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scikit-image/skimage/io/_plugins/freeimage_plugin.py
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Josh Warner cbc851bba6 FIX/STY: Remove magic and enforce PEP8 in plugins.
2015-08-13 19:47:00 -05:00

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import ctypes
import numpy
import sys
import os
import os.path
from numpy.compat import asbytes, asstr
def _generate_candidate_libs():
# look for likely library files in the following dirs:
lib_dirs = [os.path.dirname(__file__),
'/lib',
'/usr/lib',
'/usr/local/lib',
'/opt/local/lib',
os.path.join(sys.prefix, 'lib'),
os.path.join(sys.prefix, 'DLLs')
]
if 'HOME' in os.environ:
lib_dirs.append(os.path.join(os.environ['HOME'], 'lib'))
lib_dirs = [ld for ld in lib_dirs if os.path.exists(ld)]
lib_names = ['libfreeimage', 'freeimage'] # should be lower-case!
# Now attempt to find libraries of that name in the given directory
# (case-insensitive and without regard for extension)
lib_paths = []
for lib_dir in lib_dirs:
for lib_name in lib_names:
files = os.listdir(lib_dir)
lib_paths += [os.path.join(lib_dir, lib) for lib in files
if lib.lower().startswith(lib_name) and not
os.path.splitext(lib)[1] in ('.py', '.pyc', '.ini')]
lib_paths = [lp for lp in lib_paths if os.path.exists(lp)]
return lib_dirs, lib_paths
if sys.platform == 'win32':
LOADER = ctypes.windll
FUNCTYPE = ctypes.WINFUNCTYPE
else:
LOADER = ctypes.cdll
FUNCTYPE = ctypes.CFUNCTYPE
def handle_errors():
global FT_ERROR_STR
if FT_ERROR_STR:
tmp = FT_ERROR_STR
FT_ERROR_STR = None
raise RuntimeError(tmp)
FT_ERROR_STR = None
# This MUST happen in module scope, or the function pointer is garbage
# collected, leading to a segfault when error_handler is called.
@FUNCTYPE(None, ctypes.c_int, ctypes.c_char_p)
def c_error_handler(fif, message):
global FT_ERROR_STR
FT_ERROR_STR = 'FreeImage error: %s' % message
def load_freeimage():
freeimage = None
errors = []
# First try a few bare library names that ctypes might be able to find
# in the default locations for each platform. Win DLL names don't need the
# extension, but other platforms do.
bare_libs = ['FreeImage', 'libfreeimage.dylib', 'libfreeimage.so',
'libfreeimage.so.3']
lib_dirs, lib_paths = _generate_candidate_libs()
lib_paths = bare_libs + lib_paths
for lib in lib_paths:
try:
freeimage = LOADER.LoadLibrary(lib)
break
except Exception:
if lib not in bare_libs:
# Don't record errors when it couldn't load the library from
# a bare name -- this fails often, and doesn't provide any
# useful debugging information anyway, beyond "couldn't find
# library..."
# Get exception instance in Python 2.x/3.x compatible manner
e_type, e_value, e_tb = sys.exc_info()
del e_tb
errors.append((lib, e_value))
if freeimage is None:
if errors:
# No freeimage library loaded, and load-errors reported for some
# candidate libs
err_txt = ['%s:\n%s' % (l, str(e)) for l, e in errors]
raise RuntimeError('One or more FreeImage libraries were found, '
'but could not be loaded due to the following '
'errors:\n\n\n'.join(err_txt))
else:
# No errors, because no potential libraries found at all!
raise RuntimeError('Could not find a FreeImage library in any of:'
'\n\n'.join(lib_dirs))
# FreeImage found
freeimage.FreeImage_SetOutputMessage(c_error_handler)
return freeimage
_FI = load_freeimage()
