using declaration  or you could use a try finally and make sure you call dispose in your finally

User · Answer

Tested libraries like Imagemagick and GD are available for  NET  You could also read up on things like bicubic interpolation and write your own

User · Answer

This is an article I spotted being referenced in Paint NET s code for image resampling  Various Simple Image Processing Techniques by Paul Bourke

User · Answer

Here s a nicely commented Image Manipulation helper class that you can look at and use   I wrote it as an example of how to perform certain image manipulation tasks in C    You ll be interested in the ResizeImage function that takes a System Drawing Image  the width and the height as the arguments   using System  using System Collections Generic  using System Drawing  using System Drawing Imaging   namespace DoctaJonez Drawing Imaging            lt summary gt          Provides various image untilities  such as high quality resizing and the ability to save a JPEG           lt  summary gt      public static class ImageUtilities                        lt summary gt              A quick lookup for getting image encoders              lt  summary gt          private static Dictionary lt string  ImageCodecInfo gt  encoders   null                lt summary gt              A lock to prevent concurrency issues loading the encoders               lt  summary gt          private static object encodersLock   new object                  lt summary gt              A quick lookup for getting image encoders              lt  summary gt          public static Dictionary lt string  ImageCodecInfo gt  Encoders                         get accessor that creates the dictionary on demand             get                                 if the quick lookup isn t initialised  initialise it                 if  encoders    null                                          protect against concurrency issues                     lock  encodersLock                                                  check again  we might not have been the first person to acquire the lock  see the double checked lock pattern                          if  encoders    null                                                        encoders   new Dictionary lt string  ImageCodecInfo gt                                    get all the codecs                             foreach  ImageCodecInfo codec in ImageCodecInfo GetImageEncoders                                                                    add each codec to the quick lookup                                 encoders Add codec MimeType ToLower    codec                                                                                                                      return the lookup                 return encoders                                        lt summary gt              Resize the image to the specified width and height               lt  summary gt               lt param name  image  gt The image to resize  lt  param gt               lt param name  width  gt The width to resize to  lt  param gt               lt param name  height  gt The height to resize to  lt  param gt               lt returns gt The resized image  lt  returns gt          public static System Drawing Bitmap ResizeImage System Drawing Image image  int width  int height                          a holder for the result             Bitmap result   new Bitmap width  height                 set the resolutions the same to avoid cropping due to resolution differences             result SetResolution image HorizontalResolution  image VerticalResolution                  use a graphics object to draw the resized image into the bitmap             using  Graphics graphics   Graphics FromImage result                                   set the resize quality modes to high quality                 graphics CompositingQuality   System Drawing Drawing2D CompositingQuality HighQuality                  graphics InterpolationMode   System Drawing Drawing2D InterpolationMode HighQualityBicubic                  graphics SmoothingMode   System Drawing Drawing2D SmoothingMode HighQuality                    draw the image into the target bitmap                 graphics DrawImage image  0  0  result Width  result Height                                return the resulting bitmap             return result                          lt summary gt               Saves an image as a jpeg image  with the given quality               lt  summary gt                lt param name  path  gt Path to which the image would be saved  lt  param gt                lt param name  quality  gt An integer from 0 to 100  with 100 being the              highest quality lt  param gt                lt exception cref  ArgumentOutOfRangeException  gt              An invalid value was entered for image quality               lt  exception gt          public static void SaveJpeg string path  Image image  int quality                          ensure the quality is within the correct range             if   quality  lt  0      quality  gt  100                                   create the error message                 string error   string Format  Jpeg image quality must be between 0 and 100  with 100 being the highest quality   A value of  0  was specified    quality                     throw a helpful exception                 throw new ArgumentOutOfRangeException error                                create an encoder parameter for the image quality             EncoderParameter qualityParam   new EncoderParameter System Drawing Imaging Encoder Quality  quality                 get the jpeg codec             ImageCodecInfo jpegCodec   GetEncoderInfo  image jpeg                   create a collection of all parameters that we will pass to the encoder             EncoderParameters encoderParams   new EncoderParameters 1                 set the quality parameter for the codec             encoderParams Param 0    qualityParam                save the image using the codec and the parameters             image Save path  jpegCodec  encoderParams                           lt summary gt               Returns the image codec with the given mime type               lt  summary gt           public static ImageCodecInfo GetEncoderInfo string mimeType                          do a case insensitive search for the mime type             string lookupKey   mimeType ToLower                   the codec to return  default to null             ImageCodecInfo foundCodec   null                 if we have the encoder  get it to return             if  Encoders ContainsKey lookupKey                                   pull the codec from the lookup                 foundCodec   Encoders lookupKey                              return foundCodec                         Update  A few people have been asking in the comments for samples of how to consume the ImageUtilities class  so here you go     resize the image to the specified height and width using  var resized   ImageUtilities ResizeImage image  50  100           save the resized image as a jpeg with a quality of 90     ImageUtilities SaveJpeg   C  myimage jpeg   resized  90       Note  Remember that images are disposable  so you need to assign the result of your resize to a using declaration  or you could use a try finally and make sure you call dispose in your finally

