# Source code for pyvips.vimage

    # wrap VipsImage

    import numbers
    import struct
    import sys

    import pyvips
    from pyvips import ffi, glib_lib, vips_lib, Error, _to_bytes, \
        _to_string, _to_string_copy, GValue, at_least_libvips, Introspect

    # either a single number, or a table of numbers
    def _is_pixel(value):
        return (isinstance(value, numbers.Number) or
                (isinstance(value, list) and not
                isinstance(value, pyvips.Image)))

    # test for rectangular array of something
    def _is_2D(array):
        if not isinstance(array, list):
            return False

        for x in array:
            if not isinstance(x, list):
                return False
            if len(x) != len(array[0]):
                return False

        return True

    # apply a function to a thing, or map over a list
    # we often need to do something like (1.0 / other) and need to work for lists
    # as well as scalars
    def _smap(func, x):
        if isinstance(x, list):
            return list(map(func, x))
        else:
            return func(x)

    def _call_enum(image, other, base, operation):
        if _is_pixel(other):
            return pyvips.Operation.call(base + '_const', image, operation, other)
        else:
            return pyvips.Operation.call(base, image, other, operation)

    def _run_cmplx(fn, image):
        """Run a complex function on a non-complex image.

        The image needs to be complex, or have an even number of bands. The input
        can be int, the output is always float or double.
        """
        original_format = image.format

        if image.format != 'complex' and image.format != 'dpcomplex':
            if image.bands % 2 != 0:
                raise Error('not an even number of bands')

            if image.format != 'float' and image.format != 'double':
                image = image.cast('float')

            if image.format == 'double':
                new_format = 'dpcomplex'
            else:
                new_format = 'complex'

            image = image.copy(format=new_format, bands=image.bands / 2)

        image = fn(image)

        if original_format != 'complex' and original_format != 'dpcomplex':
            if image.format == 'dpcomplex':
                new_format = 'double'
            else:
                new_format = 'float'

            image = image.copy(format=new_format, bands=image.bands * 2)

        return image

    # decorator to set docstring
    def _add_doc(name):
        try:
            docstring = pyvips.Operation.generate_docstring(name)
        except Error:
            docstring = None

        def _doc(func):
            func.__doc__ = docstring
            return func

        return _doc

    # decorator to set deprecated
    def _deprecated(note):
        def _dep(func):
            func.__deprecated__ = note
            return func

        return _dep

    # Rules for the mapping between numpy typestrings and libvips formats
    # b1: bool. Above u1 so that rev. map is uchar->u1
    _numpy_endian = '<' if sys.byteorder == 'little' else '>'

    TYPESTR_TO_FORMAT = {'|b1': 'uchar',
                         '|u1': 'uchar',
                         '|i1': 'char',
                         '<u2': 'ushort',
                         '<i2': 'short',
                         '<u4': 'uint',
                         '<i4': 'int',
                         '<f4': 'float',
                         '<c8': 'complex',
                         '<f8': 'double',
                         '<c16': 'dpcomplex'}
    TYPESTR_TO_FORMAT = {typestr.replace('<', _numpy_endian): format
                          for typestr, format in TYPESTR_TO_FORMAT.items()}

    # Rules for the mapping between libvips formats and numpy typestrings
    FORMAT_TO_TYPESTR = dict((v, k) for k, v in TYPESTR_TO_FORMAT.items())

    # see https://docs.python.org/3/library/struct.html
    FORMAT_TO_PYFORMAT = {'uchar': 'B',
                          'char': 'c',
                          'ushort': 'H',
                          'short': 'h',
                          'uint': 'I',
                          'int': 'i',
                          'float': 'f',
                          'double': 'd',
                          'complex': 'f',   # n.b. no support for complex in C
                          'dpcomplex': 'd'}

    def _guess_interpretation(bands, format):
        """Return a best-guess interpretation string based on bands and libvips
        format.

        Args:
            bands (int): Number of bands in the image.
            format (str): libvips format string.

        Returns:
            str: the best-guess libvips interpretation string.

        This function is a helper for :class:`.Image` creation from arrays when the
        user specifies 'auto' for `interpretation`.

        The heuristic used here can be defined in the following table::

            | bands | format    | interpretation | reason       |
            | ----- | --------- | -------------- | ------------ |
            | 1     | uchar     | b-w            | L            |
            | 2     | uchar     | b-w            | LA           |
            | 3     | uchar     | rgb            | RGB          |
            | 4     | uchar     | rgb            | RGBA         |
            | 5+    | uchar     | multiband      | spectral     |
            | 1     | char      | matrix         | conv. kernel |
            | 2+    | char      | multiband      |              |
            | 1     | ushort    | grey16         | L            |
            | 2     | ushort    | grey16         | LA           |
            | 3     | ushort    | rgb16          | RGB          |
            | 4     | ushort    | rgb16          | RGBA         |
            | 5+    | ushort    | multiband      | spectral     |
            | any   | short     | multiband      |              |
            | 1     | float     | b-w            | L            |
            | 2     | float     | b-w            | LA           |
            | 3     | float     | scrgb          | RGB          |
            | 4     | float     | scrgb          | RGBA         |
            | 5+    | float     | multiband      | spectral     |
            | 1     | double    | b-w            | L            |
            | 2     | double    | b-w            | LA           |
            | 3     | double    | scrgb          | RGB          |
            | 4     | double    | scrgb          | RGBA         |
            | 5+    | double    | multiband      | spectral     |
            | any   | complex   | fourier        | FFT          |
            | any   | dpcomplex | fourier        | FFT          |

        """

        if format not in FORMAT_TO_TYPESTR:
            raise ValueError(f'Unknown format: {format}')
        if not isinstance(bands, int) or bands < 1:
            raise ValueError('Number of bands must be a positive integer.')

