How to use the wand.api.library.MagickSetIteratorIndex function in Wand

drawing(image)

        is equivalent to the following code which calls :meth:`draw()` method::

            drawing.draw(image)

        :param image: the image to be drawn
        :type image: :class:`~wand.image.BaseImage`

        """
        if not isinstance(image, BaseImage):
            raise TypeError('image must be a wand.image.BaseImage instance,'
                            ' not ' + repr(image))
        if isinstance(image, SingleImage):
            previous = library.MagickGetIteratorIndex(image.container.wand)
            library.MagickSetIteratorIndex(image.container.wand, image.index)
            res = library.MagickDrawImage(image.container.wand, self.resource)
            library.MagickSetIteratorIndex(image.container.wand, previous)
        else:
            res = library.MagickDrawImage(image.wand, self.resource)
        if not res:
            self.raise_exception()

try:
                filter = FILTER_TYPES.index(filter)
            except IndexError:
                raise ValueError(repr(filter) + ' is an invalid filter type; '
                                 'choose on in ' + repr(FILTER_TYPES))
        elif (isinstance(filter, numbers.Integral) and
              not (0 <= filter < len(FILTER_TYPES))):
            raise ValueError(repr(filter) + ' is an invalid filter type')
        blur = ctypes.c_double(float(blur))
        if self.animation:
            self.wand = library.MagickCoalesceImages(self.wand)
            library.MagickSetLastIterator(self.wand)
            n = library.MagickGetIteratorIndex(self.wand)
            library.MagickResetIterator(self.wand)
            for i in xrange(n + 1):
                library.MagickSetIteratorIndex(self.wand, i)
                library.MagickResizeImage(self.wand, width, height,
                                          filter, blur)
            library.MagickSetSize(self.wand, width, height)
        else:
            r = library.MagickResizeImage(self.wand, width, height,
                                          filter, blur)
            library.MagickSetSize(self.wand, width, height)
            if not r:
                self.raise_exception()

:param transparency: the percentage fade that should be performed on
                             the image, from 0.0 to 1.0
        :type transparency: :class:`numbers.Real`

        .. versionadded:: 0.2.0

        """
        if transparency:
            t = ctypes.c_double(float(self.quantum_range *
                                      float(transparency)))
            if t.value > self.quantum_range or t.value < 0:
                raise ValueError('transparency must be a numbers.Real value ' +
                                 'between 0.0 and 1.0')
            # Set the wand to image zero, in case there are multiple images
            # in it
            library.MagickSetIteratorIndex(self.wand, 0)
            # Change the pixel representation of the image
            # to RGB with an alpha channel
            library.MagickSetImageType(self.wand,
                                       IMAGE_TYPES.index('truecolormatte'))
            # Perform the black channel subtraction
            library.MagickEvaluateImageChannel(self.wand,
                                               CHANNELS['opacity'],
                                               EVALUATE_OPS.index('subtract'),
                                               t)
            self.raise_exception()

is equivalent to the following code which calls :meth:`draw()` method::

            drawing.draw(image)

        :param image: the image to be drawn
        :type image: :class:`~wand.image.BaseImage`

        """
        if not isinstance(image, BaseImage):
            raise TypeError('image must be a wand.image.BaseImage instance,'
                            ' not ' + repr(image))
        if isinstance(image, SingleImage):
            previous = library.MagickGetIteratorIndex(image.container.wand)
            library.MagickSetIteratorIndex(image.container.wand, image.index)
            res = library.MagickDrawImage(image.container.wand, self.resource)
            library.MagickSetIteratorIndex(image.container.wand, previous)
        else:
            res = library.MagickDrawImage(image.wand, self.resource)
        if not res:
            self.raise_exception()

if background is None:
            background = Color('transparent')
        elif not isinstance(background, Color):
            raise TypeError('background must be a wand.color.Color instance, '
                            'not ' + repr(background))
        if not isinstance(degree, numbers.Real):
            raise TypeError('degree must be a numbers.Real value, not ' +
                            repr(degree))
        with background:
            if self.animation:
                self.wand = library.MagickCoalesceImages(self.wand)
                library.MagickSetLastIterator(self.wand)
                n = library.MagickGetIteratorIndex(self.wand)
                library.MagickResetIterator(self.wand)
                for i in range(0, n + 1):
                    library.MagickSetIteratorIndex(self.wand, i)
                    library.MagickRotateImage(self.wand,
                                              background.resource,
                                              degree)
                    if reset_coords:
                        library.MagickResetImagePage(self.wand, None)
            else:
                result = library.MagickRotateImage(self.wand,
                                                   background.resource,
                                                   degree)
                if not result:
                    self.raise_exception()
                if reset_coords:
                    self.reset_coords()

