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)
if pointer == ffi.NULL:
raise Error('unable to write to memory')
pointer = ffi.gc(pointer, glib_lib.g_free)
return ffi.buffer(pointer, psize[0])
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])
def _marshal_write(source_custom, pointer, length, handle):
buf = ffi.buffer(pointer, length)
callback = ffi.from_handle(handle)
return callback(buf)
