libvips/python/old/vipsobject.py

105 lines
2.9 KiB
Python

#!/usr/bin/python
"""This module wraps up libvips in a less awful interface.
Wrap VipsObject.
Author: J.Cupitt
GNU LESSER GENERAL PUBLIC LICENSE
"""
import logging
import sys
import ctypes
import gobject
import finalizable
# .15 is 7.25+ with the new vips8 API
libvips = ctypes.CDLL('libvips.so.15')
libvips.vips_init(sys.argv[0])
vips_object_print = libvips.vips_object_print
vips_object_print.argtypes = [ctypes.c_void_p]
vips_object_print.restype = None
# in C:
# typedef void *(*VipsArgumentMapFn)( VipsObject *,
# GParamSpec *, VipsArgumentClass *, VipsArgumentInstance *,
# void *a, void *b );
VipsArgumentMapFn = ctypes.CFUNCTYPE(ctypes.c_void_p, ctypes.c_void_p,
ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p,
ctypes.c_void_p, ctypes.c_void_p)
vips_argument_map = libvips.vips_argument_map
vips_argument_map.argtypes = [ctypes.c_void_p, VipsArgumentMapFn,
ctypes.c_void_p, ctypes.c_void_p]
vips_argument_map.restype = ctypes.c_void_p
g_param_spec_get_name = libvips.g_param_spec_get_name
g_param_spec_get_name.argtypes = [ctypes.c_void_p]
g_param_spec_get_name.restype = ctypes.c_char_p
# given a class and value, search for a class member with that value
# handy for enum classes, use to turn numbers to strings
def class_value(classobject, value):
for name in dir(classobject):
if getattr(classobject, name) == value:
return classobject.__name__ + '.' + name
return 'unknown'
class VipsError(Exception):
"""An error from libvips.
message -- a high-level description of the error
detail -- a string with some detailed diagnostics
"""
def __init__(self, message):
self.message = message
self.detail = vips_error_buffer()
libvips.vips_error_clear()
logging.debug('vipsobject: Error: %s %s', self.message, self.detail)
def __str__(self):
return '%s %s' % (self.message, self.detail)
# handy checkers, assign to errcheck
def check_int_return(result, func, args):
if result != 0:
raise VipsError('Error calling vips function %s.' % func.__name__)
return result
def check_pointer_return(result, func, args):
if result == None:
raise VipsError('Error calling vips function %s.' % func.__name__)
return result
vips_error_buffer = libvips.vips_error_buffer
vips_error_buffer.restype = ctypes.c_char_p
class VipsObject(finalizable.Finalizable):
"""Abstract base class for libvips."""
# attributes we finalize
ghost_attributes = ('vipsobject', )
def __finalize__(self):
logging.debug('vipsobject: __finalize__')
if self.vipsobject != None:
logging.debug('vipsobject: unref %s' % hex(self.vipsobject))
libvips.g_object_unref(self.vipsobject)
self.vipsobject = None
def enable_finalize(self):
self.bind_finalizer(*self.ghost_attributes)
def __init__(self):
logging.debug('vipsobject: init')
self.vipsobject = None