コード例 #1
0
    def update(self, auto_contrast=None, **kwargs):
        ims = self.ax.images
        # Turn on centre_colormap if a diverging colormap is used.
        if self.centre_colormap == "auto":
            if "cmap" in kwargs:
                cmap = kwargs["cmap"]
            elif ims:
                cmap = ims[0].get_cmap().name
            else:
                cmap = plt.cm.get_cmap().name
            if cmap in MPL_DIVERGING_COLORMAPS:
                self.centre_colormap = True
            else:
                self.centre_colormap = False
        redraw_colorbar = False
        data = rgb_tools.rgbx2regular_array(
            self.data_function(axes_manager=self.axes_manager),
            plot_friendly=True)
        numrows, numcols = data.shape[:2]
        for marker in self.ax_markers:
            marker.update()
        if len(data.shape) == 2:

            def format_coord(x, y):
                try:
                    col = self.xaxis.value2index(x)
                except ValueError:  # out of axes limits
                    col = -1
                try:
                    row = self.yaxis.value2index(y)
                except ValueError:
                    row = -1
                if col >= 0 and row >= 0:
                    z = data[row, col]
                    return 'x=%1.4g, y=%1.4g, intensity=%1.4g' % (x, y, z)
                else:
                    return 'x=%1.4g, y=%1.4g' % (x, y)

            self.ax.format_coord = format_coord
        if (auto_contrast is True
                or auto_contrast is None and self.auto_contrast is True):
            vmax, vmin = self.vmax, self.vmin
            self.optimize_contrast(data)
            if vmax == vmin and self.vmax != self.vmin and ims:
                redraw_colorbar = True
                ims[0].autoscale()

        if 'complex' in data.dtype.name:
            data = np.log(np.abs(data))
        if self.plot_indices is True:
            self._text.set_text(self.axes_manager.indices)
        if self.no_nans:
            data = np.nan_to_num(data)
        if self.centre_colormap:
            vmin, vmax = centre_colormap_values(self.vmin, self.vmax)
        else:
            vmin, vmax = self.vmin, self.vmax
        if ims:
            ims[0].set_data(data)
            ims[0].norm.vmax, ims[0].norm.vmin = vmax, vmin
            if redraw_colorbar is True:
                ims[0].autoscale()
                self._colorbar.draw_all()
                self._colorbar.solids.set_animated(True)
            else:
                ims[0].changed()
            self._draw_animated()
            # It seems that nans they're simply not drawn, so simply replacing
            # the data does not update the value of the nan pixels to the
            # background color. We redraw everything as a workaround.
            if np.isnan(data).any():
                self.figure.canvas.draw()
        else:
            new_args = {
                'interpolation': 'nearest',
                'vmin': vmin,
                'vmax': vmax,
                'extent': self._extent,
                'aspect': self._aspect,
                'animated': True
            }
            new_args.update(kwargs)
            self.ax.imshow(data, **new_args)
            self.figure.canvas.draw()
コード例 #2
0
ファイル: image.py プロジェクト: temcode/hyperspy
    def update(self, auto_contrast=None, **kwargs):
        ims = self.ax.images
        # Turn on centre_colormap if a diverging colormap is used.
        if self.centre_colormap == "auto":
            if "cmap" in kwargs:
                cmap = kwargs["cmap"]
            elif ims:
                cmap = ims[0].get_cmap().name
            else:
                cmap = plt.cm.get_cmap().name
            if cmap in MPL_DIVERGING_COLORMAPS:
                self.centre_colormap = True
            else:
                self.centre_colormap = False
        redraw_colorbar = False
        data = rgb_tools.rgbx2regular_array(
            self.data_function(axes_manager=self.axes_manager),
            plot_friendly=True)
        numrows, numcols = data.shape[:2]
        for marker in self.ax_markers:
            marker.update()
        if len(data.shape) == 2:
            def format_coord(x, y):
                try:
                    col = self.xaxis.value2index(x)
                except ValueError:  # out of axes limits
                    col = -1
                try:
                    row = self.yaxis.value2index(y)
                except ValueError:
                    row = -1
                if col >= 0 and row >= 0:
                    z = data[row, col]
                    return 'x=%1.4g, y=%1.4g, intensity=%1.4g' % (x, y, z)
                else:
                    return 'x=%1.4g, y=%1.4g' % (x, y)
            self.ax.format_coord = format_coord
        if (auto_contrast is True or
                auto_contrast is None and self.auto_contrast is True):
            vmax, vmin = self.vmax, self.vmin
            self.optimize_contrast(data)
            if vmax == vmin and self.vmax != self.vmin and ims:
                redraw_colorbar = True
                ims[0].autoscale()