API = {
# All we're doing here is telling ctypes that some of the FreeImage
# functions return pointers instead of integers. (On 64-bit systems,
# without this information the pointers get truncated and crashes result).
# There's no need to list functions that return ints, or the types of the
# parameters to these or other functions -- that's fine to do implicitly.
# Note that the ctypes immediately converts the returned void_p back to a
# python int again! This is really not helpful, because then passing it
# back to another library call will cause truncation-to-32-bits on 64-bit
# systems. Thanks, ctypes! So after these calls one must immediately
# re-wrap the int as a c_void_p if it is to be passed back into FreeImage.
'FreeImage_AllocateT': (ctypes.c_void_p, None),
'FreeImage_FindFirstMetadata': (ctypes.c_void_p, None),
'FreeImage_GetBits': (ctypes.c_void_p, None),
'FreeImage_GetPalette': (ctypes.c_void_p, None),
'FreeImage_GetTagKey': (ctypes.c_char_p, None),
'FreeImage_GetTagValue': (ctypes.c_void_p, None),
'FreeImage_Load': (ctypes.c_void_p, None),
'FreeImage_LockPage': (ctypes.c_void_p, None),
'FreeImage_OpenMultiBitmap': (ctypes.c_void_p, None)
}
# Albert's ctypes pattern
def register_api(lib, api):
for f, (restype, argtypes) in api.items():
func = getattr(lib, f)
func.restype = restype
func.argtypes = argtypes
register_api(_FI, API)
class FiTypes(object):
FIT_UNKNOWN = 0
FIT_BITMAP = 1
FIT_UINT16 = 2
FIT_INT16 = 3
FIT_UINT32 = 4
FIT_INT32 = 5
FIT_FLOAT = 6
FIT_DOUBLE = 7
FIT_COMPLEX = 8
FIT_RGB16 = 9
FIT_RGBA16 = 10
FIT_RGBF = 11
FIT_RGBAF = 12
dtypes = {FIT_BITMAP: numpy.uint8,
FIT_UINT16: numpy.uint16,
FIT_INT16: numpy.int16,
FIT_UINT32: numpy.uint32,
FIT_INT32: numpy.int32,
FIT_FLOAT: numpy.float32,
FIT_DOUBLE: numpy.float64,
FIT_COMPLEX: numpy.complex128,
FIT_RGB16: numpy.uint16,
FIT_RGBA16: numpy.uint16,
FIT_RGBF: numpy.float32,
FIT_RGBAF: numpy.float32,
}
fi_types = {(numpy.dtype('uint8'), 1): FIT_BITMAP,
(numpy.dtype('uint8'), 3): FIT_BITMAP,
(numpy.dtype('uint8'), 4): FIT_BITMAP,
(numpy.dtype('uint16'), 1): FIT_UINT16,
(numpy.dtype('int16'), 1): FIT_INT16,
(numpy.dtype('uint32'), 1): FIT_UINT32,
(numpy.dtype('int32'), 1): FIT_INT32,
(numpy.dtype('float32'), 1): FIT_FLOAT,
(numpy.dtype('float64'), 1): FIT_DOUBLE,
(numpy.dtype('complex128'), 1): FIT_COMPLEX,
(numpy.dtype('uint16'), 3): FIT_RGB16,
(numpy.dtype('uint16'), 4): FIT_RGBA16,
(numpy.dtype('float32'), 3): FIT_RGBF,
(numpy.dtype('float32'), 4): FIT_RGBAF,
}
extra_dims = {FIT_UINT16: [],
FIT_INT16: [],
FIT_UINT32: [],
FIT_INT32: [],
FIT_FLOAT: [],
FIT_DOUBLE: [],
FIT_COMPLEX: [],
FIT_RGB16: [3],
FIT_RGBA16: [4],
FIT_RGBF: [3],
FIT_RGBAF: [4],
}
@classmethod
def get_type_and_shape(cls, bitmap):
w = _FI.FreeImage_GetWidth(bitmap)
handle_errors()
h = _FI.FreeImage_GetHeight(bitmap)
handle_errors()
fi_type = _FI.FreeImage_GetImageType(bitmap)
handle_errors()
if not fi_type:
raise ValueError('Unknown image pixel type')
dtype = cls.dtypes[fi_type]
if fi_type == cls.FIT_BITMAP:
bpp = _FI.FreeImage_GetBPP(bitmap)
handle_errors()
if bpp == 8:
extra_dims = []
elif bpp == 24:
extra_dims = [3]
