---
title: "Color field"
description: "Lets people set one color as a field of a form — a text value they can read, type and paste, a sample of it beside the text, and a button that asks for a picker — that looks and measures like a text field."
url: "https://tanrei.chnotchy.com/components/color-field/"
last_updated: 2026-10-23T21:17:12.000Z
---

# Color field

> Lets people set one color as a field of a form — a text value they can read, type and paste, a sample of it beside the text, and a button that asks for a picker — that looks and measures like a text field.

## Overview

Use a color field where people set a color as a value: a brand color in a theme, the color of a label or a category. They read it, type it or paste it from another tool, and see a sample of it beside the text. The field is drawn and measured as the text field of the same variant and size.

**Built from** a [field](https://tanrei.chnotchy.com/components/field/) and a [color input](https://tanrei.chnotchy.com/components/color-input/). The field is the frame: the label, the required or optional mark, the help and the error. The color input is the control: the box, the swatch, the value as text and the picker button. The color field draws nothing of its own and has no token: every property it has is a property of one of the two, given to it unchanged.

It is a block as wide as the place it is put in, and its box fills it. It has no width of its own: for a narrower field, give it a narrower place. It is a field already, so it is never placed inside a [field](https://tanrei.chnotchy.com/components/field/).

It draws no picker of its own. With `picker`, a button at the end asks for one: the browser’s, or a surface the product presents.

On the web it is `<tanrei-color-field>`. The other platforms have not implemented it yet.

### Usage

`value` is a number sign and six hexadecimal digits in lowercase (`#0f766e`), or an empty string for no color. It is never a half-typed text: while the input holds something that is not a color, `value` is empty.

**Web**

```html
<form>
  <tanrei-color-field name="brand" label="Brand color" value="#0f766e"
    required required-text="Required"
    supporting-text="Six hexadecimal digits, like #0f766e."
    invalid-text="Enter six hexadecimal digits, like #0f766e."
    picker picker-label="Choose color"></tanrei-color-field>
</form>

<script type="module">
  import '@tanrei/web/components/color-field';

  const brand = document.querySelector('tanrei-color-field');
  // The value changed: a color, or an empty string. It is already the new one.
  brand.addEventListener('input', () => preview(brand.value));
  // The person committed a changed value: focus left, Enter, or the picker closed.
  brand.addEventListener('change', () => save(brand.value));
  // A text that is not a color was committed. The field keeps it and shows invalidText,
  // which is also what detail.message carries.
  brand.addEventListener('entryerror', (e) => console.log(e.detail.text, e.detail.message));
  // To present a picker of your own: cancel the request, open it, and set value to what was picked.
  brand.addEventListener('pickerrequest', (e) => {
    e.preventDefault();
    openMyPicker(e.detail.value).then((color) => (brand.value = color));
  });
</script>
```

**React**

```tsx
import { ColorField } from '@tanrei/react';

<ColorField label="Brand color" value={brand} picker pickerLabel="Choose color"
  invalidText="Enter six hexadecimal digits, like #0f766e."
  onChange={(event) => setBrand(event.currentTarget.value)} />
```

### One level down

The same field, written by hand from its two members, is the same picture, and to assistive technology the same text box with the same name, description and states:

```html
<tanrei-field label="Brand color" required required-text="Required"
  supporting-text="Six hexadecimal digits, like #0f766e.">
  <tanrei-color-input name="brand" value="#0f766e"
    invalid-text="Enter six hexadecimal digits, like #0f766e."
    picker picker-label="Choose color"></tanrei-color-input>
</tanrei-field>
```

Go one level down when you need an arrangement the color field does not offer:

| You need | Use |
| --- | --- |
| A label, the box, help and an error | The color field |
| Something of your own inside the frame, beside or below the box | A [field](https://tanrei.chnotchy.com/components/field/) with a [color input](https://tanrei.chnotchy.com/components/color-input/) and your own element in it |
| The box alone, in a row or a column that already names the color: the tones of a palette, a cell of a table | The [color input](https://tanrei.chnotchy.com/components/color-input/) alone, named by its own `label` |

What changes one level down is where things are said. `name` and `value` are on the color input, which is then the control the form meets, and its events are heard on it. `label`, `error`, `disabled` and the requirement stay on the field, which passes them to the control: do not set the input’s own. The color field does nothing that the field and the color input written by hand do not do.

