reporting: @graph: add option shade_opacity

matlab/reporting/@graph/createGraph.m

@@ -88,7 +88,7 @@ if ~isempty(o.shade)
     % use patch bc area doesn't work with matlab2tikz
     sh = patch([repmat(x1, 1, 2) repmat(x2, 1, 2)], ...
                [yrange fliplr(yrange)], [0 1 0], ...
-               'FaceAlpha', .2);
+               'facealpha', o.shade_opacity);
     children =get(gca(), 'children');
     children = [children(2:end); sh];
     set(gca(), 'children', children);

matlab/reporting/@graph/graph.m

@@ -45,10 +45,12 @@ o.footnote = '';
 o.figname = '';
 o.data = '';
 o.seriestouse = '';
-o.shade = '';
 o.xrange = '';
 o.yrange = '';
 
+o.shade = '';
+o.shade_opacity = .2;
+
 o.grid = true;
 
 o.legend = false;
@@ -95,6 +97,9 @@ assert(islogical(o.legend), '@graph.graph: legend must be either true or false')
 assert(islogical(o.legend_boxoff), '@graph.graph: legend_boxoff must be either true or false');
 assert(isint(o.legend_font_size), '@graph.graph: legend_font_size must be an integer');
 assert(islogical(o.zeroline), '@graph.graph: zeroline must be either true or false');
+assert(isfloat(o.shade_opacity) && length(o.shade_opacity)==1 && ...
+       o.shade_opacity >= 0 && o.shade_opacity <= 1, ...
+       '@graph.graph: o.shade_opacity must be a real in [0 1]']);
 valid_legend_locations = ...
     {'North', 'South', 'East', 'West', ...
      'NorthEast', 'SouthEast', 'NorthWest', 'SouthWest', ...