elif bpp == 32:
extra_dims = [4]
else:
raise ValueError('Cannot convert %d BPP bitmap' % bpp)
else:
extra_dims = cls.extra_dims[fi_type]
return numpy.dtype(dtype), extra_dims + [w, h]
class IoFlags(object):
# loading: load the image header only (not supported by all plugins)
FIF_LOAD_NOPIXELS = 0x8000
BMP_DEFAULT = 0
BMP_SAVE_RLE = 1
CUT_DEFAULT = 0
DDS_DEFAULT = 0
EXR_DEFAULT = 0 # save data as half with piz-based wavelet compression
EXR_FLOAT = 0x0001 # save data as float instead of half (not recommended)
EXR_NONE = 0x0002 # save with no compression
EXR_ZIP = 0x0004 # save with zlib compression, in blocks of 16 scan lines
EXR_PIZ = 0x0008 # save with piz-based wavelet compression
EXR_PXR24 = 0x0010 # save with lossy 24-bit float compression
# save with lossy 44% float compression (22% when combined with EXR_LC)
EXR_B44 = 0x0020
# one luminance and two chroma channels rather than as RGB (lossy)
EXR_LC = 0x0040
FAXG3_DEFAULT = 0
GIF_DEFAULT = 0
# Load as 256 color image with ununsed palette entries if 16 or 2 color
GIF_LOAD256 = 1
# 'Play' the GIF generating each frame (as 32bpp) instead of raw frame data
GIF_PLAYBACK = 2
HDR_DEFAULT = 0
ICO_DEFAULT = 0
# convert to 32bpp then add an alpha channel from the AND-mask when loading
ICO_MAKEALPHA = 1
IFF_DEFAULT = 0
J2K_DEFAULT = 0 # save with a 16:1 rate
JP2_DEFAULT = 0 # save with a 16:1 rate
# loading (see JPEG_FAST)
# saving (see JPEG_QUALITYGOOD|JPEG_SUBSAMPLING_420)
JPEG_DEFAULT = 0
# load the file as fast as possible, sacrificing some quality
JPEG_FAST = 0x0001
# load the file with the best quality, sacrificing some speed
JPEG_ACCURATE = 0x0002
# load separated CMYK "as is" (use | to combine with other load flags)
JPEG_CMYK = 0x0004
# load and rotate according to Exif 'Orientation' tag if available
JPEG_EXIFROTATE = 0x0008
JPEG_QUALITYSUPERB = 0x80 # save with superb quality (100:1)
JPEG_QUALITYGOOD = 0x0100 # save with good quality (75:1)
JPEG_QUALITYNORMAL = 0x0200 # save with normal quality (50:1)
JPEG_QUALITYAVERAGE = 0x0400 # save with average quality (25:1)
JPEG_QUALITYBAD = 0x0800 # save with bad quality (10:1)
# save as a progressive-JPEG (use | to combine with other save flags)
JPEG_PROGRESSIVE = 0x2000
# save with high 4x1 chroma subsampling (4:1:1)
JPEG_SUBSAMPLING_411 = 0x1000
# save with medium 2x2 medium chroma subsampling (4:2:0) - default value
JPEG_SUBSAMPLING_420 = 0x4000
# save with low 2x1 chroma subsampling (4:2:2)
JPEG_SUBSAMPLING_422 = 0x8000
JPEG_SUBSAMPLING_444 = 0x10000 # save with no chroma subsampling (4:4:4)
# compute optimal Huffman coding tables (can reduce file size a few %)
JPEG_OPTIMIZE = 0x20000 # on saving,
JPEG_BASELINE = 0x40000 # save basic JPEG, without metadata or any markers
KOALA_DEFAULT = 0
LBM_DEFAULT = 0
MNG_DEFAULT = 0
PCD_DEFAULT = 0
PCD_BASE = 1 # load the bitmap sized 768 x 512
PCD_BASEDIV4 = 2 # load the bitmap sized 384 x 256
PCD_BASEDIV16 = 3 # load the bitmap sized 192 x 128
PCX_DEFAULT = 0
PFM_DEFAULT = 0
PICT_DEFAULT = 0
PNG_DEFAULT = 0
PNG_IGNOREGAMMA = 1 # loading: avoid gamma correction
# save using ZLib level 1 compression flag (default value is 6)
PNG_Z_BEST_SPEED = 0x0001
