def extract_image_primary_secondary_colors(self, logo, white_threshold=225, mitigate=175):
"""
Identifies dominant colors
First resizes the original image to improve performance, then discards
transparent colors and white-ish colors, then calls the averaging
method twice to evaluate both primary and secondary colors.
:param logo: logo to process
:param white_threshold: arbitrary value defining the maximum value a color can reach
:param mitigate: arbitrary value defining the maximum value a band can reach
:return colors: hex values of primary and secondary colors
"""
if not logo:
return False, False
# The "===" gives different base64 encoding a correct padding
logo += b'===' if type(logo) == bytes else '==='
try:
# Catches exceptions caused by logo not being an image
image = tools.image_fix_orientation(tools.base64_to_image(logo))
except Exception:
return False, False
base_w, base_h = image.size
w = int(50 * base_w / base_h)
h = 50
# Converts to RGBA (if already RGBA, this is a noop)
image_converted = image.convert('RGBA')
image_resized = image_converted.resize((w, h), resample=Image.NEAREST)
colors = []
for color in image_resized.getcolors(w * h):
if not(color[1][0] > white_threshold and
color[1][1] > white_threshold and
color[1][2] > white_threshold) and color[1][3] > 0:
colors.append(color)
if not colors: # May happen when the whole image is white
return False, False
primary, remaining = tools.average_dominant_color(colors, mitigate=mitigate)
secondary = tools.average_dominant_color(remaining, mitigate=mitigate)[0] if remaining else primary
# Lightness and saturation are calculated here.
# - If both colors have a similar lightness, the most colorful becomes primary
# - When the difference in lightness is too great, the brightest color becomes primary
l_primary = tools.get_lightness(primary)
l_secondary = tools.get_lightness(secondary)
if (l_primary < 0.2 and l_secondary < 0.2) or (l_primary >= 0.2 and l_secondary >= 0.2):
s_primary = tools.get_saturation(primary)
s_secondary = tools.get_saturation(secondary)
if s_primary < s_secondary:
primary, secondary = secondary, primary
elif l_secondary > l_primary:
primary, secondary = secondary, primary
return tools.rgb_to_hex(primary), tools.rgb_to_hex(secondary)
def _orientation_test(self, orientation, colors, size, expected):
# Generate the test image based on orientation and order of colors.
image = self._get_exif_colored_square(orientation, colors, size)
# The image is read again now that it has orientation added.
fixed_image = tools.image_fix_orientation(img_open(image))
# Ensure colors are in the right order (blue, yellow, green, pink).
self._assertAlmostEqualSequence(fixed_image.getpixel((0, 0)),
expected[0]) # top/left
self._assertAlmostEqualSequence(fixed_image.getpixel((size - 1, 0)),
expected[1]) # top/right
self._assertAlmostEqualSequence(fixed_image.getpixel((0, size - 1)),
expected[2]) # bottom/left
self._assertAlmostEqualSequence(
fixed_image.getpixel((size - 1, size - 1)),
expected[3]) # bottom/right
def test_03_image_fix_orientation_exif(self):
"""Test that a jpg image with exif orientation tag gets rotated"""
image = img_open(self.img_exif_jpg)
self.assertEqual(image.size, (6, 3))
image = tools.image_fix_orientation(image)
self.assertEqual(image.size, (3, 6))