Merge pull request #2325 from wiredfool/sgi_write

SGI: Save uncompressed SGI/BW/RGB/RGBA files
This commit is contained in:
wiredfool 2016-12-31 12:34:15 +00:00 committed by GitHub
commit 7db2daa1f1
3 changed files with 92 additions and 6 deletions

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@ -7,9 +7,12 @@
# See "The SGI Image File Format (Draft version 0.97)", Paul Haeberli.
# <ftp://ftp.sgi.com/graphics/SGIIMAGESPEC>
#
#
# History:
# 2016-16-10 mb Add save method without compression
# 1995-09-10 fl Created
#
# Copyright (c) 2016 by Mickael Bonfill.
# Copyright (c) 2008 by Karsten Hiddemann.
# Copyright (c) 1997 by Secret Labs AB.
# Copyright (c) 1995 by Fredrik Lundh.
@ -19,10 +22,13 @@
from PIL import Image, ImageFile, _binary
import struct
import os
__version__ = "0.2"
__version__ = "0.3"
i8 = _binary.i8
o8 = _binary.o8
i16 = _binary.i16be
@ -76,12 +82,79 @@ class SgiImageFile(ImageFile.ImageFile):
elif compression == 1:
raise ValueError("SGI RLE encoding not supported")
def _save(im, fp, filename):
if im.mode != "RGB" and im.mode != "RGBA" and im.mode != "L":
raise ValueError("Unsupported SGI image mode")
# Flip the image, since the origin of SGI file is the bottom-left corner
im = im.transpose(Image.FLIP_TOP_BOTTOM)
# Define the file as SGI File Format
magicNumber = 474
# Run-Length Encoding Compression - Unsupported at this time
rle = 0
# Byte-per-pixel precision, 1 = 8bits per pixel
bpc = 1
# Number of dimensions (x,y,z)
dim = 3
# X Dimension = width / Y Dimension = height
x, y = im.size
if im.mode == "L" and y == 1:
dim = 1
elif im.mode == "L":
dim = 2
# Z Dimension: Number of channels
z = len(im.mode)
if dim == 1 or dim == 2:
z = 1
# Minimum Byte value
pinmin = 0
# Maximum Byte value (255 = 8bits per pixel)
pinmax = 255
# Image name (79 characters max, truncated below in write)
imgName = os.path.splitext(os.path.basename(filename))[0]
if str is not bytes:
imgName = imgName.encode('ascii', 'ignore')
# Standard representation of pixel in the file
colormap = 0
fp.write(struct.pack('>h', magicNumber))
fp.write(o8(rle))
fp.write(o8(bpc))
fp.write(struct.pack('>H', dim))
fp.write(struct.pack('>H', x))
fp.write(struct.pack('>H', y))
fp.write(struct.pack('>H', z))
fp.write(struct.pack('>l', pinmin))
fp.write(struct.pack('>l', pinmax))
fp.write(struct.pack('4s', b'')) # dummy
fp.write(struct.pack('79s', imgName)) # truncates to 79 chars
fp.write(struct.pack('s', b'')) # force null byte after imgname
fp.write(struct.pack('>l', colormap))
fp.write(struct.pack('404s', b'')) # dummy
#assert we've got the right number of bands.
if len(im.getbands()) != z:
raise ValueError("incorrect number of bands in SGI write: %s vs %s" %
(z, len(im.getbands())))
for channel in im.split():
fp.write(channel.tobytes())
fp.close()
#
# registry
Image.register_open(SgiImageFile.format, SgiImageFile, _accept)
Image.register_save(SgiImageFile.format, _save)
Image.register_mime(SgiImageFile.format, "image/sgi")
Image.register_mime(SgiImageFile.format, "image/rgb")
Image.register_extension(SgiImageFile.format, ".bw")
Image.register_extension(SgiImageFile.format, ".rgb")
Image.register_extension(SgiImageFile.format, ".rgba")
Image.register_extension(SgiImageFile.format, ".sgi")
# End of file

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@ -45,6 +45,17 @@ class TestFileSgi(PillowTestCase):
lambda:
SgiImagePlugin.SgiImageFile(invalid_file))
def test_write(self):
def roundtrip(img):
out = self.tempfile('temp.sgi')
img.save(out, format='sgi')
reloaded = Image.open(out)
self.assert_image_equal(img, reloaded)
for mode in ('L', 'RGB', 'RGBA'):
roundtrip(hopper(mode))
if __name__ == '__main__':
unittest.main()

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@ -471,6 +471,12 @@ PPM
PIL reads and writes PBM, PGM and PPM files containing ``1``, ``L`` or ``RGB``
data.
SGI
^^^
Pillow reads and writes uncompressed ``L``, ``RGB``, and ``RGBA`` files.
SPIDER
^^^^^^
@ -807,10 +813,6 @@ PSD
PIL identifies and reads PSD files written by Adobe Photoshop 2.5 and 3.0.
SGI
^^^
PIL reads uncompressed ``L``, ``RGB``, and ``RGBA`` files.
TGA
^^^