I'm trying to create an app for data analysis.
I have multiple channels of acquisition of the same length, including a time vector.
Vectors as therefore synchronized (same index value corrispond to the same time instant for every array).
I display data on different figures (UIAxes) in my app figure.
To better and more easily use the application I would like the following to happen: each time the user hovers the cursor on any plot a vertical bar at the corrisponding x position of the cursor is displayed, on all the figures. All the figures display the same range of x values.
I also have a scatter figure with points from gps, still with the same length of the other arrays.
On that figure I'd really like to have, instead of the vertical line, a crosshair.
I've found this part of code here but I can't adapt it to App Designer and it's also pretty old.
Any kind of help is very welcome.
EDIT: Matlab Version 2020b
Related
I am using the Charts library in an iOS application. The required chart I am implementing, displays realtime values fed from a hardware peripheral. I already implemented adding new entries and scrolling to the latest value, so the chart appears to be updating constantly (sort of flowing to the left from the right side of the screen).
Now I need to draw a circle on the right side of the graph, but for that I would need to receive the Y value for the currently visible X. This is easy to get for the points in the DataSet, but I can't find a way to get Y value for the interpolated points between the DataSet values.
Here is what the graph looks like:
I am trying to get better quality phase plots of complex functions made with the Complex Function Explorer of E. Wegert CFE. For this purpose I apply the Matlab anti-aliasing function myaa.m to the phase plots that are made with the CFEGUI.m. For the example screenshot of the result window below I used the setting myaa([8 8]) in the Matlab command window which means that the supersampling enlarge the figure 8x and then downscale it to 1/8 to get the original h x w.
As one can see the window of the figure has no operation icons or menu options for save or print. My question is what to do with such a figure (beside making screenshots)? Can I somehow use export-fig to save such a figure or load it in an image array and if yes, how?
It is also possible to use the setting myaa([8 1]) which results in a very large figure window that is larger than my screen (and has the unpleasant attribute that it can not be moved). It would be even better if such a whole figure could be saved (not only the visible part).
You can use getframe to grab current figure information in pixels.
However, while I do not know how this affects you, notice that MATLAB versions above 2014b (included) have already anti-aliasing. The code you linked seem to be from 2008, I am not 100% sure if it has become obsolete now.
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.
When I make a figure in Matlab, with a legend and a rectangle that touches the y axis (strange, I know) upon exporting the figure to eps (or pdf) I've noticed that the rectangle obtains the line-style of the last line drawn (rather than what the rectangle was drawn with)
This behaviour also occurs for rectangles drawn after the one that touches the axis...
This doesn't happen if the rectangle is drawn before the legend is created....
Needless to say, it took me half a day to create a minimal example:
clf
L=plot(X,sin(X),'--');
legend(L,'sin(x)')
rectangle('position',[0.001,.1,.7,.7])
rectangle('position',[0,.5,.6,.7])
rectangle('position',[0.001,.3,.5,.7])
%legend(L,'sin(x)')
On the screen the 3 rectangle have solid lines, as they should. but once they are exported, the result has the last two with dashed lines (like the sin(x)). If the legend command is done later (as in the commented out line), everything works as it should....
Is this a feature or a bug?
This is not a feature. I am submitting this to development.
You found a workaround that works with minimal code gymnastics. I would document it in your code so someone does not change it unknowingly and move on.
If you are open to other output formats, notice this is not an issue with formats that use an output filter of MATLAB.
http://www.mathworks.com/access/helpdesk/help/techdoc/ref/print.html
(Graphic Format Files section, right column in table)
-Doug, Advanced Support at MathWorks dealing with graphical issues.
I want to use core-plot for drawing line graph dynamically. data won't come at a time, we will be receiving point by point dynamically.
Is it possible to draw the chart dynamically using core-plot i.e drawing point by point as on when we receive the (x,y) point?
Please help me, Thanks.
Yes, you can do this reasonably easily. For each received data point, append it to an array of values to display. As these data points come in, call -reloadData on the Core Plot graph (or just the particular plot) to redraw the graph, passing in the array you just added a value to in response to the -numbersForPlot:field:recordIndexRange: delegate method.
If you need to adjust the plot range to track your data points (for a moving ticker), recalculate the new CPPlotRange for the X axis and set the plot space's xRange property to that.
Use the CPTestApp-iPhone, AAPLot, or StockPlot examples as templates for how to set up the line chart overall, and modify from that starting point.
I do something similar to this on the Mac in a scientific application:
(source: sunsetlakesoftware.com)
Sounds like you could make use of a demo project I put together and wrote about here (not core plot related though).
It draws a EKG graph but should easily be modified to use another input than the repeated "heart beat"...See line 320 in EAGLView.m where the indata is entered into the array.