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MyGuiSync.m
5d8c15df5bafTekRSA-Freq-vs-Time

MyGuiSync.m
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			% A mechanism to implement synchronization between parameters and GUI
			% elements in app-based GUIs

			classdef MyGuiSync < handle

			properties (GetAccess = public, SetAccess = protected)

			Listeners = struct()

			% Link structures
			Links = struct( ...
			'GuiElement', {}, ... % graphics object
			'gui_element_prop', {}, ...
			'inputProcessingFcn', {}, ... % applied after a value is
			... % inputed to GUI
			'outputProcessingFcn', {}, ... % applied before a new value is
			... % displayed in GUI
			'getTargetFcn', {}, ...
			'setTargetFcn', {}, ...
			'Listener', {} ... % PostSet listener (optional)
			);

			% List of objects to be deleted when App is deleted
			cleanup_list = {}
			end

			properties (Access = protected)
			App = []
			updateGuiFcn
			createCallbackFcn
			end

			methods (Access = public)
			function this = MyGuiSync(App, varargin)
			p = inputParser();

			addRequired(p, 'App', ...
			@(x)assert(isa(x, 'matlab.apps.AppBase'), ...
			'App must be a Matlab app.'));

			% Deletion of kernel object triggers the delition of app
			addParameter(p, 'KernelObj', [], @(x)assert( ...
			ismember('ObjectBeingDeleted', events(x)), ...
			['Object must define ''ObjectBeingDeleted'' to be an ' ...
			'app kernel.']));

			% Optional function, executed after an app parameter has been
			% updated (either externally of internally)
			addParameter(p, 'updateGuiFcn', [], ...
			@(x)isa(x, 'function_handle'));

			addParameter(p, 'createCallbackFcn', [], ...
			@(x)isa(x, 'function_handle'));

			parse(p, App, varargin{:});

			this.updateGuiFcn = p.Results.updateGuiFcn;
			this.createCallbackFcn = p.Results.createCallbackFcn;

			this.App = App;
			this.Listeners.AppDeleted = addlistener(App, ...
			'ObjectBeingDeleted', @(~, ~)delete(this));

			if ~ismember('KernelObj', p.UsingDefaults)

			addToCleanup(this, KernelObj);

			this.Listeners.KernelObjDeleted = addlistener(KernelObj,...
			'ObjectBeingDeleted', @this.kernelDeletedCallback);
			end
			end


			function delete(this)

			% Delete general listeners
			try
			lnames=fieldnames(this.Listeners);
			for i=1:length(lnames)
			try
			delete(this.Listeners.(lnames{i}));
			catch
			fprintf(['Could not delete the listener to ' ...
			'''%s'' event.\n'], lnames{i})
			end
			end
			catch
			fprintf('Could not delete listeners.\n');
			end

			% Delete link listeners
			for i=1:length(this.Links)
			try
			delete(this.Links(i).Listener);
			catch
			end
			end

			% Delete the content of cleanup list
			for i = 1:length(this.cleanup_list)
			Obj = this.cleanup_list{i};
			try

			% Check if the object has an appropriate delete method.
			% This is a safety measure to never delete a file by
			% accident.
			if ismethod(Obj, 'delete')
			delete(Obj);
			else
			fprintf(['Object of class ''%s'' ' ...
			'does not have ''delete'' method.\n'], ...
			class(Obj))
			end
			catch
			fprintf(['Could not delete an object of class ' ...
			'''%s'' from the cleanup list.\n'], class(Obj))
			end
			end
			end


			% Establish a correspondence between the value of a GUI element and
			% some other property of the app
			%
			% Elem - graphics object
			% prop_tag - reference to a content of app
			function addLink(this, Elem, prop_ref, varargin)

			% Parse function inputs
			p = inputParser();
			p.KeepUnmatched = true;

			% The decision whether to create ValueChangedFcn and
			% a PostSet callback is made automatically by this function,
			% but the parameters below enforce these functions to be not
			% created.
			addParameter(p, 'create_value_changed_fcn', true, @islogical);
			addParameter(p, 'event_update', true, @islogical);

			parse(p, Elem, prop_tag, varargin{:});

			% Make the list of unmatched name-value pairs for subroutine
			sub_varargin = struct2namevalue(p.Unmatched);

			% Find the handle object which the end property belongs to,
			% the end property name and, possibly, further subscripts
			[Hobj, hobj_prop, RelSubs] = parseReference(this, prop_ref);

			% Check if the specified target is accessible for reading
			try
			if isempty(RelSubs)
			Hobj.(hobj_prop);
			else
			subsref(Hobj.(hobj_prop), RelSubs);
			end
			catch
			disp(['Property referenced by ' prop_ref ...
			' is not accessible, the corresponding GUI ' ...
			'element will be not linked and will be disabled.'])
			Elem.Enable = 'off';
			return
			end