## Specs

### The field

| Part | What it is |
| --- | --- |
| Label | Above the container (`stacked`), where the field draws it, or floating inside it (`filled`, `outlined`), where the color input draws it. It is the accessible name, drawn or hidden with `labelHidden` |
| Requirement mark | After the label: the requirement tag in its required form, an asterisk or nothing for `required`; the requirement tag in its optional form for `optional` |
| Swatch | A sample of the value at the start of the container: a small square filled with exactly the value’s color, inside a hairline. Empty, it is the hairline alone. It is not a control |
| Input | The value as text. One line, which scrolls |
| Picker button | With `picker`: an icon-only text Button at the end, named by `pickerLabel` |
| Supporting text | A line of help, starting where the value’s text starts, after the swatch. While the field is in error the error text takes its place (below it, where the design system keeps both) — `errorText` while `error` is true, and `invalidText` while the committed text is not a color, or `errorText` where `invalidText` is empty |

The three variants and the three sizes, `small` (32), `medium` (40) and `large` (56), are the text field’s. The default system ships `stacked` only. The swatch stands where a text field’s leading icon stands, at that icon’s size, so a color field under a text field with a leading icon shares its start edges.

Nothing is mixed into the swatch: no hover, no error tint, no shadow. A sample that changes under the pointer is a wrong sample. Disabled, its fill is drawn fainter and its edge is kept.

### The value and the text

| When | What happens |
| --- | --- |
| The person types, pastes or dictates | Nothing is refused or rewritten. The whole text is read: if it is a color, `value` is that color, otherwise empty. `input` fires when `value` changed |
| Focus leaves, or Enter | The text is committed. A color is rewritten in the value’s own form. `change` fires if the value differs from the last committed one |
| The committed text is not a color | The text stays. The field is in error and shows `invalidText`, and `entryerror` fires. The error ends at the next edit |
| The text is empty | `value` is empty. That is never an error of the field’s |
| The product sets `value` | The color is shown, whatever was typed. No event fires |

A text reads as a color when, with the spaces around it left out, it is exactly six hexadecimal digits, in either case, with or without the number sign: `0F766E`, `#0f766e` and ` #0F766E ` are all `#0f766e`.

Everything else is no color: three digits (`#0f7`), eight (`#0f766e80`), a name (`teal`), a functional notation (`rgb(15, 118, 110)`). Three digits are no color while a person types, because the text passes through them on the way to six; when the text is committed they are read as the six they stand for, as CSS reads them: `#0f7` becomes `#00ff77`. There is no alpha and no wide-gamut color.

Nothing is reported while a person is still typing. An entry error is raised only when they commit.

### The picker

With `picker`, the field shows a button at its end. Activating it fires `pickerrequest`, which carries the value.

| The product | What happens |
| --- | --- |
| Does nothing | The field presents the browser’s own color picker. Each pick is an edit by the person: the text, the swatch, `input`. When the picker closes, `change` fires and focus is on the picker button |
| Cancels the request | The field presents nothing. The product opens its own surface, anchored to the field, and sets `value` to what was picked. That surface returns focus to the picker button when it closes |

With the picker button shown, a press on the swatch opens the picker, as a press on the button does; focus does not move to the input, and the button stays the keyboard’s way. Without the button, a press on the swatch focuses the input, as a press anywhere else on the field does.

### What each member gives

- **From the field**: the properties `label`, `labelHidden`, `supportingText`, `errorText`, `error`, `disabled`, `required`, `optional`, `requiredMark`, `requiredText` and `optionalText`; the slot `label-icon`; the tokens `comp.field.*`.
- **From the color input**: the properties `variant`, `size`, `value`, `invalidText`, `picker` and `pickerLabel`; the events `input`, `change`, `pickerRequest` and `entryError`; the tokens `comp.input-box.*` for the box, which every input box reads, and `comp.color-input.*` for the swatch.