        # the default
        interp = 'multiband'

        if format == 'uchar':
            if bands in [1, 2]:
                interp = 'b-w'
            elif bands in [3, 4]:
                interp = 'rgb'
        elif format == 'char':
            if bands == 1:
                interp = 'matrix'
        elif format == 'ushort':
            if bands in [1, 2]:
                interp = 'grey16'
            elif bands in [3, 4]:
                interp = 'rgb16'
        elif format == 'short':
            if bands == 1:
                interp = 'matrix'
        elif format in ['float', 'double']:
            if bands in [1, 2]:
                interp = 'b-w'
            elif bands in [3, 4]:
                interp = 'scrgb'
        elif format in ['complex', 'dpcomplex']:
            interp = 'fourier'

        return interp

    # metaclass for Image ... getattr on this implements the class methods
    class ImageType(type):
        def __getattr__(cls, name):
            # logger.debug('ImageType.__getattr__ %s', name)

            # does the method exist in libvips?
            try:
                # this will throw an exception if not
                Introspect.get(name)
            except Error:
                # we need to throw this exception for missing methods, eg. numpy
                # checks for this
                raise AttributeError

            @_add_doc(name)
            def call_function(*args, **kwargs):
                return pyvips.Operation.call(name, *args, **kwargs)

            return call_function

    class Image(pyvips.VipsObject, metaclass=ImageType):
        """Wrap a VipsImage object.

        """
        __slots__ = ('_references',)

        # private static

        @staticmethod
        def _imageize(self, value):
            # careful! self can be None if value is a 2D array
            if isinstance(value, Image):
                return value
            elif _is_2D(value):
                return Image.new_from_array(value)
            else:
                return self.new_from_image(value)

        def __init__(self, pointer):
            # a list of other objects which this object depends on and which need
            # to be kept alive
            # we can't use a set because set elements are unique under "==", and
            # Python checks memoryview equality with hash functions, not pointer
            # equality
            self._references = []
            # logger.debug('Image.__init__: pointer = %s', pointer)
            super(Image, self).__init__(pointer)

        # constructors

        @staticmethod
        def new_from_file(vips_filename, **kwargs):
            """Load an image from a file.

            This method can load images in any format supported by vips. The
            filename can include load options, for example::

                image = pyvips.Image.new_from_file('fred.jpg[shrink=2]')

            You can also supply options as keyword arguments, for example::

                image = pyvips.Image.new_from_file('fred.jpg', shrink=2)

            The full set of options available depend upon the load operation that
            will be executed. Try something like::

                $ vips jpegload

            at the command-line to see a summary of the available options for the
            JPEG loader.

            Loading is fast: only enough of the image is loaded to be able to fill
            out the header. Pixels will only be decompressed when they are needed.

            Args:
                vips_filename (str): The disc file to load the image from, with
                    optional appended arguments.

            All loaders support at least the following options:

            Keyword args:
                memory (bool): If set True, load the image via memory rather than
                    via a temporary disc file. See :meth:`.new_temp_file` for
                    notes on where temporary files are created. Small images are
                    loaded via memory by default, use ``VIPS_DISC_THRESHOLD`` to
                    set the definition of small.
                access (Access): Hint the expected access pattern for the image.
                fail (bool): If set True, the loader will fail with an error on
                    the first serious error in the file. By default, libvips
                    will attempt to read everything it can from a damaged image.

            Returns:
                A new :class:`.Image`.

            Raises:
                :class:`.Error`

            """
            vips_filename = _to_bytes(vips_filename)
            pointer = vips_lib.vips_filename_get_filename(vips_filename)
            filename = _to_string_copy(pointer)

            pointer = vips_lib.vips_filename_get_options(vips_filename)
            options = _to_string_copy(pointer)

            pointer = vips_lib.vips_foreign_find_load(vips_filename)
            if pointer == ffi.NULL:
                raise Error(f'unable to load from file {vips_filename}')
            name = _to_string(pointer)

            return pyvips.Operation.call(name, filename,
                                         string_options=options, **kwargs)

        @staticmethod
        def new_from_buffer(data, options, **kwargs):
            """Load a formatted image from memory.

            This behaves exactly as :meth:`new_from_file`, but the image is
            loaded from the memory object rather than from a file. The memory
            object can be anything that supports the Python buffer protocol.

            Args:
                data (array, bytearray, bytes, buffer): The memory object to
                    load the image from.
                options (str): Load options as a string. Use ``""`` for no options.

            All loaders support at least the following options:

            Keyword args:
                access (Access): Hint the expected access pattern for the image.
                fail (bool): If set True, the loader will fail with an error on the
                    first serious error in the image. By default, libvips will
                    attempt to read everything it can from a damaged image.

            Returns:
                A new :class:`Image`.

            Raises:
                :class:`.Error`

            """
            pointer = vips_lib.vips_foreign_find_load_buffer(data, len(data))
            if pointer == ffi.NULL:
                raise Error('unable to load from buffer')
            name = _to_string(pointer)

            return pyvips.Operation.call(name, data,
                                         string_options=options, **kwargs)

        @staticmethod
        def new_from_list(array, scale=1.0, offset=0.0):
            """Create an image from a list or list of lists.

            A new one-band image with :class:`BandFormat` ``'double'`` pixels is
            created from the array. These image are useful with the libvips
            convolution operator :meth:`Image.conv`.

            Args:
                array (list[list[float]]): Create the image from these values.
                    1D arrays become a single row of pixels.
                scale (float): Default to 1.0. What to divide each pixel by after
                    convolution.  Useful for integer convolution masks.
                offset (float): Default to 0.0. What to subtract from each pixel
                    after convolution.  Useful for integer convolution masks.

            Returns:
                A new :class:`Image`.

            Raises:
                :class:`.Error`

            """
            if not _is_2D(array):
                array = [array]

            height = len(array)
            width = len(array[0])

            n = width * height
            a = ffi.new('double[]', n)
            for y in range(0, height):
                for x in range(0, width):
                    a[x + y * width] = array[y][x]

            vi = vips_lib.vips_image_new_matrix_from_array(width, height, a, n)
            if vi == ffi.NULL:
                raise Error('unable to make image from matrix')
            image = pyvips.Image(vi)

            image.set_type(GValue.gdouble_type, 'scale', scale)
            image.set_type(GValue.gdouble_type, 'offset', offset)

            return image

        @classmethod
        def new_from_array(cls, obj, scale=1.0, offset=0.0, interpretation=None):
            """Create a new Image from a list or an array-like object.

            Array-like objects are those which define `__array_interface__` or
            `__array__`. For details about the array interface, see `The Array
            Interface
            <https://numpy.org/doc/stable/reference/arrays.interface.html>`_.

            If `__array_interface__` is not available, `__array__` is used as a
            fallback.

            The behavior for input objects with different dimensions is summarized
            as::

                | array ndim | array shape | Image w | Image h | Image bands |
                |------------|-------------|---------|---------|-------------|
                | 0          | ()          | 1       | 1       | 1           |
                | 1          | (W,)        | W       | 1       | 1           |
                | 2          | (H, W)      | W       | H       | 1           |
                | 3          | (H, W, C)   | W       | H       | C           |

            Args:
                obj (list or object width `__array_interface__` or `__array__`):
                    The object to convert to an image.

