Pillow/docs/reference/Image.rst
Hugo van Kemenade 20282dd23c
Merge pull request #4733 from nulano/refs-mod
Fix documentation references: modules
2020-06-29 11:57:53 +03:00

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.. py:module:: PIL.Image
.. py:currentmodule:: PIL.Image
:py:mod:`~PIL.Image` Module
===========================
The :py:mod:`~PIL.Image` module provides a class with the same name which is
used to represent a PIL image. The module also provides a number of factory
functions, including functions to load images from files, and to create new
images.
Examples
--------
Open, rotate, and display an image (using the default viewer)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The following script loads an image, rotates it 45 degrees, and displays it
using an external viewer (usually xv on Unix, and the Paint program on
Windows).
.. code-block:: python
from PIL import Image
im = Image.open("bride.jpg")
im.rotate(45).show()
Create thumbnails
^^^^^^^^^^^^^^^^^
The following script creates nice thumbnails of all JPEG images in the
current directory preserving aspect ratios with 128x128 max resolution.
.. code-block:: python
from PIL import Image
import glob, os
size = 128, 128
for infile in glob.glob("*.jpg"):
file, ext = os.path.splitext(infile)
im = Image.open(infile)
im.thumbnail(size)
im.save(file + ".thumbnail", "JPEG")
Functions
---------
.. autofunction:: open
.. warning::
To protect against potential DOS attacks caused by "`decompression bombs`_" (i.e. malicious files
which decompress into a huge amount of data and are designed to crash or cause disruption by using up
a lot of memory), Pillow will issue a ``DecompressionBombWarning`` if the image is over a certain
limit. If desired, the warning can be turned into an error with
``warnings.simplefilter('error', Image.DecompressionBombWarning)`` or suppressed entirely with
``warnings.simplefilter('ignore', Image.DecompressionBombWarning)``. See also `the logging
documentation`_ to have warnings output to the logging facility instead of stderr.
.. _decompression bombs: https://en.wikipedia.org/wiki/Zip_bomb
.. _the logging documentation: https://docs.python.org/3/library/logging.html#integration-with-the-warnings-module
Image processing
^^^^^^^^^^^^^^^^
.. autofunction:: alpha_composite
.. autofunction:: blend
.. autofunction:: composite
.. autofunction:: eval
.. autofunction:: merge
Constructing images
^^^^^^^^^^^^^^^^^^^
.. autofunction:: new
.. autofunction:: fromarray
.. autofunction:: frombytes
.. autofunction:: frombuffer
Generating images
^^^^^^^^^^^^^^^^^
.. autofunction:: effect_mandelbrot
.. autofunction:: effect_noise
.. autofunction:: linear_gradient
.. autofunction:: radial_gradient
Registering plugins
^^^^^^^^^^^^^^^^^^^
.. note::
These functions are for use by plugin authors. Application authors can
ignore them.
.. autofunction:: register_open
.. autofunction:: register_mime
.. autofunction:: register_save
.. autofunction:: register_save_all
.. autofunction:: register_extension
.. autofunction:: register_extensions
.. autofunction:: registered_extensions
.. autofunction:: register_decoder
.. autofunction:: register_encoder
The Image Class
---------------
.. autoclass:: PIL.Image.Image
An instance of the :py:class:`~PIL.Image.Image` class has the following
methods. Unless otherwise stated, all methods return a new instance of the
:py:class:`~PIL.Image.Image` class, holding the resulting image.
.. automethod:: PIL.Image.Image.alpha_composite
.. automethod:: PIL.Image.Image.convert
The following example converts an RGB image (linearly calibrated according to
ITU-R 709, using the D65 luminant) to the CIE XYZ color space:
.. code-block:: python
rgb2xyz = (
0.412453, 0.357580, 0.180423, 0,
0.212671, 0.715160, 0.072169, 0,
0.019334, 0.119193, 0.950227, 0)
out = im.convert("RGB", rgb2xyz)
.. automethod:: PIL.Image.Image.copy
.. automethod:: PIL.Image.Image.crop
This crops the input image with the provided coordinates:
.. code-block:: python
from PIL import Image
im = Image.open("hopper.jpg")