        if 'complex' in data.dtype.name:
            data = np.log(np.abs(data))
        if self.plot_indices is True:
            self._text.set_text(self.axes_manager.indices)
        if self.no_nans:
            data = np.nan_to_num(data)
        if self.centre_colormap:
            vmin, vmax = centre_colormap_values(self.vmin, self.vmax)
        else:
            vmin, vmax = self.vmin, self.vmax
        if ims:
            ims[0].set_data(data)
            ims[0].norm.vmax, ims[0].norm.vmin = vmax, vmin
            if redraw_colorbar is True:
                ims[0].autoscale()
                self._colorbar.draw_all()
                self._colorbar.solids.set_animated(True)
            else:
                ims[0].changed()
            self._draw_animated()
            # It seems that nans they're simply not drawn, so simply replacing
            # the data does not update the value of the nan pixels to the
            # background color. We redraw everything as a workaround.
            if np.isnan(data).any():
                self.figure.canvas.draw()
        else:
            new_args = {'interpolation': 'nearest',
                        'vmin': vmin,
                        'vmax': vmax,
                        'extent': self._extent,
                        'aspect': self._aspect,
                        'animated': True}
            new_args.update(kwargs)
            self.ax.imshow(data,
                           **new_args)
            self.figure.canvas.draw()
コード例 #3
0
ファイル: utils.py プロジェクト: jerevon/hyperspy
def plot_images(images,
                cmap=None,
                no_nans=False,
                per_row=3,
                label='auto',
                labelwrap=30,
                suptitle=None,
                suptitle_fontsize=18,
                colorbar='multi',
                centre_colormap="auto",
                saturated_pixels=0,
                scalebar=None,
                scalebar_color='white',
                axes_decor='all',
                padding=None,
                tight_layout=False,
                aspect='auto',
                min_asp=0.1,
                namefrac_thresh=0.4,
                fig=None,
                *args,
                **kwargs):
    """Plot multiple images as sub-images in one figure.

        Parameters
        ----------
        images : list
            `images` should be a list of Signals (Images) to plot
            If any signal is not an image, a ValueError will be raised
            multi-dimensional images will have each plane plotted as a separate
            image
        cmap : matplotlib colormap, optional
            The colormap used for the images, by default read from pyplot
        no_nans : bool, optional
            If True, set nans to zero for plotting.
        per_row : int, optional
            The number of plots in each row
        label : None, str, or list of str, optional
            Control the title labeling of the plotted images.
            If None, no titles will be shown.
            If 'auto' (default), function will try to determine suitable titles
            using Image titles, falling back to the 'titles' option if no good
            short titles are detected.
            Works best if all images to be plotted have the same beginning
            to their titles.
            If 'titles', the title from each image's metadata.General.title
            will be used.
            If any other single str, images will be labeled in sequence using
            that str as a prefix.
            If a list of str, the list elements will be used to determine the
            labels (repeated, if necessary).
        labelwrap : int, optional
            integer specifying the number of characters that will be used on
            one line
            If the function returns an unexpected blank figure, lower this
            value to reduce overlap of the labels between each figure
        suptitle : str, optional
            Title to use at the top of the figure. If called with label='auto',
            this parameter will override the automatically determined title.
        suptitle_fontsize : int, optional
            Font size to use for super title at top of figure
        colorbar : {'multi', None, 'single'}
            Controls the type of colorbars that are plotted.
            If None, no colorbar is plotted.
            If 'multi' (default), individual colorbars are plotted for each
            (non-RGB) image
            If 'single', all (non-RGB) images are plotted on the same scale,
            and one colorbar is shown for all
        centre_colormap : {"auto", True, False}
            If True the centre of the color scheme is set to zero. This is
            specially useful when using diverging color schemes. If "auto"
            (default), diverging color schemes are automatically centred.
        saturated_pixels: scalar
            The percentage of pixels that are left out of the bounds.  For example,
            the low and high bounds of a value of 1 are the 0.5% and 99.5%
            percentiles. It must be in the [0, 100] range.
        scalebar : {None, 'all', list of ints}, optional
            If None (or False), no scalebars will be added to the images.
            If 'all', scalebars will be added to all images.
            If list of ints, scalebars will be added to each image specified.
        scalebar_color : str, optional
            A valid MPL color string; will be used as the scalebar color
        axes_decor : {'all', 'ticks', 'off', None}, optional
            Controls how the axes are displayed on each image; default is 'all'
            If 'all', both ticks and axis labels will be shown
            If 'ticks', no axis labels will be shown, but ticks/labels will
            If 'off', all decorations and frame will be disabled
            If None, no axis decorations will be shown, but ticks/frame will
        padding : None or dict, optional
            This parameter controls the spacing between images.
            If None, default options will be used
            Otherwise, supply a dictionary with the spacing options as
            keywords and desired values as values
            Values should be supplied as used in pyplot.subplots_adjust(),
            and can be:
                'left', 'bottom', 'right', 'top', 'wspace' (width),
                and 'hspace' (height)
        tight_layout : bool, optional
            If true, hyperspy will attempt to improve image placement in
            figure using matplotlib's tight_layout
            If false, repositioning images inside the figure will be left as
            an exercise for the user.
        aspect : str or numeric, optional
            If 'auto', aspect ratio is auto determined, subject to min_asp.
            If 'square', image will be forced onto square display.
            If 'equal', aspect ratio of 1 will be enforced.
            If float (or int/long), given value will be used.
        min_asp : float, optional
            Minimum aspect ratio to be used when plotting images
        namefrac_thresh : float, optional
            Threshold to use for auto-labeling. This parameter controls how
            much of the titles must be the same for the auto-shortening of
            labels to activate. Can vary from 0 to 1. Smaller values
            encourage shortening of titles by auto-labeling, while larger
            values will require more overlap in titles before activing the
            auto-label code.
        fig : mpl figure, optional
            If set, the images will be plotted to an existing MPL figure
        *args, **kwargs, optional
            Additional arguments passed to matplotlib.imshow()

        Returns
        -------
        axes_list : list
            a list of subplot axes that hold the images

        See Also
        --------
        plot_spectra : Plotting of multiple spectra
        plot_signals : Plotting of multiple signals
        plot_histograms : Compare signal histograms

        Notes
        -----
        `interpolation` is a useful parameter to provide as a keyword
        argument to control how the space between pixels is interpolated. A
        value of ``'nearest'`` will cause no interpolation between pixels.

