Add an option to adjust the size of the link and note icons in book details.

In the tag browser and booklist the icons resize automatically with the font. That doesn't happen in book details because there isn't any notion of a "row". With this option the user can make the size as desired. For more background see the first few posts of https://www.mobileread.com/forums/showthread.php?t=365537

src/calibre/ebooks/metadata/book/render.py

@@ -107,13 +107,15 @@ def mi_to_html(
         mi,
         field_list=None, default_author_link=None, use_roman_numbers=True,
         rating_font='Liberation Serif', rtl=False, comments_heading_pos='hide',
-        for_qt=False, vertical_fields=(), show_links=True, item_id_if_has_note=None
+        for_qt=False, vertical_fields=(), show_links=True, item_id_if_has_note=None,
+        link_note_icon_size=16
     ):
 
     link_markup =  '↗️'
     if for_qt:
-        link_markup = '<img valign="bottom" src="calibre-icon:///external-link.png" width=16 height=16>'
-        note_markup = '<img valign="bottom" src="calibre-icon:///notes.png" width=16 height=16>'
+        s = link_note_icon_size
+        link_markup = f'<img valign="bottom" src="calibre-icon:///external-link.png" width={s} height={s}>'
+        note_markup = f'<img valign="bottom" src="calibre-icon:///notes.png" width={s} height={s}>'
     def get_link_map(column):
         try:
             return mi.link_maps[column]

src/calibre/gui2/__init__.py

@@ -485,6 +485,7 @@ def create_defs():
     defs['dark_palettes'] = {}
     defs['light_palettes'] = {}
     defs['saved_layouts'] = {}
+    defs['book_details_note_link_icon_width'] = 16
 
     def migrate_tweak(tweak_name, pref_name):
         # If the tweak has been changed then leave the tweak in the file so

src/calibre/gui2/book_details.py

@@ -398,7 +398,8 @@ def render_data(mi, use_roman_numbers=True, all_fields=False, pref_name='book_di
         mi, field_list=field_list, use_roman_numbers=use_roman_numbers, rtl=is_rtl(),
         rating_font=rating_font(), default_author_link=default_author_link(),
         comments_heading_pos=gprefs['book_details_comments_heading_pos'], for_qt=True,
-        vertical_fields=vertical_fields, show_links=show_links, item_id_if_has_note=item_id_if_has_note
+        vertical_fields=vertical_fields, show_links=show_links, item_id_if_has_note=item_id_if_has_note,
+        link_note_icon_size=gprefs['book_details_note_link_icon_width']
     )
 
 # }}}

src/calibre/gui2/preferences/look_feel.py

@@ -678,6 +678,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         r('booklist_grid', gprefs)
         r('book_details_comments_heading_pos', gprefs, choices=[
             (_('Never'), 'hide'), (_('Above text'), 'above'), (_('Beside text'), 'side')])
+        r('book_details_note_link_icon_width', gprefs)
         self.cover_browser_title_template_button.clicked.connect(self.edit_cb_title_template)
         self.id_links_button.clicked.connect(self.edit_id_link_rules)
 

src/calibre/gui2/preferences/look_feel.ui

@@ -957,7 +957,7 @@ A value of zero means calculate automatically.</string>
          </item>
         </layout>
        </item>
-       <item row="1" column="0" colspan="2">
+       <item row="1" column="0" colspan="3">
         <layout class="QHBoxLayout" name="horizontalLayout_2">
          <item>
           <widget class="QLabel" name="label_25">
@@ -979,6 +979,58 @@ A value of zero means calculate automatically.</string>
            </property>
           </widget>
          </item>
+         <item>
+          <spacer name="horizontalSpacer_bd13">
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+           <property name="sizeHint" stdset="0">
+            <size>
+             <width>10</width>
+             <height>0</height>
+            </size>
+           </property>
+          </spacer>
+         </item>
+         <item>
+          <widget class="QLabel" name="label_1022">
+           <property name="text">
+            <string>Link and note icon si&amp;ze:</string>
+           </property>
+           <property name="buddy">
+            <cstring>opt_book_details_note_link_icon_width</cstring>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <widget class="QSpinBox" name="opt_book_details_note_link_icon_width">
+           <property name="toolTip">
+            <string>Specify the size (width and height) of the links and notes icons</string>
+           </property>
+           <property name="suffix">
+            <string> pixels</string>
+           </property>
+           <property name="maximum">
+            <number>48</number>
+           </property>
+           <property name="minimum">
+            <number>12</number>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <spacer name="horizontalSpacer_bd13">
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+           <property name="sizeHint" stdset="0">
+            <size>
+             <width>30</width>
+             <height>0</height>
+            </size>
+           </property>
+          </spacer>
+         </item>
         </layout>
        </item>
       </layout>