			% Create the basis of link structure (everything except for
			% set/get functions)
			Link = makeLinkBase(this, Elem, prop_ref, sub_varargin{:});

			% Do additional link processing in the case of
			% MyInstrument commands
			if isa(Hobj, 'MyInstrument') && ...
			ismember(hobj_prop, Hobj.command_names)
			Link = extendMyInstrumentLink(this, Link, Hobj, hobj_prop);
			end

			% Assign the function that returns the value of reference
			Link.getTargetFcn = createGetTargetFcn(this, Hobj, ...
			hobj_prop, RelSubs);

			% Check if ValueChanged callback needs to be created
			create_vcf = p.Results.create_value_changed_fcn && ...
			checkCreateVcf(this, Elem, elem_prop, Hobj, hobj_prop);

			if create_vcf

			% A public CreateCallback method needs to intorduced in the
			% app, as officially Matlab apps do not support external
			% callback assignment (as of the version of Matlab 2019a)
			assert(~isempty(this.createCallbackFcn), ...
			['Matlab app must define a public wrapper for ' ...
			'createCallbackFcn in order for GuiSync to be able to ' ...
			'automatically assign ValueChanged callbacks. ' ...
			'The wrapper method must have signature ' ...
			'publicCreateCallbackFcn(app, callbackFunction).']);

			% Assign the function that sets new value to reference
			Link.setTargetFcn = createSetTargetFcn(this, Hobj, ...
			hobj_prop, RelSubs);

			Elem.ValueChangedFcn = createValueChangedCallback(this, ...
			LinkStruct);
			end

			% Attempt creating a callback to PostSet event for the target
			% property. If such callback is not created, the link needs to
			% be updated manually.
			if p.Results.event_update
			try
			Link.Listener = addlistener(Hobj, hobj_prop, ...
			'PostSet', createPostSetCallback(this, LinkStruct));
			catch
			end
			end

			% Update the value of GUI element
			updateLinkedElement(this, Link);

			% Store the link structure
			this.Links(end+1) = Link;
			end

			function reLink(this, Elem, prop_ref)

			% Find the link structure corresponding to Elem
			ind = find(arrayfun( @(x)isequal(x.GuiElement, Elem), ...
			this.Links));

			assert(length(ind) == 1, ['No or multiple existing links ' ...
			'found during a relinking attempt.'])

			% Delete and clear the existing listener
			if ~isempty(this.Links(ind).Listener)
			delete(this.Links(ind).Listener);
			this.Links(ind).Listener = [];
			end

			[Hobj, hobj_prop, RelSubs] = parseReference(this, prop_ref);

			this.Links(ind).getTargetFcn = createGetTargetFcn(this, ...
			Hobj, hobj_prop, RelSubs);

			if ~isempty(this.Links(ind).setTargetFcn)

			% Create a new ValueChanged callback
			this.Links(ind).setTargetFcn = createSetTargetFcn(this, ...
			Hobj, hobj_prop, RelSubs);

			this.Links(ind).Elem.ValueChangedFcn = ...
			createValueChangedCallback(this, LinkStruct);
			end

			% Attempt creating a new listener
			try
			this.Links(ind).Listener = addlistener(Hobj, hobj_prop, ...
			'PostSet', createPostSetCallback(this, LinkStruct));
			catch
			end

			% Update the value of GUI element according to the new
			% reference
			updateLinkedElement(this, this.Links(ind));
			end

			function updateLinkedElements(this)
			for i=1:length(this.Links)

			% Elements updated by callbacks should not be updated
			% manually
			if isempty(this.Links(i).Listener)
			updateLinkedElement(this, this.Links(i));
			end
			end

			% Optionally execute the update function defined within
			% the App
			if ~isempty(this.updateGuiFcn)
			this.updateGuiFcn();
			end
			end

			% Update the value of one linked GUI element.
			% Arg2 can be a link structure or a GUI element for which the
			% corresponding link structure needs to be found.
			function updateLinkedElement(this, Arg2)
			if isstruct(Arg2)
			Link = Arg2;

			val = Link.getTargetFcn();
			if ~isempty(Link.outputProcessingFcn)
			val = Link.outputProcessingFcn(val);
			end

			% Setting value to a matlab app elemen is time consuming,
			% so first check if the value has actually changed
			setIfChanged(Link.GuiElement, Link.gui_element_prop, val);
			else
			Elem = Arg2;

			% Find the link structure corresponding to Elem
			ind = arrayfun( @(x)isequal(x.GuiElement, Elem), ...
			this.Links);

