PIL Package (autodoc of remaining modules)¶
Reference for modules whose documentation has not yet been ported or written can be found here.
ContainerIO Module¶
GdImageFile Module¶
GimpGradientFile Module¶
GimpPaletteFile Module¶
ImageShow Module¶
ImageTransform Module¶
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class
PIL.ImageTransform.AffineTransform(data)[源代码]¶ 基类：
PIL.ImageTransform.Transform-
method= 0¶
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class
PIL.ImageTransform.ExtentTransform(data)[源代码]¶ 基类：
PIL.ImageTransform.Transform-
method= 1¶
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class
PIL.ImageTransform.MeshTransform(data)[源代码]¶ 基类：
PIL.ImageTransform.Transform-
method= 4¶
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class
PIL.ImageTransform.QuadTransform(data)[源代码]¶ 基类：
PIL.ImageTransform.Transform-
method= 3¶
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JpegPresets Module¶
JPEG quality settings equivalent to the Photoshop settings.
More presets can be added to the presets dict if needed.
Can be use when saving JPEG file.
To apply the preset, specify:
quality="preset_name"
To apply only the quantization table:
qtables="preset_name"
To apply only the subsampling setting:
subsampling="preset_name"
Example:
im.save("image_name.jpg", quality="web_high")
Subsampling¶
Subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information. (ref.: https://en.wikipedia.org/wiki/Chroma_subsampling)
Possible subsampling values are 0, 1 and 2 that correspond to 4:4:4, 4:2:2 and 4:1:1 (or 4:2:0?).
You can get the subsampling of a JPEG with the JpegImagePlugin.get_subsampling(im) function.
Quantization tables¶
They are values use by the DCT (Discrete cosine transform) to remove unnecessary information from the image (the lossy part of the compression). (ref.: https://en.wikipedia.org/wiki/Quantization_matrix#Quantization_matrices, https://en.wikipedia.org/wiki/JPEG#Quantization)
You can get the quantization tables of a JPEG with:
im.quantization
This will return a dict with a number of arrays. You can pass this dict directly as the qtables argument when saving a JPEG.
The tables format between im.quantization and quantization in presets differ in 3 ways:
- The base container of the preset is a list with sublists instead of dict. dict[0] -> list[0], dict[1] -> list[1], ...
- Each table in a preset is a list instead of an array.
- The zigzag order is remove in the preset (needed by libjpeg >= 6a).
You can convert the dict format to the preset format with the JpegImagePlugin.convert_dict_qtables(dict_qtables) function.
Libjpeg ref.: http://web.archive.org/web/20120328125543/http://www.jpegcameras.com/libjpeg/libjpeg-3.html
PaletteFile Module¶
PngImagePlugin.iTXt Class¶
PngImagePlugin.PngInfo Class¶
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class
PIL.PngImagePlugin.PngInfo[源代码]¶ 基类：
objectPNG chunk container (for use with save(pnginfo=))
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add(cid, data)[源代码]¶ Appends an arbitrary chunk. Use with caution.
参数: - cid – a byte string, 4 bytes long.
- data – a byte string of the encoded data
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add_itxt(key, value, lang='', tkey='', zip=False)[源代码]¶ Appends an iTXt chunk.
参数: - key – latin-1 encodable text key name
- value – value for this key
- lang – language code
- tkey – UTF-8 version of the key name
- zip – compression flag
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add_text(key, value, zip=0)[源代码]¶ Appends a text chunk.
参数: - key – latin-1 encodable text key name
- value – value for this key, text or an
PIL.PngImagePlugin.iTXtinstance - zip – compression flag
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_binary Module¶
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PIL._binary.i16le(c, o=0)[源代码]¶ Converts a 2-bytes (16 bits) string to an integer.
c: string containing bytes to convert o: offset of bytes to convert in string