def calculate_difference(preview, original_image_id):
"""Calculate difference between two images.
@param preview: preview dict
@param original_image_id: original image ID
@return: difference, difference percentage
"""
try:
i1 = utils.str2image(get_file(original_image_id).read())
except IOError as e:
logger.warning("Comparer error reading image: {0}".format(e))
return
# Check if thumb was resized.
if "original_file" in preview:
i2 = utils.str2image(get_file(preview["original_file"]).read())
else:
i2 = utils.str2image(get_file(preview["file"]).read())
# Resize.
width, height = i2.size
try:
i1 = i1.resize([width, height], Image.ANTIALIAS)
except IOError as e:
logger.warning("Comparer error reading image: {0}".format(e))
return
# Checks.
#assert i1.mode == i2.mode, "Different kinds of images."
#assert i1.size == i2.size, "Different sizes."
# Calculate difference.
pairs = izip(i1.getdata(), i2.getdata())
if len(i1.getbands()) == 1:
# for gray-scale jpegs
dif = sum(abs(p1 - p2) for p1, p2 in pairs)
else:
dif = sum(
abs(c1 - c2) for p1, p2 in pairs for c1, c2 in zip(p1, p2))
ncomponents = i1.size[0] * i1.size[1] * 3
# Get diff percentage.
diff_perc = int((dif / 255.0 * 100) / ncomponents)
# Binary option.
if diff_perc >= 15:
diff = True
else:
diff = False
return diff, diff_perc
def calculate_difference(preview, original_image_id):
"""Calculate difference between two images.
@param preview: preview dict
@param original_image_id: original image ID
@return: difference, difference percentage
"""
try:
i1 = utils.str2image(get_file(original_image_id).read())
except IOError as e:
logger.warning("Comparer error reading image: {0}".format(e))
return
# Check if thumb was resized.
if "original_file" in preview:
i2 = utils.str2image(get_file(preview["original_file"]).read())
else:
i2 = utils.str2image(get_file(preview["file"]).read())
# Resize.
width, height = i2.size
try:
i1 = i1.resize([width, height], Image.ANTIALIAS)
except IOError as e:
logger.warning("Comparer error reading image: {0}".format(e))
return
# Checks.
# assert i1.mode == i2.mode, "Different kinds of images."
# assert i1.size == i2.size, "Different sizes."
# Calculate difference.
pairs = izip(i1.getdata(), i2.getdata())
if len(i1.getbands()) == 1:
# for gray-scale jpegs
dif = sum(abs(p1 - p2) for p1, p2 in pairs)
else:
dif = sum(abs(c1 - c2) for p1, p2 in pairs for c1, c2 in zip(p1, p2))
ncomponents = i1.size[0] * i1.size[1] * 3
# Get diff percentage.
diff_perc = int((dif / 255.0 * 100) / ncomponents)
# Binary option.
if diff_perc >= 15:
diff = True
else:
diff = False
return diff, diff_perc
def _get_previews(self):
"""Extract previews."""
if len(self.metadata.get_preview_properties()) > 0:
# Fetched previews key.
self.results["preview"] = []
for preview in self.metadata.get_preview_properties():
p = AutoVivification()
p["mime_type"] = preview.get_mime_type()
p["size"] = len(self.metadata.get_preview_image(preview).get_data())
p["ext"] = preview.get_extension()
p["dimensions"] = [preview.get_width(), preview.get_height()]
# Resize if needed, and store.
try:
img = utils.str2image(self.metadata.get_preview_image(preview).get_data())
if preview.get_width() > 256 or preview.get_height() > 160:
p["original_file"] = save_file(utils.image2str(img), content_type="image/jpeg")
img.thumbnail([256, 160], Image.ANTIALIAS)
p["file"] = save_file(utils.image2str(img), content_type="image/jpeg")
except Exception as e:
logger.warning("Error reading preview: {0}".format(e))
continue
finally:
# Save.
self.results["preview"].append(p)
def _get_previews(self):
"""Extract previews."""
if len(self.metadata.get_preview_properties()) > 0:
# Fetched previews key.
self.results["preview"] = []
for preview in self.metadata.get_preview_properties():
p = AutoVivification()
p["mime_type"] = preview.get_mime_type()
p["size"] = len(
self.metadata.get_preview_image(preview).get_data())
p["ext"] = preview.get_extension()
p["dimensions"] = [preview.get_width(), preview.get_height()]
# Resize if needed, and store.
try:
img = utils.str2image(
self.metadata.get_preview_image(preview).get_data())
if preview.get_width() > 256 or preview.get_height() > 160:
p["original_file"] = save_file(
utils.image2str(img), content_type="image/jpeg")
img.thumbnail([256, 160], Image.ANTIALIAS)
p["file"] = save_file(utils.image2str(img),
content_type="image/jpeg")
except Exception as e:
logger.warning("Error reading preview: {0}".format(e))
continue
finally:
# Save.
self.results["preview"].append(p)
