縮放和位圖採樣有什麼區別？

我有Android位圖縮放和採樣混淆這裏可能有兩個代碼縮放和另一個採樣任何人都可以幫助我確定這兩個代碼的工作和它們之間的主要區別是什麼。
縮放和位圖採樣有什麼區別？

縮放：

public static Bitmap getScaleBitmap(Bitmap bitmap, int newWidth, int newHeight) { 
    int width = bitmap.getWidth(); 
    int height = bitmap.getHeight(); 
    float scaleWidth = ((float) newWidth)/width; 
    float scaleHeight = ((float) newHeight)/height; 

    Matrix matrix = new Matrix(); 
    matrix.postScale(scaleWidth, scaleHeight); 
    return Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, false); 
}

採樣：

mImageView.setImageBitmap(decodeSampledBitmapFromResource(getResources(),R.id.myimage, 100, 100)); 

public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, 
     int reqWidth, int reqHeight) { 

    final BitmapFactory.Options options = new BitmapFactory.Options(); 
    options.inJustDecodeBounds = true; 
    BitmapFactory.decodeResource(res, resId, options); 

    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); 

    options.inJustDecodeBounds = false; 
    return BitmapFactory.decodeResource(res, resId, options); 
} 

public static int calculateInSampleSize(
      BitmapFactory.Options options, int reqWidth, int reqHeight) { 
    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; 

     while ((halfHeight/inSampleSize) >= reqHeight 
       && (halfWidth/inSampleSize) >= reqWidth) { 
      inSampleSize *= 2; 
     } 
    } 

    return inSampleSize; 
}

這裏既有代碼執行圖像尺寸調整，但不同的方式，使我怎麼能辨別哪一個是好的和簡單。

來源

2017-02-17 Kishan Donga