App Slow With UIAxes

Hi. I'm creating apps on app designer which use components such as sliders to control a plot. When plotting on a UIAxes, there is significant delay. However, when having the app plot on a separate figure, there is no delay. Does anyone know the reason for this and if there's a way to plot on the UIAxes without the delay? Thanks.

I'm going to use an app modelling a cylinder removing a lot of the additional unnecessary stuff, so the type of problem is as clear as possible. The plot consists of surf, patch, and plot3. For all apps, the goal is not plotting data per say, but rather creating shapes, often in 3 dimensions. Therefore, the data is generally arrays of type double which don't generally get over 100 elements.

I'm using MATLAB R2020a.

These are the two methods:

• I drag and drop a UIAxes on to the app and plot on that axis. This takes about 3 seconds to update the plot each time I move the slider. This is a screenshot of the setup:

• I create a separate regular figure (not uifigure) and plot it on that. This has almost no delay:

This is the code used to create the separate figure and have them aligned neatly (I don't think it's that important but it clarifies what I'm doing):

global ax %needed so it can be accessed through component callbacks

divide=.2;%the fraction of the screen filled by the app

set(0,'units','pixels')
pixels=get(0,'screensize');
app.UIFigure.Position=[0,0,divide*pixels(3),pixels(4)];

fig=figure; %new figure
fig.Position=[divide*pixels(3),0,(1-divide)*pixels(3),pixels(4)];
ax=axes(fig); %axis it will be plotted on

Here is the code which I used (I removed much of the code used in the original app to simplify things) (the code is based off of Clay M. Thompson's cylinder function, and I kept the copyright text in the code):

function torsion(ax,ax2,M,G,L,r,display_in)

%   Clay M. Thompson 4-24-91, CBM 8-21-92.
%   Copyright 1984-2002 The MathWorks, Inc. 
cla(ax)

% engineering equations:
J=1/4*r^4;
phi=M*L/(J*G);

% set up cylinder:
n = 50;
r = [r r]';
r = r(:); % Make sure r is a vector.
m = length(r); if m==1, r = [r;r]; m = 2; end
theta = (0:n)/n*2*pi;
sintheta = sin(theta); sintheta(n+1) = 0;

x = r * cos(theta);
y = r * sintheta;
z = (0:m-1)'/(m-1) *L* ones(1,n+1);
hold(ax,'on')

% plot cylinder
surf(ax,x,y,z,'EdgeColor','none','FaceAlpha',1)
patch(ax,x(1,:),y(1,:),z(1,:),[.25 0 .7])
patch(ax,x(1,:),y(1,:),z(2,:),[.25 0 .7])


%plot helices
z_vals=linspace(0,L,n*L/(2*pi*r(1)));
for i=0:n-1
    angle0=i*(2*pi)/n;
    anglef=angle0+phi;
    theta_part=linspace(angle0,anglef,length(z_vals));
    x_part=(r*1.01)*cos(theta_part);
    y_part=(r*1.01)*sin(theta_part);
    z_vals=linspace(0,L,length(x_part));
    plot3(ax,x_part,y_part,z_vals,'k','LineWidth',.5)
end

% plot circles
for i=z_vals
plot3(ax,x,y,i*ones(1,n+1),'k','LineWidth',.5)
end

end

[J. Alex Lee]

is the separate figure created using "figure" or "uifigure"? I've also perceived (no hard data) that the new uifigure system is generally slower...

if using uifigure, are you creating a "uiaxes" inside it, or just an "axes"?

[Chris Portal]

Ephraim, can you share a little more info? Specifically:

• What kind of plot you're creating
• Data sizes / datatypes you're trying to display
• Sample code you're using that might illustrate the problem
• What MATLAB release you're working on

Thanks!

[Ephraim Bryski]

Thanks for the responses! I updated the question with the information.

[Adam Danz]

Could you attach the app, any data needed to run the app, and instructions on how to use the app to recreate the problem?

There are some suboptimalities in the code you shared that probably aren't causing the timing issues but could potentially cause other problems at some point.

1) Don't use global variables. The correct way to pass variables from within the app is to define public or private properties. Instructions:

https://www.mathworks.com/help/matlab/creating_guis/share-data-across-callbacks-in-app-designer.html.

2) Rather than using set(0, ___), set the properties to specific objects.

What's up with the last loop? Nothing changes within the loop so you're just plotting the same thing repeatedly.

[Ephraim Bryski]

Here is the link to the app on File Exchange. No data is needed to run it, simply run the TORSION file. The app also has some additional things displayed (e.g. text to label the cylinder) so you won't be able to recreate the screenshots exactly, but you can just adjust the sliders to get to the same position as the screenshots.

