Customize System Block Appearance Programmatically

You can customize the icon for a MATLAB System block by adding descriptive text, port labels, and icon image.

Note

From R2023b, you can use the Mask Editor to design a MATLAB System block icon. You can also migrate existing icon customizations to the Mask Editor. This capability eliminates the need to develop or maintain the getInputNamesImpl, getOutputNamesImpl, and getIconImpl methods in a System object™ file. For more information, see Customize MATLAB System Icon and Dialog Box Using Mask Editor.

Specify Input and Output Names

Specify the names of the input and output ports of a System object–based block implemented using a MATLAB System block.

Use getInputNamesImpl and getOutputNamesImpl to specify the names of the input port as “source data” and the output port as “count.”

If you do not specify the getInputNamesImpl and getOutputNamesImpl methods, the object uses the stepImpl method input and output variable names for the input and output port names, respectively. If the stepImpl method uses varargin and varargout instead of variable names, the port names default to empty character vectors.

methods (Access = protected)
   function inputName = getInputNamesImpl(~)
          inputName = 'source data';
   end
   
   function outputName = getOutputNamesImpl(~)
          outputName = 'count';
   end
end

 Complete Class Definition with Named Inputs and Outputs

classdef MyCounter < matlab.System
  
   % MyCounter Count values above a threshold
     
    properties
       Threshold = 1
    end
    properties (DiscreteState)
       Count
    end
 
    methods
       function obj = MyCounter(varargin)
          setProperties (obj,nargin,varargin{:});
       end
    end
 
    methods (Access = protected)
       function setupImpl(obj)
          obj.Count = 0;
       end
       function resetImpl(obj)
          obj.Count = 0;
       end
       function y = stepImpl(obj,u)
          if (u > obj.Threshold)
             obj.Count = obj.Count + 1;
          end
          y = obj.Count;
       end
       function inputName = getInputNamesImpl(~)
          inputName = 'source data';
       end
       function outputName = getOutputNamesImpl(~)
          outputName = 'count';
       end
    end
end

Add Text to Block Icon

Add text to the block icon of a System object–based block implemented using a MATLAB System block.

1. Subclass from custom icon class.

   classdef MyCounter < matlab.System & matlab.system.mixin.CustomIcon

2. Use getIconImpl to specify the block icon as New Counter with a line break between the two words.

   methods (Access = protected)
       function icon = getIconImpl(~)
           icon = {'New','Counter'};
       end
   end

    Complete Class Definition File with Defined Icon

   classdef MyCounter < matlab.System & ...
      matlab.system.mixin.CustomIcon
     
      % MyCounter Count values above a threshold
        
       properties
          Threshold = 1
       end
       properties (DiscreteState)
          Count
       end
    
       methods
          function obj = MyCounter(varargin)
             setProperties(obj,nargin,varargin{:});
          end
       end
    
       methods (Access = protected)
          function setupImpl(obj)
             obj.Count = 0;
          end
          function resetImpl(obj)
             obj.Count = 0;
          end
          function y = stepImpl(obj,u)
             if (u > obj.Threshold)
                obj.Count = obj.Count + 1;
             end
             y = obj.Count;
          end
          function icon = getIconImpl(~)
             icon = {'New','Counter'};
          end
       end
   end

Add Image to Block Icon

Define an image on the block icon of a System object–based block implemented using a MATLAB System block.

1. Subclass from custom icon class.

   classdef MyCounter < matlab.System & matlab.system.mixin.CustomIcon

2. Use getIconImpl method to call the matlab.system.display.Icon class and specify the image.

   methods (Access = protected)
       function icon = getIconImpl(~)
           icon = matlab.system.display.Icon('counter.png');
       end
   end

    Complete Class Definition File with Icon Image

   classdef MyCounter < matlab.System & ...
      matlab.system.mixin.CustomIcon
     
      % MyCounter Count values above a threshold
        
       properties
          Threshold = 1
       end
       properties (DiscreteState)
          Count
       end
    
       methods
          function obj = MyCounter(varargin)
             setProperties(obj,nargin,varargin{:});
          end
       end
    
       methods (Access = protected)
          function setupImpl(obj)
             obj.Count = 0;
          end
          function resetImpl(obj)
             obj.Count = 0;
          end
          function y = stepImpl(obj,u)
             if (u > obj.Threshold)
                obj.Count = obj.Count + 1;
             end
             y = obj.Count;
          end
          function icon = getIconImpl(~)
             icon = matlab.system.display.Icon('counter.png');
          end
       end
   end