Plot legend customization

8 Responses

1. 
   sco1 July 13, 2018 at 04:40 Reply

   Very interesting! I never explored NodeChildren when I was building legtools and was using PlotChildren instead to do things like rearrange the legend, add/remove entries, etc.

   Have you had luck utilizing NodeChildren to perform similar options in MATLAB >= R2017a?
   R2017a introduced AutoUpdate to legend objects which broke pretty much all of the functionality I got from manipulating PlotChildren.

2. 
   Peter Cook July 17, 2018 at 18:17 Reply

   I have recently incorporated the Legend’s ItemHitFcn callback property into a utility I built.
   You can access and edit some relevant objects in the callback function, e.g.

   hLegend.ItemHitFcn = myLegendItemHitFcn(src,evnt);   % The following in the callback function: evnt.Peer %access line, patch, image, GraphPlot, etc... evnt.Item.Label %access text object for that legend entry src.String{evnt.Item.Index} = 'new string'; %edit the legend entry name

   hLegend.ItemHitFcn = myLegendItemHitFcn(src,evnt); % The following in the callback function: evnt.Peer %access line, patch, image, GraphPlot, etc... evnt.Item.Label %access text object for that legend entry src.String{evnt.Item.Index} = 'new string'; %edit the legend entry name

• 
  Yair Altman July 18, 2018 at 10:58 Reply

  @Peter – while the legend object’s ItemHitFcn callback property is documented/supported, the Item property of the eventData object (which is passed to the callback function in run-time when you click a legend entry) is indeed hidden/undocumented. This eventData.Item property contains the LegendEntry item that was clicked. Thanks for pointing it out.

3. 
   Aaron March 8, 2019 at 13:38 Reply

   It would appear that if you’re using these properties in a function or loop it is important to call drawnow before attempting to utilise any of the LegendEntry objects, otherwise they will not exist yet and you will get errors.

4. 
   Praveen March 27, 2019 at 19:55 Reply

   Hi That’s alright, how do I set for example, marker size in the legend, when I try to set it: hLegend.EntryContainer.NodeChildren(1).Icon.Transform.Children.Children.Size = 15; I get an error saying I can’t set readonly properties, any tips how to go about that. Thanks

• 
  Yair Altman March 29, 2019 at 16:40 Reply

  @Praveen – first note that you have to call drawnow before accessing any of the internal legend components. In addition, note that hLegend.EntryContainer.NodeChildren(1).Icon.Transform.Children.Children returns an array of objects (Marker and LineStrip) and you can only set the Size property of the Marker, not the LineStrip (duh). Here’s a working example:

  figure; hold all; hLine1 = plot(1:5,'o-b'); hLine2 = plot(2:6,'-sr'); hLegend = legend([hLine1,hLine2], 'Location','SouthEast'); hLegend.Title.String = 'MyLegend'; drawnow; hLegend.EntryContainer.NodeChildren(1).Icon.Transform.Children.Children(1).Size = 15;

  figure; hold all; hLine1 = plot(1:5,'o-b'); hLine2 = plot(2:6,'-sr'); hLegend = legend([hLine1,hLine2], 'Location','SouthEast'); hLegend.Title.String = 'MyLegend'; drawnow; hLegend.EntryContainer.NodeChildren(1).Icon.Transform.Children.Children(1).Size = 15;

5. 
   Dev June 25, 2019 at 14:42 Reply

   Same question as sco1: Have you had luck utilizing NodeChildren to perform similar options in MATLAB >= R2017a?

6. 
   Gres June 15, 2022 at 07:35 Reply

   In 2018b, you can get the icons by calling [hh,icons,plots,txt] = legend({‘Line 1’});

Leave a Reply

<pre lang="matlab">
a = magic(3);
disp(sum(a))
</pre>

Click here to cancel reply.