        `tight_layout` is known to be quite brittle, so an option is provided
        to disable it. Turn this option off if output is not as expected,
        or try adjusting `label`, `labelwrap`, or `per_row`

    """
    from hyperspy.drawing.widgets import Scale_Bar
    from hyperspy.misc import rgb_tools
    from hyperspy.signal import Signal

    if isinstance(images, Signal) and len(images) is 1:
        images.plot()
        ax = plt.gca()
        return ax
    elif not isinstance(images, (list, tuple, Signal)):
        raise ValueError("images must be a list of image signals or "
                         "multi-dimensional signal."
                         " " + repr(type(images)) + " was given.")

    # Get default colormap from pyplot:
    if cmap is None:
        cmap = plt.get_cmap().name
    elif isinstance(cmap, mpl.colors.Colormap):
        cmap = cmap.name
    if centre_colormap == "auto":
        if cmap in MPL_DIVERGING_COLORMAPS:
            centre_colormap = True
        else:
            centre_colormap = False

    # If input is >= 1D signal (e.g. for multi-dimensional plotting),
    # copy it and put it in a list so labeling works out as (x,y) when plotting
    if isinstance(
            images, Signal) and images.axes_manager.navigation_dimension > 0:
        images = [images._deepcopy_with_new_data(images.data)]

    n = 0
    for i, sig in enumerate(images):
        if sig.axes_manager.signal_dimension != 2:
            raise ValueError("This method only plots signals that are images. "
                             "The signal dimension must be equal to 2. "
                             "The signal at position " + repr(i) +
                             " was " + repr(sig) + ".")
        # increment n by the navigation size, or by 1 if the navigation size is
        # <= 0
        n += (sig.axes_manager.navigation_size
              if sig.axes_manager.navigation_size > 0
              else 1)

    # Sort out the labeling:
    div_num = 0
    all_match = False
    shared_titles = False
    user_labels = False

    if label is None:
        pass
    elif label is 'auto':
        # Use some heuristics to try to get base string of similar titles
        label_list = [x.metadata.General.title for x in images]

        # Find the shortest common string between the image titles
        # and pull that out as the base title for the sequence of images
        # array in which to store arrays
        res = np.zeros((len(label_list), len(label_list[0]) + 1))
        res[:, 0] = 1

        # j iterates the strings
        for j in range(len(label_list)):
            # i iterates length of substring test
            for i in range(1, len(label_list[0]) + 1):
                # stores whether or not characters in title match
                res[j, i] = label_list[0][:i] in label_list[j]

        # sum up the results (1 is True, 0 is False) and create
        # a substring based on the minimum value (this will be
        # the "smallest common string" between all the titles
        if res.all():
            basename = label_list[0]
            div_num = len(label_list[0])
            all_match = True
        else:
            div_num = int(min(np.sum(res, 1)))
            basename = label_list[0][:div_num - 1]
            all_match = False

        # trim off any '(' or ' ' characters at end of basename
        if div_num > 1:
            while True:
                if basename[len(basename) - 1] == '(':
                    basename = basename[:-1]
                elif basename[len(basename) - 1] == ' ':
                    basename = basename[:-1]
                else:
                    break

        # namefrac is ratio of length of basename to the image name
        # if it is high (e.g. over 0.5), we can assume that all images
        # share the same base
        if len(label_list[0]) > 0:
            namefrac = float(len(basename)) / len(label_list[0])
        else:
            # If label_list[0] is empty, it means there was probably no
            # title set originally, so nothing to share
            namefrac = 0

        if namefrac > namefrac_thresh:
            # there was a significant overlap of label beginnings
            shared_titles = True
            # only use new suptitle if one isn't specified already
            if suptitle is None:
                suptitle = basename

        else:
            # there was not much overlap, so default back to 'titles' mode
            shared_titles = False
            label = 'titles'
            div_num = 0

    elif label is 'titles':
        # Set label_list to each image's pre-defined title
        label_list = [x.metadata.General.title for x in images]

    elif isinstance(label, basestring):
        # Set label_list to an indexed list, based off of label
        label_list = [label + " " + repr(num) for num in range(n)]

    elif isinstance(label, list) and all(
            isinstance(x, basestring) for x in label):
        label_list = label
        user_labels = True
        # If list of labels is longer than the number of images, just use the
        # first n elements
        if len(label_list) > n:
            del label_list[n:]
        if len(label_list) < n:
            label_list *= (n / len(label_list)) + 1
            del label_list[n:]

    else:
        # catch all others to revert to default if bad input
        print "Did not understand input of labels. Defaulting to image titles."
        label_list = [x.metadata.General.title for x in images]

    # Determine appropriate number of images per row
    rows = int(np.ceil(n / float(per_row)))
    if n < per_row:
        per_row = n

    # Set overall figure size and define figure (if not pre-existing)
    if fig is None:
        k = max(plt.rcParams['figure.figsize']) / max(per_row, rows)
        f = plt.figure(figsize=(tuple(k * i for i in (per_row, rows))))
    else:
        f = fig

    # Initialize list to hold subplot axes
    axes_list = []

    # Initialize list of rgb tags
    isrgb = [False] * len(images)

    # Check to see if there are any rgb images in list
    # and tag them using the isrgb list
    for i, img in enumerate(images):
        if rgb_tools.is_rgbx(img.data):
            isrgb[i] = True

    # Determine how many non-rgb Images there are
    non_rgb = list(itertools.compress(images, [not j for j in isrgb]))
    if len(non_rgb) is 0 and colorbar is not None:
        colorbar = None
        print "Sorry, colorbar is not implemented for RGB images."

