Merge pull request #1938 from wiredfool/python-decoder

Pure Python Decoders - fix for MSP decoding
This commit is contained in:
wiredfool 2017-03-12 17:20:19 +00:00 committed by GitHub
commit c9f54c98a5
15 changed files with 750 additions and 156 deletions

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@ -208,6 +208,8 @@ MIME = {}
SAVE = {}
SAVE_ALL = {}
EXTENSION = {}
DECODERS = {}
ENCODERS = {}
# --------------------------------------------------------------------
# Modes supported by this version
@ -413,6 +415,11 @@ def _getdecoder(mode, decoder_name, args, extra=()):
elif not isinstance(args, tuple):
args = (args,)
try:
decoder = DECODERS[decoder_name]
return decoder(mode, *args + extra)
except KeyError:
pass
try:
# get decoder
decoder = getattr(core, decoder_name + "_decoder")
@ -430,6 +437,11 @@ def _getencoder(mode, encoder_name, args, extra=()):
elif not isinstance(args, tuple):
args = (args,)
try:
encoder = ENCODERS[encoder_name]
return encoder(mode, *args + extra)
except KeyError:
pass
try:
# get encoder
encoder = getattr(core, encoder_name + "_encoder")
@ -2603,6 +2615,33 @@ def registered_extensions():
init()
return EXTENSION
def register_decoder(name, decoder):
"""
Registers an image decoder. This function should not be
used in application code.
:param name: The name of the decoder
:param decoder: A callable(mode, args) that returns an
ImageFile.PyDecoder object
.. versionadded:: 4.1.0
"""
DECODERS[name] = decoder
def register_encoder(name, encoder):
"""
Registers an image encoder. This function should not be
used in application code.
:param name: The name of the encoder
:param encoder: A callable(mode, args) that returns an
ImageFile.PyEncoder object
.. versionadded:: 4.1.0
"""
ENCODERS[name] = encoder
# --------------------------------------------------------------------
# Simple display support. User code may override this.

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@ -193,10 +193,7 @@ class ImageFile(Image.Image):
decoder = Image._getdecoder(self.mode, decoder_name,
args, self.decoderconfig)
seek(offset)
try:
decoder.setimage(self.im, extents)
except ValueError:
continue
decoder.setimage(self.im, extents)
if decoder.pulls_fd:
decoder.setfd(self.fp)
status, err_code = decoder.decode(b"")
@ -520,3 +517,128 @@ def _safe_read(fp, size):
data.append(block)
size -= len(block)
return b"".join(data)
class PyCodecState(object):
def __init__(self):
self.xsize = 0
self.ysize = 0
self.xoff = 0
self.yoff = 0
def extents(self):
return (self.xoff, self.yoff,
self.xoff+self.xsize, self.yoff+self.ysize)
class PyDecoder(object):
"""
Python implementation of a format decoder. Override this class and
add the decoding logic in the `decode` method.
See :ref:`Writing Your Own File Decoder in Python<file-decoders-py>`
"""
_pulls_fd = False
def __init__(self, mode, *args):
self.im = None
self.state = PyCodecState()
self.fd = None
self.mode = mode
self.init(args)
def init(self, args):
"""
Override to perform decoder specific initialization
:param args: Array of args items from the tile entry
:returns: None
"""
self.args = args
@property
def pulls_fd(self):
return self._pulls_fd
def decode(self, buffer):
"""
Override to perform the decoding process.
:param buffer: A bytes object with the data to be decoded. If `handles_eof`
is set, then `buffer` will be empty and `self.fd` will be set.
:returns: A tuple of (bytes consumed, errcode). If finished with decoding
return <0 for the bytes consumed. Err codes are from `ERRORS`
"""
raise NotImplementedError()
def cleanup(self):
"""
Override to perform decoder specific cleanup
:returns: None
"""
pass
def setfd(self, fd):
"""
Called from ImageFile to set the python file-like object
:param fd: A python file-like object
:returns: None
"""
self.fd = fd
def setimage(self, im, extents=None):
"""
Called from ImageFile to set the core output image for the decoder
:param im: A core image object
:param extents: a 4 tuple of (x0, y0, x1, y1) defining the rectangle
for this tile
:returns: None
"""
# following c code
self.im = im
if extents:
(x0, y0, x1, y1) = extents
else:
(x0, y0, x1, y1) = (0, 0, 0, 0)
if x0 == 0 and x1 == 0:
self.state.xsize, self.state.ysize = self.im.size
else:
self.state.xoff = x0
self.state.yoff = y0
self.state.xsize = x1 - x0
self.state.ysize = y1 - y0
if self.state.xsize <= 0 or self.state.ysize <= 0:
raise ValueError("Size cannot be negative")
if (self.state.xsize + self.state.xoff > self.im.size[0] or
self.state.ysize + self.state.yoff > self.im.size[1]):
raise ValueError("Tile cannot extend outside image")
def set_as_raw(self, data, rawmode=None):
"""
Convenience method to set the internal image from a stream of raw data
:param data: Bytes to be set
:param rawmode: The rawmode to be used for the decoder. If not specified,
it will default to the mode of the image
:returns: None
"""
if not rawmode:
rawmode = self.mode
d = Image._getdecoder(self.mode, 'raw', (rawmode))
d.setimage(self.im, self.state.extents())
s = d.decode(data)
if s[0] >= 0:
raise ValueError("not enough image data")
if s[1] != 0:
raise ValueError("cannot decode image data")