User · Answer

Tested libraries like Imagemagick and GD are available for  NET  You could also read up on things like bicubic interpolation and write your own

User · Answer

CodeProject articles discussing and sharing source code for scaling images    Two Pass Scaling using Filters Matrix Transformation of Images in C   using  NET GDI  Resizing a Photographic image with GDI  for  NET Fast Dyadic Image Scaling with Haar Transform

User · Answer

I have some improve for Doctor Jones s answer   It works for who wanted to how to proportional resize the image  It tested and worked for me   The methods of class I added   public static System Drawing Bitmap ResizeImage System Drawing Image image  Size size        return ResizeImage image  size Width  size Height       public static Size GetProportionedSize Image image  int maxWidth  int maxHeight  bool withProportion        if  withProportion                double sourceWidth   image Width          double sourceHeight   image Height           if  sourceWidth  lt  maxWidth  amp  amp  sourceHeight  lt  maxHeight                        maxWidth    int sourceWidth              maxHeight    int sourceHeight                    else                       double aspect   sourceHeight   sourceWidth               if  sourceWidth  lt  sourceHeight                                maxWidth   Convert ToInt32 Math Round  maxHeight   aspect   0                              else                               maxHeight   Convert ToInt32 Math Round  maxWidth   aspect   0                                       return new Size maxWidth  maxHeight       and new available using according to this codes   using  var resized   ImageUtilities ResizeImage image  ImageUtilities GetProportionedSize image  50  100          ImageUtilities SaveJpeg   C  myimage jpeg   resized  90

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You can try dotImage  one of my company s products  which includes an object for resampling images that has 18 filter types for various levels of quality   Typical usage is      BiCubic is one technique available in PhotoShop ResampleCommand resampler   new ResampleCommand newSize  ResampleMethod BiCubic   AtalaImage newImage   resampler Apply oldImage  Image    in addition  dotImage includes 140 some odd image processing commands including many filters similar to those in PhotoShop  if that s what you re looking for

User · Answer

You could try the magic kernel  It produces less pixelation artifacts than bicubic resample when upscaling and it also gives very good results when downscaling  The source code is available in c  from the web site

User · Answer

You can try dotImage  one of my company s products  which includes an object for resampling images that has 18 filter types for various levels of quality   Typical usage is      BiCubic is one technique available in PhotoShop ResampleCommand resampler   new ResampleCommand newSize  ResampleMethod BiCubic   AtalaImage newImage   resampler Apply oldImage  Image    in addition  dotImage includes 140 some odd image processing commands including many filters similar to those in PhotoShop  if that s what you re looking for

User · Answer

Try the different values for Graphics InterpolationMode  There are several typical scaling algorithms available in GDI   If one of these is sufficient for your need  you can go this route instead of relying on an external library

User · Answer

When you draw the image using GDI  it scales quite well in my opinion  You can use this to create a scaled image   If you want to scale your image with GDI  you can do something like this   Bitmap original       Bitmap scaled   new Bitmap new Size original Width   4  original Height   4    using  Graphics graphics   Graphics FromImage scaled       graphics DrawImage original  new Rectangle 0  0  scaled Width  scaled Height

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you could try this one if it s a lowres cgi 2D Image Filter