# save using ZLib level 6 compression flag (default recommended value)
PNG_Z_DEFAULT_COMPRESSION = 0x0006
# save using ZLib level 9 compression flag (default value is 6)
PNG_Z_BEST_COMPRESSION = 0x0009
PNG_Z_NO_COMPRESSION = 0x0100 # save without ZLib compression
# save using Adam7 interlacing (use | to combine with other save flags)
PNG_INTERLACED = 0x0200
PNM_DEFAULT = 0
PNM_SAVE_RAW = 0 # Writer saves in RAW format (i.e. P4, P5 or P6)
PNM_SAVE_ASCII = 1 # Writer saves in ASCII format (i.e. P1, P2 or P3)
PSD_DEFAULT = 0
PSD_CMYK = 1 # reads tags for separated CMYK (default converts to RGB)
PSD_LAB = 2 # reads tags for CIELab (default is conversion to RGB)
RAS_DEFAULT = 0
RAW_DEFAULT = 0 # load the file as linear RGB 48-bit
# try to load embedded JPEG preview from Exif Data or default to RGB 24-bit
RAW_PREVIEW = 1
RAW_DISPLAY = 2 # load the file as RGB 24-bit
SGI_DEFAULT = 0
TARGA_DEFAULT = 0
TARGA_LOAD_RGB888 = 1 # Convert RGB555 and ARGB8888 -> RGB888.
TARGA_SAVE_RLE = 2 # Save with RLE compression
TIFF_DEFAULT = 0
# reads/stores tags for separated CMYK
# (use | to combine with compression flags)
TIFF_CMYK = 0x0001
TIFF_PACKBITS = 0x0100 # save using PACKBITS compression
TIFF_DEFLATE = 0x0200 # save using DEFLATE (a.k.a. ZLIB) compression
TIFF_ADOBE_DEFLATE = 0x0400 # save using ADOBE DEFLATE compression
TIFF_NONE = 0x0800 # save without any compression
TIFF_CCITTFAX3 = 0x1000 # save using CCITT Group 3 fax encoding
TIFF_CCITTFAX4 = 0x2000 # save using CCITT Group 4 fax encoding
TIFF_LZW = 0x4000 # save using LZW compression
TIFF_JPEG = 0x8000 # save using JPEG compression
TIFF_LOGLUV = 0x10000 # save using LogLuv compression
WBMP_DEFAULT = 0
XBM_DEFAULT = 0
XPM_DEFAULT = 0
class MetadataModels(object):
FIMD_COMMENTS = 0
FIMD_EXIF_MAIN = 1
FIMD_EXIF_EXIF = 2
FIMD_EXIF_GPS = 3
FIMD_EXIF_MAKERNOTE = 4
FIMD_EXIF_INTEROP = 5
FIMD_IPTC = 6
FIMD_XMP = 7
FIMD_GEOTIFF = 8
FIMD_ANIMATION = 9
class MetadataDatatype(object):
FIDT_BYTE = 1 # 8-bit unsigned integer
FIDT_ASCII = 2 # 8-bit bytes w/ last byte null
FIDT_SHORT = 3 # 16-bit unsigned integer
FIDT_LONG = 4 # 32-bit unsigned integer
FIDT_RATIONAL = 5 # 64-bit unsigned fraction
FIDT_SBYTE = 6 # 8-bit signed integer
FIDT_UNDEFINED = 7 # 8-bit untyped data
FIDT_SSHORT = 8 # 16-bit signed integer
FIDT_SLONG = 9 # 32-bit signed integer
FIDT_SRATIONAL = 10 # 64-bit signed fraction
FIDT_FLOAT = 11 # 32-bit IEEE floating point
FIDT_DOUBLE = 12 # 64-bit IEEE floating point
FIDT_IFD = 13 # 32-bit unsigned integer (offset)
FIDT_PALETTE = 14 # 32-bit RGBQUAD
FIDT_LONG8 = 16 # 64-bit unsigned integer
FIDT_SLONG8 = 17 # 64-bit signed integer
FIDT_IFD8 = 18 # 64-bit unsigned integer (offset)
dtypes = {FIDT_BYTE: numpy.uint8,
FIDT_SHORT: numpy.uint16,
FIDT_LONG: numpy.uint32,
FIDT_RATIONAL: [('numerator', numpy.uint32),
('denominator', numpy.uint32)],
FIDT_SBYTE: numpy.int8,
FIDT_UNDEFINED: numpy.uint8,
FIDT_SSHORT: numpy.int16,
FIDT_SLONG: numpy.int32,
FIDT_SRATIONAL: [('numerator', numpy.int32),
('denominator', numpy.int32)],
FIDT_FLOAT: numpy.float32,
FIDT_DOUBLE: numpy.float64,
