setup

Class: matlab.graphics.chartcontainer.ChartContainer
Namespace: matlab.graphics.chartcontainer

Set up instance of chart container subclass

Syntax

setup(obj)


Description

setup(obj) sets the initial state of the chart. It executes once when the chart object is created. Any property values passed as name-value pair arguments to the chart's constructor method are assigned after the setup method executes.

Define this method to execute initialization code for each new instance of your class. For example, you can use this method to create the underlying graphics objects and set initial property values on those objects.

Input Arguments

obj — Object of the class

chart object

Object of the class that inherits from the matlab.graphics.chartcontainer.ChartContainer base class.

Attributes

Abstract	true
Protected	true

To learn about attributes of methods, see Method Attributes.

Examples

Smooth Line Plot

Define a class called SmoothPlot that plots a set of data using a dotted blue line with a smoothed version of the line.

To define the class, create a file called SmoothPlot.m that contains the following class definition with these features:

• XData and YData public properties that store the x- and y-coordinate data for the original line.

• SmoothColor and SmoothWidth public properties that control the color and width of the smooth line.

• OriginalLine and SmoothLine private properties that store the Line objects for original and smoothed data.

• A setup method that initializes OriginalLine and SmoothLine.

• An update method that updates the plot when the user changes the value of a property.

• A createSmoothData method that calculates a smoothed version of YData.

classdef SmoothPlot < matlab.graphics.chartcontainer.ChartContainer
    properties
        XData (1,:) double = NaN
        YData (1,:) double = NaN
        SmoothColor (1,3) double {mustBeGreaterThanOrEqual(SmoothColor,0),...
            mustBeLessThanOrEqual(SmoothColor,1)} = [0.9290 0.6940 0.1250]
        SmoothWidth (1,1) double = 2
    end
    properties(Access = private,Transient,NonCopyable)
        OriginalLine (1,1) matlab.graphics.chart.primitive.Line
        SmoothLine (1,1) matlab.graphics.chart.primitive.Line
    end
    
    methods(Access = protected)
        function setup(obj)
            % Create the axes
            ax = getAxes(obj);
            
            % Create the original and smooth lines
            obj.OriginalLine = plot(ax,NaN,NaN,'LineStyle',':');
            hold(ax,'on')
            obj.SmoothLine = plot(ax,NaN,NaN);
            hold(ax,'off')
        end
        function update(obj)
            % Update line data
            obj.OriginalLine.XData = obj.XData;
            obj.OriginalLine.YData = obj.YData;
            obj.SmoothLine.XData = obj.XData;
            obj.SmoothLine.YData = createSmoothData(obj);
            
            % Update line color and width
            obj.SmoothLine.Color = obj.SmoothColor;
            obj.SmoothLine.LineWidth = obj.SmoothWidth;
        end
        function sm = createSmoothData(obj)
            % Calculate smoothed data
            v = ones(1,10)*0.1;
            sm = conv(obj.YData,v,'same');
        end
    end
end

Next, create a pair of x and y vectors. Plot x and y by calling the SmoothPlot constructor method, which is provided by the ChartContainer class. Specify the 'XData' and 'YData' name-value pair arguments and return the object as c.

x = 1:1:100;
y = 10*sin(x./5) + 8*sin(10.*x + 0.5);
c = SmoothPlot('XData',x,'YData',y);

Use c to change the color of the smooth line to red.

c.SmoothColor = [1 0 0];

Tips

Avoid calling drawnow within the setup and update methods of your chart class. Calling drawnow in the setup and update methods can cause extraneous updates within your chart, leading to visual flickering and extraneous updates to objects outside your chart, which will negatively impact performance.

Version History

Introduced in R2019b

R2020a: ChartContainer subclasses assign property values after the setup method runs

When you create an instance of ChartContainer subclass, and pass property name-value pair arguments to the constructor, the property values are assigned after the setup method runs. In R2019b, the property values are assigned before the setup method runs.

If the setup method of your class references the value of a property on the object, you can update your code in either of the following ways:

• Assign a default value for the property when you define it.

• Move the code that references the property to the update method.