Dala.Theme.Theme (dala v0.10.0)

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Design token system for Dala apps.

A theme is a compiled %Dala.Theme{} struct — a flat map of semantic tokens for colors, spacing, radii, and scale factors. The renderer resolves these tokens at render time so every component picks up the active theme automatically.

Using a named theme

Named themes are plain modules that export theme/0. Pass the module to use Dala.App:

use Dala.App, theme: Dala.Theme.Obsidian

Override individual tokens without leaving the theme:

use Dala.App, theme: {Dala.Theme.Obsidian, primary: :rose_500}

Anyone can publish a theme as a Hex package — any module with theme/0 returning a Dala.Theme.t() works:

use Dala.App, theme: AcmeCorp.BrandTheme

Building a theme from scratch

Pass a keyword list of overrides against the neutral base:

use Dala.App, theme: [primary: :emerald_500, type_scale: 1.1]

Or change the theme at runtime (e.g. for accessibility or user preference):

Dala.Theme.set(Dala.Theme.Obsidian)
Dala.Theme.set({Dala.Theme.Obsidian, type_scale: 1.2})
Dala.Theme.set(primary: :pink_500)

Base theme

When no theme is set the renderer uses the neutral base — plain dark grays with a standard blue primary. Functional, not opinionated. Good enough for hello world; swap in a named theme when you want personality.

Token reference

Semantic color tokens

:primary        — main action colour          (default :blue_500)
:on_primary     — text/icons on primary        (default :white)
:secondary      — secondary action colour      (default :gray_600)
:on_secondary   — text/icons on secondary      (default :white)
:background     — page/screen background       (default :gray_900)
:on_background  — text on background           (default :gray_100)
:surface        — card / sheet background      (default :gray_800)
:surface_raised — elevated card background     (default :gray_700)
:on_surface     — text/icons on surface        (default :gray_100)
:muted          — secondary/placeholder text   (default :gray_500)
:error          — error state colour           (default :red_500)
:on_error       — text/icons on error          (default :white)
:border         — dividers and outlines        (default :gray_700)

Spacing tokens (scaled by space_scale)

:space_xs  →  4 × scale
:space_sm  →  8 × scale
:space_md  → 16 × scale
:space_lg  → 24 × scale
:space_xl  → 32 × scale

Radius tokens

:radius_sm   → theme.radius_sm   (default  6)
:radius_md   → theme.radius_md   (default 10)
:radius_lg   → theme.radius_lg   (default 16)
:radius_pill → theme.radius_pill (default 100)

Line-height tokens (scaled by type_scale)

:line_height_tight   → 1.25
:line_height_normal  → 1.5
:line_height_relaxed → 1.75

Scale factors

type_scale:  1.0  # multiply all text sizes by this
space_scale: 1.0  # multiply all spacing tokens by this

Summary

Types

color_value()
t()

Functions

build(overrides \\ [])

Build a theme from a keyword list of overrides against the neutral base.

color_scheme()

Returns the current OS appearance: :light or :dark.

current()

Return the currently active theme (or the neutral base if none is set).

default()

Return the neutral base theme.

prefers_reduced_motion()

Returns true if the OS accessibility setting "Reduce Motion" is enabled.

resolve(token)

Resolve a design token to its current value.

set(theme)

Set the active theme. Accepts

set_accent(color)

Override the accent (primary) color of the current theme.

Types

color_value()

@type color_value() :: atom() | non_neg_integer()

t()

@type t() :: %Dala.Theme.Theme{
  background: term(),
  border: term(),
  error: term(),
  line_height_normal: term(),
  line_height_relaxed: term(),
  line_height_tight: term(),
  muted: term(),
  on_background: term(),
  on_error: term(),
  on_primary: term(),
  on_secondary: term(),
  on_surface: term(),
  primary: term(),
  radius_lg: term(),
  radius_md: term(),
  radius_pill: term(),
  radius_sm: term(),
  secondary: term(),
  space_scale: term(),
  surface: term(),
  surface_raised: term(),
  type_scale: term()
}

Functions

build(overrides \\ [])

@spec build(keyword()) :: t()

Build a theme from a keyword list of overrides against the neutral base.

Dala.Theme.build(primary: :emerald_500, type_scale: 1.1)

color_scheme()

@spec color_scheme() :: :light | :dark

Returns the current OS appearance: :light or :dark.

Reads from the platform NIF (UITraitCollection.userInterfaceStyle on iOS, Configuration.uiMode & UI_MODE_NIGHT_MASK on Android). Falls back to :light when running on the host BEAM (no NIF loaded), on platforms that don't expose appearance, or on legacy Android apps that haven't added dalaBridge.getColorScheme() yet.

current()

@spec current() :: t()

Return the currently active theme (or the neutral base if none is set).

default()

@spec default() :: t()

Return the neutral base theme.

prefers_reduced_motion()

@spec prefers_reduced_motion() :: boolean()

Returns true if the OS accessibility setting "Reduce Motion" is enabled.

Reads from the platform NIF. Falls back to false when running on the host BEAM (no NIF loaded) or on platforms that don't expose the setting.

resolve(token)

@spec resolve(atom()) :: non_neg_integer()

Resolve a design token to its current value.

Color tokens return ARGB integers, spacing/radius tokens return integers.

Dala.Theme.resolve(:primary)     #=> 0xFF3B82F6
Dala.Theme.resolve(:space_md)    #=> 16
Dala.Theme.resolve(:radius_pill) #=> 100

set(theme)

@spec set(t() | module() | {module(), keyword()} | keyword()) :: :ok

Set the active theme. Accepts:

  • A compiled %Dala.Theme{} struct
  • A theme module (Dala.Theme.Obsidian)
  • A {module, overrides} tuple
  • A keyword list of overrides against the neutral base

set_accent(color)

@spec set_accent(atom() | non_neg_integer()) :: :ok

Override the accent (primary) color of the current theme.

Accepts any color value — raw ARGB integer or named color token. :on_primary is automatically chosen for WCAG contrast (white for dark colors, near-black for light colors).

Dala.Theme.set_accent(:violet_500)
Dala.Theme.set_accent(0xFF8B5CF6)