The color input has a `label`, a `labelHidden`, an `error` and a `disabled` of its own. They are not what the color field sets: its `label` is the field’s, which names the input and, in a filled or an outlined field, is what floats in the box.

### Tokens

The color field has no token of its own. Its box reads the [color input’s tokens](https://tanrei.chnotchy.com/components/color-input/#specs) and its rows — the label, the mark, the help and the error — read the [field’s tokens](https://tanrei.chnotchy.com/components/field/#specs), wherever they are set. The table below lists the field’s. To change one instance, set a member’s token on it:

```html
<tanrei-color-field label="Brand color"
  style="--tanrei-comp-field-label-gap: 12px"></tanrei-color-field>
```

- Category: Text inputs
- Level: composed
- Listing: default
- Built from: Field, Color input
- Page: https://tanrei.chnotchy.com/components/color-field/
- Spec: https://github.com/chnotchy/tanrei/blob/main/specs/color-field.spec.json

### Availability

| Design system | Has it | Notes |
| --- | --- | --- |
| Tanrei (`tanrei`) | Yes | Variants left out: `filled`, `outlined`. |
| Cupertino (Apple HIG-inspired) (`cupertino`) | Yes | — |
| M3 Expressive-like (Material 3 Expressive-inspired) (`m3-expressive-like`) | Yes | — |
| M3-like (Material 3-inspired) (`m3-like`) | Yes | — |

### Platforms

- Web: the element `<tanrei-color-field>`, registered by importing `@tanrei/web` (or only its own module, `@tanrei/web/components/color-field`).
- React: `ColorField` from `@tanrei/react`.

| Platform | Name | Status |
| --- | --- | --- |
| Web | `tanrei-color-field` | lagging |
| SwiftUI | `TanreiColorField` | planned |
| Jetpack Compose | `TanreiColorField` | planned |
| Flutter | `TanreiColorField` | planned |
| React Native | `ColorField` | planned |

Names a platform gives in its own idiom:

| Spec | Web | SwiftUI | Jetpack Compose | Flutter | React Native |
| --- | --- | --- | --- | --- | --- |
| `value` (prop) | `value` | `hex` | `value` | `controller` | `value` |
| `label` (prop) | `label` | `label` | `label` | `labelText` | `label` |
| `labelHidden` (prop) | `labelHidden` | `labelsHidden` | `labelHidden` | `labelHidden` | `labelHidden` |
| `supportingText` (prop) | `supportingText` | `supportingText` | `supportingText` | `helperText` | `supportingText` |
| `error` (prop) | `error` | `error` | `isError` | `isError` | `error` |
| `disabled` (prop) | `disabled` | `disabled` | `enabled` | `enabled` | `disabled` |
| `required` (prop) | `required` | `isRequired` | `required` | `required` | `required` |
| `optional` (prop) | `optional` | `isOptional` | `optional` | `optional` | `optional` |
| `picker` (prop) | `picker` | `showsPicker` | `onPickerRequest` | `onPickerRequest` | `onPickerRequest` |
| `pickerLabel` (prop) | `pickerLabel` | `pickerLabel` | `pickerContentDescription` | `pickerSemanticLabel` | `pickerAccessibilityLabel` |
| `input` (event) | `input` | `hex` | `onValueChange` | `onChanged` | `onValueChange` |
| `change` (event) | `change` | `onCommit` | `onCommit` | `onCommit` | `onEndEditing` |
| `pickerRequest` (event) | `pickerrequest` | `onPickerRequest` | `onPickerRequest` | `onPickerRequest` | `onPickerRequest` |
| `entryError` (event) | `entryerror` | `onEntryError` | `onEntryError` | `onEntryError` | `onEntryError` |

Statuses: `planned` — In the inventory. Nothing shippable exists yet. `lagging` — An implementation of an earlier spec exists; it has not caught up with the current one. `alpha` — Implemented with tests. The API may still change. `beta` — Feature complete and at parity. Only fixes are expected. `stable` — Covered by semantic versioning. `deprecated` — Still shipped; scheduled for removal.