# The crop method from the Image module takes four coordinates as input.
# The right can also be represented as (left+width)
# and lower can be represented as (upper+height).
(left, upper, right, lower) = (20, 20, 100, 100)
# Here the image "im" is cropped and assigned to new variable im_crop
im_crop = im.crop((left, upper, right, lower))
.. automethod:: PIL.Image.Image.draft
.. automethod:: PIL.Image.Image.effect_spread
.. automethod:: PIL.Image.Image.entropy
.. automethod:: PIL.Image.Image.filter
This blurs the input image using a filter from the ``ImageFilter`` module:
.. code-block:: python
from PIL import Image, ImageFilter
im = Image.open("hopper.jpg")
# Blur the input image using the filter ImageFilter.BLUR
im_blurred = im.filter(filter=ImageFilter.BLUR)
.. automethod:: PIL.Image.Image.getbands
This helps to get the bands of the input image:
.. code-block:: python
from PIL import Image
im = Image.open("hopper.jpg")
print(im.getbands()) # Returns ('R', 'G', 'B')
.. automethod:: PIL.Image.Image.getbbox
This helps to get the bounding box coordinates of the input image:
.. code-block:: python
from PIL import Image
im = Image.open("hopper.jpg")
print(im.getbbox())
# Returns four coordinates in the format (left, upper, right, lower)
.. automethod:: PIL.Image.Image.getchannel
.. automethod:: PIL.Image.Image.getcolors
.. automethod:: PIL.Image.Image.getdata
.. automethod:: PIL.Image.Image.getexif
.. automethod:: PIL.Image.Image.getextrema
.. automethod:: PIL.Image.Image.getpalette
.. automethod:: PIL.Image.Image.getpixel
.. automethod:: PIL.Image.Image.getprojection
.. automethod:: PIL.Image.Image.histogram
.. automethod:: PIL.Image.Image.offset
.. automethod:: PIL.Image.Image.paste
.. automethod:: PIL.Image.Image.point
.. automethod:: PIL.Image.Image.putalpha
.. automethod:: PIL.Image.Image.putdata
.. automethod:: PIL.Image.Image.putpalette
.. automethod:: PIL.Image.Image.putpixel
.. automethod:: PIL.Image.Image.quantize
.. automethod:: PIL.Image.Image.reduce
.. automethod:: PIL.Image.Image.remap_palette
.. automethod:: PIL.Image.Image.resize
This resizes the given image from ``(width, height)`` to ``(width/2, height/2)``:
.. code-block:: python
from PIL import Image
im = Image.open("hopper.jpg")
# Provide the target width and height of the image
(width, height) = (im.width // 2, im.height // 2)
im_resized = im.resize((width, height))
.. automethod:: PIL.Image.Image.rotate
This rotates the input image by ``theta`` degrees counter clockwise:
.. code-block:: python
from PIL import Image
im = Image.open("hopper.jpg")
# Rotate the image by 60 degrees counter clockwise
theta = 60
# Angle is in degrees counter clockwise
im_rotated = im.rotate(angle=theta)
.. automethod:: PIL.Image.Image.save
.. automethod:: PIL.Image.Image.seek
.. automethod:: PIL.Image.Image.show
.. automethod:: PIL.Image.Image.split
.. automethod:: PIL.Image.Image.tell
.. automethod:: PIL.Image.Image.thumbnail
.. automethod:: PIL.Image.Image.tobitmap
.. automethod:: PIL.Image.Image.tobytes
.. automethod:: PIL.Image.Image.tostring
.. automethod:: PIL.Image.Image.transform
.. automethod:: PIL.Image.Image.transpose
This flips the input image by using the :data:`FLIP_LEFT_RIGHT` method.
.. code-block:: python
from PIL import Image
im = Image.open("hopper.jpg")
# Flip the image from left to right
im_flipped = im.transpose(method=Image.FLIP_LEFT_RIGHT)
# To flip the image from top to bottom,
# use the method "Image.FLIP_TOP_BOTTOM"
.. automethod:: PIL.Image.Image.verify
.. automethod:: PIL.Image.Image.fromstring
.. automethod:: PIL.Image.Image.load
.. automethod:: PIL.Image.Image.close
Attributes
----------
Instances of the :py:class:`Image` class have the following attributes:
.. py:attribute:: Image.filename
:type: str
The filename or path of the source file. Only images created with the
factory function ``open`` have a filename attribute. If the input is a
file like object, the filename attribute is set to an empty string.
