PDF Output: Add an option to shift text horizontally on odd/even pages. Fixes #1853155 [PDF Output with even/odd page margins](https://bugs.launchpad.net/calibre/+bug/1853155)

src/calibre/ebooks/conversion/config.py

@@ -304,7 +304,7 @@ OPTIONS = {
             'pdf_footer_template', 'pdf_header_template', 'pdf_add_toc',
             'toc_title', 'pdf_page_margin_left', 'pdf_page_margin_top',
             'pdf_page_margin_right', 'pdf_page_margin_bottom',
-            'pdf_use_document_margins', 'pdf_page_number_map',),
+            'pdf_use_document_margins', 'pdf_page_number_map', 'pdf_odd_even_offset'),
 
         'pml': ('inline_toc', 'full_image_depth', 'pml_output_encoding'),
 

src/calibre/ebooks/conversion/plugins/pdf_output.py

@@ -130,6 +130,18 @@ class PDFOutput(OutputFormatPlugin):
             recommended_value=False, help=_(
                 'Generate an uncompressed PDF, useful for debugging.')
         ),
+        OptionRecommendation(name='pdf_odd_even_offset', recommended_value=0.0,
+            level=OptionRecommendation.LOW,
+            help=_(
+                'Shift the text horizontally by the specified offset (in pts).'
+                ' On odd numbered pages, it is shifted to the right and on even'
+                ' numbered pages to the left. Use negative numbers for the opposite'
+                ' effect. Note that this setting is ignored on pages where the margins'
+                ' are smaller than the specified offset. Shifting is done by setting'
+                ' the PDF CropBox, not all software respects the CropBox.'
+            )
+        ),
+
     }
 
     def specialize_options(self, log, opts, input_fmt):

src/calibre/ebooks/pdf/html_writer.py

@@ -1213,6 +1213,16 @@ def convert(opf_path, opts, metadata=None, output_path=None, log=default_log, co
     if num_removed:
         log('Removed', num_removed, 'duplicate images')
 
+    if opts.pdf_odd_even_offset:
+        for i in range(1, pdf_doc.page_count()):
+            margins = page_margins_map[i]
+            mult = -1 if i % 2 else 1
+            val = opts.pdf_odd_even_offset
+            if abs(val) < min(margins.left, margins.right):
+                box = list(pdf_doc.get_page_box("CropBox", i))
+                box[0] += val * mult
+                pdf_doc.set_page_box("CropBox", i, *box)
+
     if cover_data:
         add_cover(pdf_doc, cover_data, page_layout, opts)
 

src/calibre/gui2/convert/pdf_output.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>638</width>
-    <height>634</height>
+    <height>665</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -210,14 +210,14 @@
    <item row="16" column="1">
     <widget class="QLineEdit" name="opt_pdf_page_number_map"/>
    </item>
-   <item row="17" column="0" colspan="2">
+   <item row="18" column="0" colspan="2">
     <widget class="QGroupBox" name="page_margins_box">
      <property name="title">
       <string>Page  margins</string>
      </property>
     </widget>
    </item>
-   <item row="18" column="0" colspan="2">
+   <item row="19" column="0" colspan="2">
     <widget class="QGroupBox" name="template_box">
      <property name="title">
       <string>Page headers and footers</string>
@@ -272,6 +272,32 @@
      </property>
     </widget>
    </item>
+   <item row="17" column="0">
+    <widget class="QLabel" name="label_2">
+     <property name="text">
+      <string>Odd/even &amp;offset:</string>
+     </property>
+     <property name="buddy">
+      <cstring>opt_pdf_odd_even_offset</cstring>
+     </property>
+    </widget>
+   </item>
+   <item row="17" column="1">
+    <widget class="QDoubleSpinBox" name="opt_pdf_odd_even_offset">
+     <property name="suffix">
+      <string> pt</string>
+     </property>
+     <property name="decimals">
+      <number>1</number>
+     </property>
+     <property name="minimum">
+      <double>-100000.000000000000000</double>
+     </property>
+     <property name="maximum">
+      <double>100000.000000000000000</double>
+     </property>
+    </widget>
+   </item>
   </layout>
  </widget>
  <resources/>

src/pyj/book_list/conversion_widgets.pyj

@@ -664,6 +664,7 @@ def pdf_output(container):
     g.appendChild(float_spin('pdf_page_margin_top', indent + _('Top page margin'), unit='pt', min=-100, max=500))
     g.appendChild(float_spin('pdf_page_margin_right', indent + _('Right page margin'), unit='pt', min=-100, max=500))
     g.appendChild(float_spin('pdf_page_margin_bottom', indent + _('Bottom page margin'), unit='pt', min=-100, max=500))
+    g.appendChild(float_spin('pdf_odd_even_offset', indent + _('Odd/event offset'), unit='pt', min=-500, max=500))
     g.appendChild(lineedit('pdf_header_template', _('&Header template:')))
     g.appendChild(lineedit('pdf_footer_template', _('&Footer template:')))
 # }}}