### Anatomy

- `field`: The Field: the label row with its glyph and its requirement mark, and the supporting row with the help and the error text. In a look whose input floats the label it draws no label row.
- `color-input`: The color input, as the Field's one control: the box, the swatch, the value as text, the picker button, and the label that floats in the box in the looks that float one.

### Props

| Prop | Type | Default | Web attribute | Description |
| --- | --- | --- | --- | --- |
| `variant` | `enum`: `stacked`, `filled`, `outlined` | `"stacked"` | `variant` | The text input's three looks, so that a color input is drawn as the text inputs beside it. Stacked is a filled box that shows focus and error with a line inside its edge and draws no label: the label of the Field that frames it stands above it. Filled and outlined float the label inside the box. Use one style per form. A design system may leave some out (the Tanrei system ships stacked only) or add values. (From Color input.) |
| `size` | `enum`: `small`, `medium`, `large` | `"medium"` | `size` | Minimum height of the container: stacked 32 / 40 / 56, as tall as a Button of the same size, so that the box and a Button side by side in one row stand as tall as each other; filled and outlined 40 / 48 / 56, which hold the label that floats inside them. These are the text input's three sizes, small for a bar, a toolbar or a dense row of controls. The hit area always meets the minimum target. A design system may add values. (From Color input.) |
| `value` | `string` | `""` | `value` | The color the input holds: a number sign and six hexadecimal digits in lowercase ("#0f766e"), an opaque sRGB color; or empty for no color. It is never a half-typed text: while the input holds something that is not a color, value is empty. (From Color input: What the color field reports as its own is the value its color input holds, in that value's own form (CLF-43, CLI-16, CLI-21).) |
| `label` | `string` | `""` | `label` | Names the control, visibly and to assistive technology. Required, unless the control names itself (a checkbox or a switch with its own label): then leave it empty and the field adds only help and an error. (From Field: Names the color input. In a filled or outlined look the input draws it, floating in its box, and the Field draws no label row (FLD-25, CLI-15).) |
| `labelHidden` | `boolean` | `false` | `label-hidden` | Does not draw the label, which stays the accessible name. For a control whose visible label is elsewhere (a table column, a toolbar). (From Field: Hides the label wherever it would be drawn: the Field's row, or the input's floating label (FLD-25).) |
| `supportingText` | `string` | `""` | `supporting-text` | Help shown below the control and given to assistive technology as the control's description. While the field is in error it gives way to errorText, unless the design system keeps both (comp.field.error-text.placement append). (From Field.) |
| `errorText` | `string` | `""` | `error-text` | Shown while error is true, in supportingText's place — or below it, which then stays, where the design system's comp.field.error-text.placement is append: what is wrong and how to put it right, in words. (From Field.) |
| `error` | `boolean` | `false` | `error` | Puts the field in the error condition: the error text is drawn, the control is exposed as invalid and, where it has an error condition of its own, drawn in it. What a value means is the product's to validate; the field never sets this itself. (From Field: The Field puts its color input in the input's own error condition (FLD-8, CLI-9).) |
| `disabled` | `boolean` | `false` | `disabled` | Disables the control and draws the frame as disabled. Disable a framed control here, not on the control, so that its label follows. (From Field: The Field disables its color input, the picker button with it (FLD-14, CLI-31); the color field is then left out of its form (CLF-44).) |
| `required` | `boolean` | `false` | `required` | What the form asks of the control: true exposes it as required and draws the required mark beside the label. It never validates: a missing answer is the product's to report with error. (From Field: The Field exposes its color input as required (FLD-10, CLI-11).) |
| `optional` | `boolean` | `false` | `optional` | Draws the optional tag after the label and adds optionalText to the control's description, because assistive technology has no state for it. Ignored while required is true: a control is never both. (From Field.) |
| `requiredMark` | `enum`: `auto`, `tag`, `asterisk`, `none` | `"auto"` | `required-mark` | How this control shows that it is required: tag is a small filled Tag with requiredText, asterisk is "*" after the label, none draws nothing and keeps the semantics. Auto takes comp.field.requirement.mark, which follows sys.behavior.requirement-mark, the system's one answer. Ignored unless required is true. (From Field.) |
| `requiredText` | `string` | `""` | `required-text` | The text of the required tag, in the product's language ("Required", "必須"). The product's: Tanrei has no word for it. Empty reads the product's words; with neither, FLD-24 says what is drawn. (From Field.) |
| `optionalText` | `string` | `""` | `optional-text` | The text of the optional tag, in the product's language ("Optional", "任意"); also read to assistive technology as part of the description. The product's: Tanrei has no word for it. Empty reads the product's words. (From Field.) |
| `invalidText` | `string` | `""` | `invalid-text` | The words for an input committed with a text that is not a color ("Enter six hexadecimal digits, like #0f766e"), in the product's language: given to the Field that frames the input, which shows them as its error text (CLI-20). While it is empty that Field shows its own errorText. (From Color input: Shown by the Field, in its supporting row (FLD-28).) |
| `picker` | `boolean` | `false` | `picker` | Shows the picker button. Activated, it emits pickerRequest, and where the platform has a color picker of its own the input presents that picker unless the product cancelled the request. The input draws no picker surface itself. (From Color input.) |
| `pickerLabel` | `string` | `""` | `picker-label` | The accessible name of the picker button ("Choose color"). Required while picker is shown. (From Color input.) |

