Remove PILKit functionality

This commit removes the functionality now in the PILKit project, and
adds PILKit as a dependency. Import hooks have been used to expose the
processors under "imagekit.processors".
This commit is contained in:
Matthew Tretter 2013-02-07 23:10:05 -05:00
parent d0ba353be3
commit 36313194ac
10 changed files with 40 additions and 981 deletions

View file

@ -1,5 +1,5 @@
# flake8: noqa
from . import importers
from . import conf
from . import generatorlibrary
from .specs import ImageSpec

View file

@ -1,3 +1,6 @@
from pilkit.exceptions import UnknownExtension, UnknownFormat
class AlreadyRegistered(Exception):
pass
@ -6,13 +9,10 @@ class NotRegistered(Exception):
pass
class UnknownExtensionError(Exception):
pass
class UnknownFormatError(Exception):
pass
class MissingGeneratorId(Exception):
pass
# Aliases for backwards compatibility
UnknownExtensionError = UnknownExtension
UnknownFormatError = UnknownFormat

29
imagekit/importers.py Normal file
View file

@ -0,0 +1,29 @@
from django.utils.importlib import import_module
import re
import sys
class ProcessorImporter(object):
"""
The processors were moved to the PILKit project so they could be used
separtely from ImageKit (which has a bunch of Django dependencies). However,
there's no real need to expose this fact (and we want to maintain backwards
compatibility), so we proxy all "imagekit.processors" imports to
"pilkit.processors" using this object.
"""
pattern = re.compile(r'^imagekit\.processors((\..*)?)$')
def find_module(self, name, path=None):
if self.pattern.match(name):
return self
def load_module(self, name):
if name in sys.modules:
return sys.modules[name]
new_name = self.pattern.sub(r'pilkit.processors\1', name)
return import_module(new_name)
sys.meta_path.append(ProcessorImporter())

View file

@ -1,15 +0,0 @@
# flake8: noqa
"""
Imagekit image processors.
A processor accepts an image, does some stuff, and returns the result.
Processors can do anything with the image you want, but their responsibilities
should be limited to image manipulations--they should be completely decoupled
from both the filesystem and the ORM.
"""
from .base import *
from .crop import *
from .resize import *

