发布于 2015-09-11 16:14:14 | 187 次阅读 | 评论: 0 | 来源: 网络整理
The Python Imaging Library supports a wide variety of raster file formats. Nearly 30 different file formats can be identified and read by the library. Write support is less extensive, but most common interchange and presentation formats are supported.
The open() function identifies files from their contents, not their names, but the save() method looks at the name to determine which format to use, unless the format is given explicitly.
PIL reads and writes Windows and OS/2 BMP files containing 1, L, P, or RGB data. 16-colour images are read as P images. Run-length encoding is not supported.
The open() method sets the following info properties:
PIL identifies EPS files containing image data, and can read files that contain embedded raster images (ImageData descriptors). If Ghostscript is available, other EPS files can be read as well. The EPS driver can also write EPS images.
If Ghostscript is available, you can call the load() method with the following parameter to affect how Ghostscript renders the EPS
Affects the scale of the resultant rasterized image. If the EPS suggests that the image be rendered at 100px x 100px, setting this parameter to 2 will make the Ghostscript render a 200px x 200px image instead. The relative position of the bounding box is maintained:
im = Image.open(...)
im.size #(100,100)
im.load(scale=2)
im.size #(200,200)
PIL reads GIF87a and GIF89a versions of the GIF file format. The library writes run-length encoded GIF87a files. Note that GIF files are always read as grayscale (L) or palette mode (P) images.
The open() method sets the following info properties:
The GIF loader supports the seek() and tell() methods. You can seek to the next frame (im.seek(im.tell() + 1), or rewind the file by seeking to the first frame. Random access is not supported.
The GIF loader creates an image memory the same size as the GIF file’s logical screen size, and pastes the actual pixel data (the local image) into this image. If you only want the actual pixel rectangle, you can manipulate the size and tile attributes before loading the file:
im = Image.open(...)
if im.tile[0][0] == "gif":
# only read the first "local image" from this GIF file
tag, (x0, y0, x1, y1), offset, extra = im.tile[0]
im.size = (x1 - x0, y1 - y0)
im.tile = [(tag, (0, 0) + im.size, offset, extra)]
IM is a format used by LabEye and other applications based on the IFUNC image processing library. The library reads and writes most uncompressed interchange versions of this format.
IM is the only format that can store all internal PIL formats.
PIL reads JPEG, JFIF, and Adobe JPEG files containing L, RGB, or CMYK data. It writes standard and progressive JFIF files.
Using the draft() method, you can speed things up by converting RGB images to L, and resize images to 1/2, 1/4 or 1/8 of their original size while loading them. The draft() method also configures the JPEG decoder to trade some quality for speed.
The open() method sets the following info properties:
The save() method supports the following options:
注解
To enable JPEG support, you need to build and install the IJG JPEG library before building the Python Imaging Library. See the distribution README for details.
2.4.0 新版功能.
PIL reads and writes JPEG 2000 files containing L, LA, RGB or RGBA data. It can also read files containing YCbCr data, which it converts on read into RGB or RGBA depending on whether or not there is an alpha channel. PIL supports JPEG 2000 raw codestreams (.j2k files), as well as boxed JPEG 2000 files (.j2p or .jpx files). PIL does not support files whose components have different sampling frequencies.
When loading, if you set the mode on the image prior to the load() method being invoked, you can ask PIL to convert the image to either RGB or RGBA rather than choosing for itself. It is also possible to set reduce to the number of resolutions to discard (each one reduces the size of the resulting image by a factor of 2), and layers to specify the number of quality layers to load.
The save() method supports the following options:
注解
To enable JPEG 2000 support, you need to build and install the OpenJPEG library, version 2.0.0 or higher, before building the Python Imaging Library.
Windows users can install the OpenJPEG binaries available on the OpenJPEG website, but must add them to their PATH in order to use PIL (if you fail to do this, you will get errors about not being able to load the _imaging DLL).
PIL identifies and reads MSP files from Windows 1 and 2. The library writes uncompressed (Windows 1) versions of this format.
PIL reads and writes PCX files containing 1, L, P, or RGB data.
PIL identifies, reads, and writes PNG files containing 1, L, P, RGB, or RGBA data. Interlaced files are supported as of v1.1.7.
The open() method sets the following info properties, when appropriate:
The save() method supports the following options:
注解
To enable PNG support, you need to build and install the ZLIB compression library before building the Python Imaging Library. See the distribution README for details.
PIL reads and writes PBM, PGM and PPM files containing 1, L or RGB data.
PIL reads and writes SPIDER image files of 32-bit floating point data (“F;32F”).
PIL also reads SPIDER stack files containing sequences of SPIDER images. The seek() and tell() methods are supported, and random access is allowed.
The open() method sets the following attributes:
A convenience method, convert2byte(), is provided for converting floating point data to byte data (mode L):
im = Image.open('image001.spi').convert2byte()
The extension of SPIDER files may be any 3 alphanumeric characters. Therefore the output format must be specified explicitly:
im.save('newimage.spi', format='SPIDER')
For more information about the SPIDER image processing package, see the SPIDER home page at Wadsworth Center.
PIL reads and writes TIFF files. It can read both striped and tiled images, pixel and plane interleaved multi-band images, and either uncompressed, or Packbits, LZW, or JPEG compressed images.