### Events

| Event | Description |
| --- | --- |
| `input` | The person changed the value — by an edit of the text that made it a color, another color or no color, or by a pick in the platform's picker; carries the new value. Not emitted when the product sets value, nor for an edit that leaves value as it was. (From Color input.) |
| `change` | The person committed a changed value: focus left the input, the action key was pressed, or the platform's picker closed; carries the value. (From Color input.) |
| `pickerRequest` | The person activated the picker button; carries the value. Cancelling it keeps the input from presenting the platform's picker: the product then presents its own surface and sets value to what was picked. (From Color input.) |
| `entryError` | The person committed a text that is not empty and is not a color; carries the text as typed and invalidText, the words the input has for it (empty where the product gave none: the Field that frames the input then shows its own errorText). (From Color input.) |

### Slots

| Slot | Description |
| --- | --- |
| `label-icon` | A glyph before the label. (From Field.) |

### States

`enabled`, `disabled`, `hovered`, `focused`, `error`

### Accessibility

- Role: `textbox`
- Labeling: The color field adds nothing to what its members expose and coordinates nothing: the Field gives the color input its name, its description and its required, invalid and disabled states (FLD-8, FLD-10, FLD-11, FLD-14), and the color input carries them on its own element (CLI-11). Assistive technology meets one text box named by label whose value is the color as text, and, while picker is true, one button named by pickerLabel — exactly as it meets a Field around a color input written by hand.
- Minimum target size: yes

| Keys | Action |
| --- | --- |
| Every key | The color input's (its accessibility block; CLI-13, CLI-19, CLI-28). The color field handles no key and adds no focus stop (CLF-45). |

- One level down is the same thing: a Field with a color input in it. Every fixture has that pair as its twin, and the accessibility tree of the two is the same (CLF-43).
- On the web the two members stand in the color field's own shadow root, so the form meets the color field and not the input (CLF-44); focus passes through to the input (CLF-45).
- The color is never told by the swatch alone (WCAG 1.4.1), an error is always words (WCAG 3.3.1), and the swatch alone keeps its color in forced colors: each is the color input's or the Field's, and is said there (CLI-25, CLI-35, FLD-7, FLD-17).

### Behaviour

Requirements in EARS form, each with its stable id.