View file

@ -1,209 +0,0 @@
from imagekit.lib import Image, ImageColor, ImageEnhance
class ProcessorPipeline(list):
"""
A :class:`list` of other processors. This class allows any object that
knows how to deal with a single processor to deal with a list of them.
For example::
processed_image = ProcessorPipeline([ProcessorA(), ProcessorB()]).process(image)
"""
def process(self, img):
for proc in self:
img = proc.process(img)
return img
class Adjust(object):
"""
Performs color, brightness, contrast, and sharpness enhancements on the
image. See :mod:`PIL.ImageEnhance` for more imformation.
"""
def __init__(self, color=1.0, brightness=1.0, contrast=1.0, sharpness=1.0):
"""
:param color: A number between 0 and 1 that specifies the saturation
of the image. 0 corresponds to a completely desaturated image
(black and white) and 1 to the original color.
See :class:`PIL.ImageEnhance.Color`
:param brightness: A number representing the brightness; 0 results in
a completely black image whereas 1 corresponds to the brightness
of the original. See :class:`PIL.ImageEnhance.Brightness`
:param contrast: A number representing the contrast; 0 results in a
completely gray image whereas 1 corresponds to the contrast of
the original. See :class:`PIL.ImageEnhance.Contrast`
:param sharpness: A number representing the sharpness; 0 results in a
blurred image; 1 corresponds to the original sharpness; 2
results in a sharpened image. See
:class:`PIL.ImageEnhance.Sharpness`
"""
self.color = color
self.brightness = brightness
self.contrast = contrast
self.sharpness = sharpness
def process(self, img):
original = img = img.convert('RGBA')
for name in ['Color', 'Brightness', 'Contrast', 'Sharpness']:
factor = getattr(self, name.lower())
if factor != 1.0:
try:
img = getattr(ImageEnhance, name)(img).enhance(factor)
except ValueError:
pass
else:
# PIL's Color and Contrast filters both convert the image
# to L mode, losing transparency info, so we put it back.
# See https://github.com/jdriscoll/django-imagekit/issues/64
if name in ('Color', 'Contrast'):
img = Image.merge('RGBA', img.split()[:3] +
original.split()[3:4])
return img
class Reflection(object):
"""
Creates an image with a reflection.
"""
def __init__(self, background_color='#FFFFFF', size=0.0, opacity=0.6):
self.background_color = background_color
self.size = size
self.opacity = opacity
def process(self, img):
# Convert bgcolor string to RGB value.
background_color = ImageColor.getrgb(self.background_color)
# Handle palleted images.
img = img.convert('RGBA')
# Copy orignial image and flip the orientation.
reflection = img.copy().transpose(Image.FLIP_TOP_BOTTOM)
# Create a new image filled with the bgcolor the same size.
background = Image.new("RGBA", img.size, background_color)
# Calculate our alpha mask.
start = int(255 - (255 * self.opacity)) # The start of our gradient.
steps = int(255 * self.size) # The number of intermedite values.
increment = (255 - start) / float(steps)
mask = Image.new('L', (1, 255))
for y in range(255):
if y < steps:
val = int(y * increment + start)
else:
val = 255
mask.putpixel((0, y), val)
alpha_mask = mask.resize(img.size)
# Merge the reflection onto our background color using the alpha mask.
reflection = Image.composite(background, reflection, alpha_mask)
# Crop the reflection.
reflection_height = int(img.size[1] * self.size)
reflection = reflection.crop((0, 0, img.size[0], reflection_height))
# Create new image sized to hold both the original image and
# the reflection.
composite = Image.new("RGBA", (img.size[0], img.size[1] + reflection_height), background_color)
# Paste the orignal image and the reflection into the composite image.
composite.paste(img, (0, 0))
composite.paste(reflection, (0, img.size[1]))
# Return the image complete with reflection effect.
return composite
class Transpose(object):
"""
Rotates or flips the image.
"""
AUTO = 'auto'
FLIP_HORIZONTAL = Image.FLIP_LEFT_RIGHT
FLIP_VERTICAL = Image.FLIP_TOP_BOTTOM
ROTATE_90 = Image.ROTATE_90
ROTATE_180 = Image.ROTATE_180
ROTATE_270 = Image.ROTATE_270
methods = [AUTO]
_EXIF_ORIENTATION_STEPS = {
1: [],
2: [FLIP_HORIZONTAL],
3: [ROTATE_180],
4: [FLIP_VERTICAL],
5: [ROTATE_270, FLIP_HORIZONTAL],
6: [ROTATE_270],
7: [ROTATE_90, FLIP_HORIZONTAL],
8: [ROTATE_90],
}
def __init__(self, *args):
"""
Possible arguments:
- Transpose.AUTO
- Transpose.FLIP_HORIZONTAL
- Transpose.FLIP_VERTICAL
- Transpose.ROTATE_90
- Transpose.ROTATE_180
- Transpose.ROTATE_270
The order of the arguments dictates the order in which the
Transposition steps are taken.
If Transpose.AUTO is present, all other arguments are ignored, and
the processor will attempt to rotate the image according to the
EXIF Orientation data.
"""
super(Transpose, self).__init__()
if args:
self.methods = args
def process(self, img):
if self.AUTO in self.methods:
try:
orientation = img._getexif()[0x0112]
ops = self._EXIF_ORIENTATION_STEPS[orientation]
except (KeyError, TypeError, AttributeError):
ops = []
else:
ops = self.methods
for method in ops:
img = img.transpose(method)
return img
class Anchor(object):
"""
Defines all the anchor points needed by the various processor classes.
"""
TOP_LEFT = 'tl'
TOP = 't'
TOP_RIGHT = 'tr'
BOTTOM_LEFT = 'bl'
BOTTOM = 'b'
BOTTOM_RIGHT = 'br'
CENTER = 'c'
LEFT = 'l'
RIGHT = 'r'
_ANCHOR_PTS = {
TOP_LEFT: (0, 0),
TOP: (0.5, 0),
TOP_RIGHT: (1, 0),
LEFT: (0, 0.5),
CENTER: (0.5, 0.5),
RIGHT: (1, 0.5),
BOTTOM_LEFT: (0, 1),
BOTTOM: (0.5, 1),
BOTTOM_RIGHT: (1, 1),
}
@staticmethod
def get_tuple(anchor):
"""Normalizes anchor values (strings or tuples) to tuples.
"""
# If the user passed in one of the string values, convert it to a
# percentage tuple.
if anchor in Anchor._ANCHOR_PTS.keys():
anchor = Anchor._ANCHOR_PTS[anchor]
return anchor