                    If the input object is a list, `Image.new_from_list` is used
                    with the given `scale` and `offset`

                    If the input object is an array-like object, a new image is
                    created from the object's data and shape.  The memory is shared
                    except in the following cases:

                    - The object's memory is not contiguous.  In this case, a copy
                      is made by attempting to call the object's `tobytes()` method
                      or its `tostring()` method.

                    - The object is an array of bools, in which case it is
                      converted to a pyvips uchar image with True values becoming
                      255 and False values becoming 0.

                scale (float): Default to 1.0. **Ignored for non-list inputs**.
                    What to divide each pixel by after convolution.  Useful for
                    integer convolution masks.
                offset (float): Default to 0.0.  **Ignored for non-list inputs**.
                    What to subtract from each pixel after convolution.  Useful for
                    integer convolution masks.
                interpretation (str, optional): **Ignored for list inputs** The
                    libvips interpretation of the array. If None, the
                    interpretation defaults to the pyvips one for
                    `Image.new_from_memory`.

                    If 'auto', a heuristic is used to determine a best-guess
                    interpretation as defined in the `_guess_interpretation`
                    function.

                    Must be one of None, 'auto', 'error', 'multiband', 'b-w',
                    'histogram', 'xyz', 'lab', 'cmyk', 'labq', 'rgb', 'cmc', 'lch',
                    'labs', 'srgb', 'yxy', 'fourier', 'rgb16', 'grey16', 'matrix',
                    'scrgb', or 'hsv'

            Returns:
                The new image.

            See Also:
                :func:`_guess_interpretation`
            """
            if isinstance(obj, list):
                return cls.new_from_list(obj, scale, offset)

            if hasattr(obj, '__array_interface__'):
                a = obj.__array_interface__
                shape = a['shape']
                typestr = a['typestr']
                ndim = len(shape)

                # strides is optional
                strides = a.get('strides', None)

                if ndim > 3:
                    raise ValueError('array has more than 3 dimensions')
                if typestr not in TYPESTR_TO_FORMAT:
                    raise ValueError(f'conversion from {typestr} not supported')

                if ndim == 0:
                    width = 1
                    height = 1
                    bands = 1
                elif ndim == 1:
                    width = shape[0]
                    height = 1
                    bands = 1
                elif ndim == 2:
                    height, width = shape
                    bands = 1
                elif ndim == 3:
                    height, width, bands = shape

                format = TYPESTR_TO_FORMAT[typestr]

                if strides is None and hasattr(obj, 'data'):
                    data = obj.data
                else:
                    # To obtain something with a contiguous memory layout
                    if hasattr(obj, 'tobytes'):
                        data = obj.tobytes()
                    elif hasattr(obj, 'tostring'):
                        data = obj.tostring()
                    else:
                        raise TypeError('object has no .tobytes or .tostring')

                im = cls.new_from_memory(
                    data,
                    width,
                    height,
                    bands,
                    format
                )

                if typestr == '|b1':
                    # special case for bool: true in vips is uchar(255)
                    im = im.ifthenelse(255, 0)

                if interpretation is not None:
                    if interpretation == 'auto':
                        interpretation = _guess_interpretation(bands, format)

                    im = im.copy(interpretation=interpretation)

                return im

            elif hasattr(obj, '__array__'):
                # make it into something that *does* define __array_interface__
                return cls.new_from_array(obj.__array__())
            else:
                raise TypeError('does not define __array_interface__ '
                                'or __array__')

        @staticmethod
        def new_from_memory(data, width, height, bands, format):
            """Wrap an image around a memory array.

            Wraps an Image around an area of memory containing a C-style array. For
            example, if the ``data`` memory array contains four bytes with the
            values 1, 2, 3, 4, you can make a one-band, 2x2 uchar image from
            it like this::

                image = Image.new_from_memory(data, 2, 2, 1, 'uchar')

            A reference is kept to the data object, so it will not be
            garbage-collected until the returned image is garbage-collected.

            This method is useful for efficiently transferring images from PIL or
            NumPy into libvips.

            See :meth:`.write_to_memory` for the opposite operation.

            Use :meth:`.copy` to set other image attributes.

            Args:
                data (bytes): A memoryview or buffer object.
                width (int): Image width in pixels.
                height (int): Image height in pixels.
                bands (int): Number of bands.
                format (BandFormat): Band format.

            Returns:
                A new :class:`Image`.

            Raises:
                :class:`.Error`

            """
            format_value = GValue.to_enum(GValue.format_type, format)
            pointer = ffi.from_buffer(data)
            nbytes = data.nbytes if hasattr(data, 'nbytes') else len(data)
            vi = vips_lib.vips_image_new_from_memory(pointer,
                                                     nbytes,
                                                     width, height, bands,
                                                     format_value)
            if vi == ffi.NULL:
                raise Error('unable to make image from memory')

            image = pyvips.Image(vi)

            # keep a secret ref to the underlying object .. this reference will be
            # inherited by things that in turn depend on us, so the memory we are
            # using will not be freed
            image._references.append(data)

            return image

        @staticmethod
        def new_from_source(source, options, **kwargs):
            """Load a formatted image from a source.

            This behaves exactly as :meth:`new_from_file`, but the image is
            loaded from the source rather than from a file.

            Args:
                source (Source): The source to load the image from.
                options (str): Load options as a string. Use ``""`` for no options.

            All loaders support at least the following options:

            Keyword args:
                access (Access): Hint the expected access pattern for the image.
                fail (bool): If set True, the loader will fail with an error on the
                    first serious error in the image. By default, libvips will
                    attempt to read everything it can from a damaged image.

            Returns:
                A new :class:`Image`.

            Raises:
                :class:`.Error`

            """
            pointer = vips_lib.vips_foreign_find_load_source(source.pointer)
            if pointer == ffi.NULL:
                raise Error('unable to load from source')
            name = _to_string(pointer)

            image = pyvips.Operation.call(name, source,
                                          string_options=options, **kwargs)

            # keep a secret ref to the source object .. we need that to stay
            # alive, since it might be a custom source that triggers a python
            # callback
            image._references.append(source)

            return image

        @staticmethod
        def new_temp_file(format):
            """Make a new temporary image.