    # Find global min and max values of all the non-rgb images for use with
    # 'single' scalebar
    if colorbar is 'single':
        global_max = max([i.data.max() for i in non_rgb])
        global_min = min([i.data.min() for i in non_rgb])
        g_vmin, g_vmax = contrast_stretching(i.data, saturated_pixels)
        if centre_colormap:
            g_vmin, g_vmax = centre_colormap_values(g_vmin, g_vmax)

    # Check if we need to add a scalebar for some of the images
    if isinstance(scalebar, list) and all(isinstance(x, int)
                                          for x in scalebar):
        scalelist = True
    else:
        scalelist = False

    idx = 0
    ax_im_list = [0] * len(isrgb)
    # Loop through each image, adding subplot for each one
    for i, ims in enumerate(images):
        # Get handles for the signal axes and axes_manager
        axes_manager = ims.axes_manager
        if axes_manager.navigation_dimension > 0:
            ims = ims._deepcopy_with_new_data(ims.data)
        for j, im in enumerate(ims):
            idx += 1
            ax = f.add_subplot(rows, per_row, idx)
            axes_list.append(ax)
            data = im.data

            # Enable RGB plotting
            if rgb_tools.is_rgbx(data):
                data = rgb_tools.rgbx2regular_array(data, plot_friendly=True)
                l_vmin, l_vmax = None, None
            else:
                data = im.data
                # Find min and max for contrast
                l_vmin, l_vmax = contrast_stretching(data, saturated_pixels)
                if centre_colormap:
                    l_vmin, l_vmax = centre_colormap_values(l_vmin, l_vmax)

            # Remove NaNs (if requested)
            if no_nans:
                data = np.nan_to_num(data)

            # Get handles for the signal axes and axes_manager
            axes_manager = im.axes_manager
            axes = axes_manager.signal_axes

            # Set dimensions of images
            xaxis = axes[0]
            yaxis = axes[1]

            extent = (
                xaxis.low_value,
                xaxis.high_value,
                yaxis.high_value,
                yaxis.low_value,
            )

            if not isinstance(aspect, (int, long, float)) and aspect not in [
                    'auto', 'square', 'equal']:
                print 'Did not understand aspect ratio input. ' \
                      'Using \'auto\' as default.'
                aspect = 'auto'

            if aspect is 'auto':
                if float(yaxis.size) / xaxis.size < min_asp:
                    factor = min_asp * float(xaxis.size) / yaxis.size
                elif float(yaxis.size) / xaxis.size > min_asp ** -1:
                    factor = min_asp ** -1 * float(xaxis.size) / yaxis.size
                else:
                    factor = 1
                asp = np.abs(factor * float(xaxis.scale) / yaxis.scale)
            elif aspect is 'square':
                asp = abs(extent[1] - extent[0]) / abs(extent[3] - extent[2])
            elif aspect is 'equal':
                asp = 1
            elif isinstance(aspect, (int, long, float)):
                asp = aspect
            if ('interpolation' in kwargs.keys()) is False:
                kwargs['interpolation'] = 'nearest'

            # Plot image data, using vmin and vmax to set bounds,
            # or allowing them to be set automatically if using individual
            # colorbars
            if colorbar is 'single' and not isrgb[i]:
                axes_im = ax.imshow(data,
                                    cmap=cmap, extent=extent,
                                    vmin=g_vmin, vmax=g_vmax,
                                    aspect=asp,
                                    *args, **kwargs)
                ax_im_list[i] = axes_im
            else:
                axes_im = ax.imshow(data,
                                    cmap=cmap, extent=extent,
                                    vmin=l_vmin, vmax=l_vmax,
                                    aspect=asp,
                                    *args, **kwargs)
                ax_im_list[i] = axes_im

            # If an axis trait is undefined, shut off :
            if isinstance(xaxis.units, trait_base._Undefined) or  \
                    isinstance(yaxis.units, trait_base._Undefined) or \
                    isinstance(xaxis.name, trait_base._Undefined) or \
                    isinstance(yaxis.name, trait_base._Undefined):
                if axes_decor is 'all':
                    warnings.warn(
                        'Axes labels were requested, but one '
                        'or both of the '
                        'axes units and/or name are undefined. '
                        'Axes decorations have been set to '
                        '\'ticks\' instead.')
                    axes_decor = 'ticks'
            # If all traits are defined, set labels as appropriate:
            else:
                ax.set_xlabel(axes[0].name + " axis (" + axes[0].units + ")")
                ax.set_ylabel(axes[1].name + " axis (" + axes[1].units + ")")

            if label:
                if all_match:
                    title = ''
                elif shared_titles:
                    title = label_list[i][div_num - 1:]
                else:
                    if len(ims) == n:
                        # This is true if we are plotting just 1
                        # multi-dimensional Image
                        title = label_list[idx - 1]
                    elif user_labels:
                        title = label_list[idx - 1]
                    else:
                        title = label_list[i]

                if ims.axes_manager.navigation_size > 1 and not user_labels:
                    title += " %s" % str(ims.axes_manager.indices)

                ax.set_title(textwrap.fill(title, labelwrap))

