Deprecated since version 2.6: The jpeg
module has been removed in Python 3.
The module jpeg
provides access to the jpeg compressor and decompressor written by the Independent JPEG Group (IJG). JPEG is a standard for compressing pictures; it is defined in ISO 10918. For details on JPEG or the Independent JPEG Group software refer to the JPEG standard or the documentation provided with the software.
A portable interface to JPEG image files is available with the Python Imaging Library (PIL) by Fredrik Lundh. Information on PIL is available at http://www.pythonware.com/products/pil/.
The jpeg
module defines an exception and some functions.
exception jpeg.error
Exception raised by compress()
and decompress()
in case of errors.
jpeg.compress(data, w, h, b)
Treat data as a pixmap of width w and height h, with b bytes per pixel. The data is in SGI GL order, so the first pixel is in the lower-left corner. This means that gl.lrectread()
return data can immediately be passed to compress()
. Currently only 1 byte and 4 byte pixels are allowed, the former being treated as greyscale and the latter as RGB color. compress()
returns a string that contains the compressed picture, in JFIF format.
jpeg.decompress(data)
Data is a string containing a picture in JFIF format. It returns a tuple (data, width, height, bytesperpixel)
. Again, the data is suitable to pass to gl.lrectwrite()
.
jpeg.setoption(name, value)
Set various options. Subsequent compress()
and decompress()
calls will use these options. The following options are available:
Option | Effect |
---|---|
'forcegray' | Force output to be grayscale, even if input is RGB. |
'quality' | Set the quality of the compressed image to a value between 0 and 100 (default is 75 ). This only affects compression. |
'optimize' | Perform Huffman table optimization. Takes longer, but results in smaller compressed image. This only affects compression. |
'smooth' | Perform inter-block smoothing on uncompressed image. Only useful for low- quality images. This only affects decompression. |
See also
© 2001–2017 Python Software Foundation
Licensed under the PSF License.
https://docs.python.org/2.7/library/jpeg.html