If you have libtiff and its headers installed, PIL can read and write many more kinds of compressed TIFF files. If not, PIL will always write uncompressed files.
The open() method sets the following info properties:
Image resolution as an (xdpi, ydpi) tuple, where applicable. You can use the tag attribute to get more detailed information about the image resolution.
1.1.5 新版功能.
In addition, the tag attribute contains a dictionary of decoded TIFF fields. Values are stored as either strings or tuples. Note that only short, long and ASCII tags are correctly unpacked by this release.
The save() method can take the following keyword arguments:
A ImageFileDirectory object or dict object containing tiff tags and values. The TIFF field type is autodetected for Numeric and string values, any other types require using an ImageFileDirectory object and setting the type in tagtype with the appropriate numerical value from TiffTags.TYPES.
2.3.0 新版功能.
These arguments to set the tiff header fields are an alternative to using the general tags available through tiffinfo.
description
software
date time
artist
resolution
x resolution
y resolution
PIL reads and writes WebP files. The specifics of PIL’s capabilities with this format are currently undocumented.
The save() method supports the following options:
PIL reads and writes X bitmap files (mode 1).
PIL can read XV thumbnail files.
CUR is used to store cursors on Windows. The CUR decoder reads the largest available cursor. Animated cursors are not supported.
DCX is a container file format for PCX files, defined by Intel. The DCX format is commonly used in fax applications. The DCX decoder can read files containing 1, L, P, or RGB data.
When the file is opened, only the first image is read. You can use seek() or ImageSequence to read other images.
PIL reads Autodesk FLI and FLC animations.
The open() method sets the following info properties:
PIL reads Kodak FlashPix files. In the current version, only the highest resolution image is read from the file, and the viewing transform is not taken into account.
注解
To enable full FlashPix support, you need to build and install the IJG JPEG library before building the Python Imaging Library. See the distribution README for details.
The GBR decoder reads GIMP brush files.
The open() method sets the following info properties:
PIL reads uncompressed GD files. Note that this file format cannot be automatically identified, so you must use PIL.GdImageFile.open() to read such a file.
The open() method sets the following info properties:
ICO is used to store icons on Windows. The largest available icon is read.
PIL reads Mac OS X .icns files. By default, the largest available icon is read, though you can override this by setting the size property before calling load(). The open() method sets the following info property:
PIL reads Image Tools images containing L data.
PIL provides limited read support for IPTC/NAA newsphoto files.
PIL identifies and reads 8-bit McIdas area files.
MIC (read only)
PIL identifies and reads Microsoft Image Composer (MIC) files. When opened, the first sprite in the file is loaded. You can use seek() and tell() to read other sprites from the file.
PIL reads PhotoCD files containing RGB data. By default, the 768x512 resolution is read. You can use the draft() method to read the lower resolution versions instead, thus effectively resizing the image to 384x256 or 192x128. Higher resolutions cannot be read by the Python Imaging Library.
PIL identifies and reads PSD files written by Adobe Photoshop 2.5 and 3.0.
PIL reads uncompressed L, RGB, and RGBA files.
PIL reads 24- and 32-bit uncompressed and run-length encoded TGA files.
1.1.4 新版功能.
PIL reads Quake2 WAL texture files.
Note that this file format cannot be automatically identified, so you must use the open function in the WalImageFile module to read files in this format.
By default, a Quake2 standard palette is attached to the texture. To override the palette, use the putpalette method.
PIL reads X pixmap files (mode P) with 256 colors or less.
The open() method sets the following info properties:
PIL provides write-only support for PALM pixmap files.
The format code is Palm, the extension is .palm.
PIL can write PDF (Acrobat) images. Such images are written as binary PDF 1.1 files, using either JPEG or HEX encoding depending on the image mode (and whether JPEG support is available or not).
PIXAR (read only)
PIL provides limited support for PIXAR raster files. The library can identify and read “dumped” RGB files.
The format code is PIXAR.
1.1.3 新版功能.
PIL provides a stub driver for BUFR files.
To add read or write support to your application, use PIL.BufrStubImagePlugin.register_handler().
1.1.5 新版功能.
PIL provides a stub driver for FITS files.
To add read or write support to your application, use PIL.FitsStubImagePlugin.register_handler().
1.1.5 新版功能.
PIL provides a stub driver for GRIB files.
The driver requires the file to start with a GRIB header. If you have files with embedded GRIB data, or files with multiple GRIB fields, your application has to seek to the header before passing the file handle to PIL.
To add read or write support to your application, use PIL.GribStubImagePlugin.register_handler().
1.1.5 新版功能.
PIL provides a stub driver for HDF5 files.
To add read or write support to your application, use PIL.Hdf5StubImagePlugin.register_handler().
PIL identifies MPEG files.
PIL can identify placable WMF files.
In PIL 1.1.4 and earlier, the WMF driver provides some limited rendering support, but not enough to be useful for any real application.
In PIL 1.1.5 and later, the WMF driver is a stub driver. To add WMF read or write support to your application, use PIL.WmfImagePlugin.register_handler() to register a WMF handler.
from PIL import Image
from PIL import WmfImagePlugin
class WmfHandler:
def open(self, im):
...
def load(self, im):
...
return image
def save(self, im, fp, filename):
...
wmf_handler = WmfHandler()
WmfImagePlugin.register_handler(wmf_handler)
im = Image.open("sample.wmf")