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@ -1,6 +1,5 @@
#
# The Python Imaging Library.
# $Id$
#
# MSP file handling
#
@ -9,16 +8,24 @@
# History:
# 95-09-05 fl Created
# 97-01-03 fl Read/write MSP images
# 17-02-21 es Fixed RLE interpretation
#
# Copyright (c) Secret Labs AB 1997.
# Copyright (c) Fredrik Lundh 1995-97.
# Copyright (c) Eric Soroos 2017.
#
# See the README file for information on usage and redistribution.
#
# More info on this format: https://archive.org/details/gg243631
# Page 313:
# Figure 205. Windows Paint Version 1: "DanM" Format
# Figure 206. Windows Paint Version 2: "LinS" Format. Used in Windows V2.03
#
# See also: http://www.fileformat.info/format/mspaint/egff.htm
from . import Image, ImageFile
from ._binary import i16le as i16, o16le as o16
from ._binary import i16le as i16, o16le as o16, i8
import struct, io
__version__ = "0.1"
@ -60,7 +67,90 @@ class MspImageFile(ImageFile.ImageFile):
if s[:4] == b"DanM":
self.tile = [("raw", (0, 0)+self.size, 32, ("1", 0, 1))]
else:
self.tile = [("msp", (0, 0)+self.size, 32+2*self.size[1], None)]
self.tile = [("MSP", (0, 0)+self.size, 32, None)]
class MspDecoder(ImageFile.PyDecoder):
# The algo for the MSP decoder is from
# http://www.fileformat.info/format/mspaint/egff.htm
# cc-by-attribution -- That page references is taken from the
# Encyclopedia of Graphics File Formats and is licensed by
# O'Reilly under the Creative Common/Attribution license
#
# For RLE encoded files, the 32byte header is followed by a scan
# line map, encoded as one 16bit word of encoded byte length per
# line.
#
# NOTE: the encoded length of the line can be 0. This was not
# handled in the previous version of this encoder, and there's no
# mention of how to handle it in the documentation. From the few
# examples I've seen, I've assumed that it is a fill of the
# background color, in this case, white.
#
#
# Pseudocode of the decoder:
# Read a BYTE value as the RunType
# If the RunType value is zero
# Read next byte as the RunCount
# Read the next byte as the RunValue
# Write the RunValue byte RunCount times
# If the RunType value is non-zero
# Use this value as the RunCount
# Read and write the next RunCount bytes literally
#
# e.g.:
# 0x00 03 ff 05 00 01 02 03 04
# would yield the bytes:
# 0xff ff ff 00 01 02 03 04
#
# which are then interpreted as a bit packed mode '1' image
_pulls_fd = True
def decode(self, buffer):
img = io.BytesIO()
blank_line = bytearray((0xff,)*((self.state.xsize+7)//8))
try:
self.fd.seek(32)
rowmap = struct.unpack_from("<%dH" % (self.state.ysize),
self.fd.read(self.state.ysize*2))
except struct.error:
raise IOError("Truncated MSP file in row map")
for x, rowlen in enumerate(rowmap):
try:
if rowlen == 0:
img.write(blank_line)
continue
row = self.fd.read(rowlen)
if len(row) != rowlen:
raise IOError("Truncated MSP file, expected %d bytes on row %s",
(rowlen, x))
idx = 0
while idx < rowlen:
runtype = i8(row[idx])
idx += 1
if runtype == 0:
(runcount, runval) = struct.unpack("Bc", row[idx:idx+2])
img.write(runval * runcount)
idx += 2
else:
runcount = runtype
img.write(row[idx:idx+runcount])
idx += runcount
except struct.error:
raise IOError("Corrupted MSP file in row %d" %x)
self.set_as_raw(img.getvalue(), ("1", 0, 1))
return 0,0
Image.register_decoder('MSP', MspDecoder)
#
# write MSP files (uncompressed only)
@ -92,6 +182,7 @@ def _save(im, fp, filename):
# image body
ImageFile._save(im, fp, [("raw", (0, 0)+im.size, 32, ("1", 0, 1))])
#
# registry

