Distinguish between color extraction strategies

By default, use fast color sampling. Run heavy edge weighted extraction
only on demand.

lib/music_library/records/dominant_colors.ex

@@ -1,121 +0,0 @@
-defmodule MusicLibrary.Records.DominantColors do
-  @moduledoc """
-  Simple edge-weighted color extraction using Vix.
-
-  This approach weights colors based on their proximity to edges,
-  giving more importance to colors from visually significant regions
-  without requiring complex algorithms.
-
-  Generated by Claude, using Sonnet 4.
-  """
-
-  alias Vix.Vips.{Image, Operation}
-
-  @doc """
-  Extracts dominant colors weighted by edge proximity.
-  Colors near edges (important features) are given higher importance.
-  """
-  def extract_dominant_colors(image_data, num_colors \\ 5) do
-    with {:ok, image} <- Image.new_from_buffer(image_data),
-         {:ok, resized} <- Operation.thumbnail_image(image, 200),
-         {:ok, rgb_image} <- ensure_rgb_channels(resized),
-         {:ok, edge_map} <- create_edge_map(rgb_image),
-         {:ok, colors} <- extract_edge_weighted_colors(rgb_image, edge_map, num_colors) do
-      hex_colors = Enum.map(colors, &rgb_to_hex/1)
-      {:ok, hex_colors}
-    end
-  end
-
-  @doc """
-  Same as `extract_dominant_colors/2`, but raises an error on failure.
-  """
-  @spec extract_dominant_colors!(binary(), 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: #{reason}"
-    end
-  end
-
-  defp create_edge_map(image) do
-    # Convert to grayscale for edge detection
-    # Apply Sobel edge detection - built into Vix!
-    with {:ok, gray} <- Operation.colourspace(image, :VIPS_INTERPRETATION_B_W) do
-      Operation.sobel(gray)
-    end
-  end
-
-  defp ensure_rgb_channels(image) do
-    bands = Image.bands(image)
-
-    cond do
-      bands >= 3 -> {:ok, image}
-      bands == 1 -> Operation.bandjoin([image, image, image])
-      true -> {:error, "Unsupported image format"}
-    end
-  end
-
-  defp extract_edge_weighted_colors(rgb_image, edge_map, num_colors) do
-    width = Image.width(rgb_image)
-    height = Image.height(rgb_image)
-
-    # Sample pixels with edge-based weighting
-    # Sample every 3rd pixel for performance
-    weighted_pixels =
-      for y <- 0..(height - 1)//3,
-          x <- 0..(width - 1)//3 do
-        with {:ok, [r, g, b | _]} <- Operation.getpoint(rgb_image, x, y),
-             {:ok, [edge_strength]} <- Operation.getpoint(edge_map, x, y) do
-          # Weight this pixel by edge strength
-          # Normalize edge strength
-          weight = max(1, trunc(edge_strength / 50))
-          color = {trunc(r), trunc(g), trunc(b)}
-
-          # Return the color multiple times based on edge weight
-          List.duplicate(color, weight)
-        else
-          _ -> []
-        end
-      end
-      |> List.flatten()
-      |> Enum.reject(fn {r, g, b} ->
-        # Filter out very dark/light colors
-        brightness = (r + g + b) / 3
-        brightness < 15 || brightness > 240
-      end)
-
-    if length(weighted_pixels) > 0 do
-      colors = cluster_weighted_colors(weighted_pixels, num_colors)
-      {:ok, colors}
-    else
-      {:error, "No valid edge-weighted pixels found"}
-    end
-  end
-
-  defp cluster_weighted_colors(pixels, num_colors) do
-    pixels
-    # Slightly larger buckets for better clustering
-    |> group_similar_colors(40)
-    |> Enum.frequencies()
-    |> Enum.sort_by(fn {_color, count} -> count end, :desc)
-    |> Enum.take(num_colors)
-    |> Enum.map(fn {{r, g, b}, _count} -> {r, g, b} end)
-  end
-
-  defp group_similar_colors(pixels, bucket_size) do
-    Enum.map(pixels, fn {r, g, b} ->
-      {
-        div(r, bucket_size) * bucket_size,
-        div(g, bucket_size) * bucket_size,
-        div(b, bucket_size) * bucket_size
-      }
-    end)
-  end
-
-  defp rgb_to_hex({r, g, b}) do
-    "#" <>
-      (r |> Integer.to_string(16) |> String.pad_leading(2, "0") |> String.upcase()) <>
-      (g |> Integer.to_string(16) |> String.pad_leading(2, "0") |> String.upcase()) <>
-      (b |> Integer.to_string(16) |> String.pad_leading(2, "0") |> String.upcase())
-  end
-end

lib/music_library/records/record.ex

@@ -5,7 +5,8 @@ defmodule MusicLibrary.Records.Record do
 
   alias MusicBrainz.{Release, ReleaseGroup}
   alias MusicLibrary.Artists.Artist
-  alias MusicLibrary.Records.{Cover, DominantColors}
+  alias MusicLibrary.Colors.ColorFrequencyExtractor
+  alias MusicLibrary.Records.Cover
 
   @formats [:cd, :backup, :vinyl, :blu_ray, :dvd, :multi]
   @types [:album, :ep, :live, :compilation, :single, :other]
@@ -170,7 +171,7 @@ defmodule MusicLibrary.Records.Record do
   end
 
   def generate_dominant_colors(%__MODULE__{cover_data: cover_data} = record) do
-    change(record, dominant_colors: DominantColors.extract_dominant_colors!(cover_data))
+    change(record, dominant_colors: ColorFrequencyExtractor.extract_dominant_colors!(cover_data))
   end
 
   def generate_dominant_colors(changeset) do
@@ -182,7 +183,7 @@ defmodule MusicLibrary.Records.Record do
         put_change(
           changeset,
           :dominant_colors,
-          DominantColors.extract_dominant_colors!(cover_data)
+          ColorFrequencyExtractor.extract_dominant_colors!(cover_data)
         )
     end
   end