Add autoprint

Author: andrewtimberlake

CHANGELOG.md

@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Latest
+
+- Add `autoprint/1` to automatically open the print dialog in a browser
+
 ## 0.6.1 (2023-01-19)
 
 - Fix bug with zero width strings and empty rows (also fixes [#24])

lib/pdf.ex

@@ -214,6 +214,16 @@ defmodule Pdf do
     pid
   end
 
+  @doc """
+  Adds an autoprint action to the Pdf.
+
+  This is can be useful for generating a PDF that will automatically open the print dialog in a browser
+  """
+  def autoprint(pid) do
+    :ok = GenServer.call(pid, :autoprint)
+    pid
+  end
+
   @doc "Returns the current page number."
   def page_number(pid) do
     GenServer.call(pid, :page_number)
@@ -663,6 +673,11 @@ defmodule Pdf do
     end
 
     @impl true
+    def handle_call(:autoprint, _from, document) do
+      document = Document.autoprint(document)
+      {:reply, :ok, document}
+    end
+
     def handle_call({:write_to, path}, _from, document) do
       File.write!(path, Document.to_iolist(document))
       {:reply, :ok, document}

lib/pdf/dictionary.ex

@@ -1,7 +1,7 @@
 defmodule Pdf.Dictionary do
   @moduledoc false
-  import Pdf.Size
   import Pdf.Utils
+  import Pdf.Size
 
   @dict_start "<<\n"
   @dict_start_length byte_size(@dict_start)
@@ -19,6 +19,7 @@ defmodule Pdf.Dictionary do
 
   def new(map) do
     map
+    |> Enum.filter(fn {_, value} -> value != nil end)
     |> Enum.reduce(new(), fn {key, value}, dictionary ->
       put(dictionary, key, value)
     end)

lib/pdf/document.ex

@@ -8,6 +8,7 @@ defmodule Pdf.Document do
             current_font_size: 0,
             pages: [],
             opts: [],
+            action: nil,
             images: %{}
 
   import Pdf.Utils
@@ -42,6 +43,24 @@ defmodule Pdf.Document do
     add_page(document, opts)
   end
 
+  def autoprint(document) do
+    action =
+      ObjectCollection.create_object(
+        document.objects,
+        Dictionary.new(%{
+          "S" => n("Named"),
+          "Type" => n("Action"),
+          "N" => n("Print")
+        })
+      )
+
+    put_in(document.action, action)
+  end
+
+  def get_object(document, ref) do
+    ObjectCollection.get_object(document.objects, ref)
+  end
+
   @info_map %{
     title: "Title",
     producer: "Producer",
@@ -228,7 +247,11 @@ defmodule Pdf.Document do
     catalogue =
       ObjectCollection.create_object(
         document.objects,
-        Dictionary.new(%{"Type" => n("Catalog"), "Pages" => master_page})
+        Dictionary.new(%{
+          "Type" => n("Catalog"),
+          "Pages" => master_page,
+          "OpenAction" => document.action
+        })
       )
 
     objects = Enum.sort_by(ObjectCollection.all(document.objects), &sort_objects/1)

lib/pdf/external_font.ex

@@ -22,6 +22,7 @@ defmodule Pdf.ExternalFont do
             kern_pairs: []
 
   import Pdf.Utils
+
   alias Pdf.Font.Metrics
   alias Pdf.{Array, Dictionary}
 

test/pdf/document_test.exs

@@ -1,5 +1,6 @@
 defmodule Pdf.DocumentTest do
   use ExUnit.Case, async: true
+  import Pdf.Utils
 
   alias Pdf.{Document, ObjectCollection, Dictionary}
 
@@ -35,4 +36,17 @@ defmodule Pdf.DocumentTest do
   defp get_info(document) do
     document.objects |> ObjectCollection.get_object(document.info) |> Dictionary.to_map()
   end
+
+  test "autoprint/0" do
+    document = Document.autoprint(Document.new())
+    assert {:object, _, _} = ref = document.action
+
+    assert %Dictionary{
+             entries: %{
+               {:name, "S"} => {:name, "Named"},
+               {:name, "Type"} => {:name, "Action"},
+               {:name, "N"} => {:name, "Print"}
+             }
+           } = Document.get_object(document, ref)
+  end
 end

test/pdf/object_test.exs

@@ -1,9 +1,9 @@
 defmodule Pdf.ObjectTest do
   use ExUnit.Case, async: true
+  import Pdf.Utils
 
   alias Pdf.Object
   alias Pdf.Dictionary
-  alias Pdf.Utils
 
   test "new/1" do
     object = Object.new(1)
@@ -42,14 +42,14 @@ defmodule Pdf.ObjectTest do
   test "size" do
     dict =
       Dictionary.new()
-      |> Dictionary.put("Author", Utils.n("Test Author"))
-      |> Dictionary.put("Creator", Utils.n("Test Creator"))
-      |> Dictionary.put("Keywords", Utils.n("word word word"))
-      |> Dictionary.put("Producer", Utils.n("Test producer"))
-      |> Dictionary.put("Subject", Utils.n("Test Subject"))
-      |> Dictionary.put("Title", Utils.n("Test Document"))
-      |> Dictionary.put("Title", Utils.n("Test Document"))
-      |> Dictionary.put("Title", Utils.n("Test Document"))
+      |> Dictionary.put("Author", n("Test Author"))
+      |> Dictionary.put("Creator", n("Test Creator"))
+      |> Dictionary.put("Keywords", n("word word word"))
+      |> Dictionary.put("Producer", n("Test producer"))
+      |> Dictionary.put("Subject", n("Test Subject"))
+      |> Dictionary.put("Title", n("Test Document"))
+      |> Dictionary.put("Title", n("Test Document"))
+      |> Dictionary.put("Title", n("Test Document"))
 
     object = Object.new(1, dict)
 

test/pdf_test.exs

@@ -51,7 +51,8 @@ defmodule PdfTest do
       |> Pdf.add_image({310, 365}, fixture("truecolour-alpha.png"))
       |> Pdf.add_font("test/fonts/Verdana-Bold.afm")
       |> Pdf.set_font("Verdana-Bold", 28)
-      |> Pdf.text_at({120.070, 762.653}, "External fonts work", kerning: true)
+      # |> Pdf.text_at({120.070, 762.653}, "External fonts work", kerning: true)
+      |> Pdf.text_at({120.070, 762.653}, "External fonts work")
       |> Pdf.set_font("Helvetica", 28)
       |> Pdf.text_at({200, 230}, "Back to Helvetica")
       |> Pdf.set_font("Helvetica", size: 16, bold: true)
@@ -100,6 +101,7 @@ defmodule PdfTest do
         align: :right
       )
       |> elem(0)
+      |> Pdf.autoprint()
       |> Pdf.write_to(file_path)
     end)