Graphics and Export

This reference targets MATLAB R2026a. Rendering and property support differ in GNU Octave and across MATLAB releases/platforms.

Build figures with explicit ownership

Use handles instead of relying on gcf/gca in reusable code:

fig = figure(Color="white");
layout = tiledlayout(fig, 2, 1, ...
    TileSpacing="compact", ...
    Padding="compact");

ax1 = nexttile(layout);
plot(ax1, time, signal, LineWidth=1.5);
xlabel(ax1, "Time (s)");
ylabel(ax1, "Amplitude (V)");
title(ax1, "Measured signal");
grid(ax1, "on");

ax2 = nexttile(layout);
histogram(ax2, residual, Normalization="pdf");
xlabel(ax2, "Residual (V)");
ylabel(ax2, "Density");

Explicit handles make tests, nested layouts, apps, and exports predictable. Set limits, aspect ratio, color limits, and view deliberately when comparison across figures matters.

Scientific communication checklist

Include quantities and units in labels.
State transformations, normalization, aggregation, and uncertainty.
Use colorblind-aware, perceptually ordered palettes; do not use color alone for categories.
Keep data and annotations distinguishable in grayscale when required.
Match marker/line width, font size, and panel size to final publication size.
Avoid misleading axis truncation or 3-D effects.
Set deterministic sorting/group order before plotting categorical data.
Add alternative text/caption information in the surrounding document.
Inspect embedded raster content even when the container format is vector.

Graphics functions can belong to separate products. For example, basic plot, scatter, histogram, imagesc, surf, and tiledlayout are base MATLAB, while domain-specific statistical, mapping, image, signal, or medical visualizations can require named toolboxes.

Export with `exportgraphics`

Prefer exportgraphics for current workflows:

exportgraphics(fig, "overview.pdf", ContentType="vector");
exportgraphics(ax1, "signal.png", Resolution=300);

R2026a-supported output includes:

raster: PNG, JPEG, TIFF, GIF;
vector-capable: PDF, SVG, EPS, and Windows-only EMF;
interactive HTML web canvas (new in R2026a).

SVG support was added in R2025a. Append=true is supported for PDF and GIF, not every format. ContentType="vector" applies where supported, but some plot content can still be rasterized. Resolution is for raster output. R2025a added dimensions/padding controls; verify exact option and unit support in the target release.

Interactive HTML is active web content, not a static image. Review its embedded assets and distribution context; do not open an untrusted exported HTML file automatically.

Which export API?

API	Prefer for	Notes
`exportgraphics`	axes, layouts, figures, publication files	current default; crop/padding, vector/raster, multipage PDF
`copygraphics`	clipboard	interactive transfer; not reproducible file output
`exportapp`	app/UI capture	UI-focused behavior
`print`	legacy/device-specific workflows	behavior and UI support differ
`savefig`	editable MATLAB figure	MATLAB object artifact, not archival interchange
`saveas`	simple legacy save	less control than `exportgraphics`
`imwrite`	image arrays/animated GIF construction	not a general figure renderer

Never treat .fig as passive. It stores MATLAB graphics objects and should be handled as an untrusted MATLAB object artifact unless its provenance is known.

Headless and batch behavior

matlab -batch starts without the desktop but can still display figure windows unless -noFigureWindows or -nodisplay is added. Rendering may depend on graphics hardware, fonts, installed system support, and platform. A planner should distinguish:

compute-only: no figures;
off-screen export: figures created but not shown;
interactive graphics: requires a display and user;
web-canvas export: generates active HTML.

The bundled command planner only returns argv and never starts MATLAB. Review trusted code, fonts, output paths, overwrite policy, and license before an approved run.

For deterministic export:

create a new explicit figure;
set size/units, axes limits, color limits, and fonts;
avoid dependence on desktop defaults and current objects;
set RNG before randomized jitter/layout;
export to a new local path and refuse unintended overwrite;
inventory output dimensions, file type, fonts, and embedded raster content;
compare images with an appropriate visual tolerance, not byte equality.

Color and layout

colororder(ax1, orderedColors);
colormap(ax2, "parula");
clim(ax2, [lowerLimit upperLimit]);
axis(ax2, "tight");

Use a sequential map for ordered magnitude, a diverging map around a meaningful center, and distinct categorical colors for unordered groups. Avoid jet for quantitative interpretation. Keep a shared color scale when panels are meant to be compared.

Use tiledlayout/nexttile rather than new subplot code. Legends and colorbars can belong to an axes or layout; make ownership explicit.

Time, table, and categorical plots

Many plotting functions accept tables directly. This preserves variable-name selection but does not remove the need to validate types and missing data.

plot(T, "Time", ["Observed" "Predicted"]);
legend(["Observed" "Predicted"], Location="best");

Sort time values and define duplicate/missing handling before plotting. Categorical order controls axis/group order. Avoid silently dropping missing values without reporting the count.

3-D, transparency, and large data

3-D surfaces, transparency, lighting, and very dense primitives can force rasterization or produce platform-specific output. For large data:

decimate only with a documented visual/statistical rule;
preserve extremes and events;
distinguish display reduction from analysis data;
record the displayed sample count and aggregation;
test export memory and file size.

Review checklist

[ ] Every object has an explicit parent handle.
[ ] Data transformations and missing-value counts are documented.
[ ] Axes, units, limits, and color scale are intentional.
[ ] Product/toolbox requirements are declared.
[ ] Output path is local, new, and reviewed.
[ ] Vector versus raster intent is explicit.
[ ] HTML and .fig outputs are treated as active/object artifacts.
[ ] Fonts and embedded raster content are inspected.
[ ] Batch mode and display requirements are compatible.
[ ] Accessibility and final-size readability were reviewed.