Binary file not shown.

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@ -2,7 +2,11 @@ from helper import unittest, PillowTestCase, hopper
from PIL import Image, MspImagePlugin
import os
TEST_FILE = "Tests/images/hopper.msp"
EXTRA_DIR = "Tests/images/picins"
YA_EXTRA_DIR = "Tests/images/msp"
class TestFileMsp(PillowTestCase):
@ -24,14 +28,48 @@ class TestFileMsp(PillowTestCase):
self.assertRaises(SyntaxError,
lambda: MspImagePlugin.MspImageFile(invalid_file))
def test_open(self):
def test_bad_checksum(self):
# Arrange
# This was created by forcing Pillow to save with checksum=0
bad_checksum = "Tests/images/hopper_bad_checksum.msp"
# Act / Assert
self.assertRaises(SyntaxError,
lambda: MspImagePlugin.MspImageFile(bad_checksum))
def test_open_windows_v1(self):
# Arrange
# Act
im = Image.open(TEST_FILE)
# Assert
self.assertEqual(im.size, (128, 128))
self.assert_image_equal(im, hopper("1"), 4)
self.assert_image_equal(im, hopper("1"))
self.assertIsInstance(im, MspImagePlugin.MspImageFile)
def _assert_file_image_equal(self, source_path, target_path):
with Image.open(source_path) as im:
target = Image.open(target_path)
self.assert_image_equal(im, target)
@unittest.skipIf(not os.path.exists(EXTRA_DIR),
"Extra image files not installed")
def test_open_windows_v2(self):
files = (os.path.join(EXTRA_DIR, f) for f in os.listdir(EXTRA_DIR)
if os.path.splitext(f)[1] == '.msp')
for path in files:
self._assert_file_image_equal(path,
path.replace('.msp','.png'))
@unittest.skipIf(not os.path.exists(YA_EXTRA_DIR),
"Even More Extra image files not installed")
def test_msp_v2(self):
for f in os.listdir(YA_EXTRA_DIR):
if not '.MSP' in f: continue
path = os.path.join(YA_EXTRA_DIR, f)
self._assert_file_image_equal(path,
path.replace('.MSP','.png'))
def test_cannot_save_wrong_mode(self):
# Arrange

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@ -375,5 +375,30 @@ class TestImage(PillowTestCase):
self.assert_image_equal(im, target)
class MockEncoder(object):pass
def mock_encode(*args):
encoder = MockEncoder()
encoder.args = args
return encoder
class TestRegistry(PillowTestCase):
def test_encode_registry(self):
Image.register_encoder('MOCK', mock_encode)
self.assert_('MOCK' in Image.ENCODERS)
enc = Image._getencoder('RGB', 'MOCK', ('args',), extra=('extra',))
self.assertIsInstance(enc, MockEncoder)
self.assertEqual(enc.args, ('RGB', 'args', 'extra'))
def test_encode_registry_fail(self):
self.assertRaises(IOError, lambda: Image._getencoder('RGB',
'DoesNotExist',
('args',),
extra=('extra',)))
if __name__ == '__main__':
unittest.main()