- **CLF-43** THE color field SHALL be a Field that frames one color input, and nothing else. It SHALL give label, labelHidden, supportingText, errorText, error, disabled, required, optional, requiredMark, requiredText and optionalText to its Field and variant, size, value, invalidText, picker and pickerLabel to its color input, each unchanged; SHALL hold the label-icon slot for its Field; and SHALL emit its color input's events as its own, each once. THE color field SHALL be as wide as the place it stands in, and its color input SHALL fill it: it is a block with no width of its own, as its Field is (FLD-1), around a control that fills the width it is given (CLI-44). Its value SHALL at every moment be the value its color input holds — a color in the value's own form, or the empty string (CLI-16) — and not the text the product set where the two differ (CLI-21). It SHALL draw no part of its own, hold no state of its own and have no token of its own: what it shows, how it behaves and what it exposes to assistive technology SHALL be exactly what that Field and that color input do when a product places the one in the other (FLD-1 to FLD-28; CLI-1 to CLI-44) — the label row and its requirement mark (FLD-2 to FLD-6), or the label that floats in the box with the Field's row left out (FLD-25, CLI-15, CLI-7); the supporting row, started at the value's text, after the swatch (FLD-7 to FLD-9, FLD-26, CLI-43); the name, the description and the states (FLD-10, FLD-11, FLD-14, CLI-11); and the entry error of a text that is not a color, shown in the Field's row (FLD-28, CLI-20).
- **CLF-44** WHERE the platform has forms (the web) THE color field SHALL be the one control the form sees: it SHALL take name, submit its color input's value, reset to the value it was first given, restore it on navigation, report to the form's constraint validation exactly what its color input would report there (CLI-11, CLI-20), and be left out WHILE disabled is true or a disabled group of the form holds it; its color input and its Field SHALL take no part in the form themselves. WHEN the action key asks for the form's submission (CLI-19) the form asked SHALL be the color field's own.
- **CLF-45** WHEN the color field is given focus — by the product, by a press on any part of it that FLD-12 or CLI-24 gives to the input, or by a form that reports its validity — THE color field SHALL pass the focus to the input of its color input, never to the picker button, and SHALL add no stop to the focus order: the stops inside it are its color input's, in that input's order (the input, then the picker button while it is shown, CLI-13). WHILE focus is anywhere inside it, the picker button included, THE color field SHALL count as focused for its Field, whose rows take their focused colors (FLD-13); the box takes its own only WHILE its input has focus (CLI-22). WHEN a picker the color input presented closes, focus SHALL be on the picker button (CLI-29), inside the color field.
- **CLF-46** IF the color field is placed in a Field THE color field SHALL in debug builds report that it is a field already and that the bare control is the color input, and both SHALL still render (FLD-15). WHILE it stands in a field group THE color field SHALL follow that group's disabled, through its own Field, and take nothing else from the group (FGR-20).
- **CLF-47** THE color field SHALL have no words of its own and SHALL read none: requiredText and optionalText are read by its Field (FLD-24), each from the instance's prop and then from the product's words; invalidText and pickerLabel are the instance's alone and are given to its color input as they are (CLI-42).
- **CLF-48** WHERE the platform has ARIA attributes (the web), WHEN the product sets an aria- attribute on the host, by the attribute or by the ARIA property that reflects it, THE color field SHALL move it to the data-aria- attribute of the same name, so that the host is no second node with its name, description or state, and SHALL expose it on the element that carries its role — an id reference by the elements it names in the host's tree or a tree around it, an error message as part of the description while the color field is invalid — except those the color field owns (aria-label, aria-labelledby, aria-disabled), which it SHALL move and not expose: its name is label (CLF-43). WHEN the product removes the aria- attribute or its data-aria- twin, or sets the ARIA property that reflects it (ariaLabel, ariaDescribedByElements…) to null, THE color field SHALL take it off that element. WHEN the product sets an aria- attribute the color field owns THE color field SHALL report it in debug builds.

### Tokens

As written in the token documents (DTCG): an alias in braces names the token it takes its value from, which each design system resolves. On the web each token is a CSS custom property: `--tanrei` and the name after `tanrei`, joined by hyphens (`tanrei.comp.field.…` → `--tanrei-comp-field-…`).

