forked from s444420/AL-2020
552 lines
18 KiB
Python
552 lines
18 KiB
Python
#
|
|
# The Python Imaging Library.
|
|
# $Id$
|
|
#
|
|
# standard image operations
|
|
#
|
|
# History:
|
|
# 2001-10-20 fl Created
|
|
# 2001-10-23 fl Added autocontrast operator
|
|
# 2001-12-18 fl Added Kevin's fit operator
|
|
# 2004-03-14 fl Fixed potential division by zero in equalize
|
|
# 2005-05-05 fl Fixed equalize for low number of values
|
|
#
|
|
# Copyright (c) 2001-2004 by Secret Labs AB
|
|
# Copyright (c) 2001-2004 by Fredrik Lundh
|
|
#
|
|
# See the README file for information on usage and redistribution.
|
|
#
|
|
|
|
import functools
|
|
import operator
|
|
|
|
from . import Image
|
|
|
|
#
|
|
# helpers
|
|
|
|
|
|
def _border(border):
|
|
if isinstance(border, tuple):
|
|
if len(border) == 2:
|
|
left, top = right, bottom = border
|
|
elif len(border) == 4:
|
|
left, top, right, bottom = border
|
|
else:
|
|
left = top = right = bottom = border
|
|
return left, top, right, bottom
|
|
|
|
|
|
def _color(color, mode):
|
|
if isinstance(color, str):
|
|
from . import ImageColor
|
|
|
|
color = ImageColor.getcolor(color, mode)
|
|
return color
|
|
|
|
|
|
def _lut(image, lut):
|
|
if image.mode == "P":
|
|
# FIXME: apply to lookup table, not image data
|
|
raise NotImplementedError("mode P support coming soon")
|
|
elif image.mode in ("L", "RGB"):
|
|
if image.mode == "RGB" and len(lut) == 256:
|
|
lut = lut + lut + lut
|
|
return image.point(lut)
|
|
else:
|
|
raise OSError("not supported for this image mode")
|
|
|
|
|
|
#
|
|
# actions
|
|
|
|
|
|
def autocontrast(image, cutoff=0, ignore=None):
|
|
"""
|
|
Maximize (normalize) image contrast. This function calculates a
|
|
histogram of the input image, removes **cutoff** percent of the
|
|
lightest and darkest pixels from the histogram, and remaps the image
|
|
so that the darkest pixel becomes black (0), and the lightest
|
|
becomes white (255).
|
|
|
|
:param image: The image to process.
|
|
:param cutoff: How many percent to cut off from the histogram.
|
|
:param ignore: The background pixel value (use None for no background).
|
|
:return: An image.
|
|
"""
|
|
histogram = image.histogram()
|
|
lut = []
|
|
for layer in range(0, len(histogram), 256):
|
|
h = histogram[layer : layer + 256]
|
|
if ignore is not None:
|
|
# get rid of outliers
|
|
try:
|
|
h[ignore] = 0
|
|
except TypeError:
|
|
# assume sequence
|
|
for ix in ignore:
|
|
h[ix] = 0
|
|
if cutoff:
|
|
# cut off pixels from both ends of the histogram
|
|
# get number of pixels
|
|
n = 0
|
|
for ix in range(256):
|
|
n = n + h[ix]
|
|
# remove cutoff% pixels from the low end
|
|
cut = n * cutoff // 100
|
|
for lo in range(256):
|
|
if cut > h[lo]:
|
|
cut = cut - h[lo]
|
|
h[lo] = 0
|
|
else:
|
|
h[lo] -= cut
|
|
cut = 0
|
|
if cut <= 0:
|
|
break
|
|
# remove cutoff% samples from the hi end
|
|
cut = n * cutoff // 100
|
|
for hi in range(255, -1, -1):
|
|
if cut > h[hi]:
|
|
cut = cut - h[hi]
|
|
h[hi] = 0
|
|
else:
|
|
h[hi] -= cut
|
|
cut = 0
|
|
if cut <= 0:
|
|
break
|
|
# find lowest/highest samples after preprocessing
|
|
for lo in range(256):
|
|
if h[lo]:
|
|
break
|
|
for hi in range(255, -1, -1):
|
|
if h[hi]:
|
|
break
|
|
if hi <= lo:
|
|
# don't bother
|
|
lut.extend(list(range(256)))
|
|
else:
|
|
scale = 255.0 / (hi - lo)
|
|
offset = -lo * scale
|
|
for ix in range(256):
|
|
ix = int(ix * scale + offset)
|
|
if ix < 0:
|
|
ix = 0
|
|
elif ix > 255:
|
|
ix = 255
|
|
lut.append(ix)
|
|
return _lut(image, lut)
|
|
|
|
|
|
def colorize(image, black, white, mid=None, blackpoint=0, whitepoint=255, midpoint=127):
|
|
"""
|
|
Colorize grayscale image.