FIDT_IFD: numpy.uint32,
FIDT_PALETTE: [('R', numpy.uint8), ('G', numpy.uint8),
('B', numpy.uint8), ('A', numpy.uint8)],
FIDT_LONG8: numpy.uint64,
FIDT_SLONG8: numpy.int64,
FIDT_IFD8: numpy.uint64,
}
def _process_bitmap(filename, flags, process_func):
filename = asbytes(filename)
ftype = _FI.FreeImage_GetFileType(filename, 0)
handle_errors()
if ftype == -1:
raise ValueError('Cannot determine type of file %s' % filename)
bitmap = _FI.FreeImage_Load(ftype, filename, flags)
handle_errors()
bitmap = ctypes.c_void_p(bitmap)
if not bitmap:
raise ValueError('Could not load file %s' % filename)
try:
return process_func(bitmap)
finally:
_FI.FreeImage_Unload(bitmap)
handle_errors()
def read(filename, flags=0):
"""Read an image to a numpy array of shape (height, width) for
greyscale images, or shape (height, width, nchannels) for RGB or
RGBA images.
The `flags` parameter should be one or more values from the IoFlags
class defined in this module, or-ed together with | as appropriate.
(See the source-code comments for more details.)
"""
return _process_bitmap(filename, flags, _array_from_bitmap)
def read_metadata(filename):
"""Return a dict containing all image metadata.
Returned dict maps (metadata_model, tag_name) keys to tag values, where
metadata_model is a string name based on the FreeImage "metadata models"
defined in the class MetadataModels.
"""
flags = IoFlags.FIF_LOAD_NOPIXELS
return _process_bitmap(filename, flags, _read_metadata)
def _process_multipage(filename, flags, process_func):
filename = asbytes(filename)
ftype = _FI.FreeImage_GetFileType(filename, 0)
handle_errors()
if ftype == -1:
raise ValueError('Cannot determine type of file %s' % filename)
create_new = False
read_only = True
keep_cache_in_memory = True
multibitmap = _FI.FreeImage_OpenMultiBitmap(
ftype, filename, create_new, read_only, keep_cache_in_memory, flags)
handle_errors()
multibitmap = ctypes.c_void_p(multibitmap)
if not multibitmap:
raise ValueError('Could not open %s as multi-page image.' % filename)
try:
pages = _FI.FreeImage_GetPageCount(multibitmap)
handle_errors()
out = []
for i in range(pages):
bitmap = _FI.FreeImage_LockPage(multibitmap, i)
handle_errors()
bitmap = ctypes.c_void_p(bitmap)
if not bitmap:
raise ValueError('Could not open %s as a multi-page image.'
% filename)
try:
out.append(process_func(bitmap))
finally:
_FI.FreeImage_UnlockPage(multibitmap, bitmap, False)
handle_errors()
return out
finally:
_FI.FreeImage_CloseMultiBitmap(multibitmap, 0)
handle_errors()
def read_multipage(filename, flags=0):
"""Read a multipage image to a list of numpy arrays, where each
array is of shape (height, width) for greyscale images, or shape
(height, width, nchannels) for RGB or RGBA images.
The `flags` parameter should be one or more values from the IoFlags
class defined in this module, or-ed together with | as appropriate.
(See the source-code comments for more details.)
"""
return _process_multipage(filename, flags, _array_from_bitmap)
def read_multipage_metadata(filename):
"""Read a multipage image to a list of metadata dicts, one dict for each
page. The dict format is as in read_metadata().
