delete line plot via handles not working

Hi, I am plotting a histogram and want to draw a line that represents the mode:

bar(x,counts,'b','EdgeColor','b');
xm=mode(IM(:));

Now as I will want to replot this linen with a slider callback later, and wont want to have to replot the barchart, I thought adding the line plot here using handles, would then allow me to delete it later and replot it (whilst keeping the barchart still present)

So to plot the line using handles (on my axes component)

AxesH = axes(handles.axes5);
LineH=plot([xm xm],[0 max(counts)],'r', 'LineWidth',1); %draw line representing the mode (most frequent)
set(AxesH, 'UserData', LineH);    %save so can recall or delete later
guidata(hObject, handles);

Then under a slider callback, firstly I want to delete the current line:

OldLineH = get(handles.axes5, 'UserData');
delete(OldLineH);

and then plot the new one based on the slider value

LineH=plot([x(p) x(p)],[0 max(counts)],'r', 'LineWidth',1);       
guidata(hObject, handles);
drawnow;
hold on;

But its not deleting the first one, so I get an accumulation of lines.

[Jason]

Think I have sorted it. On the slider callback, I also need to add the line to the handles structure so it can delete it next time round:

AxesH = handles.axes5;
LineH=plot([x(p) x(p)],[0 max(counts)],'r', 'LineWidth',1);       
set(AxesH, 'UserData', LineH);
guidata(hObject, handles);
drawnow;

[Daniel Melendrez]

Your solution saved my life!

Kudos

Daniel

Answer 1

[Orion]

Hi,

I think this should work

axes(handles.axes5);
if ~isfield(handles,'LineH')
    % create the field the first time
    handles.LineH = plot([x(p) x(p)],[0 max(counts)],'r', 'LineWidth',1);       
else
    % update the already existing plot
    set(handles.LineH,'XData',[x(p) x(p)],'YData',[0 max(counts)]);
end
guidata(hObject, handles);
drawnow;