            Returns an image backed by a temporary file. When written to with
            :func:`Image.write`, a temporary file will be created on disc in the
            specified format. When the image is closed, the file will be deleted
            automatically.

            The file is created in the temporary directory. This is set with
            the environment variable ``TMPDIR``. If this is not set, then on
            Unix systems, vips will default to ``/tmp``. On Windows, vips uses
            ``GetTempPath()`` to find the temporary directory.

            vips uses ``g_mkstemp()`` to make the temporary filename. They
            generally look something like ``"vips-12-EJKJFGH.v"``.

            Args:
                format (str): The format for the temp file, for example
                    ``"%s.v"`` for a vips format file. The ``%s`` is
                    substituted by the file path.

            Returns:
                A new :class:`Image`.

            Raises:
                :class:`.Error`

            """
            vi = vips_lib.vips_image_new_temp_file(_to_bytes(format))
            if vi == ffi.NULL:
                raise Error('unable to make temp file')

            return pyvips.Image(vi)

        def new_from_image(self, value):
            """Make a new image from an existing one.

            A new image is created which has the same size, format, interpretation
            and resolution as ``self``, but with every pixel set to ``value``.

            Args:
                value (float, list[float]): The value for the pixels. Use a
                    single number to make a one-band image; use an array constant
                    to make a many-band image.

            Returns:
                A new :class:`Image`.

            Raises:
                :class:`.Error`

            """
            pixel = (Image.black(1, 1) + value).cast(self.format)
            image = pixel.embed(0, 0, self.width, self.height,
                                extend='copy')
            image = image.copy(interpretation=self.interpretation,
                               xres=self.xres,
                               yres=self.yres,
                               xoffset=self.xoffset,
                               yoffset=self.yoffset)

            return image

        def copy_memory(self):
            """Copy an image to memory.

            A large area of memory is allocated, the image is rendered to that
            memory area, and a new image is returned which wraps that large memory
            area.

            Returns:
                A new :class:`Image`.

            Raises:
                :class:`.Error`

            """
            vi = vips_lib.vips_image_copy_memory(self.pointer)
            if vi == ffi.NULL:
                raise Error('unable to copy to memory')

            return pyvips.Image(vi)

        # writers

        def write_to_file(self, vips_filename, **kwargs):
            """Write an image to a file on disc.

            This method can save images in any format supported by vips. The format
            is selected from the filename suffix. The filename can include embedded
            save options, see :func:`Image.new_from_file`.

            For example::

                image.write_to_file('fred.jpg[Q=95]')

            You can also supply options as keyword arguments, for example::

                image.write_to_file('fred.jpg', Q=95)

            The full set of options available depend upon the load operation that
            will be executed. Try something like::

                $ vips jpegsave

            at the command-line to see a summary of the available options for the
            JPEG saver.

            Args:
                vips_filename (str): The disc file to save the image to, with
                    optional appended arguments.

            Other arguments depend upon the save operation.

            Returns:
                None

            Raises:
                :class:`.Error`

            """
            vips_filename = _to_bytes(vips_filename)
            pointer = vips_lib.vips_filename_get_filename(vips_filename)
            filename = _to_string_copy(pointer)

            pointer = vips_lib.vips_filename_get_options(vips_filename)
            options = _to_string_copy(pointer)

            pointer = vips_lib.vips_foreign_find_save(vips_filename)
            if pointer == ffi.NULL:
                raise Error(f'unable to write to file {vips_filename}')
            name = _to_string(pointer)

            return pyvips.Operation.call(name, self, filename,
                                         string_options=options, **kwargs)

        def write_to_buffer(self, format_string, **kwargs):
            """Write an image to memory.

            This method can save images in any format supported by vips. The format
            is selected from the suffix in the format string. This can include
            embedded save options, see :func:`Image.write_to_file`.

            For example::

                data = image.write_to_buffer('.jpg[Q=95]')

            You can also supply options as keyword arguments, for example::

                data = image.write_to_buffer('.jpg', Q=95)

            The full set of options available depend upon the load operation that
            will be executed. Try something like::

                $ vips jpegsave_buffer

            at the command-line to see a summary of the available options for the
            JPEG saver.

            Args:
                format_string (str): The suffix, plus any string-form arguments.

            Other arguments depend upon the save operation.

            Returns:
                A byte string.

            Raises:
                :class:`.Error`

            """
            format_string = _to_bytes(format_string)

            filename = vips_lib.vips_filename_get_filename(format_string)
            filename = ffi.gc(filename, glib_lib.g_free)

            pointer = vips_lib.vips_filename_get_options(format_string)
            options = _to_string_copy(pointer)

            pointer = ffi.NULL
            if at_least_libvips(8, 9):
                vips_lib.vips_error_freeze()
                pointer = vips_lib.vips_foreign_find_save_target(filename)
                vips_lib.vips_error_thaw()

            if pointer != ffi.NULL:
                name = _to_string(pointer)
                target = pyvips.Target.new_to_memory()
                pyvips.Operation.call(name, self, target,
                                      string_options=options, **kwargs)
                buffer = target.get("blob")
            else:
                pointer = vips_lib.vips_foreign_find_save_buffer(filename)
                if pointer == ffi.NULL:
                    raise Error('unable to write to buffer')

                name = _to_string(pointer)
                buffer = pyvips.Operation.call(name, self,
                                               string_options=options, **kwargs)

            return buffer

        def write_to_target(self, target, format_string, **kwargs):
            """Write an image to a target.

            This method will write the image to the target in the format
            specified in the suffix in the format string. This can include
            embedded save options, see :func:`Image.write_to_file`.

            For example::

                image.write_to_target(target, '.jpg[Q=95]')

            You can also supply options as keyword arguments, for example::

                image.write_to_target(target, '.jpg', Q=95)

            The full set of options available depend upon the save operation that
            will be executed. Try something like::

                $ vips jpegsave_target

            at the command-line to see a summary of the available options for the
            JPEG saver.

            Args:
                target (Target): The target to write the image to
                format_string (str): The suffix, plus any string-form arguments.

            Other arguments depend upon the save operation.

            Returns:
                None

            Raises:
                :class:`.Error`

            """
            format_string = _to_bytes(format_string)

            pointer = vips_lib.vips_filename_get_options(format_string)
            options = _to_string_copy(pointer)

            pointer = vips_lib.vips_foreign_find_save_target(format_string)
            if pointer == ffi.NULL:
                raise Error('unable to write to target')
            name = _to_string(pointer)

            return pyvips.Operation.call(name, self, target,
                                         string_options=options, **kwargs)

        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 write(self, other):
            """Write an image to another image.

