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# 10.2.0

## Security

### ImageFont.getmask: Applied ImageFont.MAX_STRING_LENGTH

To protect against potential DOS attacks when using arbitrary strings as text input, Pillow will now raise a `ValueError` if the number of characters passed into `PIL.ImageFont.ImageFont.getmask()` is over a certain limit, `PIL.ImageFont.MAX_STRING_LENGTH`.

This threshold can be changed by setting `PIL.ImageFont.MAX_STRING_LENGTH`. It can be disabled by setting `ImageFont.MAX_STRING_LENGTH = None`.

A decompression bomb check has also been added to `PIL.ImageFont.ImageFont.getmask()`.

### ImageFont.getmask: Trim glyph size

To protect against potential DOS attacks when using PIL fonts, `PIL.ImageFont.ImageFont` now trims the size of individual glyphs so that they do not extend beyond the bitmap image.

### CVE 2023-50447: ImageMath.eval: Restricted environment keys

If an attacker has control over the keys passed to the `environment` argument of `PIL.ImageMath.eval()`, they may be able to execute arbitrary code. To prevent this, keys matching the names of builtins and keys containing double underscores will now raise a `ValueError`.

## Deprecations

### ImageFile.raise_oserror

`ImageFile.raise_oserror()` has been deprecated and will be removed in Pillow 12.0.0 (2025-10-15). The function is undocumented and is only useful for translating error codes returned by a codec’s `decode()` method, which ImageFile already does automatically.

### IptcImageFile helper functions

The functions `IptcImageFile.dump` and `IptcImageFile.i`, and the constant `IptcImageFile.PAD` have been deprecated and will be removed in Pillow 12.0.0 (2025-10-15). These are undocumented helper functions intended for internal use, so there is no replacement. They can each be replaced by a single line of code using builtin functions in Python.

## API changes

### Zero or negative font size error

When creating a `FreeTypeFont` instance, either directly or through `truetype()`, if the font size is zero or less, a `ValueError` will now be raised.

## API additions

### Added DdsImagePlugin enums

`DDSD`, `DDSCAPS`, `DDSCAPS2`, `DDPF`, `DXGI_FORMAT` and `D3DFMT` enums have been added to `PIL.DdsImagePlugin`.

### JPEG RGB color space

When saving JPEG files, `keep_rgb` can now be set to `True`. This will store RGB images in the RGB color space instead of being converted to YCbCr automatically by libjpeg. When this option is enabled, attempting to chroma-subsample RGB images with the `subsampling` option will raise an `OSError`.

### JPEG restart marker interval

When saving JPEG files, `restart_marker_blocks` and `restart_marker_rows` can now be used to emit restart markers whenever the specified number of MCU blocks or rows have been produced.

### JPEG tables-only streamtype

When saving JPEG files, `streamtype` can now be set to 1, for tables-only. This will output only the quantization and Huffman tables for the image.

## Other changes

### Added DDS BC4U and DX10 BC1 and BC4 reading

Support has been added to read the BC4U format of DDS images.

Support has also been added to read DX10 BC1 and BC4, whether UNORM or TYPELESS.

### Support arbitrary masks for uncompressed RGB DDS images

All masks are now supported when reading DDS images with uncompressed RGB data, allowing for bit counts other than 24 and 32.

### Saving TIFF tag RowsPerStrip

When saving TIFF images, the TIFF tag RowsPerStrip can now be one of the tags set by the user, rather than always being calculated by Pillow.

### Optimized ImageColor.getrgb and getcolor

The color calculations of `getrgb` and `getcolor` are now cached using `functools.lru_cache()`. Cached calls of `getrgb` are 3.1 - 91.4 times as fast and `getcolor` are 5.1 - 19.6 times as fast.

### Optimized ImageMode.getmode

The lookups made by `getmode` are now cached using `functools.lru_cache()` instead of a custom cache. Cached calls are 1.2 times as fast.

### Optimized ImageStat.Stat count and extrema

Calculating the `count` and `extrema` statistics is now faster. After the histogram is created in `st = ImageStat.Stat(im)`, `st.count` is 3 times as fast on average and `st.extrema` is 12 times as fast on average.

### Encoder errors now report error detail as string

`OSError` exceptions from image encoders now include a textual description of the error instead of a numeric error code.

### Type hints

Work has begun to add type annotations to Pillow, including:

- `ContainerIO`

- `FontFile`, `BdfFontFile` and `PcfFontFile`

- `ImageChops`

- `ImageMode`

- `ImageSequence`

- `ImageTransform`

- `TarIO`