How to resize image Bitmap to a given size

Question

How to resize image  Bitmap  to for example 800 480 programatically   I have retrieved a picture in my app which is  1MB and I need to scale it down to 800 480 I have loaded that picture and compressed it but how do I do to make it smaller    ByteArrayOutputStream bos   new ByteArrayOutputStream 8192   photo compress CompressFormat JPEG  25  bos

User · Accepted Answer

Bitmap scaledBitmap   scaleDown realImage  MAX IMAGE SIZE  true     Scale down method   public static Bitmap scaleDown Bitmap realImage  float maxImageSize          boolean filter        float ratio   Math min               float  maxImageSize   realImage getWidth                 float  maxImageSize   realImage getHeight         int width   Math round  float  ratio   realImage getWidth         int height   Math round  float  ratio   realImage getHeight          Bitmap newBitmap   Bitmap createScaledBitmap realImage  width              height  filter       return newBitmap

User · Answer

In MonoDroid here s how  c         lt summary gt      Graphics support for resizing images      lt  summary gt  public static class Graphics       public static Bitmap ScaleDownBitmap Bitmap originalImage  float maxImageSize  bool filter                float ratio   Math Min  float maxImageSize   originalImage Width   float maxImageSize   originalImage Height           int width    int Math Round ratio    float originalImage Width           int height   int  Math Round ratio    float originalImage Height            Bitmap newBitmap   Bitmap CreateScaledBitmap originalImage  width  height  filter           return newBitmap             public static Bitmap ScaleBitmap Bitmap originalImage  int wantedWidth  int wantedHeight                Bitmap output   Bitmap CreateBitmap wantedWidth  wantedHeight  Bitmap Config Argb8888           Canvas canvas   new Canvas output           Matrix m   new Matrix            m SetScale  float wantedWidth   originalImage Width   float wantedHeight   originalImage Height           canvas DrawBitmap originalImage  m  new Paint             return output

User · Answer

Bitmap yourBitmap   Bitmap resized   Bitmap createScaledBitmap yourBitmap  newWidth  newHeight  true     or    resized   Bitmap createScaledBitmap yourBitmap  int  yourBitmap getWidth   0 8    int  yourBitmap getHeight   0 8   true

User · Answer

The other answers are correct as to  how  to resize them  but I would also thrown in the recommendation to just grab the resolution you are interested in  to begin with  Most Android devices offer a range of resolutions and you should pick one that gives you a file size that you re comfortable with  The biggest reason for this is that the native Android scaling algorithm  as detailed by Jin35 and Padma Kumar  produces pretty crappy results  It s not going to give you Photoshop quality resizing  even downscaling  to say nothing of upscaling  which I know you re not asking about  but that s just a non-starter     So  you should try their solution and if you re happy with the outcome  great  But if not  I d write a function that offers a range of width that you re happy with  and looks for that dimension  or whatever s closest  in the device s available picture size array and just set it and use it

User · Answer

You can scale bitmaps by using canvas drawBitmap with providing matrix  for example   public static Bitmap scaleBitmap Bitmap bitmap  int wantedWidth  int wantedHeight            Bitmap output   Bitmap createBitmap wantedWidth  wantedHeight  Config ARGB 8888           Canvas canvas   new Canvas output           Matrix m   new Matrix            m setScale  float  wantedWidth   bitmap getWidth     float  wantedHeight   bitmap getHeight             canvas drawBitmap bitmap  m  new Paint              return output

[android] How to resize image (Bitmap) to a given size?

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