            # Set axes decorations based on user input
            if axes_decor is 'off':
                ax.axis('off')
            elif axes_decor is 'ticks':
                ax.set_xlabel('')
                ax.set_ylabel('')
            elif axes_decor is 'all':
                pass
            elif axes_decor is None:
                ax.set_xlabel('')
                ax.set_ylabel('')
                ax.set_xticklabels([])
                ax.set_yticklabels([])

            # If using independent colorbars, add them
            if colorbar is 'multi' and not isrgb[i]:
                div = make_axes_locatable(ax)
                cax = div.append_axes("right", size="5%", pad=0.05)
                plt.colorbar(axes_im, cax=cax)

            # Add scalebars as necessary
            if (scalelist and i in scalebar) or scalebar is 'all':
                ax.scalebar = Scale_Bar(
                    ax=ax,
                    units=axes[0].units,
                    color=scalebar_color,
                )

    # If using a single colorbar, add it, and do tight_layout, ensuring that
    # a colorbar is only added based off of non-rgb Images:
    if colorbar is 'single':
        foundim = None
        for i in range(len(isrgb)):
            if (not isrgb[i]) and foundim is None:
                foundim = i

        if foundim is not None:
            f.subplots_adjust(right=0.8)
            cbar_ax = f.add_axes([0.9, 0.1, 0.03, 0.8])
            f.colorbar(ax_im_list[foundim], cax=cbar_ax)
            if tight_layout:
                # tight_layout, leaving room for the colorbar
                plt.tight_layout(rect=[0, 0, 0.9, 1])
        elif tight_layout:
            plt.tight_layout()

    elif tight_layout:
        plt.tight_layout()

    # Set top bounds for shared titles and add suptitle
    if suptitle:
        f.subplots_adjust(top=0.85)
        f.suptitle(suptitle, fontsize=suptitle_fontsize)

    # If we want to plot scalebars, loop through the list of axes and add them
    if scalebar is None or scalebar is False:
        # Do nothing if no scalebars are called for
        pass
    elif scalebar is 'all':
        # scalebars were taken care of in the plotting loop
        pass
    elif scalelist:
        # scalebars were taken care of in the plotting loop
        pass
    else:
        raise ValueError("Did not understand scalebar input. Must be None, "
                         "\'all\', or list of ints.")

    # Adjust subplot spacing according to user's specification
    if padding is not None:
        plt.subplots_adjust(**padding)

    return axes_list
コード例 #4
0
def plot_images(images,
                cmap=None,
                no_nans=False,
                per_row=3,
                label='auto',
                labelwrap=30,
                suptitle=None,
                suptitle_fontsize=18,
                colorbar='multi',
                centre_colormap="auto",
                saturated_pixels=0,
                scalebar=None,
                scalebar_color='white',
                axes_decor='all',
                padding=None,
                tight_layout=False,
                aspect='auto',
                min_asp=0.1,
                namefrac_thresh=0.4,
                fig=None,
                *args,
                **kwargs):
    """Plot multiple images as sub-images in one figure.

