Matlab – Cycle over colors while plotting in MATLAB

You can use the code you have, and just concatenate the handles from each line into a vector of handles. When you want to change the properties of both lines simultaneously, the SET function is able to accept the vector of handles as an argument. From the documentation for SET:

set(H,'PropertyName',PropertyValue,...) sets the named properties to the specified values on the object(s) identified by H. H can be a vector of handles, in which case set sets the properties' values for all the objects.

Here's an example:

h1 = plot([1 1],[0 1],'r');    %# Plot line 1
hold on;
h2 = plot([1 1],[0 1],'--b');  %# Plot line 2
hVector = [h1 h2];             %# Vector of handles
set(hVector,'XData',[2 3]);    %# Shifts the x data points for both lines

UPDATE: Since you mention you are using draggable from the MathWorks File Exchange, here's an alternate solution. From the description of draggable:

A function which is called when the object is moved can be provided as an optional argument, so that the movement triggers further actions.

You could then try the following solution:

• Plot your two lines, saving the handle for each (i.e. h1 and h2).

• Put the handle for each in the 'UserData' property of the other:

  set(h1,'UserData',h2);
  set(h2,'UserData',h1);
  

• Create the following function:

  function motionFcn(hMoving)  %# Currently moving handle is passed in
    hOther = get(hMoving,'UserData');  %# Get the other plot handle
    set(hOther,'XData',get(hMoving,'XData'),...  %# Update the x data
               'YData',get(hMoving,'YData'));    %# Update the y data
  end
  

• Turn on draggable for both lines, using the above function as the one called when either object is moved:

  draggable(h1,@motionFcn);
  draggable(h2,@motionFcn);
  

There is a function adjustcolor in grDevices package, that works like this in your case:

    adjustcolor( "red", alpha.f = 0.2)