From bb2cb303959d76987ec226763b1c3504b5d226e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20Bu=CC=88nemann?= <buenemann@louis.info>
Date: Mon, 30 Oct 2017 14:24:11 +0100
Subject: [PATCH] Support customizing font name, size, family

This adds support for overriding the default font settings for the whole
workbook. The default settings are:

    { font: { name: 'Calibri', size: 12, family: 'Swiss' } }

Example with Arial 10pt:

    Workbook.new('foo.xlsx', font: { name: 'Arial', size: 10 })
---
 lib/xlsxtream/errors.rb         |  3 ++
 lib/xlsxtream/workbook.rb       | 24 ++++++++++++--
 test/xlsxtream/workbook_test.rb | 57 +++++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+), 3 deletions(-)
 create mode 100644 lib/xlsxtream/errors.rb

diff --git a/lib/xlsxtream/errors.rb b/lib/xlsxtream/errors.rb
new file mode 100644
index 0000000..78d5ab2
--- /dev/null
+++ b/lib/xlsxtream/errors.rb
@@ -0,0 +1,3 @@
+module Xlsxtream
+  class Error < StandardError; end
+end
diff --git a/lib/xlsxtream/workbook.rb b/lib/xlsxtream/workbook.rb
index 4e11f04..0c6cd31 100644
--- a/lib/xlsxtream/workbook.rb
+++ b/lib/xlsxtream/workbook.rb
@@ -1,5 +1,6 @@
 # encoding: utf-8
 require "stringio"
+require "xlsxtream/errors"
 require "xlsxtream/xml"
 require "xlsxtream/shared_string_table"
 require "xlsxtream/workbook"
@@ -10,6 +11,15 @@
 module Xlsxtream
   class Workbook
 
+    FONT_FAMILY_IDS = {
+      ''           => 0,
+      'roman'      => 1,
+      'swiss'      => 2,
+      'modern'     => 3,
+      'script'     => 4,
+      'decorative' => 5
+    }.freeze
+
     class << self
 
       def open(data = nil, options = {})
@@ -98,6 +108,14 @@ def write_workbook
     end
 
     def write_styles
+      font_options = @options.fetch(:font, {})
+      font_size = font_options.fetch(:size, 12).to_s
+      font_name = font_options.fetch(:name, 'Calibri').to_s
+      font_family = font_options.fetch(:family, 'Swiss').to_s.downcase
+      font_family_id = FONT_FAMILY_IDS[font_family] or fail Error,
+        "Invalid font family #{font_family}, must be one of "\
+        + FONT_FAMILY_IDS.keys.map(&:inspect).join(', ')
+
       @io.add_file "xl/styles.xml"
       @io << XML.header
       @io << XML.strip(<<-XML)
@@ -108,9 +126,9 @@ def write_styles
           </numFmts>
           <fonts count="1">
             <font>
-              <sz val="12"/>
-              <name val="Calibri"/>
-              <family val="2"/>
+              <sz val="#{XML.escape_attr font_size}"/>
+              <name val="#{XML.escape_attr font_name}"/>
+              <family val="#{font_family_id}"/>
             </font>
           </fonts>
           <fills count="2">
diff --git a/test/xlsxtream/workbook_test.rb b/test/xlsxtream/workbook_test.rb
index 827aa84..d5ce02a 100644
--- a/test/xlsxtream/workbook_test.rb
+++ b/test/xlsxtream/workbook_test.rb
@@ -253,6 +253,63 @@ def test_styles_content
       assert_equal expected, actual
     end
 
+    def test_custom_font_size
+      iow_spy = io_wrapper_spy
+      font_options = { :size => 23 }
+      Workbook.open(nil, :io_wrapper => iow_spy, :font => font_options) {}
+      expected = '<sz val="23"/>'
+      actual = iow_spy['xl/styles.xml'][/<sz [^>]+>/]
+      assert_equal expected, actual
+    end
+
+    def test_custom_font_name
+      iow_spy = io_wrapper_spy
+      font_options = { :name => 'Comic Sans' }
+      Workbook.open(nil, :io_wrapper => iow_spy, :font => font_options) {}
+      expected = '<name val="Comic Sans"/>'
+      actual = iow_spy['xl/styles.xml'][/<name [^>]+>/]
+      assert_equal expected, actual
+    end
+
+    def test_custom_font_family
+      iow_spy = io_wrapper_spy
+      font_options = { :family => 'Script' }
+      Workbook.open(nil, :io_wrapper => iow_spy, :font => font_options) {}
+      expected = '<family val="4"/>'
+      actual = iow_spy['xl/styles.xml'][/<family [^>]+>/]
+      assert_equal expected, actual
+    end
+
+    def test_font_family_mapping
+      tests = {
+        nil => 0,
+        ''  => 0,
+        'ROMAN' => 1,
+        :roman => 1,
+        'Roman' => 1,
+        :swiss => 2,
+        :modern => 3,
+        :script => 4,
+        :decorative => 5
+      }
+      tests.each do |value, id|
+        iow_spy = io_wrapper_spy
+        font_options = { :family => value }
+        Workbook.open(nil, :io_wrapper => iow_spy, :font => font_options) {}
+        expected = "<family val=\"#{id}\"/>"
+        actual = iow_spy['xl/styles.xml'][/<family [^>]+>/]
+        assert_equal expected, actual
+      end
+    end
+
+    def test_invalid_font_family
+      iow_spy = io_wrapper_spy
+      font_options = { :family => 'Foo' }
+      assert_raises Xlsxtream::Error do
+        Workbook.open(nil, :io_wrapper => iow_spy, :font => font_options) {}
+      end
+    end
+
     def test_tempfile_is_not_closed
       tempfile = Tempfile.new('workbook')
       Workbook.open(tempfile) {}