question: protected int calculateBestSubsampleFactor ( Size imageSize , Size targetSize ) { int maxSubsample = Math . min ( imageSize . getWidth ( ) / targetSize . getWidth ( ) , imageSize . getHeight ( ) / targetSize . getHeight ( ) ) ; if ( maxSubsample < 1 ) { return 1 ; } for ( int i = maxSubsample ; i >= 1 ; i -- ) { if ( ( ( imageSize . getWidth ( ) % ( 2 * i ) == 0 ) && ( imageSize . getHeight ( ) % ( 2 * i ) == 0 ) ) ) { return i ; } } return 1 ; }
target:  Calculates the best integer subsample from a given height and width to a target width and height It is assumed that the exact scaling will be done with the Android Bitmap framework; this subsample value is to best convert raw images into the lowest resolution raw images in visually lossless manner without changing the aspect ratio or creating subsample artifacts.