View file

@ -1,170 +0,0 @@
from .base import Anchor # noqa
from .utils import histogram_entropy
from ..lib import Image, ImageChops, ImageDraw, ImageStat
class Side(object):
TOP = 't'
RIGHT = 'r'
BOTTOM = 'b'
LEFT = 'l'
ALL = (TOP, RIGHT, BOTTOM, LEFT)
def _crop(img, bbox, sides=Side.ALL):
bbox = (
bbox[0] if Side.LEFT in sides else 0,
bbox[1] if Side.TOP in sides else 0,
bbox[2] if Side.RIGHT in sides else img.size[0],
bbox[3] if Side.BOTTOM in sides else img.size[1],
)
return img.crop(bbox)
def detect_border_color(img):
mask = Image.new('1', img.size, 1)
w, h = img.size[0] - 2, img.size[1] - 2
if w > 0 and h > 0:
draw = ImageDraw.Draw(mask)
draw.rectangle([1, 1, w, h], 0)
return ImageStat.Stat(img.convert('RGBA').histogram(mask)).median
class TrimBorderColor(object):
"""Trims a color from the sides of an image.
"""
def __init__(self, color=None, tolerance=0.3, sides=Side.ALL):
"""
:param color: The color to trim from the image, in a 4-tuple RGBA value,
where each component is an integer between 0 and 255, inclusive. If
no color is provided, the processor will attempt to detect the
border color automatically.
:param tolerance: A number between 0 and 1 where 0. Zero is the least
tolerant and one is the most.
:param sides: A list of sides that should be trimmed. Possible values
are provided by the :class:`Side` enum class.
"""
self.color = color
self.sides = sides
self.tolerance = tolerance
def process(self, img):
source = img.convert('RGBA')
border_color = self.color or tuple(detect_border_color(source))
bg = Image.new('RGBA', img.size, border_color)
diff = ImageChops.difference(source, bg)
if self.tolerance not in (0, 1):
# If tolerance is zero, we've already done the job. A tolerance of
# one would mean to trim EVERY color, and since that would result
# in a zero-sized image, we just ignore it.
if not 0 <= self.tolerance <= 1:
raise ValueError('%s is an invalid tolerance. Acceptable values'
' are between 0 and 1 (inclusive).' % self.tolerance)
tmp = ImageChops.constant(diff, int(self.tolerance * 255)) \
.convert('RGBA')
diff = ImageChops.subtract(diff, tmp)
bbox = diff.getbbox()
if bbox:
img = _crop(img, bbox, self.sides)
return img
class Crop(object):
"""
Crops an image, cropping it to the specified width and height. You may
optionally provide either an anchor or x and y coordinates. This processor
functions exactly the same as ``ResizeCanvas`` except that it will never
enlarge the image.
"""
def __init__(self, width=None, height=None, anchor=None, x=None, y=None):
self.width = width
self.height = height
self.anchor = anchor
self.x = x
self.y = y
def process(self, img):
from .resize import ResizeCanvas
original_width, original_height = img.size
new_width, new_height = min(original_width, self.width), \
min(original_height, self.height)
return ResizeCanvas(new_width, new_height, anchor=self.anchor,
x=self.x, y=self.y).process(img)
class SmartCrop(object):
"""
Crop an image to the specified dimensions, whittling away the parts of the
image with the least entropy.
Based on smart crop implementation from easy-thumbnails:
https://github.com/SmileyChris/easy-thumbnails/blob/master/easy_thumbnails/processors.py#L193
"""
def __init__(self, width=None, height=None):
"""
:param width: The target width, in pixels.
:param height: The target height, in pixels.
"""
self.width = width
self.height = height
def compare_entropy(self, start_slice, end_slice, slice, difference):
"""
Calculate the entropy of two slices (from the start and end of an axis),
returning a tuple containing the amount that should be added to the start
and removed from the end of the axis.
"""
start_entropy = histogram_entropy(start_slice)
end_entropy = histogram_entropy(end_slice)
if end_entropy and abs(start_entropy / end_entropy - 1) < 0.01:
# Less than 1% difference, remove from both sides.
if difference >= slice * 2:
return slice, slice
half_slice = slice // 2
return half_slice, slice - half_slice
if start_entropy > end_entropy:
return 0, slice
else:
return slice, 0
def process(self, img):
source_x, source_y = img.size
diff_x = int(source_x - min(source_x, self.width))
diff_y = int(source_y - min(source_y, self.height))
left = top = 0
right, bottom = source_x, source_y
while diff_x:
slice = min(diff_x, max(diff_x // 5, 10))
start = img.crop((left, 0, left + slice, source_y))
end = img.crop((right - slice, 0, right, source_y))
add, remove = self.compare_entropy(start, end, slice, diff_x)
left += add
right -= remove
diff_x = diff_x - add - remove
while diff_y:
slice = min(diff_y, max(diff_y // 5, 10))
start = img.crop((0, top, source_x, top + slice))
end = img.crop((0, bottom - slice, source_x, bottom))
add, remove = self.compare_entropy(start, end, slice, diff_y)
top += add
bottom -= remove
diff_y = diff_y - add - remove
box = (left, top, right, bottom)
img = img.crop(box)
return img

