colormap — Set the active colormap in MATLAB and RunMat plotting.
colormap sets the active color palette for the current plotting context. It affects colormap-driven visualizations such as imagesc, surf, and contourf, scoped to the active axes in MATLAB and RunMat.
Syntax
ok = colormap(name)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
name | StringScalar | Yes | — | Colormap name. |
Returns
| Name | Type | Description |
|---|---|---|
ok | LogicalArray | True on successful colormap update. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:colormap:InvalidArgument | Colormap name is missing, non-string, or unknown. | colormap: invalid argument |
How colormap works
- Supported colormap names include
parula,viridis,plasma,inferno,magma,turbo,jet,hot,cool,spring,summer,autumn,winter,gray,bone,copper,pink, andlines. - Unknown colormap names raise errors rather than silently falling back.
- Colormap state composes naturally with
colorbar,imagesc,surf, and filled contour plots. - Colormap changes apply to the current axes context in the plotting state model.
Examples
Apply a palette to a scaled image
[X, Y] = meshgrid(linspace(-3, 3, 60), linspace(-3, 3, 60));
A = sin(X) .* cos(Y);
imagesc(A);
colormap('jet');
colorbar;Compare palettes across subplots
[X, Y] = meshgrid(linspace(-3, 3, 40), linspace(-3, 3, 40));
Z = sin(X) .* cos(Y);
subplot(1, 2, 1);
surf(X, Y, Z);
colormap('parula');
subplot(1, 2, 2);
contourf(X, Y, Z);
colormap('turbo');Using colormap with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how colormap changes the result.
Run a small colormap example, explain the result, then change one input and compare the output.
FAQ
What colormaps are available?⌄
RunMat ships with: parula, viridis, plasma, inferno, magma, turbo, jet, hot, cool, spring, summer, autumn, winter, gray, bone, copper, pink, and lines. Unknown names raise an error — no silent fallback.
Which colormaps are perceptually uniform?⌄
viridis, plasma, inferno, and magma are designed so that equal steps in data value produce equal perceptual changes in color. Use these for quantitative data where you want the visual contrast to faithfully represent magnitude differences. parula is also a good default. Avoid jet for quantitative work — it introduces false banding.
Can I define a custom colormap?⌄
Not yet — colormap currently accepts named strings only. Custom N×3 RGB matrices are on the roadmap. For now, pick the closest built-in option or combine subplot-level colormaps to get variety across panels.
Related Plotting functions
More plotting resources
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how colormap is executed, line by line, in Rust.
- View the source for colormap in Rust on GitHub
- Learn how the RunMat runtime works
- Found a bug? Open an issue with a minimal reproduction.
About RunMat
RunMat is an open-source runtime that executes MATLAB-syntax code blazing on any GPU. It is licensed under the Apache 2.0 license.
- RunMat automatically optimizes your math for GPU execution on Apple, Nvidia, and AMD hardware. No code changes needed. Simulations that took hours now take minutes.
- Start running code in seconds. RunMat runs in the browser, on the desktop, or from the CLI. No license server, no IT ticket.