When we plot a bode/nichols locus, the name of workspace variable is used
tmp=ss(1,1,1,0);
nichols(tmp);
will use 'tmp' as label.
When using more complex data, matlab is using 'untitled1','untitled2',...
tmp={ss(1,1,1,0) , ss(1.2,1,1,0)};
nichols(tmp{:});
How can I change this label programmatically?
Ideally, I'd like a solution working with Matlab 6.5.1, but I'm also interested in solutions restricted to newer versions.
You can modify the labels programmatically via their graphics handles. It looks like the values you want to change are the DisplayName property of some of the children of the current axis. So in your first example, I can change the display name like this:
ch = get(gca,'Children');
set(ch(1),'DisplayName','Fred');
In general, I'm not sure how to predict which children of the current axis are the ones you need to change. For the second example you give, the two curves appear to be the second and third children when I run your code.
Related
Problem
In a GUI I've written I've realized that the largest bottleneck in my code performance is creating/updating the legend.
Currently I delete and recreate the legend at each update of the GUI as the user needs to be able to adjust what is in the legend. I'm currently toggling what is in the legend by adjusting the setting of LINEHANDLE.Annotation.LegendInformation.IconDisplayStyle and updating the legend using legend('off');legend('show');
Testing
The following code snippet shows that the call of legend mostly is limited by the call to legend>make_legend and is fairly independent of the legend content.
close all
n=50; % number of plot lines
S=rand(n); % data
legs=cellstr(char(26*rand(n,10)+97)); % legend entries
profile on %start profiler
plot(S)
legend(legs{:})
profile viewer % view call stats
Question
Is there a better way of updating legend content without deleting it and therefore forcing it to re-call make_legend at recreation?
Furthermore I wonder if it is known why legend in general is so slow and has such odd behavior.
Purpose
I'm adding some information here to avoid the XY Problem.
A minimal example of what I'm trying to do is:
I'm building a GUI which plots four lines, let's call them data1, data2, linear model 1, and linear model 2. The data lines are independent in both color and content, while the linear models both have the same appearance and are connected to respective data line.
I want there to be a legend which only has three entries: data1, data2, and linear model. So far, no problem.
I also want there to be three toggle-buttons which toggle the visibility of the four lines on the axes and legend. The buttons are:
data1, which toggles the visibility of both the data1, and linear model 1 data lines.
data2, which toggles the visibility of both the data2, and linear model 2 data lines.
linear model, which toggles the visibility of the linear model 1, and linear model 2 data lines.
Attempted Solutions
My first approach was to first only pass three handles to legend and then have the button callbacks adjust the visibility property of the line objects according to above.
This creates the issue that when disabling the first data line and respective linear model the legend entry for linear model also blanks out as it is connected to that specific line object, even though the other is still visible.
My current working approach instead manually sets the DisplayNameproperty of all lines and then the button callbacks adjust each lines Annotation.LegendInformation.IconDisplayStyle property. According to the documentation the user then needs to call legend to force an update.
But this is not implemented, looking at the code of legend.m it is clear that this option only returns the current legend object without any other manipulation. Therefore I'm forced to call legend('off');legend('show'); which triggers a (slow) creation of a new legend object.
This currently works but using profile I can see that the legend creation is half my computation time and has a fairly large effect on user experience when using the GUI on a slower laptop. I've already ensured that my code runs legend('off');legend('show'); only if it really has to.
The question is if any user here is able to call the unreadable, yet accessible class methods of matlab.graphics.illustration.Legend to trigger an update of an existing object without forcing it to delete and recreate. Thereby doing what the MATHWORKS documentation claims to be implemented (although it is not) in legend.
Alternatively I'm open to finding a different way of changing which line objects the current legend is tracking efficiently.
You can try to change the properties of the legend object directly. Look at http://www.mathworks.com/help/matlab/ref/legend-properties.html for a list of properties. The legend object can be accessed by:
% Assign the output of legend to a variable. Do this only once at creation.
l = legend(<some arguments>);
% Example: change the location of the legend to 'north'
l.Location = 'north';
I think this is what you asked for, but I'm not sure about any efficiency gains.
In Matlab, I create a fairly complicated 3D plot, then manipulate the view option by hand up to a point where I am happy with what I see (below). How can I reuse the parameters of the final view? I can get the output of the view command which is a 4 by 4 matrix, but the latter does not seem to be reusable?
In order to get something out of view that you can then pass to view to reconstruct the viewpoint, you need to specify two outputs to view which will yield the current azimuth and elevation.
[az, el] = view(ax1);
You can then pass these to view on a different (or the same) axes to specify the viewpoint
view(ax2, az, el);
You can also use the View property of the axes object.
AzEl = get(ax1, 'View');
set(ax2, 'View', AzEl);
Note, however, that there are many properties which control the view of an axes including the Projection, the DataAspectRatio, the PlotBoxAspectRatio and all of the camera properties. Depending on your use case, you may need to specify these as well.
ok, based on Suever's comments, I realized that all the figure properties I need can be accessed through the Graphical Interface called matlab.graphics.axis.Axes. This is where the parameters of the camera can be found. Another approach is to find them one by one as follows:
get(gca,'Projection')
get(gca,'CameraPosition')
get(gca,'CameraViewAngle')
get(gca,'CameraTarget')
and then set them directly in the script:
set(gca,'Projection','perspective')
set(gca,'CameraPosition',[-7 -5 3]/15)
set(gca,'CameraViewAngle',85)
set(gca,'CameraTarget',[0 .5 0])
I originally thought the view command would provide this information at once.
I try to remove the Matlab-given units from this plot but I don't find a way:
figure(1)
hold on
set(gcf,'PaperUnits','centimeters',...
