add event debouncer dependency

Author: tjdcs

EventDebouncer.m

@@ -0,0 +1,65 @@
+classdef EventDebouncer < handle
+    % EventDebouncer
+    %
+    % Very useful for limiting the number of times a callback is executed. For
+    % example when listening to markedClean events on graphics objects.
+    %
+    % debounce = EventDebouncer(1); %Throttle to 1s
+    % for i = 1:10 
+    %    debounce(@() disp(i)); 
+    %    pause(.2);
+    % end
+    %
+    % Can debounce any number of function handles. debounce(@f1,@f2,@f3...);
+    % Can be default constructed for 100ms.
+    %
+    % For an explination of what debounce vs. throttling does see:
+    % https://redd.one/blog/debounce-vs-throttle
+    %
+    properties (SetObservable)
+        delay (1,1) double; %Secconds
+    end
+    properties (Access=private)
+        time (1,1) timer;
+        functionList;
+    end
+    methods 
+        function this = EventDebouncer(delay)
+            arguments
+                delay (1,1) double = .1;
+            end
+            this.delay = delay;
+            this.time = timer(...
+                "StartDelay", this.delay,...
+                "TimerFcn", @(~,~) this.callFcns());
+            
+            this.addlistener("delay", "PostSet", @(~,~) this.updateTimerDelay());
+        end
+        function subsref(this,ref)
+            for i = 1:numel(ref.subs)
+                if ~isa(ref.subs{i}, "function_handle")
+                    error("throttleCalls:MustBeFcnHandle", "Must call with a function handle");
+                end
+            end            
+            if this.time.Running
+                this.time.stop();
+            end
+            this.functionList = ref.subs;
+            this.time.start();
+        end
+        function delete(this)
+            this.time.stop();
+            delete(this.time);
+        end
+    end
+    methods (Access=private)
+        function callFcns(this)
+            for i = 1:numel(this.functionList)
+                this.functionList{i}();
+            end
+        end
+        function updateTimerDelay(this)
+            this.time.StartDelay = this.delay;
+        end
+    end
+end