Display dominant colors from the db

lib/music_library/records/dominant_colors.ex

@@ -21,6 +21,17 @@ defmodule MusicLibrary.Records.DominantColors do
     end
   end
 
+  @doc """
+  Same as `extract-dominant_colors/2`, but raises an error if extraction fails.
+  """
+  @spec extract_dominant_colors!(binary(), pos_integer()) :: [String.t()] | no_return
+  def extract_dominant_colors!(image_data, num_colors \\ 5) do
+    case extract_dominant_colors(image_data, num_colors) do
+      {:ok, colors} -> colors
+      {:error, reason} -> raise "Failed to extract dominant colors: #{inspect(reason)}"
+    end
+  end
+
   defp prepare_image_for_analysis(image) do
     with {:ok, resized} <- Operation.thumbnail_image(image, 150) do
       ensure_rgb_channels(resized)

lib/music_library/records/record.ex

@@ -5,7 +5,7 @@ defmodule MusicLibrary.Records.Record do
 
   alias MusicBrainz.{Release, ReleaseGroup}
   alias MusicLibrary.Artists.Artist
-  alias MusicLibrary.Records.Cover
+  alias MusicLibrary.Records.{Cover, DominantColors}
 
   @formats [:cd, :backup, :vinyl, :blu_ray, :dvd, :multi]
   @types [:album, :ep, :live, :compilation, :single, :other]
@@ -27,6 +27,7 @@ defmodule MusicLibrary.Records.Record do
     field :selected_release_id, :string
     field :release_ids, {:array, :string}, default: []
     field :included_release_group_ids, {:array, :string}, default: []
+    field :dominant_colors, {:array, :string}, default: []
 
     embeds_many :artists, Artist, on_replace: :delete
 
@@ -112,16 +113,28 @@ defmodule MusicLibrary.Records.Record do
       :included_release_group_ids,
       :cover_url,
       :cover_data,
+      :dominant_colors,
       :purchased_at
     ])
     |> cast_embed(:artists)
     |> validate_required([:type, :title, :musicbrainz_id, :genres])
     |> unique_constraint(:musicbrainz_id, name: "records_musicbrainz_id_format_index")
     |> generate_cover_hash()
+    |> maybe_generate_dominant_colors()
     |> update_release_ids()
     |> update_included_release_group_ids()
   end
 
+  defp maybe_generate_dominant_colors(changeset) do
+    case get_change(changeset, :dominant_colors) do
+      nil ->
+        generate_dominant_colors(changeset)
+
+      _dominant_colors ->
+        changeset
+    end
+  end
+
   def add_genres(record, genres) do
     change(record, genres: genres)
   end
@@ -130,6 +143,7 @@ defmodule MusicLibrary.Records.Record do
     record
     |> change(cover_data: cover_data)
     |> generate_cover_hash()
+    |> generate_dominant_colors()
   end
 
   def add_musicbrainz_data(record, musicbrainz_data) do
@@ -155,6 +169,24 @@ defmodule MusicLibrary.Records.Record do
     end
   end
 
+  def generate_dominant_colors(%__MODULE__{cover_data: cover_data} = record) do
+    change(record, dominant_colors: DominantColors.extract_dominant_colors!(cover_data))
+  end
+
+  def generate_dominant_colors(changeset) do
+    case get_change(changeset, :cover_data) do
+      nil ->
+        changeset
+
+      cover_data ->
+        put_change(
+          changeset,
+          :dominant_colors,
+          DominantColors.extract_dominant_colors!(cover_data)
+        )
+    end
+  end
+
   defp update_release_ids(changeset) do
     case get_change(changeset, :musicbrainz_data) do
       nil ->

lib/music_library_web/live/collection_live/show.html.heex

@@ -17,7 +17,7 @@
           {@record.title}
         </h2>
         <p class="mt-2 flex items-center text-sm leading-5 text-zinc-500 dark:text-zinc-400">
-          <.record_colors colors={@dominant_colors} />
+          <.record_colors colors={@record.dominant_colors} />
           <span class="ml-1">
             {Records.Record.format_release_date(@record.release_date)} · {format_label(
               @record.format

lib/music_library_web/live/wishlist_live/show.html.heex

@@ -17,7 +17,7 @@
           {@record.title}
         </h2>
         <p class="flex items-center mt-2 text-sm leading-5 text-zinc-500 dark:text-zinc-400">
-          <.record_colors colors={@dominant_colors} />
+          <.record_colors colors={@record.dominant_colors} />
           {Records.Record.format_release_date(@record.release_date)}
           <span :if={@current_date && !Records.Record.released?(@record, @current_date)}>
             ({gettext("Unreleased")})

priv/repo/migrations/20250607185415_add_dominant_colors_to_records.exs

@@ -0,0 +1,9 @@
+defmodule MusicLibrary.Repo.Migrations.AddDominantColorsToRecords do
+  use Ecto.Migration
+
+  def change do
+    alter table(:records) do
+      add :dominant_colors, {:array, :string}, default: []
+    end
+  end
+end

test/music_library/records_test.exs

@@ -44,6 +44,14 @@ defmodule MusicLibrary.RecordsTest do
 
       assert record.cover_hash ==
                "599407DDF69907D4A60FE13CCAA824D25CF08DC124FD6AA3E8E7ECD98C885FFE"
+
+      assert record.dominant_colors == [
+               "#000000",
+               "#C0C0C0",
+               "#C08080",
+               "#404000",
+               "#804040"
+             ]
     end
 
     test "it queues a task to retrieve artist info data" do

test/support/fixtures/music_library/records.ex

@@ -69,7 +69,8 @@ defmodule MusicLibrary.Fixtures.Records do
         selected_release_id: "d3f9b9e2-73f5-4b47-a2a7-2c2199aad608",
         release_date: Enum.random(1969..2024) |> Integer.to_string(),
         purchased_at: current_time,
-        artists: [artist_attrs(artist_name)]
+        artists: [artist_attrs(artist_name)],
+        dominant_colors: ["#000000", "#C0C0C0", "#C08080", "#404000", "#804040"]
       })
       |> MusicLibrary.Records.create_record()