'PaperSize',[15 9],...
'PaperPosition',[0 0 15 9]);
pzmap(LB); sgrid; grid on; axis equal;
title('');
xlabel('\sigma [rad/s]')
ylabel('\omega [rad/s]')
hold off
After that commands the xlabel looks like this: \sigma [rad/s] (seconds^-1). The seconds comes with pzmap. How can I remove them?
I found, some strange behavour:
If generate code by the figure plot manager I get this:
% Create xlabel
xlabel('\sigma [rad/s] (seconds^{-1})','Units','pixels');
Why???
Now I get it - without pzmap/pzplot
pol = pole(sys)
figure(1)
plot(real(pol(:)),imag(pol(:)),'x')
title('');
xlabel('\sigma [rad/s]');
ylabel('\omega [rad/s]');
sgrid
pzmap is a high-level convenience function, but it's not the best choice for this (it's also stored in a folder of obsolete functions in R2013a, so it may get marked for official removal in the future). Instead, let's create an example plot using pzplot directly instead of pzmap. This is still a plot function that does a lot under the hood, but it returns a handle, h, to the plot:
sys = rss(3,2,2);
h = pzplot(sys);
sgrid;
axis equal;
We can via the options of a pzplot with getoptions:
p = getoptions(h)
To set the labels and units as you desire, you might try this, using setoptions:
p.Title.String = '';
p.XLabel.String = '\sigma';
p.YLabel.String = '\omega';
setoptions(h,p);
I believe that the units of 'seconds-1' that the plot displays is equivalent to the 'rad/s' that you want to specify. I know that the two look is very different (I prefer being specific about radians myself), but that's a disadvantage of using such a plot function that tries to do everything for you. If you wanted to remove the default string or add another option, you'd likely have to do some low level hacking. An easier way around, might be to use the "Generate Code..." command ("Generate M-File..." in older versions") under the "File" menu in the figure's toolbar and edit the plot labels there (there's also a programmatic option for this on the File Exchange). Or you could output to postscript and edit that.
Alternatively, you can use pzoptions to create a list of options to pass to pzplot or pzmap (undocumented in the latter case):
p = pzoptions;
p.Title.String = '';
p.XLabel.String = '\sigma';
p.YLabel.String = '\omega';
sys = rss(3,2,2);
pzplot(sys,p);
sgrid;
axis equal;
You'll see that that for some reason the text size is much smaller in this case. pzplot and pzmap must set the font size to 10 themselves. You could easily do this.
Fore more on customizing this and related Control toolbox plots, see this article.
After intense low-level digging, there is actually a pretty simple way to override the default behavior.
p = pzplot(sys);
p.AxesGrid.XUnits = 'rad/s';
p.AxesGrid.YUnits = 'rad/s';
Changes appear to take effect immediately. I have even tried setting the value to nothing, i.e.
p.AxesGrid.XUnits = '';
and it effectively removes the annoying parenthesis with the units. Technically, matlab creates a custom-class element they store under the name AxesGrid in the resppack.mpzplot class instance, with some standard LTI-behavior. You can probably work around some stuff by "injecting" a script with the same name as one of the standard library functions, so that it will be called instead, and change things in there, but this is the closest I have come to removing those annoying units in a few lines.
As a side info, the AxesGrid object is initialized in
...\controllib\graphics\#resppack\#pzplot\initialize.m
should you want to check it out.
I have drown several graphs thanks to "subplot" function on MatLab and it works well.
Nevertheless, I want all my graphs to have the same Y-scale so that I can compare them.
I used the "linkaxes" function and my all my graphs have the same scale but the problem is that some of my figures are "beheaded", lacking their upper part, or one of my figures is completely squeezed.
I don't get what happened. Could you please help me to solve the problem or tell me about another function that would be more appropriate in my case?
Here's part of my code:
for i=1:1:9
m=n(i);
fichier=sprintf('%d.txt',m);
M=load(fichier);
z=length(M(:,1));
x=M(1:z,1);
y=M(1:z,2);
a(i)=subplot(2,4,i)
contour3=plot(x,y)
linkaxes(a,'y')
end
linkaxes creates a permanent link between the scales of several axes, so that you can subsequently perform zoom operations (perhaps interactively) on one, and have the other automatically update.
If you need that functionality, then linkaxes is the right command (although you could possibly also look at linkprops).
However if all you need is to ensure that the y-axis limits of your axes are the same, it will probably be easier (and you will have more control) if you set them directly. You can retrieve the y-axis limits using ylim(axis_handle) and set them using ylim(axis_handle, [lower, upper]), or alternatively with get(axis_handle,'YLim') and set(axis_handle,'YLim',[lower,upper]). You might also look at the YLimMode property of the axis, which determines whether the axis limits are directly set or automatically resized.
I plotted few points using scatter and then label them using text. The position of these labels are same as the position of the points + some offset. Some of these text label overlap with each other and hence I moved them interactively (using mouse). I can check the new position of each of these text individually using property editor. However this is very time-consuming. Is there a better way to get the coordinates of all these text-label?
You can use findobj to get handles to text objects that are children of the current axes (or another handle... your choice):
text_handles = findobj('parent',gca,'type','text');
Then you can get the positions of these text objects:
positions = get(text_handles,'position');
You may need to do a bit more work to associate each text object with its data point - I suggest taking advantage of the property system, perhaps via the UserData field, for this, though there are many options.
If you want to do it easily later do this in your plots, for example:
h=text(2.9,7.5,'MyText');
This will put "MyText" at position 2.9, and 7.5.
Then to change the position use:
set(h,'Position',[2.5 7]);
This will change the position to 2.5 and 7.
Later if you need to see tthe position of text again use:
get(h);
Hope this helps.