obj = dynamicplot(genFcn, T)
creates a figure that is automatically updated (by calling a generator function genFcn) every T seconds. obj is a handle to the created object.
E.g.: d = dynamicplot(@() randn(1,100), 0.5);
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The DYNAMICPLOT class demonstrates how to get reference (aka. handle) semantics using MATLAB classes. Typically when one modifies a MATLAB object, it needs be returned to the caller:
obj = set(obj, 'myParameter', 10.0);
But with handle semantics, you can simply do this:
set(obj, 'myParameter', 10.0);
Handle semantics is especially useful with objects that need to be updated autonomously (e.g., acquiring data from a data aquisition device or an instrument).
The handle semantics were accomplished as follows.
(1) the constructor defines the instance variables and
(2) returns a set of function handles to access these instance variables.
(3) Other methods use only the function handles to access and modify the data.
Detailed example of handle semantics:
d = dynamicplot(@() randn(1,100), 0.5);
getdata(d) % try this several times
setUpdatePeriod(d, 0.2)
getNumUpdates(d) % try several times
setLineStyle(d,'color','r');
% Object assignment respects the
% handle semantics. d and d2 refer
% to the same object.
d2 = d;
pauseDisplay(d);
resumeDisplay(d2);
% Validity checks can be built into
% the object itself
delete(d);
getdata(d) % will generate an error
getdata(d2) % generates error also
% It is possible to have multiple
% objects without any clashes
d1 = dynamicplot(@() randn(1,100), 0.1);
d2 = dynamicplot(@() rand(1,100), 0.1);
pauseDisplay(d1);
getNumUpdates(d1)
getNumUpdates(d2)
resumeDisplay(d1);
delete(d1);
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NOTE: The primary purpose of the DYNAMICPLOT class is to demonstrate how to get handle semantics with MATLAB classes. Feel free to improve or extend the functionality. |