        Parameters
        ----------
        images : list
            `images` should be a list of Signals (Images) to plot
            If any signal is not an image, a ValueError will be raised
            multi-dimensional images will have each plane plotted as a separate
            image
        cmap : matplotlib colormap, optional
            The colormap used for the images, by default read from pyplot
        no_nans : bool, optional
            If True, set nans to zero for plotting.
        per_row : int, optional
            The number of plots in each row
        label : None, str, or list of str, optional
            Control the title labeling of the plotted images.
            If None, no titles will be shown.
            If 'auto' (default), function will try to determine suitable titles
            using Image titles, falling back to the 'titles' option if no good
            short titles are detected.
            Works best if all images to be plotted have the same beginning
            to their titles.
            If 'titles', the title from each image's metadata.General.title
            will be used.
            If any other single str, images will be labeled in sequence using
            that str as a prefix.
            If a list of str, the list elements will be used to determine the
            labels (repeated, if necessary).
        labelwrap : int, optional
            integer specifying the number of characters that will be used on
            one line
            If the function returns an unexpected blank figure, lower this
            value to reduce overlap of the labels between each figure
        suptitle : str, optional
            Title to use at the top of the figure. If called with label='auto',
            this parameter will override the automatically determined title.
        suptitle_fontsize : int, optional
            Font size to use for super title at top of figure
        colorbar : {'multi', None, 'single'}
            Controls the type of colorbars that are plotted.
            If None, no colorbar is plotted.
            If 'multi' (default), individual colorbars are plotted for each
            (non-RGB) image
            If 'single', all (non-RGB) images are plotted on the same scale,
            and one colorbar is shown for all
        centre_colormap : {"auto", True, False}
            If True the centre of the color scheme is set to zero. This is
            specially useful when using diverging color schemes. If "auto"
            (default), diverging color schemes are automatically centred.
        saturated_pixels: scalar
            The percentage of pixels that are left out of the bounds.  For example,
            the low and high bounds of a value of 1 are the 0.5% and 99.5%
            percentiles. It must be in the [0, 100] range.
        scalebar : {None, 'all', list of ints}, optional
            If None (or False), no scalebars will be added to the images.
            If 'all', scalebars will be added to all images.
            If list of ints, scalebars will be added to each image specified.
        scalebar_color : str, optional
            A valid MPL color string; will be used as the scalebar color
        axes_decor : {'all', 'ticks', 'off', None}, optional
            Controls how the axes are displayed on each image; default is 'all'
            If 'all', both ticks and axis labels will be shown
            If 'ticks', no axis labels will be shown, but ticks/labels will
            If 'off', all decorations and frame will be disabled
            If None, no axis decorations will be shown, but ticks/frame will
        padding : None or dict, optional
            This parameter controls the spacing between images.
            If None, default options will be used
            Otherwise, supply a dictionary with the spacing options as
            keywords and desired values as values
            Values should be supplied as used in pyplot.subplots_adjust(),
            and can be:
                'left', 'bottom', 'right', 'top', 'wspace' (width),
                and 'hspace' (height)
        tight_layout : bool, optional
            If true, hyperspy will attempt to improve image placement in
            figure using matplotlib's tight_layout
            If false, repositioning images inside the figure will be left as
            an exercise for the user.
        aspect : str or numeric, optional
            If 'auto', aspect ratio is auto determined, subject to min_asp.
            If 'square', image will be forced onto square display.
            If 'equal', aspect ratio of 1 will be enforced.
            If float (or int/long), given value will be used.
        min_asp : float, optional
            Minimum aspect ratio to be used when plotting images
        namefrac_thresh : float, optional
            Threshold to use for auto-labeling. This parameter controls how
            much of the titles must be the same for the auto-shortening of
            labels to activate. Can vary from 0 to 1. Smaller values
            encourage shortening of titles by auto-labeling, while larger
            values will require more overlap in titles before activing the
            auto-label code.
        fig : mpl figure, optional
            If set, the images will be plotted to an existing MPL figure
        *args, **kwargs, optional
            Additional arguments passed to matplotlib.imshow()

        Returns
        -------
        axes_list : list
            a list of subplot axes that hold the images

        See Also
        --------
        plot_spectra : Plotting of multiple spectra
        plot_signals : Plotting of multiple signals
        plot_histograms : Compare signal histograms

        Notes
        -----
        `interpolation` is a useful parameter to provide as a keyword
        argument to control how the space between pixels is interpolated. A
        value of ``'nearest'`` will cause no interpolation between pixels.

        `tight_layout` is known to be quite brittle, so an option is provided
        to disable it. Turn this option off if output is not as expected,
        or try adjusting `label`, `labelwrap`, or `per_row`

    """
    from hyperspy.drawing.widgets import ScaleBar
    from hyperspy.misc import rgb_tools
    from hyperspy.signal import Signal

    if isinstance(images, Signal) and len(images) is 1:
        images.plot()
        ax = plt.gca()
        return ax
    elif not isinstance(images, (list, tuple, Signal)):
        raise ValueError("images must be a list of image signals or "
                         "multi-dimensional signal."
                         " " + repr(type(images)) + " was given.")

    # Get default colormap from pyplot:
    if cmap is None:
        cmap = plt.get_cmap().name
    elif isinstance(cmap, mpl.colors.Colormap):
        cmap = cmap.name
    if centre_colormap == "auto":
        if cmap in MPL_DIVERGING_COLORMAPS:
            centre_colormap = True
        else:
            centre_colormap = False

    # If input is >= 1D signal (e.g. for multi-dimensional plotting),
    # copy it and put it in a list so labeling works out as (x,y) when plotting
    if isinstance(images,
                  Signal) and images.axes_manager.navigation_dimension > 0:
        images = [images._deepcopy_with_new_data(images.data)]

    n = 0
    for i, sig in enumerate(images):
        if sig.axes_manager.signal_dimension != 2:
            raise ValueError("This method only plots signals that are images. "
                             "The signal dimension must be equal to 2. "
                             "The signal at position " + repr(i) + " was " +
                             repr(sig) + ".")
        # increment n by the navigation size, or by 1 if the navigation size is
        # <= 0
        n += (sig.axes_manager.navigation_size
              if sig.axes_manager.navigation_size > 0 else 1)

    # Sort out the labeling:
    div_num = 0
    all_match = False
    shared_titles = False
    user_labels = False

    if label is None:
        pass
    elif label is 'auto':
        # Use some heuristics to try to get base string of similar titles
        label_list = [x.metadata.General.title for x in images]

        # Find the shortest common string between the image titles
        # and pull that out as the base title for the sequence of images
        # array in which to store arrays
        res = np.zeros((len(label_list), len(label_list[0]) + 1))
        res[:, 0] = 1

        # j iterates the strings
        for j in range(len(label_list)):
            # i iterates length of substring test
            for i in range(1, len(label_list[0]) + 1):
                # stores whether or not characters in title match
                res[j, i] = label_list[0][:i] in label_list[j]

