# 9.1.0

## API Changes

### Raise an error when performing a negative crop

Performing a negative crop on an image previously just returned a `(0, 0)` image. Now it will raise a `ValueError`, to help reduce confusion if a user has unintentionally provided the wrong arguments.

### Added specific error if path coordinate type is incorrect

Rather than returning a `SystemError`, passing the incorrect types of coordinates into a path will now raise a more specific `ValueError`, with the message “incorrect coordinate type”.

### Replace requirements.txt with extras

Rather than installing all dependencies for docs and tests via `requirements.txt`, `extras_require` is used instead. This installs only those needed and at the same time as installing Pillow.

For example:

    # Install with dependencies for tests:
    python3 -m pip install .[tests]

    # Or for building docs:
    python3 -m pip install .[docs]

    # Or for all:
    python3 -m pip install .[docs,tests]

On macOS, the last argument may need to be wrapped in quotes, e.g. `python3 -m pip install ".[tests]"`

Therefore `requirements.txt` has been removed along with the `make install-req` command for installing its contents.

## Deprecations

### Constants

A number of constants have been deprecated and will be removed in Pillow 10.0.0 (2023-07-01). Instead, `enum.IntEnum` classes have been added.

Note

Some of these deprecations were restored in Pillow 9.4.0. See Constants

Deprecated | Use instead
--- | ---
`Image.NONE` | Either `Image.Dither.NONE` or `Image.Resampling.NEAREST`
`Image.NEAREST` | Either `Image.Dither.NONE` or `Image.Resampling.NEAREST`
`Image.ORDERED` | `Image.Dither.ORDERED`
`Image.RASTERIZE` | `Image.Dither.RASTERIZE`
`Image.FLOYDSTEINBERG` | `Image.Dither.FLOYDSTEINBERG`
`Image.WEB` | `Image.Palette.WEB`
`Image.ADAPTIVE` | `Image.Palette.ADAPTIVE`
`Image.AFFINE` | `Image.Transform.AFFINE`
`Image.EXTENT` | `Image.Transform.EXTENT`
`Image.PERSPECTIVE` | `Image.Transform.PERSPECTIVE`
`Image.QUAD` | `Image.Transform.QUAD`
`Image.MESH` | `Image.Transform.MESH`
`Image.FLIP_LEFT_RIGHT` | `Image.Transpose.FLIP_LEFT_RIGHT`
`Image.FLIP_TOP_BOTTOM` | `Image.Transpose.FLIP_TOP_BOTTOM`
`Image.ROTATE_90` | `Image.Transpose.ROTATE_90`
`Image.ROTATE_180` | `Image.Transpose.ROTATE_180`
`Image.ROTATE_270` | `Image.Transpose.ROTATE_270`
`Image.TRANSPOSE` | `Image.Transpose.TRANSPOSE`
`Image.TRANSVERSE` | `Image.Transpose.TRANSVERSE`
`Image.BOX` | `Image.Resampling.BOX`
`Image.BILINEAR` | `Image.Resampling.BILINEAR`
`Image.LINEAR` | `Image.Resampling.BILINEAR`
`Image.HAMMING` | `Image.Resampling.HAMMING`
`Image.BICUBIC` | `Image.Resampling.BICUBIC`
`Image.CUBIC` | `Image.Resampling.BICUBIC`
`Image.LANCZOS` | `Image.Resampling.LANCZOS`
`Image.ANTIALIAS` | `Image.Resampling.LANCZOS`
`Image.MEDIANCUT` | `Image.Quantize.MEDIANCUT`
`Image.MAXCOVERAGE` | `Image.Quantize.MAXCOVERAGE`
`Image.FASTOCTREE` | `Image.Quantize.FASTOCTREE`
`Image.LIBIMAGEQUANT` | `Image.Quantize.LIBIMAGEQUANT`
`ImageCms.INTENT_PERCEPTUAL` | `ImageCms.Intent.PERCEPTUAL`
`ImageCms.INTENT_RELATIVE_COLORMETRIC` | `ImageCms.Intent.RELATIVE_COLORMETRIC`
`ImageCms.INTENT_SATURATION` | `ImageCms.Intent.SATURATION`
`ImageCms.INTENT_ABSOLUTE_COLORIMETRIC` | `ImageCms.Intent.ABSOLUTE_COLORIMETRIC`
`ImageCms.DIRECTION_INPUT` | `ImageCms.Direction.INPUT`
`ImageCms.DIRECTION_OUTPUT` | `ImageCms.Direction.OUTPUT`
`ImageCms.DIRECTION_PROOF` | `ImageCms.Direction.PROOF`
`ImageFont.LAYOUT_BASIC` | `ImageFont.Layout.BASIC`
`ImageFont.LAYOUT_RAQM` | `ImageFont.Layout.RAQM`
`BlpImagePlugin.BLP_FORMAT_JPEG` | `BlpImagePlugin.Format.JPEG`
`BlpImagePlugin.BLP_ENCODING_UNCOMPRESSED` | `BlpImagePlugin.Encoding.UNCOMPRESSED`
`BlpImagePlugin.BLP_ENCODING_DXT` | `BlpImagePlugin.Encoding.DXT`
`BlpImagePlugin.BLP_ENCODING_UNCOMPRESSED_RAW_RGBA` | `BlpImagePlugin.Encoding.UNCOMPRESSED_RAW_RGBA`
`BlpImagePlugin.BLP_ALPHA_ENCODING_DXT1` | `BlpImagePlugin.AlphaEncoding.DXT1`
`BlpImagePlugin.BLP_ALPHA_ENCODING_DXT3` | `BlpImagePlugin.AlphaEncoding.DXT3`
`BlpImagePlugin.BLP_ALPHA_ENCODING_DXT5` | `BlpImagePlugin.AlphaEncoding.DXT5`
`FtexImagePlugin.FORMAT_DXT1` | `FtexImagePlugin.Format.DXT1`
`FtexImagePlugin.FORMAT_UNCOMPRESSED` | `FtexImagePlugin.Format.UNCOMPRESSED`
`PngImagePlugin.APNG_DISPOSE_OP_NONE` | `PngImagePlugin.Disposal.OP_NONE`
`PngImagePlugin.APNG_DISPOSE_OP_BACKGROUND` | `PngImagePlugin.Disposal.OP_BACKGROUND`
`PngImagePlugin.APNG_DISPOSE_OP_PREVIOUS` | `PngImagePlugin.Disposal.OP_PREVIOUS`
`PngImagePlugin.APNG_BLEND_OP_SOURCE` | `PngImagePlugin.Blend.OP_SOURCE`
`PngImagePlugin.APNG_BLEND_OP_OVER` | `PngImagePlugin.Blend.OP_OVER`