Thank you for your advice. I will use app properties for the axis from now on and set the units to the specific object.

The last loop plots circles at different heights (the i value changes in each iteration, changing the z position).

[Adam Danz]

I'm really confused here. Your question is about a uiaxis but your app doesn't contain a uiaxis.

Also the figure sizes are so large that I cannot work with them and have to manually resize them before I can do anything else. It would be much better to remove the figure possition commands and to let the user resize the app as needed.

[Ephraim Bryski]

No, it doesn't. I would like to use a UIAxes instead of creating a separate figure, but it is very slow if I take that approach.

I didn't know that the figures don't fit when using a different computer (I've only seen it on mine so far). I think I'll make that change.

[Adam Danz]

@Ephraim Bryski & @Chris Portal, I timed the startupFcn which does all of the plotting and some other stuff (much of which is suboptimal) and compared the timing when an embedded uiaxis is used within the app and when the external figure and (regular) axis is created. This was repeated 10 times. Results are below. Note that the app-uiaxes are created prior to the tic-toc time but the external figure and axes are created within the tic-toc time. Nevertheless, the independent axis version is ~7x faster (MATLAB Version: 9.7.0.1296695 (R2019b) Update 4).

I ran the profiler on the startup function using the app's uiaxis which shows the greatest Self Time within UIAxis.set.View.

[Ephraim Bryski]

Thank you so much! I couldn't figure out how to run and time for an app. How were you able to do this?

I don't really understand what UIAxes>UIAxes.set.View is or how to optimize it. Do you think there's an way to speed it up? I also would guess that this might only be called in the startup function and not for each callback, in which case speeding it up wouldn't actually make it faster when using the app.

[Adam Danz]

A simply way to time a section of code is by using tic and toc (check out the documentation).

Example

tic
x = linspace(-pi,pi,180); 
y = sin(x); 
plot(x,y)
toc

The timing report was produced using profile. Again, see documentation.

profile on
% DO STUFF
profile viewer

Most of the stuff in the timing report I shared, including the line I highlighted, is stuff happening behind the scenes. You can't optimize much of that. However, there's a few suboptimalities in your startupFcn. I've shut down Matlab for the day so I can't view the code now but I did highlight two items in my first comment in this thread. I also recall seeing two axes being created but only one was used.

Answer 1

[Chris Portal]

Thank you @Adam Danz and @Ephraim Bryski. The additional info is useful. I see the same uifigure/uiaxes slowness Adam is showing.

Ephraim, try using a uifigure/axes combination instead. This shows similar performance results to the figure/axes combination:

• UIFIGURE/UIAXES: Elapsed time is 1.871439 seconds.
• UIFIGURE/AXES: Elapsed time is 0.205658 seconds.
• FIGURE/AXES: Elapsed time is 0.204895 seconds.

A few notes:

• UIAXES is a heavier weight version of AXES (it's effectively an axes with an invisible UI panel). This makes it slower, although the amount of slowness here is a little surprising. I'll report this to the development team to investigate.
• The axes you get in App Designer when you drag and drop from the palette is always a UIAXES. So in order to use an AXES with your UIFIGURE, you'll need to manually create and position it as part of your startup function.
• Lastly, these UIAXES/AXES differences will soon become a much simpler story with some up and coming work. Keep an eye out for the MATLAB release notes!

[Florin]

Hello,

Are the app-uiaxes issues solved with 2020b? (reading in the relase notes:'Also, UIAxes objects now have the same properties and options as Axes objects have for customizing their appearance and behavior:')

I am using this method: https://www.mathworks.com/help/matlab/ref/uigridlayout.html#mw_9f162f16-28ed-46bb-8bfa-cbd2efd0d143 to show/hide some grids in App Designer containing uiaxes and uitable and there is a noticeable lag while hiding or showing the grid. The lag is mostlty comming from 'clipping' and resizing the axes or table (do not confuse with axes clipping property!)

I tried to hide the grid childred while folding (setting RowHeight(i) = {0}) or unhide while unfolding (RowHeight(i) = {'2x'}) but it doesnt seems to bring any visual improvement for the app

Thanks!

[Mario Malic]

It still is an issue, and is probably being fixed. My issue is with 3D rotation, it takes around 3-7 seconds to even start moving. I have attached code and variables to test.

[Alberto Lutman]

In 2020b it is still an issue.

How do I use the UIFIGURE/AXES combination?

I tried to use:

app.AX=axes('parent',app.UIFigure);

in the startup function, and then plot in app.AX, it is not faster than the UIAXES generated by app designer, and the FIGURE/AXES combination is still at least 7 times faster.