xline — Draw vertical reference lines on the current axes.

xline adds one or more vertical reference lines with optional labels, line specs, and name-value styling, following MATLAB-compatible plotting behavior.

Syntax

h = xline(x)
h = xline(x, styleOrLabel)
h = xline(x, LineSpec, label)
h = xline(x, Name, Value, ...)

Inputs

Returns

Errors

How xline works

• xline(x) adds a vertical reference line at each coordinate in x. Coordinates may use any native integer class and cross to the graphics coordinate domain after validation.
• Reference lines append to the current axes without replacing existing plot content.
• Line spans follow the active axes limits, including later xlim and ylim changes.
• The returned handle supports get and set for Value, Color, LineWidth, LineStyle, Label, LabelOrientation, DisplayName, and Visible.
• Integer RGB components must be zero or one, integer line widths must be positive, and numeric Visible values must be exactly zero or one.

Examples

Add a dashed threshold line

plot(1:10, rand(1, 10));
xline(5, '--r', 'Threshold');

Expected output:

% Adds a red dashed vertical reference line at x = 5

Add multiple reference lines

plot(1:10, rand(1, 10));
xline([2 5 8], ':');

Expected output:

% Adds three dotted vertical reference lines

Rendered xline example

time = 0:0.25:12;
temperature = 62 + 1.4*time + 5*sin(0.55*time).*exp(-0.08*time);

plot(time, temperature, 'LineWidth', 2);
xline(6, '--r', 'Control change', 'LineWidth', 1.5);
title('Temperature During Test Run');
xlabel('Time (min)');
ylabel('Temperature (C)');
grid on;

Compare this result with other chart types in the MATLAB Plot Gallery.

Using xline with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how xline changes the result.

Related Plotting functions

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