[Waterloo] Draggable Line?

I'm finding the Waterloo package very useful to enhance Matlab plots. However, I'm still wrapping my head around how to work directly with some of the Java objects. (Clearly, I'm not a Java programmer!)

For example, I have a very simple GXGraph() plot:

% Generate some fake data
x = linspace(-10, 10, 100);                 % X Data
y = sin(x./10 .* 2 .* pi);                  % Y Data

% Plot the Data
gfig = GXFigure();                          % Waterloo figure handle
gr1   = subplot(gfig, 1, 1, 1);             % Create Graph 1 (gr1)
data1 = scatter(gr1, x, y);                 % Plot a scatter graph

(Of course, the above example only works after Waterloo has been added to MATLAB's path, and the initial 'waterloo.m' script has been run.)

Now, I'd like to add a line to my graph. I can do this:

% Add a line
annotation(gr1, 'line',  [5, 5], [-1, 1]);  % Add Line
gr1.getObject().repaint();                  % Update Graph

...But I don't know how to:

(1) allow the user to move the line

(2) add a callback to notify me when the line is moving

Ultimately, I'm trying to get something much like Matlab's native imrect() function -- I want to define a resizeable region on my GXGraph.

Any suggestions?

Answer 1

[Image Analyst]

I don't think that will work. annotation works on the whole figure unfortunately, not on the units of the axes control itself like you'd want. There was a discussion of this within the past two weeks. You can create draggable lines with imdistline() or improfile(), both in the Image Processing Toolbox.

[Malcolm Lidierth]

@ImageAnalyst is right as always. Also, for Waterloo, MATLAB annotations can not show up because the Waterloo graphics are painted above any MATLAB annotations in the Z-order. Waterloo provides its own annotation classes but those are presently painted in, and restricted to, a graph container (~=MATLAB axes object) within a GXFigure and are not draggable. Are you after a moveable cursor? That is on the TODO list for Waterloo.

[H.A. Camp]

Ah, I see. Thanks, both of you, for the explanation.

I'm not after a moveable cursor so much as moveable regions of interest: we are plotting spectral data and need to limit the processing to a set of specific regions (say, only the leading and trailing edges, only the middle of the spectra, etc.)

Our spectral display quality has gone way up since switching to Waterloo (yay!) but we're having trouble implementing the equivalent of Matlab's imrect() function. I tried overlaying a matlab axis on top of a Waterloo axis, but found that the Z-order of the Waterloo plot is always on top (as you mentioned).

Perhaps we can use a small Matlab axis below the Waterloo plot to control the ROIs. We'll figure something out.

[Malcolm Lidierth]

The Git repo now includes an imrect-like class: the GJRoi.