matlab.graphics.chartcontainer.ChartContainer.update - Update instance of chart container subclass after setting properties - MATLAB (original) (raw)

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

Update instance of chart container subclass after setting properties

Description

update([obj](#mw%5F21e659e0-7e34-463f-b8ec-a08539316624%5Fsep%5Fmw%5Fe72055e4-681f-4c08-a285-ed570d7c1140)) updates the contents of the chart after one or more property values change. Define this method to update the underlying graphics objects in the chart using the new property values. This method executes during the nextdrawnow execution, after the user changes one or more property values on the chart.

Input Arguments

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

Attributes

To learn about attributes of methods, seeMethod Attributes.

Examples

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

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

Tips

Avoid calling drawnow within the setup andupdate 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