def call(operation_name, *args, **kwargs):
"""Call a libvips operation.
Use this method to call any libvips operation. For example::
black_image = pyvips.Operation.call('black', 10, 10)
See the Introduction for notes on how this works.
"""
logger.debug('VipsOperation.call: operation_name = %s', operation_name)
# logger.debug('VipsOperation.call: args = %s, kwargs =%s',
# args, kwargs)
# pull out the special string_options kwarg
string_options = kwargs.pop('string_options', '')
logger.debug('VipsOperation.call: string_options = %s', string_options)
op = Operation.new_from_name(operation_name)
arguments = op.get_args()
# logger.debug('arguments = %s', arguments)
# make a thing to quickly get flags from an arg name
flags_from_name = {}
# count required input args
n_required = 0
for name, flags in arguments:
flags_from_name[name] = flags
if ((flags & _INPUT) != 0 and (flags & _REQUIRED) != 0
and (flags & _DEPRECATED) == 0):
n_required += 1
if n_required != len(args):
raise Error('unable to call {0}: {1} arguments given, '
'but {2} required'.format(operation_name, len(args),
n_required))
# the first image argument is the thing we expand constants to
# match ... look inside tables for images, since we may be passing
# an array of image as a single param
match_image = _find_inside(lambda x: isinstance(x, pyvips.Image), args)
logger.debug('VipsOperation.call: match_image = %s', match_image)
# set any string options before any args so they can't be
# overridden
if not op.set_string(string_options):
raise Error('unable to call {0}'.format(operation_name))
# set required and optional args
n = 0
for name, flags in arguments:
if ((flags & _INPUT) != 0 and (flags & _REQUIRED) != 0
and (flags & _DEPRECATED) == 0):
op.set(name, flags, match_image, args[n])
n += 1
for name, value in kwargs.items():
if name not in flags_from_name:
raise Error('{0} does not support argument '
'{1}'.format(operation_name, name))
op.set(name, flags_from_name[name], match_image, value)
# build operation
vop = vips_lib.vips_cache_operation_build(op.pointer)
if vop == ffi.NULL:
raise Error('unable to call {0}'.format(operation_name))
op = Operation(vop)
# fetch required output args, plus modified input images
result = []
for name, flags in arguments:
if ((flags & _OUTPUT) != 0 and (flags & _REQUIRED) != 0
and (flags & _DEPRECATED) == 0):
result.append(op.get(name))
if (flags & _INPUT) != 0 and (flags & _MODIFY) != 0:
result.append(op.get(name))
# fetch optional output args
opts = {}
for name, value in kwargs.items():
flags = flags_from_name[name]
if ((flags & _OUTPUT) != 0 and (flags & _REQUIRED) == 0
and (flags & _DEPRECATED) == 0):
opts[name] = op.get(name)
vips_lib.vips_object_unref_outputs(op.object)
if len(opts) > 0:
result.append(opts)
if len(result) == 0:
result = None
elif len(result) == 1:
result = result[0]
logger.debug('VipsOperation.call: result = %s', result)
return result
def call(operation_name, *args, **kwargs):
"""Call a libvips operation.
Use this method to call any libvips operation. For example::
black_image = pyvips.Operation.call('black', 10, 10)
See the Introduction for notes on how this works.
"""
logger.debug('VipsOperation.call: operation_name = %s', operation_name)
# logger.debug('VipsOperation.call: args = %s, kwargs =%s',
# args, kwargs)
intro = Introspect.get(operation_name)
if len(intro.required_input) != len(args):
raise Error('{0} needs {1} arguments, but {2} given'.format(
operation_name, len(intro.required_input), len(args)))
op = Operation.new_from_name(operation_name)
# set any string options before any args so they can't be
# overridden
string_options = kwargs.pop('string_options', '')
if not op.set_string(string_options):
raise Error('unable to call {0}'.format(operation_name))
# the first image argument is the thing we expand constants to
# match ... look inside tables for images, since we may be passing
# an array of images as a single param
match_image = _find_inside(lambda x: isinstance(x, pyvips.Image), args)
logger.debug('VipsOperation.call: match_image = %s', match_image)
# collect a list of all input references here
# we can't use a set because set elements are unique under "==", and
# Python checks memoryview equality with hash functions, not pointer
# equality
references = []
# does a list contain an element using pointer equality
# we can't use "in" since that uses "==", which means hash equality
def contains(array, x):
for y in array:
if id(x) == id(y):
return True
return False
def add_reference(x):
if isinstance(x, pyvips.Image):
for i in x._references:
if not contains(references, i):
references.append(i)
return False
# set required input args
for name, value in zip(intro.required_input, args):
_find_inside(add_reference, value)
op.set(name, intro.details[name]['flags'], match_image, value)
# set any optional args
for name in kwargs:
if (name not in intro.optional_input
and name not in intro.optional_output):
raise Error(
'{0} does not support optional argument {1}'.format(
operation_name, name))
value = kwargs[name]
details = intro.details[name]
if (details['flags'] & _DEPRECATED) != 0:
logger.info('{0} argument {1} is deprecated', operation_name,
name)
_find_inside(add_reference, value)
op.set(name, details['flags'], match_image, value)
# build operation
vop = vips_lib.vips_cache_operation_build(op.pointer)
if vop == ffi.NULL:
vips_lib.vips_object_unref_outputs(op.vobject)
raise Error('unable to call {0}'.format(operation_name))
op = Operation(vop)
# attach all input refs to output x
def set_reference(x):
if isinstance(x, pyvips.Image):
x._references.extend(references)
return False
# fetch required output args (plus modified input images)
result = []
for name in intro.required_output:
value = op.get(name)
_find_inside(set_reference, value)
result.append(value)
# fetch optional output args
opts = {}
for name in intro.optional_output:
if name in kwargs:
value = op.get(name)
_find_inside(set_reference, value)
opts[name] = value
if len(opts) > 0:
result.append(opts)
vips_lib.vips_object_unref_outputs(op.vobject)
if len(result) == 0:
result = None
elif len(result) == 1:
result = result[0]
logger.debug('VipsOperation.call: result = %s', result)
return result