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@ -135,5 +135,84 @@ class TestImageFile(PillowTestCase):
finally:
ImageFile.LOAD_TRUNCATED_IMAGES = False
class MockPyDecoder(ImageFile.PyDecoder):
def decode(self, buffer):
#eof
return (-1, 0)
xoff, yoff, xsize, ysize = 10, 20, 100, 100
class MockImageFile(ImageFile.ImageFile):
def _open(self):
self.rawmode = 'RGBA'
self.mode = 'RGBA'
self.size = (200, 200)
self.tile = [("MOCK", (xoff, yoff, xoff+xsize, yoff+ysize), 32, None)]
class TestPyDecoder(PillowTestCase):
def get_decoder(self):
decoder = MockPyDecoder(None)
def closure(mode, *args):
decoder.__init__(mode, *args)
return decoder
Image.register_decoder('MOCK', closure)
return decoder
def test_setimage(self):
buf = BytesIO(b'\x00'*255)
im = MockImageFile(buf)
d = self.get_decoder()
im.load()
self.assertEqual(d.state.xoff, xoff)
self.assertEqual(d.state.yoff, yoff)
self.assertEqual(d.state.xsize, xsize)
self.assertEqual(d.state.ysize, ysize)
self.assertRaises(ValueError, lambda: d.set_as_raw(b'\x00'))
def test_extents_none(self):
buf = BytesIO(b'\x00'*255)
im = MockImageFile(buf)
im.tile = [("MOCK", None, 32, None)]
d = self.get_decoder()
im.load()
self.assertEqual(d.state.xoff, 0)
self.assertEqual(d.state.yoff, 0)
self.assertEqual(d.state.xsize, 200)
self.assertEqual(d.state.ysize, 200)
def test_negsize(self):
buf = BytesIO(b'\x00'*255)
im = MockImageFile(buf)
im.tile = [("MOCK", (xoff, yoff, -10, yoff+ysize), 32, None)]
d = self.get_decoder()
self.assertRaises(ValueError, im.load)
im.tile = [("MOCK", (xoff, yoff, xoff+xsize, -10), 32, None)]
self.assertRaises(ValueError, im.load)
def test_oversize(self):
buf = BytesIO(b'\x00'*255)
im = MockImageFile(buf)
im.tile = [("MOCK", (xoff, yoff, xoff+xsize + 100, yoff+ysize), 32, None)]
d = self.get_decoder()
self.assertRaises(ValueError, im.load)
im.tile = [("MOCK", (xoff, yoff, xoff+xsize, yoff+ysize + 100), 32, None)]
self.assertRaises(ValueError, im.load)
if __name__ == '__main__':
unittest.main()

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@ -3290,7 +3290,6 @@ extern PyObject* PyImaging_JpegDecoderNew(PyObject* self, PyObject* args);
extern PyObject* PyImaging_Jpeg2KDecoderNew(PyObject* self, PyObject* args);
extern PyObject* PyImaging_TiffLzwDecoderNew(PyObject* self, PyObject* args);
extern PyObject* PyImaging_LibTiffDecoderNew(PyObject* self, PyObject* args);
extern PyObject* PyImaging_MspDecoderNew(PyObject* self, PyObject* args);
extern PyObject* PyImaging_PackbitsDecoderNew(PyObject* self, PyObject* args);
extern PyObject* PyImaging_PcdDecoderNew(PyObject* self, PyObject* args);
extern PyObject* PyImaging_PcxDecoderNew(PyObject* self, PyObject* args);
@ -3368,7 +3367,6 @@ static PyMethodDef functions[] = {
{"libtiff_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
{"libtiff_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
#endif
{"msp_decoder", (PyCFunction)PyImaging_MspDecoderNew, 1},
{"packbits_decoder", (PyCFunction)PyImaging_PackbitsDecoderNew, 1},
{"pcd_decoder", (PyCFunction)PyImaging_PcdDecoderNew, 1},
{"pcx_decoder", (PyCFunction)PyImaging_PcxDecoderNew, 1},

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@ -557,27 +557,6 @@ PyImaging_LibTiffDecoderNew(PyObject* self, PyObject* args)
#endif
/* -------------------------------------------------------------------- */
/* MSP */
/* -------------------------------------------------------------------- */
PyObject*
PyImaging_MspDecoderNew(PyObject* self, PyObject* args)
{
ImagingDecoderObject* decoder;
decoder = PyImaging_DecoderNew(0);
if (decoder == NULL)
return NULL;
if (get_unpacker(decoder, "1", "1") < 0)
return NULL;
decoder->decode = ImagingMspDecode;
return (PyObject*) decoder;
}
/* -------------------------------------------------------------------- */
/* PackBits */

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@ -1,11 +1,9 @@
#!/bin/bash
# install extra test images
if [ ! -f test_images.tar.gz ]; then
wget -O 'test_images.tar.gz' 'https://github.com/python-pillow/pillow-depends/blob/master/test_images.tar.gz?raw=true'
fi
rm -r test_images
tar -xvzf test_images.tar.gz
# Use SVN to just fetch a single git subdirectory
svn checkout https://github.com/python-pillow/pillow-depends/trunk/test_images
cp -r test_images/* ../Tests/images