View file

@ -1,260 +0,0 @@
from imagekit.lib import Image
from .base import Anchor
class Resize(object):
"""
Resizes an image to the specified width and height.
"""
def __init__(self, width, height):
"""
:param width: The target width, in pixels.
:param height: The target height, in pixels.
"""
self.width = width
self.height = height
def process(self, img):
return img.resize((self.width, self.height), Image.ANTIALIAS)
class ResizeToCover(object):
"""
Resizes the image to the smallest possible size that will entirely cover the
provided dimensions. You probably won't be using this processor directly,
but it's used internally by ``ResizeToFill`` and ``SmartResize``.
"""
def __init__(self, width, height):
"""
:param width: The target width, in pixels.
:param height: The target height, in pixels.
"""
self.width, self.height = width, height
def process(self, img):
original_width, original_height = img.size
ratio = max(float(self.width) / original_width,
float(self.height) / original_height)
new_width, new_height = (int(original_width * ratio),
int(original_height * ratio))
return Resize(new_width, new_height).process(img)
class ResizeToFill(object):
"""
Resizes an image, cropping it to the exact specified width and height.
"""
def __init__(self, width=None, height=None, anchor=None):
"""
:param width: The target width, in pixels.
:param height: The target height, in pixels.
:param anchor: Specifies which part of the image should be retained
when cropping.
"""
self.width = width
self.height = height
self.anchor = anchor
def process(self, img):
from .crop import Crop
img = ResizeToCover(self.width, self.height).process(img)
return Crop(self.width, self.height,
anchor=self.anchor).process(img)
class SmartResize(object):
"""
The ``SmartResize`` processor is identical to ``ResizeToFill``, except that
it uses entropy to crop the image instead of a user-specified anchor point.
Internally, it simply runs the ``ResizeToCover`` and ``SmartCrop``
processors in series.
"""
def __init__(self, width, height):
"""
:param width: The target width, in pixels.
:param height: The target height, in pixels.
"""
self.width, self.height = width, height
def process(self, img):
from .crop import SmartCrop
img = ResizeToCover(self.width, self.height).process(img)
return SmartCrop(self.width, self.height).process(img)
class ResizeCanvas(object):
"""
Resizes the canvas, using the provided background color if the new size is
larger than the current image.
"""
def __init__(self, width, height, color=None, anchor=None, x=None, y=None):
"""
:param width: The target width, in pixels.
:param height: The target height, in pixels.
:param color: The background color to use for padding.
:param anchor: Specifies the position of the original image on the new
canvas. Valid values are:
- Anchor.TOP_LEFT
- Anchor.TOP
- Anchor.TOP_RIGHT
- Anchor.LEFT
- Anchor.CENTER
- Anchor.RIGHT
- Anchor.BOTTOM_LEFT
- Anchor.BOTTOM
- Anchor.BOTTOM_RIGHT
You may also pass a tuple that indicates the position in
percentages. For example, ``(0, 0)`` corresponds to "top left",
``(0.5, 0.5)`` to "center" and ``(1, 1)`` to "bottom right". This is
basically the same as using percentages in CSS background positions.
"""
if x is not None or y is not None:
if anchor:
raise Exception('You may provide either an anchor or x and y'
' coordinate, but not both.')
else:
self.x, self.y = x or 0, y or 0
self.anchor = None
else:
self.anchor = anchor or Anchor.CENTER
self.x = self.y = None
self.width = width
self.height = height
self.color = color or (255, 255, 255, 0)
def process(self, img):
original_width, original_height = img.size
if self.anchor:
anchor = Anchor.get_tuple(self.anchor)
trim_x, trim_y = self.width - original_width, \
self.height - original_height
x = int(float(trim_x) * float(anchor[0]))
y = int(float(trim_y) * float(anchor[1]))
else:
x, y = self.x, self.y
