[Android algorithm] bitmap compress a picture to a specified size

Bitmap compressed to a specified size:

private void Imagezoom () {
Picture allows maximum space unit: KB
Double maxSize = 400.00;
Put bitmap in the array, intended to bitmap size (larger than the actual file being read)
Bytearrayoutputstream BAOs = new Bytearrayoutputstream ();
Bitmap.compress (Bitmap.CompressFormat.JPEG, BAOs);
Byte[] B = Baos.tobytearray ();
Convert Bytes to kb
Double mid = b.length/1024;
Determine if the bitmap occupy space is greater than the allowable maximum space if the compression is less than the compressed
if (Mid > MaxSize) {
Gets how many times the bitmap size is allowed for the maximum size
Double i = mid/maxsize;
Start compression Here the square root is used to compress the width and height of the corresponding square root fold (1. Keep the scale and height consistent with the original bitmap ratio, and compress to the maximum size of the space)
BitMap = Zoomimage (BitMap, Bitmap.getwidth ()/math.sqrt (i),
Bitmap.getheight ()/math.sqrt (i));
}
}



public static Bitmap Zoomimage (Bitmap bgimage, double newwidth,
Double newheight) {
Get the width and height of this picture
Float width = bgimage.getwidth ();
float height = bgimage.getheight ();
Create a Matrix object for manipulating pictures
Matrix matrix = new Matrix ();
Calculate the wide and high zoom rate
float ScaleWidth = ((float) newwidth)/width;
float ScaleHeight = ((float) newheight)/height;
Zoom picture Action
Matrix.postscale (ScaleWidth, ScaleHeight);
Bitmap Bitmap = Bitmap.createbitmap (bgimage, 0, 0, (int) width,
(int) height, matrix, true);
return bitmap;
}

The compressed picture is larger than expected 10% reasons may be the width of the bitmap graph is inconsistent, resulting in compression error!

[Android algorithm] bitmap compress a picture to a specified size