"""
flags = IoFlags.FIF_LOAD_NOPIXELS
return _process_multipage(filename, flags, _read_metadata)
def _wrap_bitmap_bits_in_array(bitmap, shape, dtype):
"""Return an ndarray view on the data in a FreeImage bitmap. Only
valid for as long as the bitmap is loaded (if single page) / locked
in memory (if multipage).
"""
pitch = _FI.FreeImage_GetPitch(bitmap)
handle_errors()
height = shape[-1]
byte_size = height * pitch
itemsize = dtype.itemsize
if len(shape) == 3:
strides = (itemsize, shape[0] * itemsize, pitch)
else:
strides = (itemsize, pitch)
bits = _FI.FreeImage_GetBits(bitmap)
handle_errors()
array = numpy.ndarray(
shape, dtype=dtype,
buffer=(ctypes.c_char * byte_size).from_address(bits), strides=strides)
return array
def _array_from_bitmap(bitmap):
"""Convert a FreeImage bitmap pointer to a numpy array.
"""
dtype, shape = FiTypes.get_type_and_shape(bitmap)
array = _wrap_bitmap_bits_in_array(bitmap, shape, dtype)
# swizzle the color components and flip the scanlines to go from
# FreeImage's BGR[A] and upside-down internal memory format to something
# more normal
def n(arr):
return arr[..., ::-1].T
if len(shape) == 3 and _FI.FreeImage_IsLittleEndian() and \
dtype.type == numpy.uint8:
b = n(array[0])
g = n(array[1])
r = n(array[2])
if shape[0] == 3:
handle_errors()
return numpy.dstack((r, g, b))
elif shape[0] == 4:
a = n(array[3])
return numpy.dstack((r, g, b, a))
else:
raise ValueError('Cannot handle images of shape %s' % shape)
# We need to copy because array does *not* own its memory
# after bitmap is freed.
return n(array).copy()
def _read_metadata(bitmap):
metadata = {}
models = [(name[5:], number) for name, number in
MetadataModels.__dict__.items() if name.startswith('FIMD_')]
tag = ctypes.c_void_p()
for model_name, number in models:
mdhandle = _FI.FreeImage_FindFirstMetadata(number, bitmap,
ctypes.byref(tag))
handle_errors()
mdhandle = ctypes.c_void_p(mdhandle)
if mdhandle:
more = True
while more:
tag_name = asstr(_FI.FreeImage_GetTagKey(tag))
tag_type = _FI.FreeImage_GetTagType(tag)
byte_size = _FI.FreeImage_GetTagLength(tag)
handle_errors()
char_ptr = ctypes.c_char * byte_size
tag_str = char_ptr.from_address(_FI.FreeImage_GetTagValue(tag))
handle_errors()
if tag_type == MetadataDatatype.FIDT_ASCII:
tag_val = asstr(tag_str.value)
else:
tag_val = numpy.fromstring(
tag_str, dtype=MetadataDatatype.dtypes[tag_type])
if len(tag_val) == 1:
tag_val = tag_val[0]
metadata[(model_name, tag_name)] = tag_val
more = _FI.FreeImage_FindNextMetadata(mdhandle,
ctypes.byref(tag))
handle_errors()
_FI.FreeImage_FindCloseMetadata(mdhandle)
handle_errors()
return metadata
def write(array, filename, flags=0):
"""Write a (height, width) or (height, width, nchannels) array to
a greyscale, RGB, or RGBA image, with file type deduced from the
filename.
The `flags` parameter should be one or more values from the IoFlags
class defined in this module, or-ed together with | as appropriate.
(See the source-code comments for more details.)
"""
array = numpy.asarray(array)
filename = asbytes(filename)
ftype = _FI.FreeImage_GetFIFFromFilename(filename)
handle_errors()
if ftype == -1:
raise ValueError('Cannot determine type for %s' % filename)
bitmap, fi_type = _array_to_bitmap(array)
try:
if fi_type == FiTypes.FIT_BITMAP:
can_write = _FI.FreeImage_FIFSupportsExportBPP(
ftype, _FI.FreeImage_GetBPP(bitmap))
handle_errors()
else:
can_write = _FI.FreeImage_FIFSupportsExportType(ftype, fi_type)
handle_errors()
if not can_write:
raise TypeError('Cannot save image of this format '
'to this file type')
res = _FI.FreeImage_Save(ftype, bitmap, filename, flags)
handle_errors()
if not res:
raise RuntimeError('Could not save image properly.')
finally:
_FI.FreeImage_Unload(bitmap)
handle_errors()
def write_multipage(arrays, filename, flags=0):
"""Write a list of (height, width) or (height, width, nchannels)
arrays to a multipage greyscale, RGB, or RGBA image, with file type
deduced from the filename.
