libvips/python/vips8/vips.py

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#!/usr/bin/python
import logging
import sys
from gi.repository import GLib
from gi.repository import GObject
# you might need this in your .bashrc
# export GI_TYPELIB_PATH=$VIPSHOME/lib/girepository-1.0
from gi.repository import Vips
class Error(Exception):
"""An error from vips.
message -- a high-level description of the error
detail -- a string with some detailed diagnostics
"""
def __init__(self, message, detail = None):
self.message = message
if detail == None:
detail = Vips.error_buffer()
Vips.error_clear()
self.detail = detail
logging.debug('vips: Error %s %s', self.message, self.detail)
def __str__(self):
return '%s %s' % (self.message, self.detail)
class Argument:
def __init__(self, op, prop):
self.op = op;
self.prop = prop;
self.name = prop.name;
self.flags = op.get_argument_flags(self.name)
self.priority = op.get_argument_priority(self.name)
self.isset = op.argument_isset(self.name)
def _call_base(name, self, required, optional):
logging.debug('_call_base name=%s, self=%s, required=%s optional=%s' %
(name, self, required, optional))
try:
op = Vips.Operation.new(name)
except TypeError, e:
raise Error('No such operator.')
# find all the args for this op, sort into priority order
args = [Argument(op, x) for x in op.props]
args.sort(lambda a, b: a.priority - b.priority)
enm = Vips.ArgumentFlags
# find all required, unassigned input args
required_input = [x for x in args if x.flags & enm.INPUT and
x.flags & enm.REQUIRED and
not x.isset]
# do we have a non-NULL self pointer? this is used to set the first
# compatible input arg
if self != None:
found = False
for x in required_input:
if GObject.type_is_a(self, x.prop.value_type):
op.props.__setattr__(x.name, self)
required_input.remove(x)
found = True
break
if not found:
raise Error('Bad arguments.', 'No %s argument to %s.' %
(str(self.__class__), name))
if len(required_input) != len(required):
raise Error('Wrong number of arguments.',
'"%s" needs %d arguments, you supplied %d' %
(name, len(required_input), len(required)))
for i in range(len(required_input)):
logging.debug('assigning %s to %s' % (required[i],
required_input[i].name))
logging.debug('%s needs a %s' % (required_input[i].name,
required_input[i].prop.value_type))
op.props.__setattr__(required_input[i].name, required[i])
# find all optional, unassigned input args ... just need the names
optional_input = [x.name for x in args if x.flags & enm.INPUT and
not x.flags & enm.REQUIRED and
not x.isset]
for key in optional.keys():
if not key in optional_input:
raise Error('Unknown argument.',
'Operator %s has no argument %s' % (name, key))
# set optional input args
for key in optional.keys():
op.props.__setattr__(key, optional[key])
# call
op2 = Vips.cache_operation_build(op)
if op2 == None:
raise Error('Error calling operator %s.' % name)
# find all required output args ... just need the names
# we can't check assigned here (since we captured the value before the call)
# but the getattr will test that for us anyway
required_output = [x.name for x in args if x.flags & enm.OUTPUT and
x.flags & enm.REQUIRED]
# gather output args
out = []
for x in required_output:
out.append(op2.props.__getattribute__(x))
# find all optional output args ... just need the names
optional_output = [x.name for x in args if x.flags & enm.OUTPUT and
not x.flags & enm.REQUIRED]
for x in optional.keys():
if x in optional_output:
out.append(op2.props.__getattribute__(x))
if len(out) == 1:
out = out[0]
# unref everything now we have refs to all outputs we want
op2.unref_outputs()
return out
# general user entrypoint
def call(name, *args, **kwargs):
return _call_base(name, None, args, kwargs)
# from getattr ... try to run the attr as a method
def _call_instance(self, name, args, kwargs):
return _call_base(name, self, args, kwargs)
class Image(Vips.Image):
def __init__(self, filename = None, mode = None):
Vips.Image.__init__(self)
if filename:
self.props.filename = filename
if not mode:
mode = "rd"
if mode:
self.props.mode = mode
if self.build() != 0:
print 'build failed'
raise Error('Unable to build image')
def __getattr__(self, name):
logging.debug('vipsimage: __getattr__ %s' % name)
return lambda *args, **kwargs: _call_instance(self, name, args, kwargs)
# start up vips!
Vips.init(sys.argv[0])