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Antialias renamed to Lanczos
Default filter for thumbnails
Image transposing
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homm 2014-11-29 23:04:51 +03:00
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@ -10,6 +10,18 @@ Bicubic and Bilinear downscalling
Antialias renamed to Lanczos
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
New :py:attr:`PIL.Image.LANCZOS` constant was added instead of
:py:attr:`PIL.Image.ANTIALIAS`.
When :py:attr:`~PIL.Image.ANTIALIAS` was initially added, it was the only
high-qality filter based on convolutions. It's name was supposed to reflect
this. Starting from 2.7 all resize method are based on convolutions. All of them
are antialias from now. And the real name of :py:attr:`~PIL.Image.ANTIALIAS`
filter is Lanczos filter.
:py:attr:`~PIL.Image.ANTIALIAS` constant is leaved for backward compatibility
and is an alias for :py:attr:`~PIL.Image.LANCZOS`.
Lanczos upscaling quality
^^^^^^^^^^^^^^^^^^^^^^^^^
@ -22,9 +34,28 @@ Resize performance
Default filter for thumbnails
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
In Pillow 2.5 default filter for :py:meth:`~PIL.Image.Image.thumbnail` was
changed from :py:attr:`~PIL.Image.NEAREST` to :py:attr:`~PIL.Image.ANTIALIAS`.
Antialias was chosen because all other filters gave poor quality for reduction.
Starting from Pillow 2.7 :py:attr:`~PIL.Image.ANTIALIAS` replaced with
:py:attr:`~PIL.Image.BICUBIC`, because bicubic is faster and
:py:attr:`~PIL.Image.ANTIALIAS` doesn't give any advantages after
downscaling with libJPEG, which uses supersampling internaly, not convolutions.
Image transposing
-----------------
New method :py:attr:`PIL.Image.TRANSPOSE` was added for
:py:meth:`~PIL.Image.Image.transpose` operation in addition to
:py:attr:`~PIL.Image.FLIP_LEFT_RIGHT`, :py:attr:`~PIL.Image.FLIP_TOP_BOTTOM`,
:py:attr:`~PIL.Image.ROTATE_90`, :py:attr:`~PIL.Image.ROTATE_180`,
:py:attr:`~PIL.Image.ROTATE_270`. :py:attr:`~PIL.Image.TRANSPOSE` is algebra
transpose, when image reflected over its main diagonal.
Speed of :py:attr:`~PIL.Image.ROTATE_90`, :py:attr:`~PIL.Image.ROTATE_270`
and :py:attr:`~PIL.Image.TRANSPOSE` was significantly improved for large images,
which doesn't fit in processor cache.
Gaussian blur and unsharp mask
------------------------------