#### `tanrei.comp.field`

| Token | Type | Value |
| --- | --- | --- |
| `comp.field.label.typescale` | `typography` | `{tanrei.sys.typescale.label}` |
| `comp.field.label.gap` | `dimension` | `{tanrei.sys.space.space100}` |
| `comp.field.label-icon.size` | `dimension` | `{tanrei.sys.icon.small}` |
| `comp.field.label-icon.gap` | `dimension` | `{tanrei.sys.space.space100}` |
| `comp.field.requirement.mark` | `number` | `{tanrei.sys.behavior.requirement-mark}` |
| `comp.field.requirement.gap` | `dimension` | `{tanrei.sys.space.space100}` |
| `comp.field.requirement.asterisk-gap` | `dimension` | `{tanrei.sys.space.space25}` |
| `comp.field.supporting-text.typescale` | `typography` | `{tanrei.sys.typescale.label-small}` |
| `comp.field.supporting-text.gap` | `dimension` | `{tanrei.sys.space.space50}` |
| `comp.field.counter.gap` | `dimension` | `{tanrei.sys.space.space200}` |
| `comp.field.motion.state-duration` | `duration` | `{tanrei.sys.motion.role.state.default}` |
| `comp.field.motion.state-easing` | `cubicBezier` | `{tanrei.sys.motion.easing.state}` |
| `comp.field.standard.label.color` | `color` | `{tanrei.sys.color.on-surface}` |
| `comp.field.standard.label-icon.color` | `color` | `{tanrei.sys.color.on-surface-variant}` |
| `comp.field.standard.supporting-text.color` | `color` | `{tanrei.sys.color.on-surface-variant}` |
| `comp.field.standard.counter.color` | `color` | `{tanrei.sys.color.on-surface-variant}` |
| `comp.field.standard.required-asterisk.color` | `color` | `{tanrei.sys.color.primary}` |
| `comp.field.standard.error.label.color` | `color` | `{tanrei.sys.color.on-surface}` |
| `comp.field.standard.error.label-icon.color` | `color` | `{tanrei.sys.color.on-surface-variant}` |
| `comp.field.standard.error.supporting-text.color` | `color` | `{tanrei.sys.color.on-surface-variant}` |
| `comp.field.standard.error.counter.color` | `color` | `{tanrei.sys.color.on-surface-variant}` |
| `comp.field.standard.error.required-asterisk.color` | `color` | `{tanrei.sys.color.primary}` |
| `comp.field.standard.error.value-text.color` | `color` | `{tanrei.sys.color.on-surface-variant}` |
| `comp.field.standard.value-text.color` | `color` | `{tanrei.sys.color.on-surface-variant}` |
| `comp.field.standard.error-text.color` | `color` | `{tanrei.sys.color.error}` |
| `comp.field.value-text.typescale` | `typography` | `{tanrei.sys.typescale.label}` |
| `comp.field.value-text.gap` | `dimension` | `{tanrei.sys.space.space200}` |
| `comp.field.error-text.gap` | `dimension` | `{tanrei.sys.space.space50}` |
| `comp.field.error-text.placement` | `number` | `0` |

Per-state tokens, valued by the design system's pattern rules (not written by hand):

- `comp.field.<variant>.<state>.<property>` for the variants `standard`, the states `focused`, `disabled` and the properties `label.color`, `label-icon.color`, `supporting-text.color`, `required-asterisk.color`, `error.label.color`, `error.label-icon.color`, `error.supporting-text.color`, `error.required-asterisk.color`, `counter.color`, `error.counter.color`, `value-text.color`, `error.value-text.color`, `error-text.color`.

### What the web draws differently

- The element’s shadow root holds a `<tanrei-field>` with a `<tanrei-color-input>` in it, and nothing else. Importing the element defines both.
- The color field is a form-associated element. It takes `name` and submits `value`: the color, or an empty string. It resets to the `value` attribute, and reports a missing value while `required` and `value` is empty, and a bad input while an entry error lasts. Its two members add no entry to the form.
- `value` is always the color input’s: a value set as `0F766E` is read back as `#0f766e`, and one that is not a color as an empty string.
- `input` and `change` are plain events: read `value` from the element. `pickerrequest` and `entryerror` are CustomEvents with `detail.value` and with `detail.text` and `detail.message`. They are the color input’s own events, with the element as their target. `detail.message` is `invalidText`, and empty where you gave none — also while the field shows `errorText` in its place.
- Parts: `field` and `color-input` are the two members. Their own parts have the same names here as one level down: `label-icon`, `supporting-text`; `container`, `outline`, `active-indicator`, `swatch`, `input`, `picker-button`. `label` and `requirement-label` are the drawn ones, whichever member draws them; `field-label`, `color-input-label`, `field-requirement-label` and `color-input-requirement-label` name one member’s.
- The element is not focusable itself and has no role: `focus()` goes to the input, never to the picker button. A press on the label row, on the box, on the swatch (while there is no picker button) or on a floating label focuses the input. A press on the help or the error text does nothing.
- The label and the help take their focused colors while focus is anywhere in the field, the picker button included. The box takes its own only while its input has focus.
- Name it with `label` — with `label-hidden` where the label is not to be drawn — and never with `aria-label`, which names nothing here.
- The element has no words of its own. `requiredText` and `optionalText` are empty until you give them. A required field without `requiredText` shows the asterisk where the tag would stand.
- The browser’s picker differs by browser: a popup of the page in Chromium, the system’s color window in Firefox and Safari. Its look, placement and keys are the browser’s.
- A text in full-width characters (`＃０ｆ７６６ｅ`) is not read as a color.
- Before the element is defined it has no size. Reserve the height.