# Also verify that only ASCII characters are included
        try:
            crop = crop.encode('ascii')
        except UnicodeEncodeError:
            raise ValueError('crop must only contain ascii-encodable ' +
                             'characters.')
        try:
            resize = resize.encode('ascii')
        except UnicodeEncodeError:
            raise ValueError('resize must only contain ascii-encodable ' +
                             'characters.')
        if self.animation:
            new_wand = library.MagickCoalesceImages(self.wand)
            length = len(self.sequence)
            for i in xrange(length):
                library.MagickSetIteratorIndex(new_wand, i)
                if i:
                    library.MagickAddImage(
                        new_wand,
                        library.MagickTransformImage(new_wand, crop, resize)
                    )
                else:
                    new_wand = library.MagickTransformImage(new_wand,
                                                            crop,
                                                            resize)
            self.sequence.instances = []
        else:
            new_wand = library.MagickTransformImage(self.wand, crop, resize)
        if not new_wand:
            self.raise_exception()
        self.wand = new_wand

elif not isinstance(height, numbers.Integral):
            raise TypeError('height must be a natural number, not ' +
                            repr(height))
        elif width < 1:
            raise ValueError('width must be a natural number, not ' +
                             repr(width))
        elif height < 1:
            raise ValueError('height must be a natural number, not ' +
                             repr(height))
        if self.animation:
            self.wand = library.MagickCoalesceImages(self.wand)
            library.MagickSetLastIterator(self.wand)
            n = library.MagickGetIteratorIndex(self.wand)
            library.MagickResetIterator(self.wand)
            for i in xrange(n + 1):
                library.MagickSetIteratorIndex(self.wand, i)
                library.MagickSampleImage(self.wand, width, height)
            library.MagickSetSize(self.wand, width, height)
        else:
            r = library.MagickSampleImage(self.wand, width, height)
            library.MagickSetSize(self.wand, width, height)
            if not r:
                self.raise_exception()

slice_ = self.validate_slice(index)
            return [self[i] for i in xrange(slice_.start, slice_.stop)]
        index = self.validate_position(index)
        instances = self.instances
        instances_length = len(instances)
        if index < instances_length:
            instance = instances[index]
            if (instance is not None and
                    getattr(instance, 'c_resource', None) is not None):
                return instance
        else:
            number_to_extend = index - instances_length + 1
            instances.extend(None for _ in xrange(number_to_extend))
        wand = self.image.wand
        tmp_idx = library.MagickGetIteratorIndex(wand)
        library.MagickSetIteratorIndex(wand, index)
        image = library.GetImageFromMagickWand(wand)
        exc = libmagick.AcquireExceptionInfo()
        single_image = libmagick.CloneImages(image, binary(str(index)), exc)
        libmagick.DestroyExceptionInfo(exc)
        single_wand = library.NewMagickWandFromImage(single_image)
        single_image = libmagick.DestroyImage(single_image)
        library.MagickSetIteratorIndex(wand, tmp_idx)
        instance = SingleImage(single_wand, self.image, image)
        self.instances[index] = instance
        return instance

if (instance is not None and
                    getattr(instance, 'c_resource', None) is not None):
                return instance
        else:
            number_to_extend = index - instances_length + 1
            instances.extend(None for _ in xrange(number_to_extend))
        wand = self.image.wand
        tmp_idx = library.MagickGetIteratorIndex(wand)
        library.MagickSetIteratorIndex(wand, index)
        image = library.GetImageFromMagickWand(wand)
        exc = libmagick.AcquireExceptionInfo()
        single_image = libmagick.CloneImages(image, binary(str(index)), exc)
        libmagick.DestroyExceptionInfo(exc)
        single_wand = library.NewMagickWandFromImage(single_image)
        single_image = libmagick.DestroyImage(single_image)
        library.MagickSetIteratorIndex(wand, tmp_idx)
        instance = SingleImage(single_wand, self.image, image)
        self.instances[index] = instance
        return instance