# 方式3 defrotate_bound(image, angle): # grab the dimensions of the image and then determine the # center (h, w) = image.shape[:2] (cX, cY) = (w // 2, h // 2) # grab the rotation matrix (applying the negative of the # angle to rotate clockwise), then grab the sine and cosine # (i.e., the rotation components of the matrix) # getRotationMatrix2D, angle正值表示逆时针旋转（坐标原点假定为左上角） M = cv2.getRotationMatrix2D((cX, cY), -angle, 1.0) cos = np.abs(M[0, 0]) sin = np.abs(M[0, 1]) # compute the new bounding dimensions of the image nW = int((h * sin) + (w * cos)) nH = int((h * cos) + (w * sin)) # adjust the rotation matrix to take into account translation M[0, 2] += (nW / 2) - cX M[1, 2] += (nH / 2) - cY # perform the actual rotation and return the image return cv2.warpAffine(image, M, (nW, nH))
# FreeBSD (and perhaps other BSDs) limit names to 14 characters. _SHM_SAFE_NAME_LENGTH = 14
# Shared memory block name prefix if _USE_POSIX: _SHM_NAME_PREFIX = "/psm_" else: _SHM_NAME_PREFIX = "wnsm_"
def_make_filename(): "Create a random filename for the shared memory object." # number of random bytes to use for name nbytes = (_SHM_SAFE_NAME_LENGTH - len(_SHM_NAME_PREFIX)) // 2 assert nbytes >= 2, "_SHM_NAME_PREFIX too long" name = _SHM_NAME_PREFIX + secrets.token_hex(nbytes) assert len(name) <= _SHM_SAFE_NAME_LENGTH return name
class_SharedMemory(SharedMemory): def__init__(self, name=None, create=False, size=0): ifnot size >= 0: raise ValueError("'size' must be a positive integer") if create: self._flags = _O_CREX | os.O_RDWR if size == 0: raise ValueError("'size' must be a positive number different from zero") if name isNoneandnot self._flags & os.O_EXCL: raise ValueError("'name' can only be None if create=True")
if _USE_POSIX:
# POSIX Shared Memory
if name isNone: whileTrue: name = _make_filename() try: self._fd = _posixshmem.shm_open( name, self._flags, mode=self._mode ) except FileExistsError: continue self._name = name break else: name = "/" + name if self._prepend_leading_slash else name self._fd = _posixshmem.shm_open(name, self._flags, mode=self._mode) self._name = name try: if create and size: os.ftruncate(self._fd, size) stats = os.fstat(self._fd) size = stats.st_size self._mmap = mmap.mmap(self._fd, size) except OSError: self.unlink() raise
from .resource_tracker import register
register(self._name, "shared_memory")
else:
# Windows Named Shared Memory
if create: whileTrue: temp_name = _make_filename() if name isNoneelse name # Create and reserve shared memory block with this name # until it can be attached to by mmap. h_map = _winapi.CreateFileMapping( _winapi.INVALID_HANDLE_VALUE, _winapi.NULL, _winapi.PAGE_READWRITE, (size >> 32) & 0xFFFFFFFF, size & 0xFFFFFFFF, temp_name, ) try: last_error_code = _winapi.GetLastError() if last_error_code == _winapi.ERROR_ALREADY_EXISTS: if name isnotNone: raise FileExistsError( errno.EEXIST, os.strerror(errno.EEXIST), name, _winapi.ERROR_ALREADY_EXISTS, ) else: continue self._mmap = mmap.mmap(-1, size, tagname=temp_name) finally: _winapi.CloseHandle(h_map) self._name = temp_name break
else: self._name = name # Dynamically determine the existing named shared memory # block's size which is likely a multiple of mmap.PAGESIZE. h_map = _winapi.OpenFileMapping(_winapi.FILE_MAP_READ, False, name) try: p_buf = _winapi.MapViewOfFile(h_map, _winapi.FILE_MAP_READ, 0, 0, 0) finally: _winapi.CloseHandle(h_map)