            This function writes ``self`` to another image. Use something like
            :func:`Image.new_temp_file` to make an image that can be written to.

            Args:
                other (Image): The :class:`Image` to write to,

            Returns:
                None

            Raises:
                :class:`.Error`

            """
            result = vips_lib.vips_image_write(self.pointer, other.pointer)
            if result != 0:
                raise Error('unable to write to image')

        def invalidate(self):
            """Drop caches on an image, and any downstream images.

            This method drops all pixel caches on an image and on all downstream
            images. Any operations which depend on this image, directly or
            indirectly, are also dropped from the libvips operation cache.

            This method can be useful if you wrap a libvips image around an area
            of memory with :meth:`.new_from_memory` and then change some bytes
            without libvips knowing.

            Returns:
                None

            """
            vips_lib.vips_image_invalidate_all(self.pointer)

        def set_progress(self, progress):
            """Enable progress reporting on an image.

            When progress reporting is enabled, evaluation of the most downstream
            image from this image will report progress using the ::preeval, ::eval,
            and ::posteval signals.

            """
            vips_lib.vips_image_set_progress(self.pointer, progress)

        def set_kill(self, kill):
            """Kill processing of an image.

            Use this to kill evaluation of an image. You can call it from one of
            the progress signals, for example. See :meth:`.set_progress`.

            """
            vips_lib.vips_image_set_kill(self.pointer, kill)

        # get/set metadata

        def get_gainmap(self):
            """Get the image gainmap, if any.

            Get the gainmap associated with this image, or None for no gainmap.
            After updating the gainmap, use :meth:`.set_type` to update the
            `"gainmap"` metadata item.

            Returns:
                The gainmap image.

            Raises:
                None

            """
            if not at_least_libvips(8, 18):
                return None
            else:
                pointer = vips_lib.vips_image_get_gainmap(self.pointer)
                if pointer == ffi.NULL:
                    return None
                else:
                    return pyvips.Image(pointer)

        def get_typeof(self, name):
            """Get the GType of an item of metadata.

            Fetch the GType of a piece of metadata, or 0 if the named item does not
            exist. See :class:`GValue`.

            Args:
                name (str): The name of the piece of metadata to get the type of.

            Returns:
                The ``GType``, or 0.

            Raises:
                None

            """
            # on libvips before 8.5, property types must be fetched separately,
            # since built-in enums were reported as ints
            if not at_least_libvips(8, 5):
                gtype = super(Image, self).get_typeof(name)
                if gtype != 0:
                    return gtype

            return vips_lib.vips_image_get_typeof(self.pointer, _to_bytes(name))

        def get(self, name):
            """Get an item of metadata.

            Fetches an item of metadata as a Python value. For example::

                orientation = image.get('orientation')

            would fetch the image orientation.

            Args:
                name (str): The name of the piece of metadata to get.

            Returns:
                The metadata item as a Python value.

            Raises:
                :class:`.Error`

            """
            # with old libvips, we must fetch properties (as opposed to
            # metadata) via VipsObject
            if not at_least_libvips(8, 5):
                gtype = super(Image, self).get_typeof(name)
                if gtype != 0:
                    return super(Image, self).get(name)

            gv = GValue()
            result = vips_lib.vips_image_get(self.pointer, _to_bytes(name),
                                             gv.pointer)
            if result != 0:
                raise Error(f'unable to get {name}')

            return gv.get()

        def get_fields(self):
            """Get a list of all the metadata fields on an image.

            Returns:
                [string]

            """
            names = []

            if at_least_libvips(8, 5):
                array = vips_lib.vips_image_get_fields(self.pointer)
                i = 0
                while array[i] != ffi.NULL:
                    name = _to_string(array[i])
                    names.append(name)
                    glib_lib.g_free(array[i])
                    i += 1
                glib_lib.g_free(array)

            return names

        def set_type(self, gtype, name, value):
            """Set the type and value of an item of metadata.

            Sets the type and value of an item of metadata. Any old item of the
            same name is removed. See :class:`GValue` for types.

            Args:
                gtype (int): The GType of the metadata item to create.
                name (str): The name of the piece of metadata to create.
                value (mixed): The value to set as a Python value. It is
                    converted to the ``gtype``, if possible.

            Returns:
                None

            Raises:
                None

            """
            gv = GValue()
            gv.set_type(gtype)
            gv.set(value)
            vips_lib.vips_image_set(self.pointer, _to_bytes(name), gv.pointer)

        def set(self, name, value):
            """Set the value of an item of metadata.

            Sets the value of an item of metadata. The metadata item must already
            exist.

            Args:
                name (str): The name of the piece of metadata to set the value of.
                value (mixed): The value to set as a Python value. It is
                    converted to the type of the metadata item, if possible.

            Returns:
                None

            Raises:
                :class:`.Error`

            """
            gtype = self.get_typeof(name)
            if gtype == 0:
                raise Error(f'metadata item {name} does not exist -'
                            ' use set_type() to create and set')
            self.set_type(gtype, name, value)

        def remove(self, name):
            """Remove an item of metadata.

            The named metadata item is removed.

            Args:
                name (str): The name of the piece of metadata to remove.

            Returns:
                None

            Raises:
                None

            """
            return vips_lib.vips_image_remove(self.pointer, _to_bytes(name)) != 0

        def tolist(self):
            """Return a single-band image as a list of lists.

            Returns:
                list of lists of values

            """
            if not self.bands == 1:
                raise NotImplementedError('tolist only implemented for ' +
                                          'single-band images')

            is_complex = self.format in ['complex', 'dpcomplex']

            row_els = self.width if not is_complex else 2 * self.width

            rowfmt = f'{row_els}{FORMAT_TO_PYFORMAT[self.format]}'
            buf = self.write_to_memory()

            lst = [list(row) for row in struct.iter_unpack(rowfmt, buf)]

            if is_complex:
                lst = [[r[i] + 1j*r[i+1] for i in range(0, row_els, 2)]
                       for r in lst]

            return lst

        # Following will be relevant if we expose the buffer interface:
        # @property
        # def __array_interface__(self):
        #     """Return a numpy-standard __array_interface__ dictionary.
        #
        #     This is used by some libraries (PIL, e.g.) to interpret the image
        #     as an array.
        #
        #     See https://numpy.org/doc/stable/reference/arrays.interface.html for
        #     more info.
        #
        #     """
        #     if self.bands == 1:
        #         shape = (self.height, self.width)
        #     else:
        #         shape = (self.height, self.width, self.bands)
        #
        #     typestr = FORMAT_TO_TYPESTR[self.format]
        #
        #     interface = {
        #         'shape': shape,
        #         'strides': None,
        #         'descr': [('', typestr)],
        #         'typestr': typestr,
        #         'version': 3
        #     }
        #
        #     return interface

        def __array__(self, dtype=None, copy=None):
            """Conversion to a NumPy array.

