Hi Stephane,
The line appearance (color and marker) in ‘stepplot’ with interactive response-plot updates, can be changed by specifying them as input arguments. Below mentioned code illustrates how it can be done.
%Defining initial values of second-order dynamic system
zeta = .5; % Damping Ratio
wn = 2; % Natural Frequency
sys = tf(wn^2,[1,2*zeta*wn,wn^2]);
% Creating figure for GUI and configuring the axes for displaying step response
f = figure;
ax = axes('Parent',f,'position',[0.13 0.39 0.77 0.54]);
h = stepplot(ax,sys,'r--');% specifying marker style and color
setoptions(h,'XLim',[0,10],'YLim',[0,2]);
%adding slider and slider label text to the figure
b = uicontrol('Parent',f,'Style','slider','Position',[81,54,419,23],'value',zeta, 'min',0, 'max',1);
bgcolor = f.Color;
bl1 = uicontrol('Parent',f,'Style','text','Position',[50,54,23,23],'String','0','BackgroundColor',bgcolor);
bl2 = uicontrol('Parent',f,'Style','text','Position',[500,54,23,23],'String','1','BackgroundColor',bgcolor);
bl3 = uicontrol('Parent',f,'Style','text','Position',[240,25,100,23],'String','Damping Ratio','BackgroundColor',bgcolor);
% Setting callback that updates the step response plot as the damping ratio slider is moved.
b.Callback = @(es,ed) updateSystem(h,tf(wn^2,[1,2*(es.Value)*wn,wn^2]));
To change line width, Property inspector can be used. For this you need to navigate to required line object (Figure 1 > Axes > sys > Line) and specify the line width as required.
Output:
Hope this helps!
