E-book viewer: Allow setting the number of pages per screen separately for portrait and landscape modes. Fixes #1483313 [[Enhancement] Viewer: auto adjust number of columns when display orientation changes](https://bugs.launchpad.net/calibre/+bug/1483313)

src/calibre/gui2/viewer/config.py

@@ -78,6 +78,9 @@ def config(defaults=None):
     c.add_opt('show_fullscreen_help', default=True, action='store_false',
               help=_('Show full screen usage help'))
     c.add_opt('cols_per_screen', default=1)
+    c.add_opt('cols_per_screen_portrait', default=1)
+    c.add_opt('cols_per_screen_landscape', default=1)
+    c.add_opt('cols_per_screen_migrated', default=False, action='store_true')
     c.add_opt('use_book_margins', default=False, action='store_true')
     c.add_opt('top_margin', default=20)
     c.add_opt('side_margin', default=40)
@@ -98,6 +101,15 @@ def config(defaults=None):
     fonts('standard_font', default='serif', help=_('The standard font type'))
     fonts('minimum_font_size', default=8, help=_('The minimum font size in px'))
 
+    oparse = c.parse
+
+    def parse():
+        ans = oparse()
+        if not ans.cols_per_screen_migrated:
+            ans.cols_per_screen_portrait = ans.cols_per_screen_landscape = ans.cols_per_screen
+        return ans
+    c.parse = parse
+
     return c
 
 def load_themes():
@@ -322,7 +334,8 @@ class ConfigDialog(QDialog, Ui_Dialog):
         self.opt_start_in_fullscreen.setChecked(opts.start_in_fullscreen)
         self.opt_show_fullscreen_help.setChecked(opts.show_fullscreen_help)
         self.opt_fullscreen_pos.setChecked(opts.fullscreen_pos)
-        self.opt_cols_per_screen.setValue(opts.cols_per_screen)
+        self.opt_cols_per_screen_portrait.setValue(opts.cols_per_screen_portrait)
+        self.opt_cols_per_screen_landscape.setValue(opts.cols_per_screen_landscape)
         self.opt_override_book_margins.setChecked(not opts.use_book_margins)
         for x in ('top', 'bottom', 'side'):
             getattr(self, 'opt_%s_margin'%x).setValue(getattr(opts,
@@ -405,7 +418,9 @@ class ConfigDialog(QDialog, Ui_Dialog):
         c.set('fullscreen_pos', self.opt_fullscreen_pos.isChecked())
         c.set('fullscreen_scrollbar', self.opt_fullscreen_scrollbar.isChecked())
         c.set('show_fullscreen_help', self.opt_show_fullscreen_help.isChecked())
-        c.set('cols_per_screen', int(self.opt_cols_per_screen.value()))
+        c.set('cols_per_screen_migrated', True)
+        c.set('cols_per_screen_portrait', int(self.opt_cols_per_screen_portrait.value()))
+        c.set('cols_per_screen_landscape', int(self.opt_cols_per_screen_landscape.value()))
         c.set('start_in_fullscreen', self.opt_start_in_fullscreen.isChecked())
         c.set('use_book_margins', not
                 self.opt_override_book_margins.isChecked())