new_img = Image.new('RGBA', (self.width, self.height), self.color)
new_img.paste(img, (x, y))
return new_img
class AddBorder(object):
"""
Add a border of specific color and size to an image.
"""
def __init__(self, thickness, color=None):
"""
:param color: Color to use for the border
:param thickness: Thickness of the border. Can be either an int or
a 4-tuple of ints of the form (top, right, bottom, left).
"""
self.color = color
if isinstance(thickness, int):
self.top = self.right = self.bottom = self.left = thickness
else:
self.top, self.right, self.bottom, self.left = thickness
def process(self, img):
new_width = img.size[0] + self.left + self.right
new_height = img.size[1] + self.top + self.bottom
return ResizeCanvas(new_width, new_height, color=self.color,
x=self.left, y=self.top).process(img)
class ResizeToFit(object):
"""
Resizes an image to fit within the specified dimensions.
"""
def __init__(self, width=None, height=None, upscale=None, mat_color=None, anchor=Anchor.CENTER):
"""
:param width: The maximum width of the desired image.
:param height: The maximum height of the desired image.
:param upscale: A boolean value specifying whether the image should
be enlarged if its dimensions are smaller than the target
dimensions.
:param mat_color: If set, the target image size will be enforced and the
specified color will be used as a background color to pad the image.
"""
self.width = width
self.height = height
self.upscale = upscale
self.mat_color = mat_color
self.anchor = anchor
def process(self, img):
cur_width, cur_height = img.size
if not self.width is None and not self.height is None:
ratio = min(float(self.width) / cur_width,
float(self.height) / cur_height)
else:
if self.width is None:
ratio = float(self.height) / cur_height
else:
ratio = float(self.width) / cur_width
new_dimensions = (int(round(cur_width * ratio)),
int(round(cur_height * ratio)))
if (cur_width > new_dimensions[0] or cur_height > new_dimensions[1]) or self.upscale:
img = Resize(new_dimensions[0], new_dimensions[1]).process(img)
if self.mat_color is not None:
img = ResizeCanvas(self.width, self.height, self.mat_color, anchor=self.anchor).process(img)
return img
class Thumbnail(object):
"""
Resize the image for use as a thumbnail. Wraps ``ResizeToFill``,
``ResizeToFit``, and ``SmartResize``.
Note: while it doesn't currently, in the future this processor may also
sharpen based on the amount of reduction.
"""
def __init__(self, width=None, height=None, anchor=None, crop=None):
self.width = width
self.height = height
if anchor:
if crop is False:
raise Exception("You can't specify an anchor point if crop is False.")
else:
crop = True
elif crop is None:
# Assume we are cropping if both a width and height are provided. If
# only one is, we must be resizing to fit.
crop = width is not None and height is not None
# A default anchor if cropping.
if crop and anchor is None:
anchor = 'auto'
self.crop = crop
self.anchor = anchor
def process(self, img):
if self.crop:
if not self.width or not self.height:
raise Exception('You must provide both a width and height when'
' cropping.')
if self.anchor == 'auto':
processor = SmartResize(self.width, self.height)
else:
processor = ResizeToFill(self.width, self.height, self.anchor)
else:
processor = ResizeToFit(self.width, self.height)
return processor.process(img)

View file

@ -1,18 +0,0 @@
import math
from imagekit.lib import Image
def histogram_entropy(im):
"""
Calculate the entropy of an images' histogram. Used for "smart cropping" in easy-thumbnails;
see: https://raw.github.com/SmileyChris/easy-thumbnails/master/easy_thumbnails/utils.py
"""
if not isinstance(im, Image.Image):
return 0 # Fall back to a constant entropy.
histogram = im.histogram()
hist_ceil = float(sum(histogram))
histonorm = [histocol / hist_ceil for histocol in histogram]
return -sum([p * math.log(p, 2) for p in histonorm if p != 0])