### ImageShow.Viewer.show_file file argument

The `file` argument in `show_file()` has been deprecated and will be removed in Pillow 10.0.0 (2023-07-01). It has been replaced by `path`.

In effect, `viewer.show_file("test.jpg")` will continue to work unchanged. `viewer.show_file(file="test.jpg")` will raise a deprecation warning, and suggest `viewer.show_file(path="test.jpg")` instead.

### FitsStubImagePlugin

Deprecated since version 9.1.0.

The stub image plugin `FitsStubImagePlugin` has been deprecated and will be removed in Pillow 10.0.0 (2023-07-01). FITS images can be read without a handler through `FitsImagePlugin` instead.

## API Additions

### Added get_photoshop_blocks() to parse Photoshop TIFF tag

`get_photoshop_blocks()` has been added, to allow users to determine what Photoshop “Image Resource Blocks” are contained within an image. The keys of the returned dictionary are the image resource IDs.

At present, the information within each block is merely returned as a dictionary with a “data” entry. This will allow more useful information to be added in the future without breaking backwards compatibility.

### Added mct and no_jp2 options for saving JPEG 2000

The `PIL.Image.Image.save()` method now supports the following options for JPEG 2000:

mct

  If `1` then enable multiple component transformation when encoding, otherwise use `0` for no component transformation (default). If MCT is enabled and `irreversible` is `True` then the Irreversible Color Transformation will be applied, otherwise encoding will use the Reversible Color Transformation. MCT works best with a `mode` of `RGB` and is only applicable when the image data has 3 components.

no_jp2

  If `True` then don’t wrap the raw codestream in the JP2 file format when saving, otherwise the extension of the filename will be used to determine the format (default).

### Added PyEncoder

`PyEncoder` has been added, allowing for file encoders to be written in Python. See Writing Your Own File Codec in Python for more information.

### GifImagePlugin loading strategy

Pillow 9.0.0 introduced the conversion of subsequent GIF frames to `RGB` or `RGBA`. This behaviour can now be changed so that the first `P` frame is converted to `RGB` as well.

    from PIL import GifImagePlugin
    GifImagePlugin.LOADING_STRATEGY = GifImagePlugin.LoadingStrategy.RGB_ALWAYS

Or subsequent frames can be kept in `P` mode as long as there is only a single palette.

    from PIL import GifImagePlugin
    GifImagePlugin.LOADING_STRATEGY = GifImagePlugin.LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY

## Other Changes

### musllinux wheels

Pillow now builds binary wheels for musllinux, suitable for Linux distributions based on the musl C standard library such as Alpine (rather than the glibc library used by manylinux wheels). See PEP 656.

### ImageShow temporary files on Unix

When calling `show()` or using `ImageShow`, a temporary file is created from the image. On Unix, Pillow will no longer delete these files, and instead leave it to the operating system to do so.

### Image._repr_pretty_

`im._repr_pretty_` has been added to provide a representation of an image without the identity of the object. This allows Jupyter to describe an image and have that description stay the same on subsequent executions of the same code.

### Added BigTIFF reading

Support has been added for reading BigTIFF images.

### Added BLP saving

Support has been added for saving BLP images. `blp_version` can be used to specify whether the image should be saved as BLP1 or BLP2, e.g. `im.save("out.blp", blp_version="BLP1")`. By default, BLP2 will be used.