[Traits](https://oods-foundry.com/traits) / ScaleLinear

# ScaleLinear

Shared linear/continuous scale definition used by positional, color, and size encodings. Provides normalized domain/range metadata plus zero baseline enforcement per RDV.3 findings.

Generated from @oods/foundry 0.10.1

- Group

  viz.scale

- Maturity

  alpha

- Contexts

  detail, form

## Fields it adds

| Field | Type | Required | Description |
| - | - | - | - |
| `viz_scale_linear_domain_min` | `number` | yes | Lower domain bound for continuous encodings. |
| `viz_scale_linear_domain_max` | `number` | yes | Upper domain bound for continuous encodings. |
| `viz_scale_linear_range_min` | `number` | yes | Lower range bound (normalized 0-1). |
| `viz_scale_linear_range_max` | `number` | yes | Upper range bound (normalized 0-1). |
| `viz_scale_linear_clamp` | `boolean` | no | Indicates whether values outside the domain clamp to bounds. |
| `viz_scale_linear_zero_baseline` | `boolean` | no | Forces zero within the domain for accessibility compliance. |
| `viz_scale_linear_mode` | `string` (continuous, band) | no | Distinguishes continuous vs band heuristics. |
| `viz_scale_linear_description` | `string` | no | Narrative summary for fallbacks. |

## What it shows in each context

- [detail](https://oods-foundry.com/contexts/detail)

  `VizScaleSummary`

- [form](https://oods-foundry.com/contexts/form)

  `VizScaleControls`

## Parameters

- `renderIntent` `string`

  JSON-encoded Cartesian viz.render input fragment for the governed authoring recipes. Data rows remain a consumer operand.

- `domainMin` `number`, required

  Default lower domain bound applied when unspecified.

- `domainMax` `number`, required

  Default upper domain bound applied when unspecified.

- `rangeMin` `number`, required

  Default lower range bound (normalized 0-1).

- `rangeMax` `number`, required

  Default upper range bound (normalized 0-1).

- `clamp` `boolean`

  Whether values outside the domain should clamp to edges.

- `zeroBaseline` `boolean`

  Forces zero to be included in the domain.

- `mode` `string`

  Whether this scale behaves as continuous or band for categories.

## Objects that use it

No shipped object uses this trait.

## The trait file

`traits/viz/scale-linear.trait.yaml`

```
trait:
  name: ScaleLinear
  version: 0.2.0
  description: |
    Shared linear/continuous scale definition used by positional, color, and
    size encodings. Provides normalized domain/range metadata plus zero baseline
    enforcement per RDV.3 findings.
  category: viz.scale
  tags:
    - viz
    - scale
    - linear

parameters:
  - {"name": "renderIntent", "type": "string", "required": false, "default": "{}", "description": "JSON-encoded Cartesian viz.render input fragment for the governed authoring recipes. Data rows remain a consumer operand."}
  - name: domainMin
    type: number
    required: true
    description: Default lower domain bound applied when unspecified.
    default: 0
  - name: domainMax
    type: number
    required: true
    description: Default upper domain bound applied when unspecified.
    default: 1
  - name: rangeMin
    type: number
    required: true
    description: Default lower range bound (normalized 0-1).
    default: 0
  - name: rangeMax
    type: number
    required: true
    description: Default upper range bound (normalized 0-1).
    default: 1
  - name: clamp
    type: boolean
    required: false
    description: Whether values outside the domain should clamp to edges.
    default: true
  - name: zeroBaseline
    type: boolean
    required: false
    description: Forces zero to be included in the domain.
    default: true
  - name: mode
    type: string
    required: false
    description: Whether this scale behaves as continuous or band for categories.
    default: continuous
    validation:
      enum:
        - continuous
        - band

schema:
  viz_scale_linear_domain_min:
    type: number
    required: true
    description: Lower domain bound for continuous encodings.
    defaultFromParameter: domainMin
  viz_scale_linear_domain_max:
    type: number
    required: true
    description: Upper domain bound for continuous encodings.
    defaultFromParameter: domainMax
  viz_scale_linear_range_min:
    type: number
    required: true
    description: Lower range bound (normalized 0-1).
    defaultFromParameter: rangeMin
  viz_scale_linear_range_max:
    type: number
    required: true
    description: Upper range bound (normalized 0-1).
    defaultFromParameter: rangeMax
  viz_scale_linear_clamp:
    type: boolean
    required: false
    description: Indicates whether values outside the domain clamp to bounds.
    defaultFromParameter: clamp
  viz_scale_linear_zero_baseline:
    type: boolean
    required: false
    description: Forces zero within the domain for accessibility compliance.
    defaultFromParameter: zeroBaseline
  viz_scale_linear_mode:
    type: string
    required: false
    description: Distinguishes continuous vs band heuristics.
    defaultFromParameter: mode
    validation:
      enum:
        - continuous
        - band
  viz_scale_linear_description:
    type: string
    required: false
    description: Narrative summary for fallbacks.
    default: Linear scale with governed domain/range.

semantics:
  viz_scale_linear_domain_min:
    semantic_type: viz.scale.domain
    token_mapping: tokenMap(viz.scale.domain)
    ui_hints:
      component: NumericPreview
  viz_scale_linear_domain_max:
    semantic_type: viz.scale.domain
    token_mapping: tokenMap(viz.scale.domain)
    ui_hints:
      component: NumericPreview
  viz_scale_linear_mode:
    semantic_type: viz.scale.mode
    token_mapping: tokenMap(viz.scale.mode)
    ui_hints:
      component: TextBadge
  viz_scale_linear_zero_baseline:
    semantic_type: viz.scale.zero
    token_mapping: tokenMap(viz.scale.zero)
    ui_hints:
      component: BooleanBadge

view_extensions:
  detail:
    - component: VizScaleSummary
      position: sidebar
      props:
        intentParameter: renderIntent
        type: linear
        domainMinField: viz_scale_linear_domain_min
        domainMaxField: viz_scale_linear_domain_max
        modeField: viz_scale_linear_mode
        zeroField: viz_scale_linear_zero_baseline
  form:
    - component: VizScaleControls
      position: top
      props:
        intentParameter: renderIntent
        type: linear
        domainMinField: viz_scale_linear_domain_min
        domainMaxField: viz_scale_linear_domain_max
        rangeMinField: viz_scale_linear_range_min
        rangeMaxField: viz_scale_linear_range_max
        zeroField: viz_scale_linear_zero_baseline
        modeField: viz_scale_linear_mode

tokens:
  viz.scale.linear.grid: "var(--cmp-viz-grid-line)"
  viz.scale.linear.axis: "var(--cmp-viz-axis-line)"
  viz.scale.linear.zero: "var(--cmp-viz-zero-line)"

dependencies: []

metadata:
  created: "2025-11-15"
  updated: "2026-02-28"
  owners:
    - viz@oods.systems
    - platform@oods.systems
  maturity: alpha
  accessibility:
    keyboard: Scale controls are keyboard-operable in VizScaleControls form component.
    screenreader: Scale summary announces domain range and zero baseline status.
  regionsUsed:
    - detail
    - form
  allows:
    - EncodingPositionX
    - EncodingPositionY
    - EncodingSize
    - EncodingColor
  references:
    - RDS.7 Trait-Driven Visualization System Specification (v0.1)
```