|
|
This function calculates a color wedge which maps all black pixels in
|
|
the source image to the first color and all white pixels to the
|
|
second color. If **mid** is specified, it uses three-color mapping.
|
|
The **black** and **white** arguments should be RGB tuples or color names;
|
|
optionally you can use three-color mapping by also specifying **mid**.
|
|
Mapping positions for any of the colors can be specified
|
|
(e.g. **blackpoint**), where these parameters are the integer
|
|
value corresponding to where the corresponding color should be mapped.
|
|
These parameters must have logical order, such that
|
|
**blackpoint** <= **midpoint** <= **whitepoint** (if **mid** is specified).
|
|
|
|
:param image: The image to colorize.
|
|
:param black: The color to use for black input pixels.
|
|
:param white: The color to use for white input pixels.
|
|
:param mid: The color to use for midtone input pixels.
|
|
:param blackpoint: an int value [0, 255] for the black mapping.
|
|
:param whitepoint: an int value [0, 255] for the white mapping.
|
|
:param midpoint: an int value [0, 255] for the midtone mapping.
|
|
:return: An image.
|
|
"""
|
|
|
|
# Initial asserts
|
|
assert image.mode == "L"
|
|
if mid is None:
|
|
assert 0 <= blackpoint <= whitepoint <= 255
|
|
else:
|
|
assert 0 <= blackpoint <= midpoint <= whitepoint <= 255
|
|
|
|
# Define colors from arguments
|
|
black = _color(black, "RGB")
|
|
white = _color(white, "RGB")
|
|
if mid is not None:
|
|
mid = _color(mid, "RGB")
|
|
|
|
# Empty lists for the mapping
|
|
red = []
|
|
green = []
|
|
blue = []
|
|
|
|
# Create the low-end values
|
|
for i in range(0, blackpoint):
|
|
red.append(black[0])
|
|
green.append(black[1])
|
|
blue.append(black[2])
|
|
|
|
# Create the mapping (2-color)
|
|
if mid is None:
|
|
|
|
range_map = range(0, whitepoint - blackpoint)
|
|
|
|
for i in range_map:
|
|
red.append(black[0] + i * (white[0] - black[0]) // len(range_map))
|
|
green.append(black[1] + i * (white[1] - black[1]) // len(range_map))
|
|
blue.append(black[2] + i * (white[2] - black[2]) // len(range_map))
|
|
|
|
# Create the mapping (3-color)
|
|
else:
|
|
|
|
range_map1 = range(0, midpoint - blackpoint)
|
|
range_map2 = range(0, whitepoint - midpoint)
|
|
|
|
for i in range_map1:
|
|
red.append(black[0] + i * (mid[0] - black[0]) // len(range_map1))
|
|
green.append(black[1] + i * (mid[1] - black[1]) // len(range_map1))
|
|
blue.append(black[2] + i * (mid[2] - black[2]) // len(range_map1))
|
|
for i in range_map2:
|
|
red.append(mid[0] + i * (white[0] - mid[0]) // len(range_map2))
|
|
green.append(mid[1] + i * (white[1] - mid[1]) // len(range_map2))
|
|
blue.append(mid[2] + i * (white[2] - mid[2]) // len(range_map2))
|
|
|
|
# Create the high-end values
|
|
for i in range(0, 256 - whitepoint):
|
|
red.append(white[0])
|
|
green.append(white[1])
|
|
blue.append(white[2])
|
|
|
|
# Return converted image
|
|
image = image.convert("RGB")
|
|
return _lut(image, red + green + blue)
|
|
|
|
|
|
def pad(image, size, method=Image.BICUBIC, color=None, centering=(0.5, 0.5)):
|
|
"""
|
|
Returns a sized and padded version of the image, expanded to fill the
|
|
requested aspect ratio and size.