## Guidelines

### Color field or text field

| Aspect | Color field | Text field |
| --- | --- | --- |
| Holds | One color, as `#` and six digits | Any text |
| Shows | A sample of the color beside the text | The text |
| Checks | That the text is a color | Nothing |

For a color that is shown and not edited, draw a sample with its value or its name in text beside it. A color field is for a color people set.

### Do

- Write a label that says what the color is for, and keep it visible in a form.
- Say the form of the value in `supportingText`. It stays while the field is in error, so `invalidText` need not repeat it.
- Name the color in words in `supportingText` where that matters (“Teal”). A hexadecimal value says little about how a color looks.
- Give `pickerLabel` whenever `picker` is set.
- Validate what the color means yourself — its contrast against a background, a color already taken — and say it with `error` and `errorText`.
- Use a [color input](https://tanrei.chnotchy.com/components/color-input/) in a row that already names each color, such as the tones of a palette: it is the box alone, named by its own `label`.

### Don’t

- Don’t tell a color by the swatch alone. The value is text; a person who cannot tell two samples apart reads two different values.
- Don’t treat an empty `value` as an error by itself. `required` never validates.
- Don’t set `aria-invalid` or `error` while a person is typing. Wait for `change` or `entryerror`.
- Don’t put a color field inside a field. It is a field already; the control a field frames is the [color input](https://tanrei.chnotchy.com/components/color-input/).

## Accessibility

### What the component handles

- The input is a text field. Its name is `label`, drawn or hidden, and its value is the text it shows.
- The shown supporting or error text is its description, with `optionalText` while the field is optional.
- It is exposed as invalid while `error` is true or an entry error lasts, and as required while `required` is set.
- An error that appears while the field has focus is announced once, politely. It never takes focus away.
- The swatch is decorative and hidden from assistive technology: the value’s text says the color.
- The picker button is a separate button, named by `pickerLabel`, that is exposed as opening a dialog. It is a focus stop after the input. Focus given to the field itself always goes to the input.
- Nothing is announced when the value changes, and the field adds no name of the color.
- While an input method is composing, the field reads nothing and handles no key.
- The field’s hit area meets the minimum target, and the picker button is a full target.
- At 200% text the label and the help wrap. The value stays on one line, and scrolls; the swatch keeps its size.
- In forced colors the field gains an edge and takes the person’s colors. The swatch alone keeps the value’s color, because showing that color is what it is for; its edge is the text color.
- In a right-to-left layout the field is mirrored: the swatch at the right, the picker button at the left. The value itself stays left to right.

Known gaps on the web:

- The browser’s picker is not Tanrei’s: its accessibility is the browser’s own.
- Before the element is defined, nothing is drawn.

### What you need to do

- Give every color field a `label`.
- Write `invalidText` and `pickerLabel` on the field, in the language of the page. Give `requiredText` and `optionalText` on the field, or once for the whole product with `setWords({ requiredText, optionalText })`. See [The product’s words](https://tanrei.chnotchy.com/foundations/words/).
- Validate the color yourself, set `error`, and write `errorText` so that it says how to put the color right.
- If you present your own picker, open it from the picker button, give it a name, and return focus to the button when it closes.