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Here s a nicely commented Image Manipulation helper class that you can look at and use   I wrote it as an example of how to perform certain image manipulation tasks in C    You ll be interested in the ResizeImage function that takes a System Drawing Image  the width and the height as the arguments   using System  using System Collections Generic  using System Drawing  using System Drawing Imaging   namespace DoctaJonez Drawing Imaging            lt summary gt          Provides various image untilities  such as high quality resizing and the ability to save a JPEG           lt  summary gt      public static class ImageUtilities                        lt summary gt              A quick lookup for getting image encoders              lt  summary gt          private static Dictionary lt string  ImageCodecInfo gt  encoders   null                lt summary gt              A lock to prevent concurrency issues loading the encoders               lt  summary gt          private static object encodersLock   new object                  lt summary gt              A quick lookup for getting image encoders              lt  summary gt          public static Dictionary lt string  ImageCodecInfo gt  Encoders                         get accessor that creates the dictionary on demand             get                                 if the quick lookup isn t initialised  initialise it                 if  encoders    null                                          protect against concurrency issues                     lock  encodersLock                                                  check again  we might not have been the first person to acquire the lock  see the double checked lock pattern                          if  encoders    null                                                        encoders   new Dictionary lt string  ImageCodecInfo gt                                    get all the codecs                             foreach  ImageCodecInfo codec in ImageCodecInfo GetImageEncoders                                                                    add each codec to the quick lookup                                 encoders Add codec MimeType ToLower    codec                                                                                                                      return the lookup                 return encoders                                        lt summary gt              Resize the image to the specified width and height               lt  summary gt               lt param name  image  gt The image to resize  lt  param gt               lt param name  width  gt The width to resize to  lt  param gt               lt param name  height  gt The height to resize to  lt  param gt               lt returns gt The resized image  lt  returns gt          public static System Drawing Bitmap ResizeImage System Drawing Image image  int width  int height                          a holder for the result             Bitmap result   new Bitmap width  height                 set the resolutions the same to avoid cropping due to resolution differences             result SetResolution image HorizontalResolution  image VerticalResolution                  use a graphics object to draw the resized image into the bitmap             using  Graphics graphics   Graphics FromImage result                                   set the resize quality modes to high quality                 graphics CompositingQuality   System Drawing Drawing2D CompositingQuality HighQuality                  graphics InterpolationMode   System Drawing Drawing2D InterpolationMode HighQualityBicubic                  graphics SmoothingMode   System Drawing Drawing2D SmoothingMode HighQuality                    draw the image into the target bitmap                 graphics DrawImage image  0  0  result Width  result Height                                return the resulting bitmap             return result                          lt summary gt               Saves an image as a jpeg image  with the given quality               lt  summary gt                lt param name  path  gt Path to which the image would be saved  lt  param gt                lt param name  quality  gt An integer from 0 to 100  with 100 being the              highest quality lt  param gt                lt exception cref  ArgumentOutOfRangeException  gt              An invalid value was entered for image quality               lt  exception gt          public static void SaveJpeg string path  Image image  int quality                          ensure the quality is within the correct range             if   quality  lt  0      quality  gt  100                                   create the error message                 string error   string Format  Jpeg image quality must be between 0 and 100  with 100 being the highest quality   A value of  0  was specified    quality                     throw a helpful exception                 throw new ArgumentOutOfRangeException error                                create an encoder parameter for the image quality             EncoderParameter qualityParam   new EncoderParameter System Drawing Imaging Encoder Quality  quality                 get the jpeg codec             ImageCodecInfo jpegCodec   GetEncoderInfo  image jpeg                   create a collection of all parameters that we will pass to the encoder             EncoderParameters encoderParams   new EncoderParameters 1                 set the quality parameter for the codec             encoderParams Param 0    qualityParam                save the image using the codec and the parameters             image Save path  jpegCodec  encoderParams                           lt summary gt               Returns the image codec with the given mime type               lt  summary gt           public static ImageCodecInfo GetEncoderInfo string mimeType                          do a case insensitive search for the mime type             string lookupKey   mimeType ToLower                   the codec to return  default to null             ImageCodecInfo foundCodec   null                 if we have the encoder  get it to return             if  Encoders ContainsKey lookupKey                                   pull the codec from the lookup                 foundCodec   Encoders lookupKey                              return foundCodec                         Update  A few people have been asking in the comments for samples of how to consume the ImageUtilities class  so here you go     resize the image to the specified height and width using  var resized   ImageUtilities ResizeImage image  50  100           save the resized image as a jpeg with a quality of 90     ImageUtilities SaveJpeg   C  myimage jpeg   resized  90       Note  Remember that images are disposable  so you need to assign the result of your resize to a using declaration  or you could use a try finally and make sure you call dispose in your finally

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This might help      public Image ResizeImage Image source  RectangleF destinationBounds                RectangleF sourceBounds   new RectangleF 0 0f 0 0f  float source Width   float source Height           RectangleF scaleBounds   new RectangleF             Image destinationImage   new Bitmap  int destinationBounds Width   int destinationBounds Height           Graphics graph   Graphics FromImage destinationImage           graph InterpolationMode               System Drawing Drawing2D InterpolationMode HighQualityBicubic              Fill with background color         graph FillRectangle new SolidBrush System Drawing Color White   destinationBounds            float resizeRatio  sourceRatio          float scaleWidth  scaleHeight           sourceRatio    float source Width    float source Height           if  sourceRatio  gt   1 0f                          landscape             resizeRatio   destinationBounds Width   sourceBounds Width              scaleWidth   destinationBounds Width              scaleHeight   sourceBounds Height   resizeRatio              float trimValue   destinationBounds Height - scaleHeight              graph DrawImage source  0   trimValue   2   destinationBounds Width  scaleHeight                     else                         portrait             resizeRatio   destinationBounds Height sourceBounds Height              scaleWidth   sourceBounds Width   resizeRatio              scaleHeight   destinationBounds Height              float trimValue   destinationBounds Width - scaleWidth              graph DrawImage source   trimValue   2   0  scaleWidth  destinationBounds Height                      return destinationImage           Note the InterpolationMode HighQualityBicubic -  this is generally a good tradeoff between performance and results

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CodeProject articles discussing and sharing source code for scaling images    Two Pass Scaling using Filters Matrix Transformation of Images in C   using  NET GDI  Resizing a Photographic image with GDI  for  NET Fast Dyadic Image Scaling with Haar Transform

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Try the different values for Graphics InterpolationMode  There are several typical scaling algorithms available in GDI   If one of these is sufficient for your need  you can go this route instead of relying on an external library

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There s an article on Code Project about using GDI  for  NET to do photo resizing using  say  Bicubic interpolation   There was also another article about this topic on another blog  MS employee  I think   but I can t find the link anywhere     Perhaps someone else can find it

[c#] High Quality Image Scaling Library

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