Vector drawing bootstrapping

lib/mudbrick/drawing.ex

@@ -0,0 +1,18 @@
+defmodule Mudbrick.Drawing do
+  defstruct lines: []
+
+  def new() do
+    struct!(__MODULE__, [])
+  end
+
+  defmodule Path do
+    @enforce_keys [:from, :to]
+    defstruct [:from, :to]
+
+    def new(drawing, opts) do
+      Map.update!(drawing, :lines, fn lines ->
+        [struct!(__MODULE__, opts) | lines]
+      end)
+    end
+  end
+end

lib/mudbrick/drawing/output.ex

@@ -0,0 +1,7 @@
+defmodule Mudbrick.Drawing.Output do
+  defstruct operations: []
+
+  def from(_) do
+    %__MODULE__{}
+  end
+end

test/mudbrick/drawing_test.exs

@@ -0,0 +1,21 @@
+defmodule Mudbrick.DrawingTest do
+  use ExUnit.Case, async: true
+
+  import Mudbrick.TestHelper, only: [output: 2]
+
+  alias Mudbrick.Drawing
+
+  test "can make an empty line drawing" do
+    assert [] =
+             output(fn ->
+               Drawing.new()
+             end)
+             |> operations()
+  end
+
+  defp output(f), do: output(fn _ -> f.() end, Mudbrick.Drawing.Output)
+
+  defp operations(ops) do
+    Enum.map(ops, &Mudbrick.TestHelper.show/1)
+  end
+end

test/mudbrick/text_block_test.exs

@@ -1,7 +1,7 @@
 defmodule Mudbrick.TextBlockTest do
   use ExUnit.Case, async: true
 
-  import Mudbrick.TestHelper, only: [output: 1]
+  import Mudbrick.TestHelper, only: [output: 2]
 
   alias Mudbrick.TextBlock
   alias Mudbrick.TextBlock.Line
@@ -283,6 +283,8 @@ defmodule Mudbrick.TextBlockTest do
     end
   end
 
+  defp output(f), do: output(f, Mudbrick.TextBlock.Output)
+
   defp operations(ops) do
     Enum.map(ops, &Mudbrick.TestHelper.show/1)
   end

test/test_helper.exs

@@ -6,7 +6,6 @@ defmodule Mudbrick.TestHelper do
   @example_png Path.join(__DIR__, "fixtures/Example.png") |> File.read!()
 
   alias Mudbrick.Page
-  alias Mudbrick.TextBlock.Output
 
   def show(o) do
     Mudbrick.Object.from(o) |> to_string()
@@ -38,7 +37,7 @@ defmodule Mudbrick.TestHelper do
     @example_png
   end
 
-  def output(f) when is_function(f) do
+  def output(f, output_mod) when is_function(f) do
     import Mudbrick
 
     {doc, _contents_obj} =
@@ -65,7 +64,7 @@ defmodule Mudbrick.TestHelper do
         }
       })
 
-    ops = Output.from(block).operations
+    ops = output_mod.from(block).operations
 
     context
     |> Mudbrick.ContentStream.put(operations: ops)