Control How Plotting Functions Select Colors and Line Styles

When you plot multiple data sets together in the same axes, MATLAB^® automatically assigns different colors (and possibly line styles and markers) to the plot objects. You can customize the colors, line styles, and markers when you call a plotting function, and you can also set properties after calling the function.

For example, plot a solid red line and a dashed green line. Then add square markers to the red line and circular markers to the green line.

p1 = plot([0 1 2 3],'-r');
hold on
p2 = plot([1 2 3 4],'--g');
hold off

% Add markers
p1.Marker = 'sq';
p2.Marker = 'o';

This approach is described in Specify Plot Colors. It is useful for customizing aspects of a few plots. However, it is less flexible in other situations, such as plotting data in a loop, or passing matrix data to plotting functions. In such cases, you can change the properties that control how MATLAB automatically assigns colors, line styles, and markers.

Note

Some of the functionality in the following examples is available starting in R2019b, and some of the functionality is available starting in R2020a. To modify plot colors and line styles in an earlier release, see Why Are Plot Lines Different Colors? and Line Styles Used for Plotting — LineStyleOrder.

How Automatic Assignment Works

MATLAB assigns colors to plot objects (such as Line, Scatter, and Bar objects) by cycling through the colors listed in the ColorOrder property of the axes. The ColorOrder property contains an array of RGB triplets, where each RGB triplet defines a color. The default ColorOrder array contains seven colors. If you create more objects than there are colors, the colors repeat.

If the plot objects support line styles and markers, MATLAB also cycles through the list in the LineStyleOrder property of the axes. The LineStyleOrder property contains a cell array of character sequences, where each character sequence corresponds to a line style (or a line style combined with a marker). The default LineStyleOrder array contains only the solid line style, ('-'). All of the colors in the ColorOrder array are used with one character sequence in the LineStyleOrder array before the next sequence is used. The cycle continues for each new plot object. If there are more objects than combinations of colors and character sequences, then the cycle repeats.

For a given pair of ColorOrder and LineStyleOrder arrays, the colors, line styles, and markers for a particular plot object are determined by the value of the object's SeriesIndex, which is a new property starting in R2020a. By default, the SeriesIndex property is a number that corresponds to the object's order of creation, starting at 1. MATLAB uses the number to calculate indices into the ColorOrder and LineStyleOrder arrays.

For example, create an axes object with two colors in its ColorOrder array (red and blue) and two line styles in its LineStyleOrder array (solid and dashed). Then plot five lines.

ax = axes;
ax.ColorOrder = [1 0 0; 0 0 1];
ax.LineStyleOrder = {'-','--'};

hold on
for i = 1:5
   plot([i i+2])
end
hold off

This table lists the SeriesIndex, the index into the ColorOrder array, and the index into the LineStyleOrder array for each line in the preceding plot.

	SeriesIndex	Index into ColorOrder Array	Index into LineStyleOrder Array	Line Appearance
First Line	1	1	1	Red solid line
Second Line	2	2	1	Blue solid line
Third Line	3	1	2	Red dashed line
Fourth Line	4	2	2	Blue dashed line
Fifth Line	5	1	1	Red solid line

You can change the colors, line styles, and markers of plot objects by modifying the ColorOrder or LineStyleOrder properties of the axes, or by changing the SeriesIndex properties of the plot objects.

Changing Color Schemes and Line Styles

Changing the ColorOrder property of the axes changes the color scheme of your plot. Changing the LineStyleOrder property of the axes changes the line styles (and possibly markers) used in your plot. For example, plot eight lines in a loop using the default colors and line style.

ax = axes;
hold on
for i = 0:7
    plot([i i+2])
end
hold off

Replace the ColorOrder array with a new array that contains four colors (you can also replace this array using the colororder function). Then replace the LineStyleOrder array with a new cell array that contains two line styles. The lines automatically use the new colors and line styles.

% Updates existing plots in R2019b or later
ax.ColorOrder = [1 0 0; 0 1 0; 0 0 1; 0 0 0];
ax.LineStyleOrder = {'-','--'};

Changing Indices into the ColorOrder and LineStyleOrder Arrays

Changing the SeriesIndex property on a plot object changes the indices into the ColorOrder and LineStyleOrder arrays. Changing the indices is useful when you want the color, line style, and marker of an object to match another object.

For example, plot four sine waves in a loop, varying the wavelength and phase. For each sine wave, set the SeriesIndex property according to the wavelength. In the resulting plot, the sine waves that have the same wavelength also have the same color.

x = linspace(0,10,200);
ax = axes;
hold on
for phi = 0:3:3
    for t = 1:2
        plot(x,sin(x/t + phi),'SeriesIndex',t) % Requires R2020a or later
    end
end
hold off

To make one pair of sine waves more prominent, change the color order to different set of colors.

ax.ColorOrder = [0.8 0.8 0.9; 0.2 0.2 0.8];