            Args:
                dtype (str or numpy dtype, optional) The dtype to use for the
                    numpy array. If None, the default dtype of the image is used
                    as defined the global `FORMAT_TO_TYPESTR` dictionary.
                copy (bool, optional) If True, always copy the data; if None, copy
                    if required; if False, never copy.

            Returns:
                numpy.ndarray: The array representation of the image.
                    * Single-band images lose their channel axis.
                    * Single-pixel single-band images are converted to a 0D array.

            See https://numpy.org/devdocs/user/basics.dispatch.html for more
            details.

            This enables a :class:`Image` to be used where a numpy array is
            expected, including in plotting and conversion to other array
            container types (pytorch, JAX, dask, etc.), for example.

            `numpy` is a runtime dependency of this function.

            See Also `Image.new_from_array` for the inverse operation. #TODO
            """
            import numpy as np

            # we always generate a new image, so if copy is False, we can't work
            if copy is False:
                raise ValueError

            arr = (
                np.frombuffer(self.write_to_memory(),
                              dtype=FORMAT_TO_TYPESTR[self.format])
                .reshape(self.height, self.width, self.bands)
            )

            if self.bands == 1:
                # flatten single-band images
                arr = arr.squeeze(axis=-1)

                if self.width == 1 and self.height == 1:
                    # flatten single-pixel single-band images
                    arr = arr.squeeze(axis=(0, 1))

            if dtype is not None:
                arr = arr.astype(dtype)

            return arr

        def numpy(self, dtype=None):
            """Convenience function to allow numpy conversion to be at the end
            of a method chain.

            This mimics the behavior of pytorch: ``arr = im.op1().op2().numpy()``

            numpy is a runtime dependency of this function.

            Args:
                dtype (str or numpy dtype): The dtype to use for the numpy array.
                    If None, the default dtype of the image is used.

            Returns:
                numpy.ndarray: The image as a numpy array.

            See Also:

                - :meth:`.__array__`
                - `FORMAT_TO_TYPESTR`: Global dictionary mapping libvips format
                  strings to numpy dtype strings.
            """
            return self.__array__(dtype=dtype)

        def __repr__(self):
            if (
                self.interpretation == "matrix"
                and self.width < 20
                and self.height < 20
                and self.bands == 1
            ):
                array = self.tolist()
                return repr(array)
            else:
                return (f'<pyvips.Image {self.width}x{self.height} {self.format}, '
                        f'{self.bands} bands, {self.interpretation}>')

        def __getattr__(self, name):
            """Divert unknown names to libvips.

            Unknown attributes are first looked up in the image properties as
            accessors, for example::

                width = image.width

            and then in the libvips operation table, where they become method
            calls, for example::

                new_image = image.invert()

            Use :func:`get` to fetch image metadata.

            A ``__getattr__`` on the metatype lets you call static members in the
            same way.

            Args:
                name (str): The name of the piece of metadata to get.

            Returns:
                Mixed.

            Raises:
                :class:`.Error`

            """
            # logger.debug('Image.__getattr__ %s', name)

            # scale and offset have default values
            if name == 'scale':
                if self.get_typeof('scale') != 0:
                    return self.get('scale')
                else:
                    return 1.0

            if name == 'offset':
                if self.get_typeof('offset') != 0:
                    return self.get('offset')
                else:
                    return 0.0

            # look up in props first (but not metadata)
            if super(Image, self).get_typeof(name) != 0:
                return super(Image, self).get(name)

            # does the method exist in libvips?
            try:
                # this will throw an exception if not
                Introspect.get(name)
            except Error:
                # we need to throw this exception for missing methods, eg. numpy
                # checks for this
                raise AttributeError

            @_add_doc(name)
            def call_function(*args, **kwargs):
                return pyvips.Operation.call(name, self, *args, **kwargs)

            return call_function

        # compatibility methods

        @_deprecated('use Image.get() instead')
        def get_value(self, name):
            return self.get(name)

        @_deprecated('use Image.set() instead')
        def set_value(self, name, value):
            self.set(name, value)

        @_deprecated('use Image.scale instead')
        def get_scale(self):
            return self.scale

        @_deprecated('use Image.offset instead')
        def get_offset(self):
            return self.offset

        # support with in the most trivial way

        def __enter__(self):
            return self

        def __exit__(self, type, value, traceback):
            pass

        def __getitem__(self, arg):
            """Overload [] to pull out band elements from an image.

            The following arguments types are accepted:

            * int::

                green = rgb_image[1]

              Will make a new one-band image from band 1 (the middle band).

            * slice::

                last_two = rgb_image[1:]
                last_band = rgb_image[-1]
                middle_few = multiband[1:-2]
                reversed  = multiband[::-1]
                every_other = multiband[::2]
                other_every_other = multiband[1::2]

            * list of int::

                # list of integers
                desired_bands = [1, 2, 2, -1]
                four_band = multiband[desired_bands]

            * list of bool::

                wanted_bands = [True, False, True, True, False]
                three_band = five_band[wanted_bands]

            In the case of integer or slice arguments, the semantics of slicing
            exactly match those of slicing `range(self.bands)`.

            In the case of list arguments, the semantics match those of numpy's
            extended slicing syntax. Thus, lists of booleans must have as many
            elements as there are bands in the image.