View file

@ -1,26 +1,11 @@
import logging
import os
import mimetypes
import sys
from tempfile import NamedTemporaryFile
import types
from django.core.exceptions import ImproperlyConfigured
from django.core.files import File
from django.db.models.loading import cache
from django.utils.functional import wraps
from django.utils.importlib import import_module
from .exceptions import UnknownExtensionError, UnknownFormatError
from .lib import Image, ImageFile, StringIO
RGBA_TRANSPARENCY_FORMATS = ['PNG']
PALETTE_TRANSPARENCY_FORMATS = ['PNG', 'GIF']
def img_to_fobj(img, format, autoconvert=True, **options):
return save_image(img, StringIO(), format, options, autoconvert)
from pilkit.utils import *
def get_spec_files(instance):
@ -30,116 +15,6 @@ def get_spec_files(instance):
return []
def open_image(target):
target.seek(0)
img = Image.open(target)
img.copy = types.MethodType(_wrap_copy(img.copy), img, img.__class__)
return img
def _wrap_copy(f):
@wraps(f)
def copy(self):
img = f()
try:
img.app = self.app
except AttributeError:
pass
try:
img._getexif = self._getexif
except AttributeError:
pass
return img
return copy
_pil_init = 0
def _preinit_pil():
"""Loads the standard PIL file format drivers. Returns True if ``preinit()``
was called (and there's a potential that more drivers were loaded) or False
if there is no possibility that new drivers were loaded.
"""
global _pil_init
if _pil_init < 1:
Image.preinit()
_pil_init = 1
return True
return False
def _init_pil():
"""Loads all PIL file format drivers. Returns True if ``init()`` was called
(and there's a potential that more drivers were loaded) or False if there is
no possibility that new drivers were loaded.
"""
global _pil_init
_preinit_pil()
if _pil_init < 2:
Image.init()
_pil_init = 2
return True
return False
def _extension_to_format(extension):
return Image.EXTENSION.get(extension.lower())
def _format_to_extension(format):
if format:
for k, v in Image.EXTENSION.iteritems():
if v == format.upper():
return k
return None
def extension_to_mimetype(ext):
try:
filename = 'a%s' % (ext or '') # guess_type requires a full filename, not just an extension
mimetype = mimetypes.guess_type(filename)[0]
except IndexError:
mimetype = None
return mimetype
def format_to_mimetype(format):
return extension_to_mimetype(format_to_extension(format))
def extension_to_format(extension):
"""Returns the format that corresponds to the provided extension.
"""
format = _extension_to_format(extension)
if not format and _preinit_pil():
format = _extension_to_format(extension)
if not format and _init_pil():
format = _extension_to_format(extension)
if not format:
raise UnknownExtensionError(extension)
return format
def format_to_extension(format):
"""Returns the first extension that matches the provided format.
"""
extension = None
if format:
extension = _format_to_extension(format)
if not extension and _preinit_pil():
extension = _format_to_extension(format)
if not extension and _init_pil():
extension = _format_to_extension(format)
if not extension:
raise UnknownFormatError(format)
return extension
def _get_models(apps):
models = []
for app_label in apps or []:
@ -148,180 +23,6 @@ def _get_models(apps):
return models
def suggest_extension(name, format):
original_extension = os.path.splitext(name)[1]
try:
suggested_extension = format_to_extension(format)
except UnknownFormatError:
extension = original_extension
else:
if suggested_extension.lower() == original_extension.lower():
extension = original_extension
else:
try:
original_format = extension_to_format(original_extension)
except UnknownExtensionError:
extension = suggested_extension
else:
# If the formats match, give precedence to the original extension.
if format.lower() == original_format.lower():
extension = original_extension
else:
extension = suggested_extension
return extension
def save_image(img, outfile, format, options=None, autoconvert=True):
"""
Wraps PIL's ``Image.save()`` method. There are two main benefits of using
this function over PIL's:
1. It gracefully handles the infamous "Suspension not allowed here" errors.
2. It prepares the image for saving using ``prepare_image()``, which will do
some common-sense processing given the target format.
"""
options = options or {}
if autoconvert:
img, save_kwargs = prepare_image(img, format)
options = dict(save_kwargs.items() + options.items())
# Attempt to reset the file pointer.
try:
outfile.seek(0)
except AttributeError:
