Stacked bars for +ive and -ive values

Hello everybody,


I tried to create a chart as in Excell, with bars stacked columns,
which compares the contribution of each values to a total across
categories, I have a serious problem because I have 4 set of 12
values and one of this is negative. When I use the normal statement:
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bar(res.monthly,'stacked');
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the negative values are substracted from the associated positive
values, that's not what I want.

In a second hand I tried to realize my script as follow:
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axes(handles.axes1);
bar(res.monthly(:,1),'stacked','r');
hold on
bar(res.monthly(:,2),'stacked','c');
bar(res.monthly(:,4),'stacked','y');
bar(res.monthly(:,3),'stacked','g');

set(gca,'XLim',[0 13],'Layer','top')
title 'consumption per floor square meter';
xlabel('month');
ylabel('kwh/m2');
grid on;
---------------------------------------------
Also, I wanted to affect a defined colour to each category, that's
the
cause of my 4 first lines. and I suppose that is the cause of my
troubles, the 4 columns are superposed and not stacked, I'd like to
know if there is a mean to stack them?

Does Anyone have an issue to resolve my problem??
thank for reading
max
.