.. py:attribute:: Image.format
:type: Optional[str]
The file format of the source file. For images created by the library
itself (via a factory function, or by running a method on an existing
image), this attribute is set to ``None``.
.. py:attribute:: Image.mode
:type: str
Image mode. This is a string specifying the pixel format used by the image.
Typical values are “1”, “L”, “RGB”, or “CMYK.” See
:ref:`concept-modes` for a full list.
.. py:attribute:: Image.size
:type: tuple[int]
Image size, in pixels. The size is given as a 2-tuple (width, height).
.. py:attribute:: Image.width
:type: int
Image width, in pixels.
.. py:attribute:: Image.height
:type: int
Image height, in pixels.
.. py:attribute:: Image.palette
:type: Optional[PIL.ImagePalette.ImagePalette]
Colour palette table, if any. If mode is "P" or "PA", this should be an
instance of the :py:class:`~PIL.ImagePalette.ImagePalette` class.
Otherwise, it should be set to ``None``.
.. py:attribute:: Image.info
:type: dict
A dictionary holding data associated with the image. This dictionary is
used by file handlers to pass on various non-image information read from
the file. See documentation for the various file handlers for details.
Most methods ignore the dictionary when returning new images; since the
keys are not standardized, its not possible for a method to know if the
operation affects the dictionary. If you need the information later on,
keep a reference to the info dictionary returned from the open method.
Unless noted elsewhere, this dictionary does not affect saving files.
Constants
---------
.. data:: NONE
Transpose methods
^^^^^^^^^^^^^^^^^
Used to specify the :meth:`Image.transpose` method to use.
.. data:: FLIP_LEFT_RIGHT
.. data:: FLIP_TOP_BOTTOM
.. data:: ROTATE_90
.. data:: ROTATE_180
.. data:: ROTATE_270
.. data:: TRANSPOSE
.. data:: TRANSVERSE
Transform methods
^^^^^^^^^^^^^^^^^
Used to specify the :meth:`Image.transform` method to use.
.. data:: AFFINE
Affine transform
.. data:: EXTENT
Cut out a rectangular subregion
.. data:: PERSPECTIVE
Perspective transform
.. data:: QUAD
Map a quadrilateral to a rectangle
.. data:: MESH
Map a number of source quadrilaterals in one operation
Resampling filters
^^^^^^^^^^^^^^^^^^
See :ref:`concept-filters` for details.
.. data:: NEAREST
:noindex:
.. data:: BOX
:noindex:
.. data:: BILINEAR
:noindex:
.. data:: HAMMING
:noindex:
.. data:: BICUBIC
:noindex:
.. data:: LANCZOS
:noindex:
Some filters are also available under the following names for backwards compatibility:
.. data:: NONE
:noindex:
:value: NEAREST
.. data:: LINEAR
:value: BILINEAR
.. data:: CUBIC
:value: BICUBIC
.. data:: ANTIALIAS
:value: LANCZOS
Dither modes
^^^^^^^^^^^^
Used to specify the dithering method to use for the
:meth:`~Image.convert` and :meth:`~Image.quantize` methods.
.. data:: NONE
:noindex:
No dither
.. comment: (not implemented)
.. data:: ORDERED
.. data:: RASTERIZE
.. data:: FLOYDSTEINBERG
Floyd-Steinberg dither
Palettes
^^^^^^^^
Used to specify the pallete to use for the :meth:`~Image.convert` method.
.. data:: WEB
.. data:: ADAPTIVE
Quantization methods
^^^^^^^^^^^^^^^^^^^^
Used to specify the quantization method to use for the :meth:`~Image.quantize` method.
.. data:: MEDIANCUT
Median cut
.. data:: MAXCOVERAGE
Maximum coverage
.. data:: FASTOCTREE
Fast octree
.. data:: LIBIMAGEQUANT
libimagequant
Check support using :py:func:`PIL.features.check_feature`
with ``feature="libimagequant"``.
.. comment: These are not referenced anywhere?
Categories
^^^^^^^^^^
.. data:: NORMAL
.. data:: SEQUENCE
.. data:: CONTAINER