How to Resize a Bitmap in Android

Question

I have a bitmap taken of a Base64 String from my remote database   encodedImage is the string representing the image with Base64    profileImage    ImageView findViewById R id profileImage    byte   imageAsBytes null  try       imageAsBytes   Base64 decode encodedImage getBytes       catch  IOException e   e printStackTrace      profileImage setImageBitmap      BitmapFactory decodeByteArray imageAsBytes  0  imageAsBytes length       profileImage is my ImageView  Ok  but I have to resize this image before showing it on my ImageView of my layout  I have to resize it to 120x120   Can someone tell me the code to resize it   The examples I found could not be applied to a base64 string obtained bitmap

User · Answer

Scale a bitmap with a target maximum size and width  while maintaining aspect ratio   int maxHeight   2000  int maxWidth   2000      float scale   Math min   float maxHeight   bitmap getWidth       float maxWidth   bitmap getHeight       Matrix matrix   new Matrix    matrix postScale scale  scale    bitmap   Bitmap createBitmap bitmap  0  0  bitmap getWidth    bitmap getHeight    matrix  true

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Change   profileImage setImageBitmap      BitmapFactory decodeByteArray imageAsBytes  0  imageAsBytes length    To   Bitmap b   BitmapFactory decodeByteArray imageAsBytes  0  imageAsBytes length  profileImage setImageBitmap Bitmap createScaledBitmap b  120  120  false

User · Answer

try this this code     BitmapDrawable drawable    BitmapDrawable  imgview getDrawable    Bitmap bmp   drawable getBitmap    Bitmap b   Bitmap createScaledBitmap bmp  120  120  false     I hope it s useful

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Keeping the aspect ratio     public Bitmap resizeBitmap Bitmap source  int width int height        if source getHeight      height  amp  amp  source getWidth      width  return source      int maxLength Math min width height       try           source source copy source getConfig   true           if  source getHeight    lt   source getWidth                  if  source getHeight    lt   maxLength       if image already smaller than the required height                 return source                             double aspectRatio    double  source getWidth      double  source getHeight                int targetWidth    int   maxLength   aspectRatio                return Bitmap createScaledBitmap source  targetWidth  maxLength  false             else                if  source getWidth    lt   maxLength       if image already smaller than the required height                 return source                             double aspectRatio     double  source getHeight        double  source getWidth                 int targetHeight    int   maxLength   aspectRatio                return Bitmap createScaledBitmap source  maxLength  targetHeight  false                        catch  Exception e                return source

User · Answer

Although the accepted answer is correct  it doesn t resize Bitmap by keeping the same Aspect Ratio  If you are looking for a method to resize Bitmap by keeping the same aspect ratio you can use the following utility function  The usage details and explanation of the function are present at this link   public static Bitmap resizeBitmap Bitmap source  int maxLength           try              if  source getHeight    gt   source getWidth                     int targetHeight   maxLength                 if  source getHeight    lt   targetHeight       if image already smaller than the required height                    return source                                   double aspectRatio    double  source getWidth      double  source getHeight                   int targetWidth    int   targetHeight   aspectRatio                   Bitmap result   Bitmap createScaledBitmap source  targetWidth  targetHeight  false                  if  result    source                                    return result               else                  int targetWidth   maxLength                  if  source getWidth    lt   targetWidth       if image already smaller than the required height                    return source                                   double aspectRatio     double  source getHeight        double  source getWidth                    int targetHeight    int   targetWidth   aspectRatio                   Bitmap result   Bitmap createScaledBitmap source  targetWidth  targetHeight  false                  if  result    source                                    return result                                catch  Exception e                      return source

User · Answer

Someone asked how to keep aspect ratio in this situation   Calculate the factor you are using for scaling and use it for both dimensions  Let  s say you want an image to be 20  of the screen in height  int scaleToUse   20     this will be our percentage Bitmap bmp   BitmapFactory decodeResource      context getResources    R drawable mypng   int sizeY   screenResolution y   scaleToUse   100  int sizeX   bmp getWidth     sizeY   bmp getHeight    Bitmap scaled   Bitmap createScaledBitmap bmp  sizeX  sizeY  false     for getting the screen resolution you have this solution  Get screen dimensions in pixels

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As of API 19  Bitmap setWidth int width  and setHeight int height  exist  http   developer android com reference android graphics Bitmap html

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Kotlin method for Bitmap scaling     param bitmap the bitmap to be scaled     param pixel  the target pixel size     param width  the width     param height the height     param max    the max height  width      return the scaled bitmap     fun scaleBitmap bitmap Bitmap  pixel Float  width Int  height Int  max Int  Bitmap       val scale   px   max     val h   Math round scale   height      val w   Math round scale   width      return Bitmap createScaledBitmap bitmap  w  h  true

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Try this  This function resizes a bitmap proportionally  When the last parameter is set to  X  the newDimensionXorY is treated as s new width and when set to  Y  a new height   public Bitmap getProportionalBitmap Bitmap bitmap                                       int newDimensionXorY                                       String XorY        if  bitmap    null            return null             float xyRatio   0      int newWidth   0      int newHeight   0       if  XorY toLowerCase   equals  x              xyRatio    float  newDimensionXorY   bitmap getWidth            newHeight    int   bitmap getHeight     xyRatio           bitmap   Bitmap createScaledBitmap              bitmap  newDimensionXorY  newHeight  true         else if  XorY toLowerCase   equals  y              xyRatio    float  newDimensionXorY   bitmap getHeight            newWidth    int   bitmap getWidth     xyRatio           bitmap   Bitmap createScaledBitmap              bitmap  newWidth  newDimensionXorY  true             return bitmap

