More docs, add A3 page size.

Author: camelpunch

lib/mudbrick/page.ex

@@ -8,6 +8,7 @@ defmodule Mudbrick.Page do
   @dpi 72
 
   @page_sizes %{
+    a3: {11.7 * @dpi, 16.5 * @dpi},
     a4: {8.3 * @dpi, 11.7 * @dpi},
     letter: {8.5 * @dpi, 11 * @dpi}
   }
@@ -17,6 +18,20 @@ defmodule Mudbrick.Page do
     struct!(__MODULE__, opts)
   end
 
+  @doc """
+  Returns predefined page sizes in points.
+
+  ## Examples
+
+      iex> Mudbrick.Page.size(:a4)
+      {597.6, 842.4}
+
+      iex> Mudbrick.Page.size(:a3)
+      {842.4, 1188.0}
+
+      iex> Mudbrick.Page.size(:letter)
+      {612.0, 792}
+  """
   def size(name) do
     @page_sizes[name]
   end

lib/mudbrick/predicates.ex

@@ -1,11 +1,44 @@
 defmodule Mudbrick.Predicates do
+  @moduledoc """
+  Useful for testing PDF documents.
+
+  While these predicates do check the PDF in a black-box way, it's not expected
+  that they will work on all PDFs found in the wild.
+  """
+
+  @doc """
+  Checks for presence of `text` in the `pdf` `iodata`. Searches compressed and uncompressed data.
+
+  This arity only works with text that can be found in literal form inside a stream, compressed or uncompressed, 
+  """
+  @spec has_text?(pdf :: iodata(), text :: binary()) :: boolean()
   def has_text?(pdf, text) do
     binary = IO.iodata_to_binary(pdf)
     streams = extract_streams(binary)
     Enum.any?(streams, &String.contains?(&1, text))
   end
 
-  def has_text?(pdf, text, in_font: font) do
+  @doc """
+  Checks for presence of `text` in the `pdf` `iodata`. Searches compressed and uncompressed data.
+
+  This arity requires you to pass the raw font data in which the text is
+  expected to be written. It must be present in raw hexadecimal form
+  corresponding to the font's glyph IDs.
+
+  The [OpenType](https://hexdocs.pm/opentype) library is used to find font
+  features, such as ligatures, which are expected to have been used in the PDF.
+
+  ## Options
+
+  - `:in_font` - raw font data in which the text is expected.
+
+  ## Example
+
+      iex> Mudbrick.Predicates.has_text?("some-pdf", "hello", in_font: Mudbrick.TestHelper.bodoni())
+  """
+  @spec has_text?(pdf :: iodata(), text :: binary(), opts :: list()) :: boolean()
+  def has_text?(pdf, text, opts) do
+    font = Keyword.fetch!(opts, :in_font)
     parsed_font = OpenType.new() |> OpenType.parse(font)
     {glyph_ids_decimal, _positions} = OpenType.layout_text(parsed_font, text)
     glyph_ids_hex = Enum.map_join(glyph_ids_decimal, "", &Mudbrick.to_hex/1)

test/mudbrick/page_test.exs

@@ -0,0 +1,4 @@
+defmodule Mudbrick.PageTest do
+  use ExUnit.Case, async: true
+  doctest Mudbrick.Page
+end

test/predicates_test.exs

@@ -1,5 +1,6 @@
-defmodule Mbc.PredicatesTest do
+defmodule Mudbrick.PredicatesTest do
   use ExUnit.Case, async: true
+  doctest Mudbrick.Predicates
 
   import Mudbrick
   import Mudbrick.Predicates