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@ -0,0 +1,286 @@
"""
A Pillow loader for .dds files (S3TC-compressed aka DXTC)
Jerome Leclanche <jerome@leclan.ch>
Documentation:
http://oss.sgi.com/projects/ogl-sample/registry/EXT/texture_compression_s3tc.txt
The contents of this file are hereby released in the public domain (CC0)
Full text of the CC0 license:
https://creativecommons.org/publicdomain/zero/1.0/
"""
import struct
from io import BytesIO
from PIL import Image, ImageFile
# Magic ("DDS ")
DDS_MAGIC = 0x20534444
# DDS flags
DDSD_CAPS = 0x1
DDSD_HEIGHT = 0x2
DDSD_WIDTH = 0x4
DDSD_PITCH = 0x8
DDSD_PIXELFORMAT = 0x1000
DDSD_MIPMAPCOUNT = 0x20000
DDSD_LINEARSIZE = 0x80000
DDSD_DEPTH = 0x800000
# DDS caps
DDSCAPS_COMPLEX = 0x8
DDSCAPS_TEXTURE = 0x1000
DDSCAPS_MIPMAP = 0x400000
DDSCAPS2_CUBEMAP = 0x200
DDSCAPS2_CUBEMAP_POSITIVEX = 0x400
DDSCAPS2_CUBEMAP_NEGATIVEX = 0x800
DDSCAPS2_CUBEMAP_POSITIVEY = 0x1000
DDSCAPS2_CUBEMAP_NEGATIVEY = 0x2000
DDSCAPS2_CUBEMAP_POSITIVEZ = 0x4000
DDSCAPS2_CUBEMAP_NEGATIVEZ = 0x8000
DDSCAPS2_VOLUME = 0x200000
# Pixel Format
DDPF_ALPHAPIXELS = 0x1
DDPF_ALPHA = 0x2
DDPF_FOURCC = 0x4
DDPF_PALETTEINDEXED8 = 0x20
DDPF_RGB = 0x40
DDPF_LUMINANCE = 0x20000
# dds.h
DDS_FOURCC = DDPF_FOURCC
DDS_RGB = DDPF_RGB
DDS_RGBA = DDPF_RGB | DDPF_ALPHAPIXELS
DDS_LUMINANCE = DDPF_LUMINANCE
DDS_LUMINANCEA = DDPF_LUMINANCE | DDPF_ALPHAPIXELS
DDS_ALPHA = DDPF_ALPHA
DDS_PAL8 = DDPF_PALETTEINDEXED8
DDS_HEADER_FLAGS_TEXTURE = (DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH |
DDSD_PIXELFORMAT)
DDS_HEADER_FLAGS_MIPMAP = DDSD_MIPMAPCOUNT
DDS_HEADER_FLAGS_VOLUME = DDSD_DEPTH
DDS_HEADER_FLAGS_PITCH = DDSD_PITCH
DDS_HEADER_FLAGS_LINEARSIZE = DDSD_LINEARSIZE
DDS_HEIGHT = DDSD_HEIGHT
DDS_WIDTH = DDSD_WIDTH
DDS_SURFACE_FLAGS_TEXTURE = DDSCAPS_TEXTURE
DDS_SURFACE_FLAGS_MIPMAP = DDSCAPS_COMPLEX | DDSCAPS_MIPMAP
DDS_SURFACE_FLAGS_CUBEMAP = DDSCAPS_COMPLEX
DDS_CUBEMAP_POSITIVEX = DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEX
DDS_CUBEMAP_NEGATIVEX = DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEX
DDS_CUBEMAP_POSITIVEY = DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEY
DDS_CUBEMAP_NEGATIVEY = DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEY
DDS_CUBEMAP_POSITIVEZ = DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEZ
DDS_CUBEMAP_NEGATIVEZ = DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEZ
# DXT1
DXT1_FOURCC = 0x31545844
# DXT3
DXT3_FOURCC = 0x33545844
# DXT5
DXT5_FOURCC = 0x35545844
def _decode565(bits):
a = ((bits >> 11) & 0x1f) << 3
b = ((bits >> 5) & 0x3f) << 2
c = (bits & 0x1f) << 3
return a, b, c
def _c2a(a, b):
return (2 * a + b) // 3
def _c2b(a, b):
return (a + b) // 2
def _c3(a, b):
return (2 * b + a) // 3
def _dxt1(data, width, height):
# TODO implement this function as pixel format in decode.c
ret = bytearray(4 * width * height)
for y in range(0, height, 4):
for x in range(0, width, 4):
color0, color1, bits = struct.unpack("<HHI", data.read(8))
r0, g0, b0 = _decode565(color0)
r1, g1, b1 = _decode565(color1)
# Decode this block into 4x4 pixels
for j in range(4):
for i in range(4):
# get next control op and generate a pixel
control = bits & 3
bits = bits >> 2
if control == 0:
r, g, b = r0, g0, b0
elif control == 1:
r, g, b = r1, g1, b1
elif control == 2:
if color0 > color1:
