Adjust leading per font family

Author: blocknotes

examples/headings.pdf

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 module PrawnHtml
+  ADJUST_LEADING = { nil => 0.18, 'Courier' => -0.07, 'Helvetica' => -0.17, 'Times-Roman' => 0.03 }.freeze
   PX = 0.6 # conversion constant for pixel sixes
 
   COLORS = {

examples/misc_elements.pdf

@@ -133,7 +133,10 @@ def apply_callbacks(buffer)
     def adjust_leading(buffer, leading)
       return leading if leading
 
-      (buffer.map { |item| item[:size] || Context::DEFAULT_STYLES[:size] }.max * 0.055).round(4)
+      leadings = buffer.map do |item|
+        (item[:size] || Context::DEFAULT_STYLES[:size]) * (ADJUST_LEADING[item[:font]] || ADJUST_LEADING[nil])
+      end
+      leadings.max.round(4)
     end
 
     def bounds(buffer, options, block_styles)

examples/random_content.pdf

@@ -3,8 +3,8 @@
 module TestUtils
   extend self
 
-  def adjust_leading(size = PrawnHtml::Context::DEFAULT_STYLES[:size])
-    (size * 0.055).round(4)
+  def adjust_leading(size = PrawnHtml::Context::DEFAULT_STYLES[:size], font = nil)
+    (size * PrawnHtml::ADJUST_LEADING[font]).round(4)
   end
 
   def default_font

examples/styles.pdf

@@ -26,7 +26,7 @@
     let(:html) { '<div style="font-family: Courier">Some content...</div>' }
 
     let(:expected_buffer) { [{ font: 'Courier', size: TestUtils.default_font_size, text: "Some content..." }] }
-    let(:expected_options) { { leading: TestUtils.adjust_leading } }
+    let(:expected_options) { { leading: TestUtils.adjust_leading(TestUtils.default_font_size, 'Courier') } }
     let(:expected_extra) { { bounding_box: nil, left_indent: 0 } }
 
     it 'sends the expected buffer elements to Prawn pdf' do