			Link = this.Links(ind);

			if length(Link) == 1
			updateLinkedElement(this, Link);
			elseif isempty(Link)
			warning(['The value of GUI element below cannot ' ...
			'be updated as no link for it is found.']);
			disp(Elem);
			else
			warning(['The value of GUI element below cannot ' ...
			'be updated, multiple link structures exist.']);
			disp(Elem);
			end
			end
			end

			function addToCleanup(this, Obj)
			this.cleanup_list{end+1} = Obj;
			end
			end

			methods (Access = protected)
			function kernelDeletedCallback(this, ~, ~)

			% Switch off the AppBeingDeleted callback in order to prevent
			% an infinite loop
			this.Listeners.AppDeleted.Enabled = false;

			delete(this.App);
			delete(this);
			end

			function f = createPostSetCallback(this, Link)
			function postSetCallback(~,~)
			val = Link.getTargetFcn();

			if ~isempty(Link.outputProcessingFcn)
			val = Link.outputProcessingFcn(val);
			end

			setIfChanged(Link.GuiElement, Link.gui_element_prop, val);

			% Optionally execute the update function defined within
			% the App
			if ~isempty(this.updateGuiFcn)
			this.updateGuiFcn();
			end
			end

			f = @postSetCallback;
			end

			% Callback that is assigned to graphics elements as ValueChangedFcn
			function f = createValueChangedCallback(this, Link)
			function valueChangedCallback(~, ~)
			val = Link.GuiElement.Value;

			if ~isempty(Link.inputProcessingFcn)
			val = Link.inputProcessingFcn(val);
			end

			Link.setTargetFcn(val);

			if ~isfield(Link, 'Listener')

			% Update non event based links
			updateLinkedElements(this);

			% Optionally execute the update function defined within
			% the App
			if ~isempty(this.updateGuiFcn)
			this.updateGuiFcn();
			end
			end
			end

			f = this.createCallbackFcn(@valueChangedCallback);
			end

			function f = createGetTargetFcn(~, Obj, prop_name, S)
			function val = refProp()
			val = Obj.(prop_name);
			end

			function val = subsrefProp(val)
			val = subsref(Obj.(prop_name), S, val);
			end

			if isempty(S)

			% Faster way to access property
			f = @refProp;
			else

			% More general way to access property
			f = @subsrefProp;
			end
			end

			function f = createSetTargetFcn(~, Obj, prop_name, S)
			function assignProp(val)
			Obj.(prop_name) = val;
			end

			function subsasgnProp(val)
			Obj.(prop_name) = subsasgn(Obj.(prop_name), S, val);
			end

			if isempty(S)

			% Faster way to assign property
			f = @assignProp;
			else

			% More general way to assign property
			f = @subsasgnProp;
			end
			end

			%% Subroutines of addLink

			% Parse input and create the base of Link structure
			function Link = makeLinkBase(~, Elem, prop_ref, varargin)

			% Parse function inputs
			p=inputParser();

			% GUI control element
			addRequired(p, 'Elem');

			% Target to which the value of GUI element will be linked
			% relative to the App itself
			addRequired(p, 'prop_ref', @ischar);

			% Linked property of the GUI element (can be e.g. 'Color')
			addParameter(p, 'elem_prop', 'Value', @ischar);

			% If input_prescaler is given, the value assigned to the instrument propery
			% is related to the value x displayed in GUI as x/input_presc.
			addParameter(p, 'input_prescaler', 1, @isnumeric);

			% Arbitrary processing functions can be specified for input and output.
			% out_proc_fcn is applied to values before assigning them to gui
			% elements and in_proc_fcn is applied before assigning
			% to the linked properties
			addParameter(p, 'outputProcessingFcn', [], ...
			@(f)isa(f,'function_handle'));
			addParameter(p, 'inputProcessingFcn', [], ...
			@(f)isa(f,'function_handle'));

			parse(p, Elem, prop_ref, varargin{:});

			assert(isempty( ...
			arrfun(@(x) isequal(p.Results.Elem, x.GuiElement), ...
			this.Links)), ['Another link for the same GUI element ' ...
			'that is attempted to be linked to ' prop_ref ...
			' already exists.'])

			% Create a new link structure
			Link = struct( ...
			'GuiElement', p.Results.Elem, ...
			'gui_element_prop', p.Results.elem_prop, ...
			'inputProcessingFcn', p.Results.inputProcessingFcn, ...
			'outputProcessingFcn', p.Results.outputProcessingFcn, ...
			'getTargetFcn', [], ...
			'setTargetFcn', [], ...
			'Listener', [] ...
			);

			% Lamp indicators is a special case. It is often convenient to
			% make a lamp indicate on/off state. If a lamp is being linked
			% to a logical-type variable we therefore assign a dedicated
			% OutputProcessingFcn that puts logical values in
			% corresponcence with colors
			if strcmpi(Elem.Type, 'uilamp')
			Link.gui_element_prop = 'Color';

			% Select between the default on and off colors.
			Link.outputProcessingFcn = @(x)select(x, ...
			MyAppColors.lampOn(), MyAppColors.lampOff());
			end