            """
            if isinstance(arg, int):
                # raises IndexError for bad integer indices
                i = range(self.bands)[arg]
                n = 1
            elif isinstance(arg, slice):
                band_seq = range(self.bands)[arg]
                if len(band_seq) == 0:
                    raise IndexError('empty slice')

                i = band_seq[0]
                n = len(band_seq)
            elif isinstance(arg, list):
                if not arg:
                    raise IndexError('empty list')

                # n.b. We don't use isinstance because isinstance(True, int)
                # is True!
                if not (all(type(x) == int for x in arg) or  # noqa: E721
                        all(type(x) == bool for x in arg)):  # noqa: E721
                    raise IndexError('list must contain only ints or only bools')

                if isinstance(arg[0], bool):
                    if len(arg) != self.bands:
                        raise IndexError('boolean index must have same ' +
                                         'length as bands')

                    band_seq = [i for i, x in enumerate(arg) if x]
                    n = len(band_seq)
                    if n == 0:
                        raise IndexError('empty boolean index')
                    if n == 1:
                        i = band_seq[0]
                else:
                    all_bands = range(self.bands)
                    # raises IndexError for bad int indices
                    band_seq = [all_bands[i] for i in arg]

                    n = len(band_seq)
                    if n == 1:
                        i = band_seq[0]
            else:
                raise IndexError('argument must be an int, slice, ' +
                                 'list of ints, or list of bools')

            if n == 1:
                # int or 1-element selection
                return self.extract_band(i)
            elif isinstance(arg, slice) and arg.step == 1:
                # sequential multi-band slice
                return self.extract_band(i, n=n)
            else:
                # nonsequential slice, list of ints, or list of bools
                bands = [self.extract_band(x) for x in band_seq]
                return bands[0].bandjoin(bands[1:])

        # overload () to mean fetch pixel

        def __call__(self, x, y):
            """Fetch a pixel value.

            Args:
                x (int): The x coordinate to fetch.
                y (int): The y coordinate to fetch.

            Returns:
                Pixel as an array of floating point numbers.

            Raises:
                :class:`.Error`

            """
            return self.getpoint(x, y)

        # operator overloads

        def __add__(self, other):
            if isinstance(other, pyvips.Image):
                return self.add(other)
            else:
                return self.linear(1, other)

        def __radd__(self, other):
            return self.__add__(other)

        def __sub__(self, other):
            if isinstance(other, pyvips.Image):
                return self.subtract(other)
            else:
                return self.linear(1, _smap(lambda x: -1 * x, other))

        def __rsub__(self, other):
            return self.linear(-1, other)

        def __mul__(self, other):
            if isinstance(other, Image):
                return self.multiply(other)
            else:
                return self.linear(other, 0)

        def __rmul__(self, other):
            return self.__mul__(other)

        # a / const has always been a float in vips, so div and truediv are the
        # same
        def __div__(self, other):
            if isinstance(other, pyvips.Image):
                return self.divide(other)
            else:
                return self.linear(_smap(lambda x: 1.0 / x, other), 0)

        def __rdiv__(self, other):
            return (self ** -1) * other

        def __truediv__(self, other):
            return self.__div__(other)

        def __rtruediv__(self, other):
            return self.__rdiv__(other)

        def __floordiv__(self, other):
            if isinstance(other, pyvips.Image):
                return self.divide(other).floor()
            else:
                return self.linear(_smap(lambda x: 1.0 / x, other), 0).floor()

        def __rfloordiv__(self, other):
            return ((self ** -1) * other).floor()

        def __mod__(self, other):
            if isinstance(other, pyvips.Image):
                return self.remainder(other)
            else:
                return self.remainder_const(other)

        def __pow__(self, other):
            return _call_enum(self, other, 'math2', 'pow')

        def __rpow__(self, other):
            return _call_enum(self, other, 'math2', 'wop')

        def __abs__(self):
            return self.abs()

        def __lshift__(self, other):
            return _call_enum(self, other, 'boolean', 'lshift')

        def __rshift__(self, other):
            return _call_enum(self, other, 'boolean', 'rshift')

        def __and__(self, other):
            return _call_enum(self, other, 'boolean', 'and')

        def __rand__(self, other):
            return self.__and__(other)

        def __or__(self, other):
            return _call_enum(self, other, 'boolean', 'or')

        def __ror__(self, other):
            return self.__or__(other)

        def __xor__(self, other):
            return _call_enum(self, other, 'boolean', 'eor')

        def __rxor__(self, other):
            return self.__xor__(other)

        def __neg__(self):
            return -1 * self

        def __pos__(self):
            return self

        def __invert__(self):
            return self ^ -1

        def __gt__(self, other):
            return _call_enum(self, other, 'relational', 'more')

        def __ge__(self, other):
            return _call_enum(self, other, 'relational', 'moreeq')

        def __lt__(self, other):
            return _call_enum(self, other, 'relational', 'less')

        def __le__(self, other):
            return _call_enum(self, other, 'relational', 'lesseq')

        def __eq__(self, other):
            # _eq version allows comparison to None
            if other is None:
                return False

            return _call_enum(self, other, 'relational', 'equal')

        def __ne__(self, other):
            # _eq version allows comparison to None
            if other is None:
                return True

            return _call_enum(self, other, 'relational', 'noteq')

        def floor(self):
            """Return the largest integral value not greater than the argument."""
            return self.round('floor')

        def ceil(self):
            """Return the smallest integral value not less than the argument."""
            return self.round('ceil')

        def rint(self):
            """Return the nearest integral value."""
            return self.round('rint')

        def bandand(self):
            """AND image bands together."""
            return self.bandbool('and')

        def bandor(self):
            """OR image bands together."""
            return self.bandbool('or')

        def bandeor(self):
            """EOR image bands together."""
            return self.bandbool('eor')

        def bandsplit(self):
            """Split an n-band image into n separate images."""
            return [x for x in self]

        def bandjoin(self, other):
            """Append a set of images or constants bandwise."""
            if not isinstance(other, list):
                other = [other]

            # guard against empty list
            if not other:
                return self

            # if [other] is all numbers, we can use bandjoin_const
            non_number = next((x for x in other
                               if not isinstance(x, numbers.Number)),
                              None)

            if non_number is None:
                return self.bandjoin_const(other)
            else:
                return pyvips.Operation.call('bandjoin', [self] + other)

        def atan2(self, other):
            return _call_enum(self, other, 'math2', 'atan2')

        def get_n_pages(self):
            """Get the number of pages in an image file, or 1.

            This is the number of pages in the file the image was loaded from, not
            the number of pages in the image.

