Cdacians

Cdacians
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Tuesday, 14 August 2012

Reduce Bitmap size using BitmapFactory.Options.inSampleSize


Reduce Bitmap size using BitmapFactory.Options.inSampleSize

In the post "Load ImageView with JPG file in SD Card", the ImageView is loaded with bitmap in full-size. It cost too much resources for a mobile device, and easy to make the app closed unexpectly.

We can generate a shrinked bitmap using BitmapFactory.Optionswith inSampleSize; such that to reduce the needed resources greatly.

?
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package com.AndroidLoadImageView;
 
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.ImageView;
 
public class AndroidLoadImageViewActivity extends Activity {
  
 String imagefile ="/sdcard/IMG_9331.JPG";
  
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
         
        ImageView image = (ImageView)findViewById(R.id.image);
        //Bitmap bm = BitmapFactory.decodeFile(imagefile);
        Bitmap bm = ShrinkBitmap(imagefile, 300, 300);
        image.setImageBitmap(bm);
    }
     
 Bitmap ShrinkBitmap(String file, int width, int height){
   
     BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
        bmpFactoryOptions.inJustDecodeBounds = true;
        Bitmap bitmap = BitmapFactory.decodeFile(file, bmpFactoryOptions);
         
        int heightRatio = (int)Math.ceil(bmpFactoryOptions.outHeight/(float)height);
        int widthRatio = (int)Math.ceil(bmpFactoryOptions.outWidth/(float)width);
         
        if (heightRatio > 1 || widthRatio > 1)
        {
         if (heightRatio > widthRatio)
         {
          bmpFactoryOptions.inSampleSize = heightRatio;
         } else {
          bmpFactoryOptions.inSampleSize = widthRatio;
         }
        }
         
        bmpFactoryOptions.inJustDecodeBounds = false;
        bitmap = BitmapFactory.decodeFile(file, bmpFactoryOptions);
     return bitmap;
    }
}


Thanks
akm
www.cdacians.com

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