r, g, b = _c2a(r0, r1), _c2a(g0, g1), _c2a(b0, b1)
else:
r, g, b = _c2b(r0, r1), _c2b(g0, g1), _c2b(b0, b1)
elif control == 3:
if color0 > color1:
r, g, b = _c3(r0, r1), _c3(g0, g1), _c3(b0, b1)
else:
r, g, b = 0, 0, 0
idx = 4 * ((y + j) * width + (x + i))
ret[idx:idx+4] = struct.pack('4B', r, g, b, 255)
return bytes(ret)
def _dxtc_alpha(a0, a1, ac0, ac1, ai):
if ai <= 12:
ac = (ac0 >> ai) & 7
elif ai == 15:
ac = (ac0 >> 15) | ((ac1 << 1) & 6)
else:
ac = (ac1 >> (ai - 16)) & 7
if ac == 0:
alpha = a0
elif ac == 1:
alpha = a1
elif a0 > a1:
alpha = ((8 - ac) * a0 + (ac - 1) * a1) // 7
elif ac == 6:
alpha = 0
elif ac == 7:
alpha = 0xff
else:
alpha = ((6 - ac) * a0 + (ac - 1) * a1) // 5
return alpha
def _dxt5(data, width, height):
# TODO implement this function as pixel format in decode.c
ret = bytearray(4 * width * height)
for y in range(0, height, 4):
for x in range(0, width, 4):
a0, a1, ac0, ac1, c0, c1, code = struct.unpack("<2BHI2HI",
data.read(16))
r0, g0, b0 = _decode565(c0)
r1, g1, b1 = _decode565(c1)
for j in range(4):
for i in range(4):
ai = 3 * (4 * j + i)
alpha = _dxtc_alpha(a0, a1, ac0, ac1, ai)
cc = (code >> 2 * (4 * j + i)) & 3
if cc == 0:
r, g, b = r0, g0, b0
elif cc == 1:
r, g, b = r1, g1, b1
elif cc == 2:
r, g, b = _c2a(r0, r1), _c2a(g0, g1), _c2a(b0, b1)
elif cc == 3:
r, g, b = _c3(r0, r1), _c3(g0, g1), _c3(b0, b1)
idx = 4 * ((y + j) * width + (x + i))
ret[idx:idx+4] = struct.pack('4B', r, g, b, alpha)
return bytes(ret)
class DdsImageFile(ImageFile.ImageFile):
format = "DDS"
format_description = "DirectDraw Surface"
def _open(self):
magic, header_size = struct.unpack("<II", self.fp.read(8))
if header_size != 124:
raise IOError("Unsupported header size %r" % (header_size))
header_bytes = self.fp.read(header_size - 4)
if len(header_bytes) != 120:
raise IOError("Incomplete header: %s bytes" % len(header_bytes))
header = BytesIO(header_bytes)
flags, height, width = struct.unpack("<3I", header.read(12))
self.size = (width, height)
self.mode = "RGBA"
pitch, depth, mipmaps = struct.unpack("<3I", header.read(12))
reserved = struct.unpack("<11I", header.read(44))
# pixel format
pfsize, pfflags = struct.unpack("<2I", header.read(8))
fourcc = header.read(4)
bitcount, rmask, gmask, bmask, amask = struct.unpack("<5I",
header.read(20))
if fourcc == b"DXT1":
self.decoder = "DXT1"
codec = _dxt1
elif fourcc == b"DXT5":
self.decoder = "DXT5"
codec = _dxt5
else:
raise NotImplementedError("Unimplemented pixel format %r" %
(fourcc))
self.tile = [
(self.decoder, (0, 0) + self.size, 0, (self.mode, 0, 1))
]
def load_seek(self, pos):
pass
class DXT1Decoder(ImageFile.PyDecoder):
_pulls_fd = True
def decode(self, buffer):
try:
self.set_as_raw(_dxt1(self.fd, self.state.xsize, self.state.ysize))
except struct.error:
raise IOError("Truncated DDS file")
return 0,0
class DXT5Decoder(ImageFile.PyDecoder):
_pulls_fd = True
def decode(self, buffer):
try:
self.set_as_raw(_dxt5(self.fd, self.state.xsize, self.state.ysize))
except struct.error:
raise IOError("Truncated DDS file")
return 0,0
Image.register_decoder('DXT1', DXT1Decoder)
Image.register_decoder('DXT5', DXT5Decoder)
def _validate(prefix):
return prefix[:4] == b"DDS "
Image.register_open(DdsImageFile.format, DdsImageFile, _validate)
Image.register_extension(DdsImageFile.format, ".dds")

