Calibrating undistortion reducing the size of image

I trying calibrate my camera, i have generated calibration matrix and undistortion parameters of

array([[449.23763332,   0.        , 288.9949981 ],
       [  0.        , 509.88847329, 195.85872177],
       [  0.        ,   0.        ,   1.        ]])

array([-0.38496184,  0.21366652, -0.00107046,  0.00090068, -0.07853835])

Following code for undistortion

file = 'snapshot_640_480_1.jpg'
img = cv2.imread(file)
h,  w = img.shape[:2]
newcameramtx, roi = cv.getOptimalNewCameraMatrix(mtx, dist, (w,h), 1, (w,h))

mapx, mapy = cv.initUndistortRectifyMap(mtx, dist, None, newcameramtx, (w,h), 5)
dst = cv.remap(img, mapx, mapy, cv.INTER_LINEAR)

# crop the image
x, y, w, h = roi
dst1 = dst[y:y+h, x:x+w]
cv.imwrite('calibresult.png', dst1)
display.Image(filename='calibresult.png')

Resulting image is getting reduced size of (95, 115, 3)

Is there any way i can undistort the image with same size ( resizing distort the image) ?

file = r'snapshot_640_480_1.jpg'
img = cv2.imread(file)
h,  w = img.shape[:2]
# New Image shape to generate
w1,h1 = 5*w,5*h
newcameramtx, roi = cv.getOptimalNewCameraMatrix(mtx, dist, (w,h), 1, (w1,h1))

mapx, mapy = cv.initUndistortRectifyMap(mtx, dist, None, newcameramtx, (w1,h1), 5)
dst = cv.remap(img, mapx, mapy, cv.INTER_LINEAR)