matlab-build-chart

name	matlab-build-chart
license	MathWorks BSD-3-Clause
metadata	{"author":"MathWorks","version":"1.0"}
description	Create and customize MATLAB charts and plots. Plot types (line, scatter, bar, histogram, heatmap, surface), axes configuration, annotations, data tips, interactive plots, animation, multiple axes with tiledlayout, colororder, and performance optimization. Works for standalone figures, Live Scripts, and uifigure apps. Use when plotting data, customizing axes, adding annotations or interactivity, animating charts, or arranging multiple axes. Triggers: plot, chart, graph, axes, uiaxes, annotation, data tips, animation, tiledlayout, colororder, heatmap, scatter, figure, visualization, export.
allowed-tools	["Read","Write","Edit","Bash"]

MATLAB Chart Builder

Create, customize, and interact with MATLAB charts and plots — in standalone figures, Live Scripts, or uifigure apps.

When to Use This Skill

Use this skill when:

• Plotting data (line, scatter, bar, histogram, heatmap, surface, polar, geo, volume) in any context
• Configuring axes (labels, limits, ticks, legend, font, export)
• Adding annotations (xline, yline, xregion, text)
• Adding or customizing data tips
• Creating interactive plots (click, hover, drag callbacks)
• Animating or streaming data to a chart
• Arranging multiple axes with tiledlayout/nexttile
• Optimizing chart rendering performance
• Exporting figures for publication or reports
• User says "help me visualize this" without a specific chart type

When NOT to Use This Skill

• Building a full app (use matlab-build-app — it invokes this skill for chart sub-steps)
• Applying dark mode, brand colors, or custom color themes (use matlab-theming)
• Working with Simulink scopes or Simscape plots
• Creating App Designer charts via the drag-and-drop GUI

Workflow

User request arrives
        |
        +-- FAST PATH (most requests)
        |   Chart type named OR unambiguous single-axes plot
        |   AND no interactivity / animation / multi-panel / performance concern
        |       |
        |       v
        |   Infer rendering context (default: standalone figure)
        |   Read relevant references --> Build directly
        |
        +-- PLAN PATH (complex or ambiguous)
                |
                +-- Ambiguous intent (no chart type named, unclear data question)
                |       --> Identify visualization intent (see Intent Taxonomy)
                |
                +-- Rendering context unclear AND it matters
                |       --> Ask: standalone figure, Live Script, or uifigure app?
                |
                v
            Present inline plan for approval
                |
                v
            User confirms --> Read references --> Build

Fast-Path Triggers (build directly, no plan)

ALL of these must hold:

• Chart type is named OR intent maps unambiguously to one type
• Single axes (no tiled/multi-panel layout)
• No custom interactivity (no user-specified callbacks)
• No animation or streaming
• No explicit performance constraints
• Rendering context is clear or defaults to standalone figure

Plan-Path Triggers (present plan first)

ANY of these fires the plan path:

• Multi-panel / tiled figure
• Custom interactivity (click, hover, drag callbacks)
• Animation or streaming data
• Performance-sensitive (large dataset, real-time update)
• Branded / designed figure requiring palette/theme coordination
• Ambiguous "help me visualize this" — unclear type or intent
• Multiple visualization intents in one figure

Rendering Context

Three contexts gate which constraint set applies:

Context	Constraints	How inferred
Standalone figure	Universal rules only	Default; figure/axes in request
Live Script	Universal rules only	User mentions Live Script, .mlx, plain-text Live Code
uifigure app	Universal + uifigure rules	User mentions uifigure; arrives as sub-step of app-builder

If context is unstated and cannot be inferred, assume standalone figure. Ask only when the distinction matters (e.g., heatmap parent differs between contexts).

Visualization Intent Taxonomy

Engages ONLY when the user has NOT named a specific chart type or function. If they say "scatter" or "heatmap," skip intent selection and build directly.

