def find_skew(self):
"""Returns a tuple (deskew angle in degrees, confidence value).
Returns (None, None) if no angle is available.
"""
with _LeptonicaErrorTrap():
angle = ffi.new('float *', 0.0)
confidence = ffi.new('float *', 0.0)
result = lept.pixFindSkew(self._cdata, angle, confidence)
if result == 0:
return (angle[0], confidence[0])
else:
return (None, None)
def _repr_png_(self):
"""iPython display hook
returns png version of image
"""
data = ffi.new('l_uint8 **')
size = ffi.new('size_t *')
err = lept.pixWriteMemPng(data, size, self._cdata, 0)
if err != 0:
raise LeptonicaIOError("pixWriteMemPng")
char_data = ffi.cast('char *', data[0])
return ffi.buffer(char_data, size[0])[:]
def __getstate__(self):
data = ffi.new('l_uint32 **')
size = ffi.new('size_t *')
err = lept.pixSerializeToMemory(self._cdata, data, size)
if err != 0:
raise LeptonicaIOError("pixSerializeToMemory")
char_data = ffi.cast('char *', data[0])
# Copy from C bytes to python bytes()
data_bytes = ffi.buffer(char_data, size[0])[:]
# Can now free C bytes
lept.lept_free(char_data)
return dict(data=data_bytes)
def _destroy(cls, cdata):
"""Destroy some cdata"""
# Leptonica API uses double-pointers for its destroy APIs to prevent
# dangling pointers. This means we need to put our single pointer,
# cdata, in a temporary CDATA**.
pp = ffi.new('{} **'.format(cls.LEPTONICA_TYPENAME), cdata)
cls.cdata_destroy(pp)
def generate_pdf_ci_data(self, type_, quality):
"Convert to PDF data, with transcoding"
p_compdata = ffi.new('L_COMP_DATA **')
result = lept.pixGenerateCIData(self._cdata, type_, quality, 0, p_compdata)
if result != 0:
raise LeptonicaError("Generate PDF data failed")
return CompressedData(p_compdata[0])
def write_implied_format(self, path, jpeg_quality=0, jpeg_progressive=0):
"""Write pix to the filename, with the extension indicating format.
jpeg_quality -- quality (iff JPEG; 1 - 100, 0 for default)
jpeg_progressive -- (iff JPEG; 0 for baseline seq., 1 for progressive)
"""
lept_format = lept.getImpliedFileFormat(os.fsencode(path))
with open(path, 'wb') as py_file:
data = ffi.new('l_uint8 **pdata')
size = ffi.new('size_t *psize')
with _LeptonicaErrorTrap():
if lept_format == lept.L_JPEG_ENCODE:
lept.pixWriteMemJpeg(data, size, self._cdata, jpeg_quality,
jpeg_progressive)
else:
lept.pixWriteMem(data, size, self._cdata, lept_format)
buffer = ffi.buffer(data[0], size[0])
py_file.write(buffer)
def __eq__(self, other):
if not isinstance(other, Pix):
return NotImplemented
same = ffi.new('l_int32 *', 0)
with _LeptonicaErrorTrap():
err = lept.pixEqual(self._cdata, other._cdata, same)
if err:
raise TypeError()
return bool(same[0])
def open(cls, path, jpeg_quality=75):
"Open compressed data, without transcoding"
filename = fspath(path)
p_compdata = ffi.new('L_COMP_DATA **')
result = lept.l_generateCIDataForPdf(os.fsencode(filename), ffi.NULL,
jpeg_quality, p_compdata)
if result != 0:
raise LeptonicaError("CompressedData.open")
return CompressedData(p_compdata[0])
def correlation_binary(pix1, pix2):
if get_leptonica_version() < 'leptonica-1.72':
# Older versions of Leptonica (pre-1.72) have a buggy
# implementation of pixCorrelationBinary that overflows on larger
# images. Ubuntu 14.04/trusty has 1.70. Ubuntu PPA
# ppa:alex-p/tesseract-ocr has leptonlib 1.75.
raise LeptonicaError("Leptonica version is too old")
correlation = ffi.new('float *', 0.0)
result = lept.pixCorrelationBinary(pix1._cdata, pix2._cdata, correlation)
if result != 0:
raise LeptonicaError("Correlation failed")
return correlation[0]
def otsu_adaptive_threshold(
self, tile_size=(300, 300), kernel_size=(4, 4), scorefract=0.1
):
with _LeptonicaErrorTrap():
sx, sy = tile_size
smoothx, smoothy = kernel_size
p_pix = ffi.new('PIX **')
pix = Pix(lept.pixConvertTo8(self._cdata, 0))
result = lept.pixOtsuAdaptiveThreshold(
pix._cdata, sx, sy, smoothx, smoothy, scorefract, ffi.NULL, p_pix
)
if result == 0:
return Pix(p_pix[0])
else:
return None
def __setstate__(self, state):
cdata_bytes = ffi.new('char[]', state['data'])
cdata_uint32 = ffi.cast('l_uint32 *', cdata_bytes)
pix = lept.pixDeserializeFromMemory(cdata_uint32, len(state['data']))
Pix.__init__(self, pix)