Upload.Filter.AnalyzeMetadata: Blurhash with a Rust NIF, and use Vix to retrieve image metadata

lib/pleroma/upload/filter/analyze_metadata.ex

@@ -8,22 +8,23 @@ defmodule Pleroma.Upload.Filter.AnalyzeMetadata do
   """
   require Logger
 
+  alias Vix.Vips.Image
+  alias Vix.Vips.Operation
+
   @behaviour Pleroma.Upload.Filter
 
   @spec filter(Pleroma.Upload.t()) ::
           {:ok, :filtered, Pleroma.Upload.t()} | {:ok, :noop} | {:error, String.t()}
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _} = upload) do
     try do
-      image =
-        file
-        |> Mogrify.open()
-        |> Mogrify.verbose()
+      {:ok, image} = Image.new_from_file(file)
+      {width, height} = {Image.width(image), Image.height(image)}
 
       upload =
         upload
-        |> Map.put(:width, image.width)
-        |> Map.put(:height, image.height)
-        |> Map.put(:blurhash, get_blurhash(file))
+        |> Map.put(:width, width)
+        |> Map.put(:height, height)
+        |> Map.put(:blurhash, get_blurhash(image))
 
       {:ok, :filtered, upload}
     rescue
@@ -53,7 +54,7 @@ defmodule Pleroma.Upload.Filter.AnalyzeMetadata do
   def filter(_), do: {:ok, :noop}
 
   defp get_blurhash(file) do
-    with {:ok, blurhash} <- :eblurhash.magick(file) do
+    with {:ok, blurhash} <- vips_blurhash(file) do
       blurhash
     else
       _ -> nil
@@ -80,4 +81,23 @@ defmodule Pleroma.Upload.Filter.AnalyzeMetadata do
       {:error, _} = error -> error
     end
   end
+
+  defp vips_blurhash(image = %Vix.Vips.Image{}) do
+    {:ok, resized_image} = Operation.thumbnail_image(image, 20)
+    {height, width} = {Image.height(resized_image), Image.width(resized_image)}
+    max = max(height, width)
+    {x, y} = {max(round(width * 5 / max), 1), max(round(height * 5 / max), 1)}
+
+    {:ok, rgba} =
+      if Image.has_alpha?(resized_image) do
+        Image.to_list(resized_image)
+      else
+        Operation.bandjoin_const!(resized_image, [255])
+        |> Image.to_list()
+      end
+
+    rgba = List.flatten(rgba)
+
+    Blurhash.encode(x, y, width, height, rgba)
+  end
 end