def encode_text(text_fp: str, img_fp: str, result_fp: str, key: str) -> str:
"""
Main process for encoding text (UTF-8 encoded) from a file into
an 8-bit, three-color image. Creates a SteganoImage() instance
for managing the pixel data.
Returns:
A copy of the given image with the given message hidden
within, at result_fp. If the text file is empty, returns
the given image unaltered.
"""
try:
with Image.open(img_fp) as og_img:
if og_img.size < (3, 3):
print("Specified image is too small to be encoded onto.")
return result_fp
except (FileNotFoundError, UnidentifiedImageError):
print("Specified image cannot be found or opened.")
except Exception as e:
print(e)
if len(key) < 8: # Additional key validation is needed
print("Key must be at least 8 characters long, no spaces.")
try:
with open(text_fp, "r", -1, "utf-8") as text_file:
img = SteganoImage(img_fp, key)
ref_x = 0
ref_y = 0
buffer = text_file.read(1)
while buffer != '':
encode_to_cluster(buffer, ref_x, ref_y, img.pixelmap)
img.occupied.add((ref_x, ref_y))
ref_x, ref_y = find_next_open(ref_x, ref_y, img)
buffer = text_file.read(1)
encoded_img = Image.fromarray(img.pixelmap)
encoded_img.save(result_fp)
img.close_fp() # Important to clean up open files
except (OSError):
print("Specified text file cannot be accessed.")
return result_fp
def test_encode_cluster_04(self):
char = FOUR_BYTE_CHAR
expected = [0, 2, 3, 2, 0, 1, 3, 0, 0, 3, 3, 0, 0, 2, 1, 3, 2, 2]
encode_to_cluster(char, 0, 1, self.pixelmap)
result = [channel for y in range (0, 2) for x in range(0, 3) for channel in self.pixelmap[y, x]]
self.assertEqual(expected, result)