|
|
|
|
:param image: The image to size and crop.
|
|
:param size: The requested output size in pixels, given as a
|
|
(width, height) tuple.
|
|
:param method: What resampling method to use. Default is
|
|
:py:attr:`PIL.Image.BICUBIC`. See :ref:`concept-filters`.
|
|
:param color: The background color of the padded image.
|
|
:param centering: Control the position of the original image within the
|
|
padded version.
|
|
|
|
(0.5, 0.5) will keep the image centered
|
|
(0, 0) will keep the image aligned to the top left
|
|
(1, 1) will keep the image aligned to the bottom
|
|
right
|
|
:return: An image.
|
|
"""
|
|
|
|
im_ratio = image.width / image.height
|
|
dest_ratio = size[0] / size[1]
|
|
|
|
if im_ratio == dest_ratio:
|
|
out = image.resize(size, resample=method)
|
|
else:
|
|
out = Image.new(image.mode, size, color)
|
|
if im_ratio > dest_ratio:
|
|
new_height = int(image.height / image.width * size[0])
|
|
if new_height != size[1]:
|
|
image = image.resize((size[0], new_height), resample=method)
|
|
|
|
y = int((size[1] - new_height) * max(0, min(centering[1], 1)))
|
|
out.paste(image, (0, y))
|
|
else:
|
|
new_width = int(image.width / image.height * size[1])
|
|
if new_width != size[0]:
|
|
image = image.resize((new_width, size[1]), resample=method)
|
|
|
|
x = int((size[0] - new_width) * max(0, min(centering[0], 1)))
|
|
out.paste(image, (x, 0))
|
|
return out
|
|
|
|
|
|
def crop(image, border=0):
|
|
"""
|
|
Remove border from image. The same amount of pixels are removed
|
|
from all four sides. This function works on all image modes.
|
|
|
|
.. seealso:: :py:meth:`~PIL.Image.Image.crop`
|
|
|
|
:param image: The image to crop.
|
|
:param border: The number of pixels to remove.
|
|
:return: An image.
|
|
"""
|
|
left, top, right, bottom = _border(border)
|
|
return image.crop((left, top, image.size[0] - right, image.size[1] - bottom))
|
|
|
|
|
|
def scale(image, factor, resample=Image.BICUBIC):
|
|
"""
|
|
Returns a rescaled image by a specific factor given in parameter.
|
|
A factor greater than 1 expands the image, between 0 and 1 contracts the
|
|
image.
|
|
|
|
:param image: The image to rescale.
|
|
:param factor: The expansion factor, as a float.
|
|
:param resample: What resampling method to use. Default is
|
|
:py:attr:`PIL.Image.BICUBIC`. See :ref:`concept-filters`.
|
|
:returns: An :py:class:`~PIL.Image.Image` object.
|
|
"""
|
|
if factor == 1:
|
|
return image.copy()
|
|
elif factor <= 0:
|
|
raise ValueError("the factor must be greater than 0")
|
|
else:
|
|
size = (round(factor * image.width), round(factor * image.height))
|
|
return image.resize(size, resample)
|
|
|
|
|
|
def deform(image, deformer, resample=Image.BILINEAR):
|
|
"""
|
|
Deform the image.
|
|
|
|
:param image: The image to deform.
|
|
:param deformer: A deformer object. Any object that implements a
|
|
**getmesh** method can be used.
|
|
:param resample: An optional resampling filter. Same values possible as
|
|
in the PIL.Image.transform function.
|
|
:return: An image.
|
|
"""
|
|
return image.transform(image.size, Image.MESH, deformer.getmesh(image), resample)
|
|
|
|
|
|
def equalize(image, mask=None):
|
|
"""
|
|
Equalize the image histogram. This function applies a non-linear
|
|
mapping to the input image, in order to create a uniform
|
|
distribution of grayscale values in the output image.
|
|
|
|
:param image: The image to equalize.
|
|
:param mask: An optional mask. If given, only the pixels selected by
|
|
the mask are included in the analysis.