            To get the number of pages in an image, divide the image height by
            the page height.
            """
            if at_least_libvips(8, 8):
                return vips_lib.vips_image_get_n_pages(self.pointer)
            else:
                return self.get("n-pages") \
                    if self.get_typeof("n-pages") != 0 else 1

        def get_page_height(self):
            """Get the page height in a many-page image, or height.
            """
            if at_least_libvips(8, 8):
                return vips_lib.vips_image_get_page_height(self.pointer)
            else:
                if self.get_typeof("page-height") != 0:
                    page_height = self.get("page-height")
                else:
                    page_height = self.height

                if page_height > 0 and \
                    page_height <= self.height and \
                        self.height % page_height == 0:
                    return page_height
                else:
                    return self.height

        def pagesplit(self):
            """Split an N-page image into a list of N separate images.
            """
            page_height = self.get_page_height()
            return [self.crop(0, y, self.width, page_height)
                    for y in range(0, self.height, page_height)]

        def pagejoin(self, other):
            """Join a set of pages vertically to make a multipage image.

            Also sets the page-height property on the result.
            """
            if not isinstance(other, list):
                other = [other]

            n_pages = 1 + len(other)

            image = Image.arrayjoin([self] + other, across=1)
            image = image.copy()
            image.set_type(GValue.gint_type, 'page-height', image.height / n_pages)

            return image

        def composite(self, other, mode, **kwargs):
            """Composite a set of images with a set of modes."""
            if not isinstance(other, list):
                other = [other]
            if not isinstance(mode, list):
                mode = [mode]

            # modes are VipsBlendMode enums, but we have to pass as array of int --
            # we need to map str->int by hand
            mode = [GValue.to_enum(GValue.blend_mode_type, x) for x in mode]

            return pyvips.Operation.call('composite', [self] + other, mode,
                                         **kwargs)

        def bandrank(self, other, **kwargs):
            """Band-wise rank filter a set of images."""
            if not isinstance(other, list):
                other = [other]

            return pyvips.Operation.call('bandrank', [self] + other, **kwargs)

        def maxpos(self):
            """Return the coordinates of the image maximum."""
            v, opts = self.max(x=True, y=True)
            x = opts['x']
            y = opts['y']
            return v, x, y

        def minpos(self):
            """Return the coordinates of the image minimum."""
            v, opts = self.min(x=True, y=True)
            x = opts['x']
            y = opts['y']
            return v, x, y

        def real(self):
            """Return the real part of a complex image."""
            return self.complexget('real')

        def imag(self):
            """Return the imaginary part of a complex image."""
            return self.complexget('imag')

        def polar(self):
            """Return an image converted to polar coordinates."""
            return _run_cmplx(lambda x: x.complex('polar'), self)

        def rect(self):
            """Return an image converted to rectangular coordinates."""
            return _run_cmplx(lambda x: x.complex('rect'), self)

        def conj(self):
            """Return the complex conjugate of an image."""
            return self.complex('conj')

        def sin(self):
            """Return the sine of an image in degrees."""
            return self.math('sin')

        def cos(self):
            """Return the cosine of an image in degrees."""
            return self.math('cos')

        def tan(self):
            """Return the tangent of an image in degrees."""
            return self.math('tan')

        def asin(self):
            """Return the inverse sine of an image in degrees."""
            return self.math('asin')

        def acos(self):
            """Return the inverse cosine of an image in degrees."""
            return self.math('acos')

        def atan(self):
            """Return the inverse tangent of an image in degrees."""
            return self.math('atan')

        def sinh(self):
            """Return the hyperbolic sine of an image in radians."""
            return self.math('sinh')

        def cosh(self):
            """Return the hyperbolic cosine of an image in radians."""
            return self.math('cosh')

        def tanh(self):
            """Return the hyperbolic tangent of an image in radians."""
            return self.math('tanh')

        def asinh(self):
            """Return the inverse hyperbolic sine of an image in radians."""
            return self.math('asinh')

        def acosh(self):
            """Return the inverse hyperbolic cosine of an image in radians."""
            return self.math('acosh')

        def atanh(self):
            """Return the inverse hyperbolic tangent of an image in radians."""
            return self.math('atanh')

        def log(self):
            """Return the natural log of an image."""
            return self.math('log')

        def log10(self):
            """Return the log base 10 of an image."""
            return self.math('log10')

        def exp(self):
            """Return e ** pixel."""
            return self.math('exp')

        def exp10(self):
            """Return 10 ** pixel."""
            return self.math('exp10')

        def erode(self, mask):
            """Erode with a structuring element."""
            return self.morph(mask, 'erode')

        def dilate(self, mask):
            """Dilate with a structuring element."""
            return self.morph(mask, 'dilate')

        def median(self, size):
            """size x size median filter."""
            return self.rank(size, size, (size * size) / 2)

        def fliphor(self):
            """Flip horizontally."""
            return self.flip('horizontal')

        def flipver(self):
            """Flip vertically."""
            return self.flip('vertical')

        def rot90(self):
            """Rotate 90 degrees clockwise."""
            return self.rot('d90')

        def rot180(self):
            """Rotate 180 degrees."""
            return self.rot('d180')

        def rot270(self):
            """Rotate 270 degrees clockwise."""
            return self.rot('d270')

        def hasalpha(self):
            """True if the image has an alpha channel."""
            return vips_lib.vips_image_hasalpha(self.pointer)

        def addalpha(self):
            """Add an alpha channel."""
            if self.interpretation == 'grey16' or self.interpretation == 'rgb16':
                max_alpha = 65535
            elif self.interpretation == 'scrgb':
                max_alpha = 1.0
            else:
                max_alpha = 255
            return self.bandjoin(max_alpha)

        # we need different _imageize rules for this operator ... we need to
        # _imageize in1 and in2 to match each other first

        @_add_doc('ifthenelse')
        def ifthenelse(self, in1, in2, **kwargs):
            for match_image in [in1, in2, self]:
                if isinstance(match_image, pyvips.Image):
                    break

            if not isinstance(in1, pyvips.Image):
                in1 = Image._imageize(match_image, in1)
            if not isinstance(in2, pyvips.Image):
                in2 = Image._imageize(match_image, in2)

            return pyvips.Operation.call('ifthenelse', self, in1, in2, **kwargs)

        def scaleimage(self, **kwargs):
            """Scale an image to 0 - 255.

            This is the libvips ``scale`` operation, renamed to avoid a clash with
            the ``scale`` for convolution masks.

            Keyword args:
                exp (float): Exponent for log scale.
                log (bool): Switch to turn on log scaling.

            Returns:
                A new :class:`Image`.

            Raises:
                :class:`.Error`

            """
            return pyvips.Operation.call('scale', self, **kwargs)

    __all__ = ['Image']