			% Simple scaling is a special case of value processing
			% functions.
			if ~ismember('input_prescaler', p.UsingDefaults)
			if isempty(Link.inputProcessingFcn) && ...
			isempty(Link.outputProcessingFcn)

			Link.inputProcessingFcn = ...
			@(x) (x/p.Result.input_prescaler);
			Link.outputProcessingFcn = ...
			@(x) (x*p.Result.input_prescaler);
			else
			warning(['input_prescaler is ignored for target ' ...
			prop_ref 'as inputProcessingFcn or ' ...
			'outputProcessingFcn has been already ' ...
			'assigned instead.']);
			end
			end
			end

			function extendMyInstrumentLink(~, Link, Instrument, tag)
			Cmd = Instrument.CommandList.(tag);

			% If supplied command does not have read permission, issue a
			% warning.
			if isempty(Cmd.readFcn)
			fprintf('Instrument property ''%s'' is nor readable\n', ...
			tag);

			% Try switching the color of the gui element to orange
			try
			Link.GuiElement.BackgroundColor = MyAppColors.warning();
			catch
			try
			Link.GuiElement.FontColor = MyAppColors.warning();
			catch
			end
			end
			end

			% Auto initialize the content of dropdown menues
			if isequal(Link.GuiElement.Type, 'uidropdown')
			if all(cellfun(@ischar, Cmd.value_list))

			% Capitalized displayed names for beauty
			Link.GuiElement.Items = cellfun( ...
			@(x)[upper(x(1)),lower(x(2:end))],...
			Cmd.value_list, 'UniformOutput', false);
			else

			% Items in a dropdown should be strings, so convert if
			% necessary
			str_value_list = cell(length(Cmd.value_list), 1);

			for i=1:length(Cmd.value_list)
			if ~ischar(Cmd.value_list{i})
			str_value_list{i} = num2str(Cmd.value_list{i});
			end
			end

			Link.GuiElement.Items = str_value_list;
			end

			% Assign the list of unprocessed values as ItemsData
			Link.GuiElement.ItemsData = Cmd.value_list;
			end
			end

			% Decide if getTargetFcn and, correpondingly, ValueChanged
			% callback needs to be created
			function bool = checkCreateVcf(~, Elem, elem_prop, Hobj, hobj_prop)

			if ~strcmp(elem_prop, 'Value')
			bool = false;
			return
			end

			% Check property attributes
			Mp = findprop(Hobj, hobj_prop);
			prop_write_accessible = strcmpi(Mp.SetAccess,'public') && ...
			(~Mp.Constant) && (~Mp.Abstract);

			% Check if the GUI element enabled and editable
			try
			gui_element_editable = strcmpi(Elem.Enable, 'on');
			catch
			gui_element_editable = true;
			end

			% A check for editability is only meaningful for uieditfieds.
			% Drop-downs also have 'Editable' property, but it corresponds
			% to the editability of elements and should not have an effect
			% on assigning callbacks.
			if (strcmpi(Elem.Type, 'uinumericeditfield') \|\| ...
			strcmpi(Elem.Type, 'uieditfield')) ...
			&& strcmpi(Elem.Editable, 'off')
			gui_element_editable = false;
			end

			bool = prop_write_accessible && gui_element_editable;

			% Do not create a new callback if one already exists (typically
			% it means that a callback was manually defined in AppDesigner)
			bool = bool && (isprop(Elem, 'ValueChangedFcn') && ...
			isempty(Elem.ValueChangedFcn));
			end

			% Extract the top-most handle object in the reference, the end
			% property name and any further subreference
			function [Hobj, prop, Subs] = parseReference(this, prop_ref)

			% Make sure the reference starts with a dot and convert to
			% subreference structure
			if prop_ref(1)~='.'
			PropSubs = str2substruct(['.',prop_ref]);
			else
			PropSubs = str2substruct(prop_ref);
			end

			% Find the handle object to which the end property belongs as
			% well as the end property name
			Hobj = this.App;

			Subs = PropSubs; % Subreference relative to Hobj.(prop)
			prop = subsref(this.App, PropSubs(1));

			for i=1:length(PropSubs)-1
			testvar = subsref(this.App, PropSubs(1:end-i));
			if isa(testvar, 'handle')
			Hobj = testvar;

			Subs = PropSubs(end-i+2:end);
			prop = subsref(this.App,PropSubs(1:end-i+1));

			break
			end
			end
			end
			end
			end

rINSTCONTROL/@MyGuiSync/MyGuiSync.m5d8c15df5bafTekRSA-Freq-vs-Time

MyGuiSync.mView Options

rINSTCONTROL/@MyGuiSync/MyGuiSync.m
5d8c15df5bafTekRSA-Freq-vs-Time

MyGuiSync.m
View Options