Generate PNG with proper theme and scale

lib/asciinema/png_generator.ex

@@ -1,10 +1,11 @@
 defmodule Asciinema.PngGenerator do
   alias Asciinema.Asciicast
+  alias Asciinema.PngGenerator.PngParams
 
   @doc "Generates PNG image from asciicast and returns path to it"
-  @callback generate(asciicast :: %Asciicast{}) :: {:ok, String.t} | {:error, term}
+  @callback generate(asciicast :: %Asciicast{}, png_params :: %PngParams{}) :: {:ok, String.t} | {:error, term}
 
-  def generate(asciicast) do
-    Application.get_env(:asciinema, :png_generator).generate(asciicast)
+  def generate(asciicast, png_params) do
+    Application.get_env(:asciinema, :png_generator).generate(asciicast, png_params)
   end
 end

lib/asciinema/png_generator/a2png.ex

@@ -2,13 +2,14 @@ defmodule Asciinema.PngGenerator.A2png do
   @behaviour Asciinema.PngGenerator
   use GenServer
   alias Asciinema.Asciicast
+  alias Asciinema.PngGenerator.PngParams
 
   @pool_name :worker
   @acquire_timeout 5000
   @a2png_timeout 30000
   @result_timeout 35000
 
-  def generate(%Asciicast{} = asciicast) do
+  def generate(%Asciicast{} = asciicast, %PngParams{} = png_params) do
     {:ok, tmp_dir_path} = Briefly.create(directory: true)
 
     try do
@@ -16,7 +17,7 @@ defmodule Asciinema.PngGenerator.A2png do
         @pool_name,
         (fn pid ->
           try do
-            GenServer.call(pid, {:generate, asciicast, tmp_dir_path}, @result_timeout)
+            GenServer.call(pid, {:generate, asciicast, png_params, tmp_dir_path}, @result_timeout)
           catch
             :exit, {:timeout, _} ->
               {:error, :timeout}
@@ -40,8 +41,8 @@ defmodule Asciinema.PngGenerator.A2png do
     {:ok, nil}
   end
 
-  def handle_call({:generate, asciicast, tmp_dir_path}, _from, state) do
-    {:reply, do_generate(asciicast, tmp_dir_path), state}
+  def handle_call({:generate, asciicast, png_params, tmp_dir_path}, _from, state) do
+    {:reply, do_generate(asciicast, png_params, tmp_dir_path), state}
   end
 
   def poolboy_config do
@@ -51,15 +52,22 @@ defmodule Asciinema.PngGenerator.A2png do
      {:max_overflow, 0}]
   end
 
-  defp do_generate(asciicast, tmp_dir_path) do
+  defp do_generate(asciicast, png_params, tmp_dir_path) do
     path = Asciicast.json_store_path(asciicast)
     json_path = Path.join(tmp_dir_path, "tmp.json")
     png_path = Path.join(tmp_dir_path, "tmp.png")
-    snapshot_at = "#{asciicast.duration / 2}"
+
+    args = [
+      json_path,
+      png_path,
+      Float.to_string(png_params.snapshot_at),
+      png_params.theme,
+      Integer.to_string(png_params.scale)
+    ]
 
     with {:ok, file} <- file_store().open(path),
          {:ok, _} <- :file.copy(file, json_path),
-         process <- Porcelain.spawn(bin_path(), [json_path, png_path, snapshot_at]),
+         process <- Porcelain.spawn(bin_path(), args),
          {:ok, %{status: 0}} <- Porcelain.Process.await(process, @a2png_timeout) do
       {:ok, png_path}
     else

lib/asciinema/png_generator/png_params.ex

@@ -0,0 +1,3 @@
+defmodule Asciinema.PngGenerator.PngParams do
+  defstruct [:snapshot_at, :theme, :scale]
+end

web/controllers/asciicast_image_controller.ex

@@ -5,8 +5,10 @@ defmodule Asciinema.AsciicastImageController do
 
   def show(conn, %{"id" => id} = _params) do
     asciicast = Repo.one!(Asciicast.by_id_or_secret_token(id))
+    user = Repo.preload(asciicast, :user).user
+    png_params = Asciicast.png_params(asciicast, user)
 
-    case PngGenerator.generate(asciicast) do
+    case PngGenerator.generate(asciicast, png_params) do
       {:ok, png_path} ->
         conn
         |> put_resp_header("content-type", MIME.path(png_path))

web/models/asciicast.ex

@@ -1,5 +1,10 @@
 defmodule Asciinema.Asciicast do
   use Asciinema.Web, :model
+  alias Asciinema.{User, Asciicast}
+  alias Asciinema.PngGenerator.PngParams
+
+  @default_png_scale 2
+  @default_theme "asciinema"
 
   schema "asciicasts" do
     field :version, :integer
@@ -10,6 +15,10 @@ defmodule Asciinema.Asciicast do
     field :private, :boolean
     field :secret_token, :string
     field :duration, :float
+    field :theme_name, :string
+    field :snapshot_at, :float
+
+    belongs_to :user, User
   end
 
   def by_id_or_secret_token(thing) do
@@ -31,4 +40,18 @@ defmodule Asciinema.Asciicast do
   def json_store_path(%__MODULE__{id: id, stdout_frames: stdout_frames}) when is_binary(stdout_frames) do
     "asciicast/stdout_frames/#{id}/#{stdout_frames}"
   end
+
+  def snapshot_at(%Asciicast{snapshot_at: snapshot_at, duration: duration}) do
+    snapshot_at || duration / 2
+  end
+
+  def theme_name(%Asciicast{theme_name: a_theme_name}, %User{theme_name: u_theme_name}) do
+    a_theme_name || u_theme_name || @default_theme
+  end
+
+  def png_params(%Asciicast{} = asciicast, %User{} = user) do
+    %PngParams{snapshot_at: snapshot_at(asciicast),
+               theme: theme_name(asciicast, user),
+               scale: @default_png_scale}
+  end
 end