def _axis_properties(self, axis, key, plot, dimension=None,
                         ax_mapping={'x': 0, 'y': 1}):
        """
        Returns a dictionary of axis properties depending
        on the specified axis.
        """
        # need to copy dictionary by calling dict() on it
        axis_props = dict(theme_attr_json(self.renderer.theme, 'Axis'))

        if ((axis == 'x' and self.xaxis in ['bottom-bare', 'top-bare', 'bare']) or
            (axis == 'y' and self.yaxis in ['left-bare', 'right-bare', 'bare'])):
            axis_props['axis_label_text_font_size'] = value('0pt')
            axis_props['major_label_text_font_size'] = value('0pt')
            axis_props['major_tick_line_color'] = None
            axis_props['minor_tick_line_color'] = None
        else:
            labelsize = self._fontsize('%slabel' % axis).get('fontsize')
            if labelsize:
                axis_props['axis_label_text_font_size'] = labelsize
            ticksize = self._fontsize('%sticks' % axis, common=False).get('fontsize')
            if ticksize:
                axis_props['major_label_text_font_size'] = value(ticksize)
            rotation = self.xrotation if axis == 'x' else self.yrotation
            if rotation:
                axis_props['major_label_orientation'] = np.radians(rotation)
            ticker = self.xticks if axis == 'x' else self.yticks
            if isinstance(ticker, Ticker):
                axis_props['ticker'] = ticker
            elif isinstance(ticker, int):
                axis_props['ticker'] = BasicTicker(desired_num_ticks=ticker)
            elif isinstance(ticker, (tuple, list)):
                if all(isinstance(t, tuple) for t in ticker):
                    ticks, labels = zip(*ticker)
                    # Ensure floats which are integers are serialized as ints
                    # because in JS the lookup fails otherwise
                    ticks = [int(t) if isinstance(t, float) and t.is_integer() else t
                             for t in ticks]
                    labels = [l if isinstance(l, util.basestring) else str(l)
                              for l in labels]
                    axis_props['ticker'] = FixedTicker(ticks=ticks)
                    axis_props['major_label_overrides'] = dict(zip(ticks, labels))
                else:
                    axis_props['ticker'] = FixedTicker(ticks=ticker)

        formatter = self.xformatter if axis == 'x' else self.yformatter
        if formatter:
            if isinstance(formatter, TickFormatter):
                pass
            elif isinstance(formatter, FunctionType):
                msg = ('%sformatter could not be '
                       'converted to tick formatter. ' % axis)
                jsfunc = py2js_tickformatter(formatter, msg)
                if jsfunc:
                    formatter = FuncTickFormatter(code=jsfunc)
                else:
                    formatter = None
            else:
                formatter = PrintfTickFormatter(format=formatter)
            if formatter is not None:
                axis_props['formatter'] = formatter
        elif FuncTickFormatter is not None and ax_mapping and isinstance(dimension, Dimension):
            formatter = None
            if dimension.value_format:
                formatter = dimension.value_format
            elif dimension.type in dimension.type_formatters:
                formatter = dimension.type_formatters[dimension.type]
            if formatter:
                msg = ('%s dimension formatter could not be '
                       'converted to tick formatter. ' % dimension.name)
                jsfunc = py2js_tickformatter(formatter, msg)
                if jsfunc:
                    formatter = FuncTickFormatter(code=jsfunc)
                    axis_props['formatter'] = formatter

        if axis == 'x':
            axis_obj = plot.xaxis[0]
        elif axis == 'y':
            axis_obj = plot.yaxis[0]

        if self.geographic and self.projection == 'mercator':
            dimension = 'lon' if axis == 'x' else 'lat'
            axis_props['ticker'] = MercatorTicker(dimension=dimension)
            axis_props['formatter'] = MercatorTickFormatter(dimension=dimension)
            box_zoom = self.state.select(type=tools.BoxZoomTool)
            if box_zoom:
                box_zoom[0].match_aspect = True
        elif isinstance(axis_obj, CategoricalAxis):
            for key in list(axis_props):
                if key.startswith('major_label'):
                    # set the group labels equal to major (actually minor)
                    new_key = key.replace('major_label', 'group')
                    axis_props[new_key] = axis_props[key]

            # major ticks are actually minor ticks in a categorical
            # so if user inputs minor ticks sizes, then use that;
            # else keep major (group) == minor (subgroup)
            msize = self._fontsize('minor_{0}ticks'.format(axis),
                common=False).get('fontsize')
            if msize is not None:
                axis_props['major_label_text_font_size'] = msize

        return axis_props
Returns a dictionary of axis properties depending
        on the specified axis.