Communicative Intents

Intent	Data question	Encouraged functions
Comparison	How do values compare across items?	bar, barh, bar3, bar3h, pareto, stem, stairs, loglog, semilogx, semilogy
Trend / time series	How does a value change over time?	plot, area, stackedplot, stairs, stem, fplot, fplot3
Distribution	How is data spread?	histogram, histogram2, boxchart, violinplot, raincloudplot, swarmchart, swarmchart3, scatterhistogram, binscatter, polarhistogram
Relationship	How do variables relate?	scatter, scatter3, bubblechart, bubblechart3, plotmatrix, parallelplot, binscatter, spy, fimplicit
Composition	Parts of a whole?	piechart, donutchart, stacked bar, stacked area, wordcloud, bubblecloud

Data-Domain Intents

Intent	When it fires	Encouraged functions
Geospatial	Geographic coordinates	geoplot, geoscatter, geobubble, geodensityplot
Directional / polar	Angular, cyclical, compass data	polarplot, polarscatter, polarhistogram, polarbubblechart, compassplot, fpolarplot
Surfaces & scalar fields	z = f(x,y), meshes, contours	surf, surfc, surfl, mesh, meshc, meshz, ribbon, pcolor, contour, contourf, contour3, fcontour, fsurf, fmesh, fimplicit3, waterfall
Vector fields & flow	Directional vector data	quiver, quiver3, feather, streamline, streamslice, streamribbon, streamtube, streamparticles, coneplot
Volume visualization	3D gridded volume data	slice, contourslice, coneplot, streamslice, isosurface/isocap workflows
Images & matrices	Display a matrix/grid	image, imagesc, heatmap, pcolor (flat), spy

Classification Rules

• The waterfall trap: MATLAB's waterfall is a 3D surface plot, NOT the financial accumulation chart. For "accumulation to total," build from bar with a hidden base series.
• f* variants follow their data counterpart's intent: fplot -> Trend, fsurf/fmesh/fcontour -> Surfaces, fimplicit -> Relationship, fpolarplot -> Directional.
• Animation is cross-cutting, not an intent. animatedline, comet, comet3 layer motion onto any chart type. See references/animation.md.
• Multi-intent functions: Classify by the user's data question, not gallery grouping. E.g., heatmap of a correlation matrix -> Relationship; heatmap of counts -> Comparison.
• Classify by communicative intent, not MATLAB docs grouping. piechart/donutchart are Composition regardless of where docs file them.

Inline Plan Template

When the plan path engages, present for approval:

**Chart Plan: [description]**

**Context:** [Standalone figure / Live Script / uifigure app]
**Intent:** [name] -> [chosen function(s)]

**Structure:**
- [Layout description]
- [Key visual elements, annotations, interactions]

**Key decisions:**
- [Performance strategy, if applicable]  [src: references/performance.md SS]
- [Interaction model, if applicable]  [src: references/interactive-plots.md SS]
- [uifigure constraints that apply, if context = uifigure]

**References to use:**
| Reference | Role | Provenance |
|-----------|------|------------|
| `references/file.md` | [what it provides] | [src: references/file.md SS] |

Shall I proceed?

Do NOT write the plan to a file unless (a) the user explicitly asks for a spec to keep, or (b) chart-builder is running as a sub-step of an app build with an existing plan artifact.

Critical Rules

Universal (all contexts)

• MUST pass axes as first argument to all plotting functions: plot(ax, x, y) not plot(x, y)
• MUST update data in place (p.XData = newX) — never replot in a loop
• MUST use drawnow limitrate for animations — never bare drawnow in tight loops
• PREFER tiledlayout/nexttile over subplot() for multiple axes
• PREFER exportgraphics() for publication-quality export

Additional constraints in uifigure apps

• MUST use uiaxes — never plain axes
• MUST use exportgraphics() or exportapp() — saveas/print not supported
• NEVER use subplot() — not supported in uifigure
• NEVER use annotation() — use text(), xline(), yline(), xregion(), yregion()
• NEVER use ginput() — use ButtonDownFcn on plot objects
• NEVER rely on gcf/gca — uiaxes has HandleVisibility = 'off' by default

Quick Start

Standalone figure

fig = figure;
ax = axes(fig);

t = 0:0.01:2*pi;
plot(ax, t, sin(t), 'LineWidth', 1.5);
hold(ax, 'on');
plot(ax, t, cos(t), '--', 'LineWidth', 1.5);
hold(ax, 'off');

title(ax, 'Sine and Cosine');
xlabel(ax, 'Time (s)');
ylabel(ax, 'Amplitude');
legend(ax, 'sin', 'cos');
grid(ax, 'on');
exportgraphics(ax, 'plot.png', 'Resolution', 300);

In a uifigure app

fig = uifigure('Name', 'Chart Demo');
gl = uigridlayout(fig, [1 1]);
ax = uiaxes(gl);

plot(ax, t, sin(t), 'LineWidth', 1.5);
% Same API from here — only axes creation differs

Once you have ax, all plotting calls (plot, scatter, bar, xline, hold, legend, colororder, etc.) are identical regardless of context.

