Struct ScaleColorDiscrete 

pub struct ScaleColorDiscrete { /* private fields */ }

Discrete color scale — maps categories to distinct colors.

Implementations

impl ScaleColorDiscrete

pub fn new(aesthetic: Aesthetic) -> Self

pub fn sorted(self) -> Self

Order levels lexicographically (instead of first appearance) so a given level always gets the same palette colour and legend position across charts, whatever order the data arrives in — no need to pre-sort levels and repeat a manual palette per chart.

pub fn with_palette(self, colors: Vec<RGBAColor>) -> Self

pub fn with_named_palette(self, name: &PaletteName) -> Self

pub fn with_levels(self, levels: Vec<String>) -> Self

Pre-seed the factor levels (order), so each level keeps a fixed palette color regardless of which levels are present in the data — e.g. for a legend whose series can be toggled without the colors reshuffling.

pub fn color_for_index(&self, idx: usize) -> RGBAColor

Get color for a given level index.

pub fn color_for_value(&self, value: &Value) -> RGBAColor

Get color for a value.

pub fn levels(&self) -> &[String]

Trait Implementations

impl Clone for ScaleColorDiscrete

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ScaleColorDiscrete

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Scale for ScaleColorDiscrete

fn aesthetic(&self) -> Aesthetic

Which aesthetic this scale is for.

fn train(&mut self, values: &[Value])

Incorporate data values to determine domain.

fn map(&self, value: &Value) -> f64

Map a data value to a [0, 1] normalized position (position scales) or to a concrete visual value index (color/size scales).

fn breaks(&self) -> Vec<(f64, String)>

Generate break positions and labels for axis/legend.

fn name(&self) -> &str

Human-readable name (axis title).

fn set_name(&mut self, name: &str)

Set the scale name.

fn is_discrete(&self) -> bool

Whether this is a discrete scale.

fn map_to_color(&self, value: &Value) -> Option<(u8, u8, u8)>

Map a data value to an RGB color. Default returns None.

fn clone_box(&self) -> Box<dyn Scale>

Clone this scale into a boxed trait object.

fn reset_training(&mut self)

Reset training state so the scale can be retrained on new data.

fn transform(&self, value: &Value) -> Value

Apply transformation to raw data (e.g., log10).

fn map_to_shape(&self, _value: &Value) -> Option<PointShape>

Map a data value to a point shape. Default returns None.

fn map_to_linetype(&self, _value: &Value) -> Option<Linetype>

Map a data value to a linetype. Default returns None.

fn map_to_size(&self, _value: &Value) -> Option<f64>

Map a data value to a point size (radius in pixels). Default returns None.

fn map_to_alpha(&self, _value: &Value) -> Option<f64>

Map a data value to an alpha (opacity) value. Default returns None.

fn sec_axis(&self) -> Option<&SecAxis>

Get the secondary axis specification, if any.

fn set_limits(&mut self, _min: f64, _max: f64)

Override the trained domain limits (used by coord_cartesian zoom).

fn filter_limits(&self) -> Option<(f64, f64)>

Return OOB filter limits if this scale was created with explicit limits (e.g., via xlim/ylim). Data outside these limits should be removed before stats.

fn domain(&self) -> Option<(f64, f64)>

Return the trained data domain (min, max) for continuous scales. Used by the colorbar legend to pass data-space values to map_to_color().

fn expanded_domain(&self) -> Option<(f64, f64)>

The data values at the panel edges (normalized 0 and 1) for a trained continuous position scale — the limits after expansion, in the scale’s transformed space. None for discrete / untrained / non-position scales.

fn axis_position_opposite(&self) -> bool

Whether this axis is drawn on the opposite side (x → top, y → right).