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I’ve got a question about the editor. About 10 1/2 minutes into the video, you edited two lines at the same time (changing “set(hdd(pairNum)” to “set(hdd(current)”. I was curious if you really did change both lines at the same time, and if so, how did you do it.
Thanks
Dan,
Sorry no, that was just video editing. In an effort to keep the video shorter this time, I was cutting out parts where I was silently typing. I highlighted them blue in an effort to give an idea that I was ‘faking it’.
Sorry for the confusion!
Doug
I am glad you are using a technique I also use for GUIs, namely saving data in the ‘userdata’ field of objects and/or the main figure. In my opinion this is much clearer then using handles to nested functions.
You can even store more information in the userdata field using a struct. It just needs some discipline and little more lines of code for adding or updating data:
str = get(gcf, ‘userdata’);
str.myfield = something;
set(gcf, ‘userdata’, str);
Markus
I am normally an advocate of SETAPPDATA, GETAPPDATA. However, for this specific case I was storing a very small amount of data and this was a very easy way of doing this.
Thanks for adding to this with your technique.
Doug
Great Post, I always tried to do this but could never get it to work properly.
Is there a similar way to do this with a ‘line’ instead of a ‘point’. If I were to make a line with a ButtdownFnc is there a way I could get the (x,y) coordinates of the clicking? I see that I could potentially plot each of the points individually as you did above, but it seems like there might be a more elegant way to do this.
Thanks
plot(rand(1,10))
k = waitforbuttonpress;
point1 = get(gca,’CurrentPoint’)
This will get you the current point that you click on. An example like this was done here:
http://blogs.mathworks.com/pick/2007/12/26/advanced-matlab-buttondownfcn/
Hi Doug,
Nice video, One question though:
How does the “highlightPair” function knows the variables hdd & hdp?
Thanks,
Yonathan
Yonathan,
hdd and hdp were in scope in the highlightPair function because it is a nested function and has access to the variables of the outer function. See this video for more details:
http://blogs.mathworks.com/pick/2008/02/01/matlab-basics-nested-functions/
Thanks,
Doug
Hi Doug,
In your demo the main function has ended. I thought when the function ends all its variables die.
The nested function is called through a callback, why does the callback revive the main function?
Thanks again,
Yonathan
Yonathan,
Two things are happening here: There is a nested function, and a function handle. The function handle (the @ symbol creates it) snapshots the workspace of the main function upon creation. This is how the variable stay “alive”. The scoping into the nested function is as discussed in my video.
Thanks for a great question!
Doug