The `flags` parameter should be one or more values from the IoFlags
class defined in this module, or-ed together with | as appropriate.
(See the source-code comments for more details.)
"""
filename = asbytes(filename)
ftype = _FI.FreeImage_GetFIFFromFilename(filename)
if ftype == -1:
raise ValueError('Cannot determine type of file %s' % filename)
create_new = True
read_only = False
keep_cache_in_memory = True
multibitmap = _FI.FreeImage_OpenMultiBitmap(ftype, filename,
create_new, read_only,
keep_cache_in_memory, 0)
multibitmap = ctypes.c_void_p(multibitmap)
if not multibitmap:
raise ValueError('Could not open %s for writing multi-page image.' %
filename)
try:
for array in arrays:
array = numpy.asarray(array)
bitmap, fi_type = _array_to_bitmap(array)
_FI.FreeImage_AppendPage(multibitmap, bitmap)
finally:
_FI.FreeImage_CloseMultiBitmap(multibitmap, flags)
# 4-byte quads of 0,v,v,v from 0,0,0,0 to 0,255,255,255
_GREY_PALETTE = numpy.arange(0, 0x01000000, 0x00010101, dtype=numpy.uint32)
def _array_to_bitmap(array):
"""Allocate a FreeImage bitmap and copy a numpy array into it.
"""
shape = array.shape
dtype = array.dtype
r, c = shape[:2]
if len(shape) == 2:
n_channels = 1
w_shape = (c, r)
elif len(shape) == 3:
n_channels = shape[2]
w_shape = (n_channels, c, r)
else:
n_channels = shape[0]
try:
fi_type = FiTypes.fi_types[(dtype, n_channels)]
except KeyError:
raise ValueError('Cannot write arrays of given type and shape.')
itemsize = array.dtype.itemsize
bpp = 8 * itemsize * n_channels
bitmap = _FI.FreeImage_AllocateT(fi_type, c, r, bpp, 0, 0, 0)
bitmap = ctypes.c_void_p(bitmap)
if not bitmap:
raise RuntimeError('Could not allocate image for storage')
try:
def n(arr): # normalise to freeimage's in-memory format
return arr.T[..., ::-1]
wrapped_array = _wrap_bitmap_bits_in_array(bitmap, w_shape, dtype)
# swizzle the color components and flip the scanlines to go to
# FreeImage's BGR[A] and upside-down internal memory format
if len(shape) == 3 and _FI.FreeImage_IsLittleEndian():
r = array[:, :, 0]
g = array[:, :, 1]
b = array[:, :, 2]
if dtype.type == numpy.uint8:
wrapped_array[0] = n(b)
wrapped_array[1] = n(g)
wrapped_array[2] = n(r)
elif dtype.type == numpy.uint16:
wrapped_array[0] = n(r)
wrapped_array[1] = n(g)
wrapped_array[2] = n(b)
if shape[2] == 4:
a = array[:, :, 3]
wrapped_array[3] = n(a)
else:
wrapped_array[:] = n(array)
if len(shape) == 2 and dtype.type == numpy.uint8:
palette = _FI.FreeImage_GetPalette(bitmap)
palette = ctypes.c_void_p(palette)
if not palette:
raise RuntimeError('Could not get image palette')
ctypes.memmove(palette, _GREY_PALETTE.ctypes.data, 1024)
return bitmap, fi_type
except:
_FI.FreeImage_Unload(bitmap)
raise
def imread(filename):
"""
img = imread(filename)
Reads an image from file `filename`
Parameters
----------
filename : file name
Returns
-------
img : ndarray
"""
img = read(filename)
return img
def imsave(filename, img):
'''
imsave(filename, img)
Save image to disk
Image type is inferred from filename
Parameters
----------
filename : file name
img : image to be saved as nd array
'''
write(img, filename)
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