How to delete all lines using line()

Hello everyone,

I have a simple question: is it possible to delete all lines (I mean, using the function line()) and not the rest of plots in an axes gui?

I am making a cursor and I am using the function line() to draw it. I have a little problem in my code, so I thought delete all my lines and then draw the lines that I need.

I can't use in my case: if ishandle(cursor) delete(cursor) end

Any advice?

Thank you in advance

Answer 1

[Image Analyst]

You have to keep track of the handles to the lines as you create them, because I think curves made by plot() might also be identified as lines by findobj(). If it's in a loop, then

for k = 1 : whatever
    hLines(k) = line(.....
end
% Delete them
delete(hLines);

Or run this demo:

t=linspace(0,6*pi, 1000);
f = 8 * exp(-0.25*t).*sin(t - 2);
plot(t, f);
grid on;
hold on;
% Make lines.
hLines(1)=line([2,8], [3,-4], 'Color', 'r', 'LineWidth', 2)
hLines(2)=line([10,16], [-2,4], 'Color', 'r', 'LineWidth', 2)
% Clear lines.
uiwait(msgbox('Click OK to clear the lines'));
delete(hLines);

[pem.cristina]

It was a great idea and it works, however I have a little problem: I can't use only delete(), before I must verify if my variable cursors exist. I've tried:

if ishandle(cursors)
  delete(cursors)
end

However, it doesn't run my loop. Any other alternative?

Thank you for your prompt reply.

[Image Analyst]

I don't know why you call your line handles "cursors" or why you need to check if they're handles or not. You know they must be or you never would have assigned them.

Here's another function I've used:

%========================================================
% Erases all lines from the axes control with handle "h".
function ClearLinesFromAxes(h)
    %fprintf('In ClearLinesFromAxes...\n');
    axesHandlesToChildObjects = findobj(h, 'Type', 'line');
    if ~isempty(axesHandlesToChildObjects)
      delete(axesHandlesToChildObjects);
    end
    %fprintf('Leaving ClearLinesFromAxes.\n');
    return; % from ClearLinesFromAxes

[pem.cristina]

It was exactly what I needed! It has been really helpful

Thanks again.