pass
try:
with quiet():
img.save(outfile, format, **options)
except IOError:
# PIL can have problems saving large JPEGs if MAXBLOCK isn't big enough,
# So if we have a problem saving, we temporarily increase it. See
# http://github.com/jdriscoll/django-imagekit/issues/50
old_maxblock = ImageFile.MAXBLOCK
ImageFile.MAXBLOCK = img.size[0] * img.size[1]
try:
img.save(outfile, format, **options)
finally:
ImageFile.MAXBLOCK = old_maxblock
try:
outfile.seek(0)
except AttributeError:
pass
return outfile
class quiet(object):
"""
A context manager for suppressing the stderr activity of PIL's C libraries.
Based on http://stackoverflow.com/a/978264/155370
"""
def __enter__(self):
self.stderr_fd = sys.__stderr__.fileno()
self.null_fd = os.open(os.devnull, os.O_RDWR)
self.old = os.dup(self.stderr_fd)
os.dup2(self.null_fd, self.stderr_fd)
def __exit__(self, *args, **kwargs):
os.dup2(self.old, self.stderr_fd)
os.close(self.null_fd)
os.close(self.old)
def prepare_image(img, format):
"""
Prepares the image for saving to the provided format by doing some
common-sense conversions. This includes things like preserving transparency
and quantizing. This function is used automatically by ``save_image()``
(and classes like ``ImageSpecField`` and ``ProcessedImageField``)
immediately before saving unless you specify ``autoconvert=False``. It is
provided as a utility for those doing their own processing.
:param img: The image to prepare for saving.
:param format: The format that the image will be saved to.
"""
matte = False
save_kwargs = {}
if img.mode == 'RGBA':
if format in RGBA_TRANSPARENCY_FORMATS:
pass
elif format in PALETTE_TRANSPARENCY_FORMATS:
# If you're going from a format with alpha transparency to one
# with palette transparency, transparency values will be
# snapped: pixels that are more opaque than not will become
# fully opaque; pixels that are more transparent than not will
# become fully transparent. This will not produce a good-looking
# result if your image contains varying levels of opacity; in
# that case, you'll probably want to use a processor to matte
# the image on a solid color. The reason we don't matte by
# default is because not doing so allows processors to treat
# RGBA-format images as a super-type of P-format images: if you
# have an RGBA-format image with only a single transparent
# color, and save it as a GIF, it will retain its transparency.
# In other words, a P-format image converted to an
# RGBA-formatted image by a processor and then saved as a
# P-format image will give the expected results.
# Work around a bug in PIL: split() doesn't check to see if
# img is loaded.
img.load()
alpha = img.split()[-1]
mask = Image.eval(alpha, lambda a: 255 if a <= 128 else 0)
img = img.convert('RGB').convert('P', palette=Image.ADAPTIVE,
colors=255)
img.paste(255, mask)
save_kwargs['transparency'] = 255
else:
# Simply converting an RGBA-format image to an RGB one creates a
# gross result, so we matte the image on a white background. If
# that's not what you want, that's fine: use a processor to deal
# with the transparency however you want. This is simply a
# sensible default that will always produce something that looks
# good. Or at least, it will look better than just a straight
# conversion.
matte = True
elif img.mode == 'P':
if format in PALETTE_TRANSPARENCY_FORMATS:
try:
save_kwargs['transparency'] = img.info['transparency']
except KeyError:
pass
elif format in RGBA_TRANSPARENCY_FORMATS:
# Currently PIL doesn't support any RGBA-mode formats that
# aren't also P-mode formats, so this will never happen.
img = img.convert('RGBA')
else:
matte = True
else:
img = img.convert('RGB')
# GIFs are always going to be in palette mode, so we can do a little
# optimization. Note that the RGBA sources also use adaptive
# quantization (above). Images that are already in P mode don't need
# any quantization because their colors are already limited.
if format == 'GIF':
img = img.convert('P', palette=Image.ADAPTIVE)
if matte:
img = img.convert('RGBA')
bg = Image.new('RGBA', img.size, (255, 255, 255))
bg.paste(img, img)
img = bg.convert('RGB')
if format == 'JPEG':
save_kwargs['optimize'] = True
return img, save_kwargs
def get_by_qname(path, desc):
try:
dot = path.rindex('.')

View file

@ -50,6 +50,7 @@ setup(
test_suite='testrunner.run_tests',
install_requires=[
'django-appconf>=0.5',
'pilkit<2.0a0',
],
classifiers=[
'Development Status :: 5 - Production/Stable',