Android Open Source - PlayTogether Image Resizer

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License

The source code is released under:

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Java Source Code

package com.rockylearnstodevelop.playtogether;
/*from   w  ww.  ja v  a2s. c  o  m*/
import java.io.ByteArrayOutputStream;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Pair;

public class ImageResizer {

  /*
   * Call this static method to resize an image to a specified width and height.
   * 
   * @param targetWidth  The width to resize to.
   * @param targetHeight The height to resize to.
   * @returns        The resized image as a Bitmap.
   */
  public static Bitmap resizeImage(byte[] imageData, int targetWidth, int targetHeight) {
    // Use BitmapFactory to decode the image
        BitmapFactory.Options options = new BitmapFactory.Options();
        
        // inSampleSize is used to sample smaller versions of the image
        options.inSampleSize = calculateInSampleSize(options, targetWidth, targetHeight);
        
        // Decode bitmap with inSampleSize and target dimensions set
        options.inJustDecodeBounds = false;  
        
        Bitmap reducedBitmap = BitmapFactory.decodeByteArray(imageData, 0, imageData.length, options);
        Bitmap resizedBitmap = Bitmap.createScaledBitmap(reducedBitmap, targetWidth, targetHeight, false);

        return resizedBitmap;        
  }

  public static Bitmap resizeImageMaintainAspectRatio(byte[] imageData, int shorterSideTarget) {
        Pair<Integer, Integer> dimensions = getDimensions(imageData);
    
        // Determine the aspect ratio (width/height) of the image
        int imageWidth = dimensions.first;
        int imageHeight = dimensions.second;
        float ratio = (float) dimensions.first / dimensions.second;
        
        int targetWidth;
        int targetHeight;

        // Determine portrait or landscape
        if (imageWidth > imageHeight) {
            // Landscape image. ratio (width/height) is > 1
          targetHeight = shorterSideTarget; 
            targetWidth = Math.round(shorterSideTarget * ratio);
        }
        else {
            // Portrait image. ratio (width/height) is < 1
          targetWidth = shorterSideTarget;
            targetHeight = Math.round(shorterSideTarget / ratio);
        }
        
    return resizeImage(imageData, targetWidth, targetHeight);
  }
  
  public static Pair<Integer, Integer> getDimensions(byte[] imageData) {
    // Use BitmapFactory to decode the image
        BitmapFactory.Options options = new BitmapFactory.Options();

        // Only decode the bounds of the image, not the whole image, to get the dimensions
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeByteArray(imageData, 0, imageData.length, options);
        
        return new Pair<Integer, Integer>(options.outWidth, options.outHeight);
  }
  
  public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
      // Raw height and width of image
      final int height = options.outHeight;
      final int width = options.outWidth;
      int inSampleSize = 1;
  
      if (height > reqHeight || width > reqWidth) {
  
          final int halfHeight = height / 2;
          final int halfWidth = width / 2;
  
          // Calculate the largest inSampleSize value that is a power of 2 and keeps both
          // height and width larger than the requested height and width.
          while ((halfHeight / inSampleSize) > reqHeight
                  && (halfWidth / inSampleSize) > reqWidth) {
              inSampleSize *= 2;
          }
      }
  
      return inSampleSize;
  }
}

Java Source Code List