|
|
:return: An image.
|
|
"""
|
|
if image.mode == "P":
|
|
image = image.convert("RGB")
|
|
h = image.histogram(mask)
|
|
lut = []
|
|
for b in range(0, len(h), 256):
|
|
histo = [_f for _f in h[b : b + 256] if _f]
|
|
if len(histo) <= 1:
|
|
lut.extend(list(range(256)))
|
|
else:
|
|
step = (functools.reduce(operator.add, histo) - histo[-1]) // 255
|
|
if not step:
|
|
lut.extend(list(range(256)))
|
|
else:
|
|
n = step // 2
|
|
for i in range(256):
|
|
lut.append(n // step)
|
|
n = n + h[i + b]
|
|
return _lut(image, lut)
|
|
|
|
|
|
def expand(image, border=0, fill=0):
|
|
"""
|
|
Add border to the image
|
|
|
|
:param image: The image to expand.
|
|
:param border: Border width, in pixels.
|
|
:param fill: Pixel fill value (a color value). Default is 0 (black).
|
|
:return: An image.
|
|
"""
|
|
left, top, right, bottom = _border(border)
|
|
width = left + image.size[0] + right
|
|
height = top + image.size[1] + bottom
|
|
out = Image.new(image.mode, (width, height), _color(fill, image.mode))
|
|
out.paste(image, (left, top))
|
|
return out
|
|
|
|
|
|
def fit(image, size, method=Image.BICUBIC, bleed=0.0, centering=(0.5, 0.5)):
|
|
"""
|
|
Returns a sized and cropped version of the image, cropped to the
|
|
requested aspect ratio and size.
|
|
|
|
This function was contributed by Kevin Cazabon.
|
|
|
|
:param image: The image to size and crop.
|
|
:param size: The requested output size in pixels, given as a
|
|
(width, height) tuple.
|
|
:param method: What resampling method to use. Default is
|
|
:py:attr:`PIL.Image.BICUBIC`. See :ref:`concept-filters`.
|
|
:param bleed: Remove a border around the outside of the image from all
|
|
four edges. The value is a decimal percentage (use 0.01 for
|
|
one percent). The default value is 0 (no border).
|
|
Cannot be greater than or equal to 0.5.
|
|
:param centering: Control the cropping position. Use (0.5, 0.5) for
|
|
center cropping (e.g. if cropping the width, take 50% off
|
|
of the left side, and therefore 50% off the right side).
|
|
(0.0, 0.0) will crop from the top left corner (i.e. if
|
|
cropping the width, take all of the crop off of the right
|
|
side, and if cropping the height, take all of it off the
|
|
bottom). (1.0, 0.0) will crop from the bottom left
|
|
corner, etc. (i.e. if cropping the width, take all of the
|
|
crop off the left side, and if cropping the height take
|
|
none from the top, and therefore all off the bottom).
|
|
:return: An image.
|
|
"""
|
|
|
|
# by Kevin Cazabon, Feb 17/2000
|
|
# kevin@cazabon.com
|
|
# http://www.cazabon.com
|
|
|
|
# ensure centering is mutable
|
|
centering = list(centering)
|
|
|
|
if not 0.0 <= centering[0] <= 1.0:
|
|
centering[0] = 0.5
|
|
if not 0.0 <= centering[1] <= 1.0:
|
|
centering[1] = 0.5
|
|
|
|
if not 0.0 <= bleed < 0.5:
|
|
bleed = 0.0
|
|
|
|
# calculate the area to use for resizing and cropping, subtracting
|
|
# the 'bleed' around the edges
|
|
|
|
# number of pixels to trim off on Top and Bottom, Left and Right
|
|
bleed_pixels = (bleed * image.size[0], bleed * image.size[1])
|
|
|
|
live_size = (
|
|
image.size[0] - bleed_pixels[0] * 2,
|
|
image.size[1] - bleed_pixels[1] * 2,
|
|
)
|
|
|
|
# calculate the aspect ratio of the live_size
|
|
live_size_ratio = live_size[0] / live_size[1]
|
|
|
|
# calculate the aspect ratio of the output image
|
|
output_ratio = size[0] / size[1]
|
|
|
|
# figure out if the sides or top/bottom will be cropped off
|
|
if live_size_ratio == output_ratio:
|
|
# live_size is already the needed ratio
|
|
crop_width = live_size[0]
|
|
crop_height = live_size[1]
|
|
elif live_size_ratio >= output_ratio:
|
|
# live_size is wider than what's needed, crop the sides
|
|
crop_width = output_ratio * live_size[1]
|
|
crop_height = live_size[1]
|
|
else:
|
|
# live_size is taller than what's needed, crop the top and bottom
|
|
crop_width = live_size[0]
|
|
crop_height = live_size[0] / output_ratio
|
|
|
|
# make the crop
|
|
crop_left = bleed_pixels[0] + (live_size[0] - crop_width) * centering[0]
|
|
crop_top = bleed_pixels[1] + (live_size[1] - crop_height) * centering[1]
|
|
|
|
crop = (crop_left, crop_top, crop_left + crop_width, crop_top + crop_height)
|
|
|
|
# resize the image and return it
|
|
return image.resize(size, method, box=crop)
|
|
|
|
|
|
def flip(image):
|
|
"""
|
|
Flip the image vertically (top to bottom).
