Color System

Every color rule is a ColorRule — a pair of one selector (which rows to affect) and one assigner (what colors to apply to those rows). Rules are applied in order; later rules override earlier ones for the selected rows.

Example

from orama.color import (
    ColorRule,
    ColorSelectMaxValue,
    ColorAssignerByCategory,
)
from polychromos.color import HSLColor

rule = ColorRule(
    assigner=ColorAssignerByCategory(
        anchor_colors=[HSLColor.from_hex("#ef4444")],
    ),
    selector=ColorSelectMaxValue(),  # highlight only the maximum bar
)

strategy = BarChartStrategy(
    fields_metadata=fields_metadata,
    category_variables=["region"],
    aggregation=Aggregation(name="count", function="count"),
    color_rules=[rule],
)

Selectors

Class	Selects
`ColorSelectorStrategy`	All entries (use as first rule to override defaults)
`ColorSelectByCategoryName(names)`	Entries whose category name is in `names`
`ColorSelectValuesBelow(threshold)`	Entries with value ≤ threshold
`ColorSelectValuesAbove(threshold)`	Entries with value ≥ threshold
`ColorSelectMinValue()`	Entry/entries with the minimum value
`ColorSelectMaxValue()`	Entry/entries with the maximum value
`ColorSelectValuesBelowMean()`	Entries with value ≤ weighted mean (bar charts only)
`ColorSelectValuesAboveMean()`	Entries with value ≥ weighted mean (bar charts only)

Assigners

Class	Assigns
`ColorAssignerByCategory(anchor_colors, shuffle=False)`	One color per distinct category, interpolated from anchor colors; `shuffle=True` alternates colors across categories
`ColorAssignerByGroup(anchor_colors, shuffle=False)`	One color per distinct group; `shuffle=True` alternates colors across groups
`ColorAssignerByValue(anchor_colors, range_min, range_max, range_center_at)`	Continuous color scale mapped to values; optionally centered at a pivot

anchor_colors is an HSLColorSequence from polychromos. When two colors are provided and more entries exist, colors are interpolated via cylindrical shortest-path. When more than two colors are provided, a multi-stop color scale is constructed.

Note

Each strategy documents which selectors and assigners it accepts. Passing an unsupported combination raises ValueError at construction time.