        # sum up the results (1 is True, 0 is False) and create
        # a substring based on the minimum value (this will be
        # the "smallest common string" between all the titles
        if res.all():
            basename = label_list[0]
            div_num = len(label_list[0])
            all_match = True
        else:
            div_num = int(min(np.sum(res, 1)))
            basename = label_list[0][:div_num - 1]
            all_match = False

        # trim off any '(' or ' ' characters at end of basename
        if div_num > 1:
            while True:
                if basename[len(basename) - 1] == '(':
                    basename = basename[:-1]
                elif basename[len(basename) - 1] == ' ':
                    basename = basename[:-1]
                else:
                    break

        # namefrac is ratio of length of basename to the image name
        # if it is high (e.g. over 0.5), we can assume that all images
        # share the same base
        if len(label_list[0]) > 0:
            namefrac = float(len(basename)) / len(label_list[0])
        else:
            # If label_list[0] is empty, it means there was probably no
            # title set originally, so nothing to share
            namefrac = 0

        if namefrac > namefrac_thresh:
            # there was a significant overlap of label beginnings
            shared_titles = True
            # only use new suptitle if one isn't specified already
            if suptitle is None:
                suptitle = basename

        else:
            # there was not much overlap, so default back to 'titles' mode
            shared_titles = False
            label = 'titles'
            div_num = 0

    elif label is 'titles':
        # Set label_list to each image's pre-defined title
        label_list = [x.metadata.General.title for x in images]

    elif isinstance(label, basestring):
        # Set label_list to an indexed list, based off of label
        label_list = [label + " " + repr(num) for num in range(n)]

    elif isinstance(label, list) and all(
            isinstance(x, basestring) for x in label):
        label_list = label
        user_labels = True
        # If list of labels is longer than the number of images, just use the
        # first n elements
        if len(label_list) > n:
            del label_list[n:]
        if len(label_list) < n:
            label_list *= (n / len(label_list)) + 1
            del label_list[n:]

    else:
        # catch all others to revert to default if bad input
        print "Did not understand input of labels. Defaulting to image titles."
        label_list = [x.metadata.General.title for x in images]

    # Determine appropriate number of images per row
    rows = int(np.ceil(n / float(per_row)))
    if n < per_row:
        per_row = n

    # Set overall figure size and define figure (if not pre-existing)
    if fig is None:
        k = max(plt.rcParams['figure.figsize']) / max(per_row, rows)
        f = plt.figure(figsize=(tuple(k * i for i in (per_row, rows))))
    else:
        f = fig

    # Initialize list to hold subplot axes
    axes_list = []

    # Initialize list of rgb tags
    isrgb = [False] * len(images)

    # Check to see if there are any rgb images in list
    # and tag them using the isrgb list
    for i, img in enumerate(images):
        if rgb_tools.is_rgbx(img.data):
            isrgb[i] = True

    # Determine how many non-rgb Images there are
    non_rgb = list(itertools.compress(images, [not j for j in isrgb]))
    if len(non_rgb) is 0 and colorbar is not None:
        colorbar = None
        print "Sorry, colorbar is not implemented for RGB images."

    # Find global min and max values of all the non-rgb images for use with
    # 'single' scalebar
    if colorbar is 'single':
        g_vmin, g_vmax = contrast_stretching(
            np.concatenate([i.data.flatten() for i in non_rgb]),
            saturated_pixels)
        if centre_colormap:
            g_vmin, g_vmax = centre_colormap_values(g_vmin, g_vmax)

    # Check if we need to add a scalebar for some of the images
    if isinstance(scalebar, list) and all(
            isinstance(x, int) for x in scalebar):
        scalelist = True
    else:
        scalelist = False

    idx = 0
    ax_im_list = [0] * len(isrgb)
    # Loop through each image, adding subplot for each one
    for i, ims in enumerate(images):
        # Get handles for the signal axes and axes_manager
        axes_manager = ims.axes_manager
        if axes_manager.navigation_dimension > 0:
            ims = ims._deepcopy_with_new_data(ims.data)
        for j, im in enumerate(ims):
            idx += 1
            ax = f.add_subplot(rows, per_row, idx)
            axes_list.append(ax)
            data = im.data

            # Enable RGB plotting
            if rgb_tools.is_rgbx(data):
                data = rgb_tools.rgbx2regular_array(data, plot_friendly=True)
                l_vmin, l_vmax = None, None
            else:
                data = im.data
                # Find min and max for contrast
                l_vmin, l_vmax = contrast_stretching(data, saturated_pixels)
                if centre_colormap:
                    l_vmin, l_vmax = centre_colormap_values(l_vmin, l_vmax)

            # Remove NaNs (if requested)
            if no_nans:
                data = np.nan_to_num(data)

            # Get handles for the signal axes and axes_manager
            axes_manager = im.axes_manager
            axes = axes_manager.signal_axes