|
|
|
|
:param image: The image to flip.
|
|
:return: An image.
|
|
"""
|
|
return image.transpose(Image.FLIP_TOP_BOTTOM)
|
|
|
|
|
|
def grayscale(image):
|
|
"""
|
|
Convert the image to grayscale.
|
|
|
|
:param image: The image to convert.
|
|
:return: An image.
|
|
"""
|
|
return image.convert("L")
|
|
|
|
|
|
def invert(image):
|
|
"""
|
|
Invert (negate) the image.
|
|
|
|
:param image: The image to invert.
|
|
:return: An image.
|
|
"""
|
|
lut = []
|
|
for i in range(256):
|
|
lut.append(255 - i)
|
|
return _lut(image, lut)
|
|
|
|
|
|
def mirror(image):
|
|
"""
|
|
Flip image horizontally (left to right).
|
|
|
|
:param image: The image to mirror.
|
|
:return: An image.
|
|
"""
|
|
return image.transpose(Image.FLIP_LEFT_RIGHT)
|
|
|
|
|
|
def posterize(image, bits):
|
|
"""
|
|
Reduce the number of bits for each color channel.
|
|
|
|
:param image: The image to posterize.
|
|
:param bits: The number of bits to keep for each channel (1-8).
|
|
:return: An image.
|
|
"""
|
|
lut = []
|
|
mask = ~(2 ** (8 - bits) - 1)
|
|
for i in range(256):
|
|
lut.append(i & mask)
|
|
return _lut(image, lut)
|
|
|
|
|
|
def solarize(image, threshold=128):
|
|
"""
|
|
Invert all pixel values above a threshold.
|
|
|
|
:param image: The image to solarize.
|
|
:param threshold: All pixels above this greyscale level are inverted.
|
|
:return: An image.
|
|
"""
|
|
lut = []
|
|
for i in range(256):
|
|
if i < threshold:
|
|
lut.append(i)
|
|
else:
|
|
lut.append(255 - i)
|
|
return _lut(image, lut)
|
|
|
|
|
|
def exif_transpose(image):
|
|
"""
|
|
If an image has an EXIF Orientation tag, return a new image that is
|
|
transposed accordingly. Otherwise, return a copy of the image.
|
|
|
|
:param image: The image to transpose.
|
|
:return: An image.
|
|
"""
|
|
exif = image.getexif()
|
|
orientation = exif.get(0x0112)
|
|
method = {
|
|
2: Image.FLIP_LEFT_RIGHT,
|
|
3: Image.ROTATE_180,
|
|
4: Image.FLIP_TOP_BOTTOM,
|
|
5: Image.TRANSPOSE,
|
|
6: Image.ROTATE_270,
|
|
7: Image.TRANSVERSE,
|
|
8: Image.ROTATE_90,
|
|
}.get(orientation)
|
|
if method is not None:
|
|
transposed_image = image.transpose(method)
|
|
del exif[0x0112]
|
|
transposed_image.info["exif"] = exif.tobytes()
|
|
return transposed_image
|
|
return image.copy()
|