roboflow/supervision · error · ValueError

color_count must be greater than or equal to 1

Error message

color_count must be greater than or equal to 1

What it means

Error "color_count must be greater than or equal to 1" thrown in roboflow/supervision.

Source

Thrown at src/supervision/draw/color.py:513

            palette_name: Name of the Matplotlib palette.
            color_count: Number of colors to sample from the palette.

        Returns:
            A ColorPalette instance.

        Example:
            ```pycon
            >>> import supervision as sv
            >>> sv.ColorPalette.from_matplotlib('viridis', 5)  # doctest: +ELLIPSIS
            ColorPalette(colors=[Color(r=68, g=1, b=84), Color(r=58, g=82, b=139), ...])

            ```

        ![visualized_color_palette](https://media.roboflow.com/
        supervision-annotator-examples/visualized_color_palette.png)
        """
        if color_count < 1:
            raise ValueError("color_count must be greater than or equal to 1")

        # Keep pyplot lazy so importing color utilities does not import matplotlib.
        import matplotlib.pyplot as plt

        mpl_palette = plt.get_cmap(palette_name)
        if hasattr(mpl_palette, "resampled"):
            mpl_palette = mpl_palette.resampled(color_count)

        if hasattr(mpl_palette, "colors"):
            colors = mpl_palette.colors
        else:
            # A single color samples the palette start and avoids division by zero.
            positions = (
                [0.0]
                if color_count == 1
                else [i / (color_count - 1) for i in range(color_count)]
            )
            colors = [mpl_palette(position) for position in positions]

View on GitHub (pinned to 7f254d9784)

Solutions

1. Request at least one color when generating a palette (color_count >= 1).
2. Guard the call so color_count is never zero or negative.

When it happens

Trigger: Thrown at src/supervision/draw/color.py:513 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of roboflow/supervision@7f254d9784 (2026-08-15). Data as JSON: /api/errors/b1cfde02f27b7745. Report an issue: GitHub.