从 Numpy 数组创建 LeptonicaPIX结构无需将数据编码为用于存储的图像格式，并以某种方式通过内核将其作为同一进程中的文件传输。将数组数据从 OpenCV 转换为 RGBA 数据，并从 Leptonica 包装足够的数据以创建PIX适当大小的空结构，然后将数组中的数据复制到PIX.
这是一个小示例，如何使用 OpenCV 加载图像，将其转换为包装PIX结构的 Python 对象，然后再次使用 Leptonica 将图像数据保存到文件中：
#!/usr/bin/env python
# coding: utf8
from __future__ import absolute_import, division, print_function
from ctypes import c_char_p, c_uint32, c_void_p, CDLL, memmove, pointer, POINTER
from ctypes.util import find_library
import cv2
LEPTONICA = CDLL(find_library('lept'))
_pix_create = LEPTONICA.pixCreate
_pix_create.argtypes = [c_uint32, c_uint32, c_uint32]
_pix_create.restype = c_void_p
_pix_destroy = LEPTONICA.pixDestroy
_pix_destroy.argtypes = [POINTER(c_void_p)]
_pix_destroy.restype = None
_pix_get_data = LEPTONICA.pixGetData
_pix_get_data.argtypes = [c_void_p]
_pix_get_data.restype = POINTER(c_uint32)
_pix_endian_byte_swap = LEPTONICA.pixEndianByteSwap
_pix_endian_byte_swap.argtypes = [c_void_p]
_pix_endian_byte_swap.restype = c_uint32
_pix_write_implied_format = LEPTONICA.pixWriteImpliedFormat
_pix_write_implied_format.argtypes = [c_char_p, c_void_p, c_uint32, c_uint32]
_pix_write_implied_format.restype = c_uint32
class Pix(object):
def __init__(self, width, height, depth):
self._as_parameter_ = _pix_create(width, height, depth)
self._pointer = pointer
self._pix_destroy = _pix_destroy
def __del__(self):
pix_pointer = self._pointer(c_void_p(self._as_parameter_))
self._pix_destroy(pix_pointer)
assert pix_pointer[0] is None
@property
def data(self):
return _pix_get_data(self)
def endian_byte_swap(self):
_pix_endian_byte_swap(self)
def save(self, filename, quality=0, progessive=False):
_pix_write_implied_format(filename, self, quality, progessive)
@classmethod
def from_rgba(cls, array):
width, height, depth = array.shape
if depth != 4 and array.itemsize != 1:
raise ValueError('array has wrong format')
result = cls(width, height, 32)
memmove(result.data, array.ctypes.data, array.size * array.itemsize)
result.endian_byte_swap()
return result
def main():
image = cv2.imread('test.jpg')
image = cv2.cvtColor(image, cv2.cv.CV_BGR2RGBA)
pix = Pix.from_rgba(image)
pix.save('test.png')
if __name__ == '__main__':
main()