def write_to_memory(self):
"""Write the image to a large memory array.
A large area of memory is allocated, the image is rendered to that
memory array, and the array is returned as a buffer.
For example, if you have a 2x2 uchar image containing the bytes 1, 2,
3, 4, read left-to-right, top-to-bottom, then::
buf = image.write_to_memory()
will return a four byte buffer containing the values 1, 2, 3, 4.
Returns:
buffer
Raises:
:class:`.Error`
"""
psize = ffi.new('size_t *')
pointer = vips_lib.vips_image_write_to_memory(self.pointer, psize)
pointer = ffi.gc(pointer, glib_lib.g_free)
return ffi.buffer(pointer, psize[0])
def __init__(self):
# allocate memory for the gvalue which will be freed on GC
self.pointer = ffi.new('GValue *')
# logger.debug('GValue.__init__: pointer = %s', self.pointer)
# and tag it to be unset on GC as well
self.gvalue = ffi.gc(self.pointer, gobject_lib.g_value_unset)
def _to_string_copy(x):
"""Convert to a unicode string, and auto-free.
As _to_string(), but also tag x as a pointer to a memory area that must
be freed with g_free().
"""
return _to_string(ffi.gc(x, glib_lib.g_free))
def __init__(self, pointer):
"""Wrap around a pointer.
Wraps a GObject instance around an underlying pointer. When the
instance is garbage-collected, the underlying object is unreferenced.
"""
# record the pointer we were given to manage
self.pointer = pointer
# logger.debug('GObject.__init__: pointer = %s', str(self.pointer))
# on GC, unref
self.gobject = ffi.gc(self.pointer, gobject_lib.g_object_unref)
def __init__(self, pointer):
"""Wrap around a pointer.
Wraps a GObject instance around an underlying pointer. When the
instance is garbage-collected, the underlying object is unreferenced.
"""
# we have to record all of the ffi.new_handle we make for callbacks on
# this object to prevent them being GC'd
self._handles = []
# record the pointer we were given to manage
# on GC, unref
self.pointer = ffi.gc(pointer, gobject_lib.g_object_unref)
def fetch(self, x, y, w, h):
"""Fill a region with pixel data.
Pixels are filled with data!
Returns:
Pixel data.
Raises:
:class:`.Error`
"""
if not at_least_libvips(8, 8):
raise Error('libvips too old')
psize = ffi.new('size_t *')
pointer = vips_lib.vips_region_fetch(self.pointer, x, y, w, h, psize)
if pointer == ffi.NULL:
raise Error('unable to fetch from region')
pointer = ffi.gc(pointer, glib_lib.g_free)
return ffi.buffer(pointer, psize[0])