View File

@ -9,7 +9,10 @@ itself. Such plug-ins usually have names like
:file:`XxxImagePlugin.py`, where ``Xxx`` is a unique format name
(usually an abbreviation).
.. warning:: Pillow >= 2.1.0 no longer automatically imports any file in the Python path with a name ending in :file:`ImagePlugin.py`. You will need to import your image plugin manually.
.. warning:: Pillow >= 2.1.0 no longer automatically imports any file
in the Python path with a name ending in
:file:`ImagePlugin.py`. You will need to import your
image plugin manually.
Pillow decodes files in 2 stages:
@ -23,21 +26,19 @@ Pillow decodes files in 2 stages:
called, which sets up a decoder for each tile and feeds the data to
it.
A decoder plug-in should contain a decoder class, based on the
:py:class:`PIL.ImageFile.ImageFile` base class. This class should provide an
:py:meth:`_open` method, which reads the file header and sets up at least the
:py:attr:`~PIL.Image.Image.mode` and :py:attr:`~PIL.Image.Image.size`
attributes. To be able to load the file, the method must also create a list of
:py:attr:`tile` descriptors. The class must be explicitly registered, via a
call to the :py:mod:`~PIL.Image` module.
An image plug-in should contain a format handler derived from the
:py:class:`PIL.ImageFile.ImageFile` base class. This class should
provide an :py:meth:`_open` method, which reads the file header and
sets up at least the :py:attr:`~PIL.Image.Image.mode` and
:py:attr:`~PIL.Image.Image.size` attributes. To be able to load the
file, the method must also create a list of :py:attr:`tile`
descriptors, which contain a decoder name, extents of the tile, and
any decoder-specific data. The format handler class must be explicitly
registered, via a call to the :py:mod:`~PIL.Image` module.
For performance reasons, it is important that the :py:meth:`_open` method
quickly rejects files that do not have the appropriate contents.
The ``raw`` decoder is useful for uncompressed image formats, but many
formats require more control of the decoding context, either with a
decoder written in ``C`` or by linking in an external library to do
the decoding. (Examples of this include PNG, Tiff, and Jpeg support)
.. note:: For performance reasons, it is important that the
:py:meth:`_open` method quickly rejects files that do not have the
appropriate contents.
Example
-------
@ -94,12 +95,12 @@ true color.
The format handler must always set the
:py:attr:`~PIL.Image.Image.size` and :py:attr:`~PIL.Image.Image.mode`
attributes. If these are not set, the file cannot be opened. To
simplify the decoder, the calling code considers exceptions like
simplify the plugin, the calling code considers exceptions like
:py:exc:`SyntaxError`, :py:exc:`KeyError`, :py:exc:`IndexError`,
:py:exc:`EOFError` and :py:exc:`struct.error` as a failure to identify
the file.
Note that the decoder must be explicitly registered using
Note that the image plugin must be explicitly registered using
:py:func:`PIL.Image.register_open`. Although not required, it is also a good
idea to register any extensions used by this format.
@ -137,6 +138,9 @@ The fields are used as follows:
Note that the :py:attr:`tile` attribute contains a list of tile descriptors,
not just a single descriptor.
Decoders
========
The raw decoder
---------------
@ -304,13 +308,14 @@ The fields are used as follows:
.. _file-decoders:
Writing Your Own File Decoder
=============================
Writing Your Own File Decoder in C
==================================
There are 3 stages in a file decoder's lifetime:
1. Setup: Pillow looks for a function named ``[decodername]_decoder``
on the internal core image object. That function is called with the ``args`` tuple
1. Setup: Pillow looks for a function in the decoder registry, falling
back to a function named ``[decodername]_decoder`` on the internal
core image object. That function is called with the ``args`` tuple
from the ``tile`` setup in the ``_open`` method.
2. Decoding: The decoder's decode function is repeatedly called with
@ -349,9 +354,6 @@ interest in this object are:
member is an opaque struct that can be used by the decoder to store
any format specific state or options.
**handles_eof**
UNDONE, set if your code handles EOF errors.
**pulls_fd**
**EXPERIMENTAL** -- **WARNING**, interface may change. If set to 1,
``state->fd`` will be a pointer to the Python file like object. The
@ -391,3 +393,25 @@ The cleanup function is called after the decoder returns a negative
value, or if there is a read error from the file. This function should
free any allocated memory and release any resources from external
libraries.
.. _file-decoders-py:
Writing Your Own File Decoder in Python
=======================================
Python file decoders should derive from
:py:class:`PIL.ImageFile.PyDecoder` and should at least override the
decode method. File decoders should be registered using
:py:meth:`PIL.Image.register_decoder`. As in the C implementation of
the file decoders, there are three stages in the lifetime of a
Python-based file decoder:
1. Setup: Pillow looks for the decoder in the registry, then
instantiates the class.
2. Decoding: The decoder instance's ``decode`` method is repeatedly
called with a buffer of data to be interpreted.
3. Cleanup: The decoder instance's ``cleanup`` method is called.