            # Set dimensions of images
            xaxis = axes[0]
            yaxis = axes[1]

            extent = (
                xaxis.low_value,
                xaxis.high_value,
                yaxis.high_value,
                yaxis.low_value,
            )

            if not isinstance(aspect, (int, long, float)) and aspect not in [
                    'auto', 'square', 'equal'
            ]:
                print 'Did not understand aspect ratio input. ' \
                      'Using \'auto\' as default.'
                aspect = 'auto'

            if aspect is 'auto':
                if float(yaxis.size) / xaxis.size < min_asp:
                    factor = min_asp * float(xaxis.size) / yaxis.size
                elif float(yaxis.size) / xaxis.size > min_asp**-1:
                    factor = min_asp**-1 * float(xaxis.size) / yaxis.size
                else:
                    factor = 1
                asp = np.abs(factor * float(xaxis.scale) / yaxis.scale)
            elif aspect is 'square':
                asp = abs(extent[1] - extent[0]) / abs(extent[3] - extent[2])
            elif aspect is 'equal':
                asp = 1
            elif isinstance(aspect, (int, long, float)):
                asp = aspect
            if ('interpolation' in kwargs.keys()) is False:
                kwargs['interpolation'] = 'nearest'

            # Plot image data, using vmin and vmax to set bounds,
            # or allowing them to be set automatically if using individual
            # colorbars
            if colorbar is 'single' and not isrgb[i]:
                axes_im = ax.imshow(data,
                                    cmap=cmap,
                                    extent=extent,
                                    vmin=g_vmin,
                                    vmax=g_vmax,
                                    aspect=asp,
                                    *args,
                                    **kwargs)
                ax_im_list[i] = axes_im
            else:
                axes_im = ax.imshow(data,
                                    cmap=cmap,
                                    extent=extent,
                                    vmin=l_vmin,
                                    vmax=l_vmax,
                                    aspect=asp,
                                    *args,
                                    **kwargs)
                ax_im_list[i] = axes_im

            # If an axis trait is undefined, shut off :
            if isinstance(xaxis.units, trait_base._Undefined) or  \
                    isinstance(yaxis.units, trait_base._Undefined) or \
                    isinstance(xaxis.name, trait_base._Undefined) or \
                    isinstance(yaxis.name, trait_base._Undefined):
                if axes_decor is 'all':
                    warnings.warn('Axes labels were requested, but one '
                                  'or both of the '
                                  'axes units and/or name are undefined. '
                                  'Axes decorations have been set to '
                                  '\'ticks\' instead.')
                    axes_decor = 'ticks'
            # If all traits are defined, set labels as appropriate:
            else:
                ax.set_xlabel(axes[0].name + " axis (" + axes[0].units + ")")
                ax.set_ylabel(axes[1].name + " axis (" + axes[1].units + ")")

            if label:
                if all_match:
                    title = ''
                elif shared_titles:
                    title = label_list[i][div_num - 1:]
                else:
                    if len(ims) == n:
                        # This is true if we are plotting just 1
                        # multi-dimensional Image
                        title = label_list[idx - 1]
                    elif user_labels:
                        title = label_list[idx - 1]
                    else:
                        title = label_list[i]

                if ims.axes_manager.navigation_size > 1 and not user_labels:
                    title += " %s" % str(ims.axes_manager.indices)

                ax.set_title(textwrap.fill(title, labelwrap))

            # Set axes decorations based on user input
            if axes_decor is 'off':
                ax.axis('off')
            elif axes_decor is 'ticks':
                ax.set_xlabel('')
                ax.set_ylabel('')
            elif axes_decor is 'all':
                pass
            elif axes_decor is None:
                ax.set_xlabel('')
                ax.set_ylabel('')
                ax.set_xticklabels([])
                ax.set_yticklabels([])

            # If using independent colorbars, add them
            if colorbar is 'multi' and not isrgb[i]:
                div = make_axes_locatable(ax)
                cax = div.append_axes("right", size="5%", pad=0.05)
                plt.colorbar(axes_im, cax=cax)

            # Add scalebars as necessary
            if (scalelist and i in scalebar) or scalebar is 'all':
                ax.scalebar = ScaleBar(
                    ax=ax,
                    units=axes[0].units,
                    color=scalebar_color,
                )

    # If using a single colorbar, add it, and do tight_layout, ensuring that
    # a colorbar is only added based off of non-rgb Images:
    if colorbar is 'single':
        foundim = None
        for i in range(len(isrgb)):
            if (not isrgb[i]) and foundim is None:
                foundim = i

        if foundim is not None:
            f.subplots_adjust(right=0.8)
            cbar_ax = f.add_axes([0.9, 0.1, 0.03, 0.8])
            f.colorbar(ax_im_list[foundim], cax=cbar_ax)
            if tight_layout:
                # tight_layout, leaving room for the colorbar
                plt.tight_layout(rect=[0, 0, 0.9, 1])
        elif tight_layout:
            plt.tight_layout()

    elif tight_layout:
        plt.tight_layout()

    # Set top bounds for shared titles and add suptitle
    if suptitle:
        f.subplots_adjust(top=0.85)
        f.suptitle(suptitle, fontsize=suptitle_fontsize)

    # If we want to plot scalebars, loop through the list of axes and add them
    if scalebar is None or scalebar is False:
        # Do nothing if no scalebars are called for
        pass
    elif scalebar is 'all':
        # scalebars were taken care of in the plotting loop
        pass
    elif scalelist:
        # scalebars were taken care of in the plotting loop
        pass
    else:
        raise ValueError("Did not understand scalebar input. Must be None, "
                         "\'all\', or list of ints.")

    # Adjust subplot spacing according to user's specification
    if padding is not None:
        plt.subplots_adjust(**padding)

    return axes_list