Switching values to plot using keyboard input

Question

I have sets of data in a matrix. I want to plot on set and then use a keyboard input to move to another one. It\'s simply possible this way:

for t=1:N
  plot(dat         


        

Answer 1

This demo shows you how to use either the left and right arrows of the keyboard to switch data set or even the mouse wheel.

It uses the KeyPressFcn and/or WindowScrollWheelFcn event of the figure.

function h = change_dataset_demo

%// sample data
nDataset = 8 ;
x = linspace(0,2*pi,50).' ;     %'// ignore this comment
data = sin( x*(1:nDataset) ) ;

index.max = nDataset ;
index.current = 1 ;

%// Plot the first one
h.fig = figure ;
h.plot = plot( data(:,index.current) ) ;

%// store data in figure appdata
setappdata( h.fig , 'data',  data )
setappdata( h.fig , 'index', index )

%// set the figure event callbacks
set(h.fig, 'KeyPressFcn', @KeyPressFcn_callback ) ;     %// Set figure KeyPressFcn function
set(h.fig, 'WindowScrollWheelFcn',@mouseWheelCallback)  %// Set figure Mouse wheel function

guidata( h.fig , h )


function mouseWheelCallback(hobj,evt)
    update_display( hobj , evt.VerticalScrollCount )


function KeyPressFcn_callback(hobj,evt)
    if ~isempty( evt.Modifier ) ; return ; end  % Bail out if there is a modifier

    switch evt.Key
        case 'rightarrow'
            increment = +1 ;
        case 'leftarrow'
            increment = -1 ;
        otherwise
            % do nothing
            return ;
    end
    update_display( hobj , increment )


function update_display( hobj , increment )

    h = guidata( hobj ) ;
    index = getappdata( h.fig , 'index' ) ;
    data  = getappdata( h.fig , 'data' ) ;

    newindex = index.current + increment ;
    %// roll over if we go out of bound
    if newindex > index.max
        newindex = 1 ;
    elseif newindex < 1
        newindex = index.max ;
    end
    set( h.plot , 'YData' , data(:,newindex) ) ;
    index.current = newindex ;
    setappdata( h.fig , 'index', index )

This will roll over when the end of the data set is reached.

done a little gif too but it's a lot less impressive because it does not show the keyboard/mouse action, only the graph updates :