View File

@ -19,7 +19,7 @@ Example: Parse an image
from PIL import ImageFile
fp = open("lena.pgm", "rb")
fp = open("hopper.pgm", "rb")
p = ImageFile.Parser()
@ -39,3 +39,9 @@ Example: Parse an image
.. autoclass:: PIL.ImageFile.Parser()
:members:
:py:class:`~PIL.ImageFile.PyDecoder`
------------------------------------
.. autoclass:: PIL.ImageFile.PyDecoder()
:members:

View File

@ -1,91 +0,0 @@
/*
* The Python Imaging Library.
* $Id$
*
* decoder for MSP version 2 data.
*
* history:
* 97-01-03 fl Created
*
* Copyright (c) Fredrik Lundh 1997.
* Copyright (c) Secret Labs AB 1997.
*
* See the README file for information on usage and redistribution.
*/
#include "Imaging.h"
int
ImagingMspDecode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
{
int n;
UINT8* ptr;
ptr = buf;
for (;;) {
if (bytes < 1)
return ptr - buf;
if (ptr[0] == 0) {
/* Run (3 bytes block) */
if (bytes < 3)
break;
n = ptr[1];
if (state->x + n > state->bytes) {
state->errcode = IMAGING_CODEC_OVERRUN;
return -1;
}
memset(state->buffer + state->x, ptr[2], n);
ptr += 3;
bytes -= 3;
} else {
/* Literal (1+n bytes block) */
n = ptr[0];
if (bytes < 1 + n)
break;
if (state->x + n > state->bytes) {
state->errcode = IMAGING_CODEC_OVERRUN;
return -1;
}
memcpy(state->buffer + state->x, ptr + 1, n);
ptr += 1 + n;
bytes -= 1 + n;
}
state->x += n;
if (state->x >= state->bytes) {
/* Got a full line, unpack it */
state->shuffle((UINT8*) im->image[state->y + state->yoff] +
state->xoff * im->pixelsize, state->buffer,
state->xsize);
state->x = 0;
if (++state->y >= state->ysize) {
/* End of file (errcode = 0) */
return -1;
}
}
}
return ptr - buf;
}

View File

@ -32,7 +32,7 @@ _LIB_IMAGING = (
"Draw", "Effects", "EpsEncode", "File", "Fill", "Filter", "FliDecode",
"Geometry", "GetBBox", "GifDecode", "GifEncode", "HexDecode", "Histo",
"JpegDecode", "JpegEncode", "LzwDecode", "Matrix", "ModeFilter",
"MspDecode", "Negative", "Offset", "Pack", "PackDecode", "Palette", "Paste",
"Negative", "Offset", "Pack", "PackDecode", "Palette", "Paste",
"Quant", "QuantOctree", "QuantHash", "QuantHeap", "PcdDecode", "PcxDecode",
"PcxEncode", "Point", "RankFilter", "RawDecode", "RawEncode", "Storage",
"SunRleDecode", "TgaRleDecode", "Unpack", "UnpackYCC", "UnsharpMask",