Implementation Checklist

Graphics

• All plot calls pass ax as first argument
• hold(ax, 'on') used before adding multiple series
• Axes labels, title, and grid configured
• Annotations use xline/yline/text (not annotation() — uifigure requirement)
• Interactive callbacks use ButtonDownFcn on plot objects (not axes — uifigure requirement)
• Animations use drawnow limitrate and pre-set axis limits
• Export uses exportgraphics() (required in uifigure; preferred everywhere)
• Multiple axes use tiledlayout/nexttile (required in uifigure; preferred everywhere)

Troubleshooting

Issues marked (uifigure only) apply only when plotting in uifigure apps.

Problem	Cause	Fix
Animation is slow/jerky	Using plot() in loop or bare drawnow	Update data in place + drawnow limitrate
Plot disappears after replot	Default NextPlot = 'replacechildren'	Use hold(ax, 'on') or update data in place
gcf/gca return wrong handle (uifigure only)	uiaxes HandleVisibility = 'off'	Always pass ax explicitly
annotation() error (uifigure only)	Not supported in uifigure	Use text(), xline(), yline()
ginput() error (uifigure only)	Not supported in uifigure	Use ButtonDownFcn on plot objects
Click callback doesn't fire on axes (uifigure only)	ButtonDownFcn unreliable on uiaxes	Put ButtonDownFcn on plot objects
Heatmap fails in uiaxes (uifigure only)	Heatmap needs figure/panel parent	Use heatmap(fig, ...) or heatmap(panel, ...)
saveas fails (uifigure only)	Not supported for uifigure	Use exportgraphics(ax, file)
subplot() errors (uifigure only)	Not supported in uifigure	Use tiledlayout/nexttile or uigridlayout
Zoom stops working after scroll callback (uifigure only)	WindowScrollWheelFcn disables zoom	Call disableDefaultInteractivity(ax)

References

Topic	File	Coverage	Intent served
Plot types	references/plot-types.md	Line, scatter, bar, histogram, heatmap, surface	Comparison, Trend, Distribution, Relationship, Surfaces (partial)
Axes configuration	references/axes-config.md	uiaxes setup, labels, limits, ticks, font, legend, export	All intents
Annotations	references/annotations.md	xline, yline, xregion, text, patch	All intents (overlay)
Data tips	references/data-tips.md	DataTipTemplate, custom rows, programmatic tips	All intents (overlay)
Interactive plots	references/interactive-plots.md	ButtonDownFcn, mouse callbacks, drag, HitTest, toolbar	Plan-path: interactivity
Chart palettes	references/chart-palettes.md	colororder, named palettes, SeriesIndex, vs colormap	All intents (styling)
Animation	references/animation.md	Update in place, animatedline, streaming, performance	Plan-path: animation
Multiple axes	references/multiple-axes.md	tiledlayout, nexttile, linkaxes, peripheral tiles	Plan-path: multi-panel
Performance	references/performance.md	Lazy-load, batch updates, throttle, parfeval, startup	Plan-path: performance

Reference Gaps (follow-up authoring needed)

These intents have no dedicated reference file. Use built-in MATLAB API knowledge:

• Composition — piechart, donutchart, stacked bar/area, wordcloud, bubblecloud
• Geospatial — geoplot, geoscatter, geobubble, geodensityplot
• Directional / polar — polarplot, polarscatter, polarhistogram, polarbubblechart, compassplot, fpolarplot
• Vector fields & flow — quiver, quiver3, feather, streamline, streamslice, streamribbon, streamtube, streamparticles, coneplot
• Volume visualization — slice, contourslice, coneplot, isosurface/isocap workflows
• Images & matrices (partial) — image, imagesc not covered; heatmap in plot-types
• Surfaces (partial) — only surf covered; mesh, contour, ribbon, pcolor pending

External Skills (invoked, not read)

• matlab-theming — when the chart needs dark mode, brand colors, or custom palettes

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Copyright 2026 The MathWorks, Inc.

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