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__author__ = "Adel Daouzli"
__licence__ = "GPLv3"
import struct
class PnmImage(object):
def __init__(self):
self._filename = None
self._image = []
self._version = None
self._maxval = None
self._width = 0
self._height = 0
def reset(self):
"""Reset all image data (dims, data,...)"""
self._filename = None
self._image = []
self._version = None
self._maxval = None
self._width = 0
self._height = 0
def _load_bin_pbm(self, fd):
"""Load image data from a file of PBM binary format
:param fd: file descriptor of the file starting to the image data so
the version and dimensions should have been skipped
"""
c = fd.read(1)
i = 0
size = self._width * self._height
while len(c) > 0:
c = struct.unpack("<B", c)[0]
# each byte is a bit array of 8 pixels
for b in range(8):
if c & 128:
self._image.append(1)
else:
self._image.append(0)
c <<= 1
i += 1
if i >= size:
break
if i >= size:
break
c = fd.read(1)
def _load_bin_pgm(self, fd):
"""Load image data from a file of PGM binary format
:param fd: file descriptor of the file starting to the image data so
the version and dimensions should have been skipped
"""
maxval = fd.readline().decode("utf-8").strip()
self._maxval = int(maxval)
c = fd.read(1)
while len(c) > 0:
c = struct.unpack("<B", c)[0]
self._image.append(c)
c = fd.read(1)
def load(self, filename):
"""Load an image pnm. Managed formats: P4, P5
:param filename: the image's file name
:return: False if failed to open the file
"""
ret = True
try:
fd = open(filename, 'rb')
except IOError:
ret = False
else:
with fd:
self.reset()
self._filename = filename
self._version = fd.readline().decode("utf-8").strip()
c = fd.read(1).decode("utf-8")
if c == "#":
comment = fd.readline().decode("utf-8").rstrip()
#print("#{}".format(comment))
c = ""
dims = c + fd.readline().decode("utf-8").strip()
width, height = dims.split(" ")
self._width = int(width)
self._height = int(height)
if self._version == "P5":
self._load_bin_pgm(fd)
elif self._version == "P4":
self._load_bin_pbm(fd)
return ret
def get_data(self):
"""Get the image data in a 1D list"""
return self._image
def get_data_bin(self, threshold=125):
"""Get the image data in a 1D list"""
return [1 if e < threshold else 0 for e in self._image]
def get_info(self):
"""Get the image information
:return: information in a dict with keys: "version", "dims", "size", "max_value"
"""
info = {
"version": self._version,
"dims": (self._width, self._height),
"size": len(self._image),
"max_value": self._maxval
}
return info
def get_size(self):
return len(self._image)
def show_image_info(self):
print("file: {}".format(self._filename))
print("version: {}".format(self._version))
print("dims: {}x{} (={})".format(self._width, self._height, self._width*self._height))
print("image size: {}".format(len(self._image)))
print("max val : {}".format(self._maxval))
print("5 first pixels: {}".format(self._image[:5]))
print("5 last pixels: {}".format(self._image[-5:]))
if __name__ == "__main__":
img = PnmImage()
img.load("data/ext_ln0_car0.pgm")
img.show_image_info()
print()
img.load("mc_p22.pgm")
img.show_image_info()
print()
img.load("tst.pbm")
img.show_image_info()