Change line type when figure handle is known

I have created a plot in a figure window. I want to change the line type to circles.

I know the figure handle. Let's say it's gcf. Can I use this to modify the plot or line? I figure they are children of the figure so I should be able to use

set(gcf, child:plot, child:line, 'o')

... something along those lines. I'm a newbie. How should this look?

Answer 1

[Arnaud Miege]

Does that do what you want?

t = 0:0.1:10;
y = sin(t);
h = plot(t,y);
set(h,'Marker','o');
set(h,'LineStyle','none');

Arnaud

[Arnaud Miege]

PS: you need the plot handle, not the figure handle:

h_fig = gcf;

h_axes = gca;

h_plot = get(h_axes,'Children')

Answer 2

[Patrick Kalita]

Starting with a figure handle f, getting its Children property will most often return an axes handle a.

a = get(f, 'Children');

You can verify what it is by looking at a's Type property:

>> get(a, 'Type')

ans =

axes

So far so good. Now the line will be a child of the axes. So get the Children property of a ...

L = get(a, 'Children')

... and verify the Type:

>> get(L, 'Type')

ans =

line

Now you can set the Marker property of the line:

set(L, 'Marker', 'o')

This documentation page is a good reference which explains which objects can be children of other objects, and which properties objects have.

[Patrick Kalita]

I should point out that Arnaud's answer is a better solution. It is always preferable to hold on to the handle that a function (like plot) returns, rather than diving through the 'Children' property of objects. This method should only be used when absolutely necessary (i.e. you use a function that doesn't return a handle).

[Matt Fig]

An alternative would be to use FINDOBJ.

L = findobj(gcf,'type','line')

Answer 3

[Matt Fig]

You could also try this tool, which allows you to make arbitrary changes with a mouse-click:

LINECMENU

The preview image shows the options available when you right click on a line.