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110 lines
3.6 KiB
ReStructuredText
110 lines
3.6 KiB
ReStructuredText
4.3.0
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-----
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API Changes
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===========
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Deprecations
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^^^^^^^^^^^^
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Several undocumented functions in ImageOps have been deprecated:
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``gaussian_blur``, ``gblur``, ``unsharp_mask``, ``usm`` and
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``box_blur``. Use the equivalent operations in ImageFilter
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instead. These functions will be removed in a future release.
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TIFF Metadata Changes
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^^^^^^^^^^^^^^^^^^^^^
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* TIFF tags with unknown type/quantity now default to being bare
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values if they are 1 element, where previously they would be a
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single element tuple. This is only with the new api, not the legacy
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api. This normalizes the handling of fields, so that the metadata
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with inferred or image specified counts are handled the same as
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metadata with count specified in the TIFF spec.
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* The ``PhotoshopInfo``, ``XMP``, and ``JPEGTables`` tags now have a
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defined type (bytes) and a count of 1.
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* The ``ImageJMetaDataByteCounts`` tag now has an arbitrary number of
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items, as there can be multiple items, one for UTF-8, and one for
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UTF-16.
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Core Image API Changes
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^^^^^^^^^^^^^^^^^^^^^^
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These are internal functions that should not have been used by user
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code, but they were accessible from the python layer.
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Debugging code within ``Image.core.grabclipboard`` was removed. It had been
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marked as ``will be removed in future versions`` since PIL. When enabled, it
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identified the format of the clipboard data.
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The ``PIL.Image.core.copy`` and ``PIL.Image.Image.im.copy2`` methods
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have been removed.
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API Additions
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=============
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Get One Channel From Image
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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A new method :py:meth:`PIL.Image.Image.getchannel` has been added to
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return a single channel by index or name. For example,
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``image.getchannel("A")`` will return alpha channel as separate image.
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``getchannel`` should work up to 6 times faster than
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``image.split()[0]`` in previous Pillow versions.
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Box Blur
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^^^^^^^^
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A new filter, :py:class:`PIL.ImageFilter.BoxBlur`, has been
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added. This is a filter with similar results to a Gaussian blur, but
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is much faster.
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Partial Resampling
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^^^^^^^^^^^^^^^^^^
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Added new argument ``box`` for :py:meth:`PIL.Image.Image.resize`. This
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argument defines a source rectangle from within the source image to be
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resized. This is very similar to the ``image.crop(box).resize(size)``
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sequence except that ``box`` can be specified with subpixel accuracy.
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New Transpose Operation
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^^^^^^^^^^^^^^^^^^^^^^^
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The ``Image.TRANSVERSE`` operation has been added to
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:py:meth:`PIL.Image.Image.transpose`. This is equivalent to a transpose
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operation about the opposite diagonal.
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Multiband Filters
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^^^^^^^^^^^^^^^^^
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There is a new :py:class:`PIL.ImageFilter.MultibandFilter` base class
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for image filters that can run on all channels of an image in one
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operation. The original :py:class:`PIL.ImageFilter.Filter` class
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remains for image filters that can process only single band images, or
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require splitting of channels prior to filtering.
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Loading 16-bit TIFF Images
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==========================
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Pillow now can read 16-bit multichannel TIFF files including files
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with alpha transparency. The image data is truncated to 8-bit
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precision.
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Performance
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===========
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This release contains several performance improvements:
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* Many memory bandwidth-bounded operations such as crop, image allocation,
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conversion, split into bands and merging from bands are up to 2x faster.
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* Upscaling of multichannel images (such as RGB) is accelerated by 5-10%
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* JPEG loading is accelerated up to 15% and JPEG saving up to 20% when
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using a recent version of libjpeg-turbo.
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* ``Image.transpose`` has been accelerated 15% or more by using a cache
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friendly algorithm.
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* ImageFilters based on Kernel convolution are significantly faster
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due to the new MultibandFilter feature.
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