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public static Bitmap resizeBitmapByScale              Bitmap bitmap  float scale  boolean recycle            int width   Math round bitmap getWidth     scale           int height   Math round bitmap getHeight     scale           if  width    bitmap getWidth                    amp  amp  height    bitmap getHeight    return bitmap          Bitmap target   Bitmap createBitmap width  height  getConfig bitmap            Canvas canvas   new Canvas target           canvas scale scale  scale           Paint paint   new Paint Paint FILTER BITMAP FLAG   Paint DITHER FLAG           canvas drawBitmap bitmap  0  0  paint           if  recycle  bitmap recycle            return target            private static Bitmap Config getConfig Bitmap bitmap            Bitmap Config config   bitmap getConfig            if  config    null                config   Bitmap Config ARGB 8888                    return config

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profileImage setImageBitmap      Bitmap createScaledBitmap          BitmapFactory decodeByteArray imageAsBytes  0  imageAsBytes length            80  80  false

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Scale based on aspect ratio   float aspectRatio   yourSelectedImage getWidth           float  yourSelectedImage getHeight    int width   480  int height   Math round width   aspectRatio    yourSelectedImage   Bitmap createScaledBitmap      yourSelectedImage  width  height  false     To use height as base intead of width change to   int height   480  int width   Math round height   aspectRatio

User · Answer

While the previous answers do scale the image and take care of the aspect ratio  the resampling itself should be done so that there is no aliasing  Taking care of scale is a matter of fixing arguments correctly  There are many comments about the quality of the output images from standard scaling call  to maintain quality of the image one should use the standard call  Bitmap resizedBitmap   Bitmap createScaledBitmap originalBitmap  newWidth  newHeight  true   with the last argument set to true because it will do the bilinear filtering for resampling to prevent aliasing  Read more about aliasing here  https   en wikipedia org wiki Aliasing From android documentation  https   developer android com reference android graphics Bitmap createScaledBitmap android graphics Bitmap  20int  20int  20boolean   public static Bitmap createScaledBitmap  Bitmap src                   int dstWidth                   int dstHeight                   boolean filter   filter      boolean  Whether or not bilinear filtering should be used when scaling the bitmap  If this is true then bilinear filtering will be used when scaling which has better image quality at the cost of worse performance  If this is false then nearest-neighbor scaling is used instead which will have worse image quality but is faster  Recommended default is to set filter to  true  as the cost of bilinear filtering is typically minimal and the improved image quality is significant

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public Bitmap scaleBitmap Bitmap mBitmap            int ScaleSize   250   max Height or width to Scale         int width   mBitmap getWidth            int height   mBitmap getHeight            float excessSizeRatio   width  gt  height   width   ScaleSize   height   ScaleSize           Bitmap bitmap   Bitmap createBitmap                  mBitmap  0  0  int   width excessSizeRatio   int   height excessSizeRatio              mBitmap recycle    if you are not using mBitmap Obj         return bitmap

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import android graphics Matrix public Bitmap getResizedBitmap Bitmap bm  int newWidth  int newHeight        int width   bm getWidth        int height   bm getHeight        float scaleWidth     float  newWidth    width      float scaleHeight     float  newHeight    height         CREATE A MATRIX FOR THE MANIPULATION     Matrix matrix   new Matrix           RESIZE THE BIT MAP     matrix postScale scaleWidth  scaleHeight            RECREATE  THE NEW BITMAP     Bitmap resizedBitmap   Bitmap createBitmap          bm  0  0  width  height  matrix  false       bm recycle        return resizedBitmap      EDIT  as suggested by by  aveschini  I have added bm recycle    for memory leaks  Please note that in case if you are using the previous object for some other purposes  then handle accordingly

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Bitmap Resize based on Any Display size  public Bitmap bitmapResize Bitmap imageBitmap         Bitmap bitmap   imageBitmap      float heightbmp   bitmap getHeight        float widthbmp   bitmap getWidth            Get Screen width     DisplayMetrics displaymetrics   new DisplayMetrics        this getWindowManager   getDefaultDisplay   getMetrics displaymetrics       float height   displaymetrics heightPixels   3      float width   displaymetrics widthPixels   3       int convertHeight    int  hight  convertWidth    int  width          higher     if  heightbmp  gt  height            convertHeight    int  height - 20          bitmap   Bitmap createScaledBitmap bitmap  convertWidth                  convertHighet  true                 wider     if  widthbmp  gt  width            convertWidth    int  width - 20          bitmap   Bitmap createScaledBitmap bitmap  convertWidth                  convertHeight  true              return bitmap

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If you already have a bitmap  you could use the following code to resize   Bitmap originalBitmap    lt original initialization gt   Bitmap resizedBitmap   Bitmap createScaledBitmap      originalBitmap  newWidth  newHeight  false

[android] How to Resize a Bitmap in Android?

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