I want to change the backgroung color of my plots.

I want to draw a graph in which for any rang that graph shows different backgroung it shows. for example in the range of o-1 red background, in 1-2 blu, in 2-3 yellow and so forth.

could I do that in matlab?

Answer 1

[Voss]

Is something like this what you mean?

colors = [1 0 0; 0 0 1; 1 1 0];
thresholds = [1 2];

figure()
subplot(2,1,1)
x = 0:0.05:2*pi;
y = 1.5+1.5*sin(x);
plot(x,y,'k','LineWidth',2);
xlim([0 2*pi]);
ylim([0 3]);
set_background(x,y,colors,thresholds)

subplot(2,1,2)
x = 0:0.025:2*pi;
y = 1.5+1.5*sin(x)+0.45*randn(1,numel(x));
plot(x,y,'k','LineWidth',2);
xlim([0 2*pi]);
ylim([-2 5]);
set_background(x,y,colors,thresholds)

function set_background(x,y,colors,thresholds)
idx = ones(1,numel(x));
thresholds = [-Inf thresholds Inf];
for ii = 2:numel(thresholds)
    idx(y >= thresholds(ii-1) & y < thresholds(ii)) = ii-1;
end
yl = get(gca(),'YLim').';
x = (x(1:end-1)+x(2:end))/2;
x = [2*x(1)-x(2) x 2*x(end)-x(end-1)];
p = patch( ...
    'XData',x((2:end)+[0;0;-1;-1;0]), ...
    'YData',repmat(yl([1 2 2 1 1]),1,numel(x)-1), ...
    'FaceColor','flat', ...
    'FaceVertexCData',colors(idx,:), ...
    'EdgeColor','none');
ch = get(gca(),'Children');
ch(ch == p) = [];
set(gca(),'Children',[ch(:); p],'Layer','top');
end

[Mohammad Sadegh Nasirianfar]

I mean in this form.

[Image Analyst]

Use patch() like he showed you already. You just have to modify the corners of the rectangle to get the rectangle sizes, shapes, and locations you want. Try it. I'm sure you can do it. Don't underestimate yourself.

[Mohammad Sadegh Nasirianfar]

I understood the first code but the used function is really advanced and i could not understand. by the way now I am trying and thank you so.

[Voss]

@Mohammad Sadegh Nasirianfar Actually it looks like, in the image you uploaded, the background color doesn't vary with the curve value at all, as it does in my answer, which is what I thought you meant. Instead, the background color varies in fixed vertical strips/stripes. So that's easier to achieve (still the same idea but the locations of the patch faces don't depend on the curve at all):

y = 0:0.5:30;
x = 2.5+0.65*sin(y)+0.35*randn(1,numel(y));
plot(x,y,'k','LineWidth',2);
xlim([1 4]);
set(gca(),'YDir','reverse')
grid on

colors = [ ...
    242 156 71; ...
    191 163 97; ...
    122 199 158; ...
    71 48 133; ...
    74 87 122; ...
    184 105 64]/255;
x_edges = [1 1.22 2 2.6 2.95 3.58 4];

p = patch( ...
    'XData',x_edges((1:end-1)+[0; 1; 1; 0; 0]), ...
    'YData',repmat([0; 0; 1; 1; 0]*30,1,size(colors,1)), ...
    'FaceColor','flat', ...
    'FaceVertexCData',colors, ...
    'EdgeColor','none');

% put the patch at the bottom of the stack, so it shows up underneath
% what's already in the axes (same as before):
ch = get(gca(),'Children');
ch(ch == p) = [];
set(gca(),'Children',[ch(:); p],'Layer','top'); % 'Layer','top' to get the grids on top

[Mohammad Sadegh Nasirianfar]

thank you very very much for your great help.

[Voss]

You're welcome!