You can use this function to update the size of the view camera within the room. You give the unique camera ID value (as returned by the different camera_create functions) and then give the width and height (in pixels) to set the camera to.
camera_set_view_size(camera_id, width, height)
Argument Description camera_id The unique camera ID value returned when you created the camera. width The width of the camera view in pixels height The height of the camera view in pixels
camera_set_view_size(view_camera, view_wport, view_hport);
The above code will set the view camera size for the camera assigned to view port.