src/calibre/gui2/viewer/config.ui

@@ -261,20 +261,27 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="1" column="0">
-            <widget class="QLabel" name="label_13">
-             <property name="text">
-              <string>The number of &amp;pages of text to show on screen </string>
-             </property>
-             <property name="buddy">
-              <cstring>opt_cols_per_screen</cstring>
+           <item row="3" column="0" colspan="2">
+            <widget class="Line" name="line">
+             <property name="orientation">
+              <enum>Qt::Horizontal</enum>
              </property>
             </widget>
            </item>
-           <item row="1" column="1">
-            <widget class="QSpinBox" name="opt_cols_per_screen">
-             <property name="suffix">
-              <string> page(s)</string>
+           <item row="5" column="0">
+            <widget class="QLabel" name="label_27">
+             <property name="text">
+              <string>In &amp;Portrait orientation:</string>
+             </property>
+             <property name="buddy">
+              <cstring>opt_cols_per_screen_portrait</cstring>
+             </property>
+            </widget>
+           </item>
+           <item row="5" column="1">
+            <widget class="QSpinBox" name="opt_cols_per_screen_portrait">
+             <property name="toolTip">
+              <string>Controls the number of pages on the screen when the viewer window's width is less than its height</string>
              </property>
              <property name="minimum">
               <number>1</number>
@@ -284,7 +291,7 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="2" column="0" colspan="2">
+           <item row="8" column="0" colspan="2">
             <widget class="QCheckBox" name="opt_override_book_margins">
              <property name="text">
               <string>&amp;Override the page margin settings specified in the book</string>
@@ -294,7 +301,7 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="3" column="0">
+           <item row="9" column="0">
             <widget class="QLabel" name="label_18">
              <property name="text">
               <string>&amp;Top margin</string>
@@ -304,7 +311,7 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="3" column="1">
+           <item row="9" column="1">
             <widget class="QSpinBox" name="opt_top_margin">
              <property name="suffix">
               <string> px</string>
@@ -317,7 +324,7 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="4" column="0">
+           <item row="10" column="0">
             <widget class="QLabel" name="label_19">
              <property name="text">
               <string>&amp;Side margin</string>
@@ -327,7 +334,7 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="4" column="1">
+           <item row="10" column="1">
             <widget class="QSpinBox" name="opt_side_margin">
              <property name="suffix">
               <string> px</string>
@@ -340,7 +347,7 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="5" column="0">
+           <item row="11" column="0">
             <widget class="QLabel" name="label_17">
              <property name="text">
               <string>&amp;Bottom margin</string>
@@ -350,7 +357,7 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="5" column="1">
+           <item row="11" column="1">
             <widget class="QSpinBox" name="opt_bottom_margin">
              <property name="suffix">
               <string> px</string>
@@ -363,6 +370,43 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
+           <item row="7" column="0" colspan="2">
+            <widget class="Line" name="line_2">
+             <property name="orientation">
+              <enum>Qt::Horizontal</enum>
+             </property>
+            </widget>
+           </item>
+           <item row="4" column="0" colspan="2">
+            <widget class="QLabel" name="label_13">
+             <property name="text">
+              <string>The number of pages of text to show on screen </string>
+             </property>
+            </widget>
+           </item>
+           <item row="6" column="0">
+            <widget class="QLabel" name="label_28">
+             <property name="text">
+              <string>In &amp;Landscape orientation: </string>
+             </property>
+             <property name="buddy">
+              <cstring>opt_cols_per_screen_landscape</cstring>
+             </property>
+            </widget>
+           </item>
+           <item row="6" column="1">
+            <widget class="QSpinBox" name="opt_cols_per_screen_landscape">
+             <property name="toolTip">
+              <string>Controls the number of pages on the screen when the viewer window's height is less than its width</string>
+             </property>
+             <property name="minimum">
+              <number>1</number>
+             </property>
+             <property name="maximum">
+              <number>5</number>
+             </property>
+            </widget>
+           </item>
           </layout>
          </widget>
          <widget class="QWidget" name="page_2">
@@ -370,8 +414,8 @@ QToolBox::tab:hover {
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>799</width>
-            <height>378</height>
+            <width>381</width>
+            <height>193</height>
            </rect>
           </property>
           <attribute name="label">
@@ -472,8 +516,8 @@ QToolBox::tab:hover {
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>799</width>
-            <height>378</height>
+            <width>340</width>
+            <height>70</height>
            </rect>
           </property>
           <attribute name="label">
@@ -551,8 +595,8 @@ QToolBox::tab:hover {
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>799</width>
-            <height>378</height>
+            <width>384</width>
+            <height>140</height>
            </rect>
           </property>
           <attribute name="label">
@@ -629,8 +673,8 @@ QToolBox::tab:hover {
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>799</width>
-            <height>378</height>
+            <width>479</width>
+            <height>226</height>
            </rect>
           </property>
           <attribute name="label">

src/calibre/gui2/viewer/documentview.py

@@ -183,7 +183,8 @@ class Document(QWebPage):  # {{{
         self.start_in_fullscreen = opts.start_in_fullscreen
         self.show_fullscreen_help = opts.show_fullscreen_help
         self.use_book_margins = opts.use_book_margins
-        self.cols_per_screen = opts.cols_per_screen
+        self.cols_per_screen_portrait = opts.cols_per_screen_portrait
+        self.cols_per_screen_landscape = opts.cols_per_screen_landscape
         self.side_margin = opts.side_margin
         self.top_margin, self.bottom_margin = opts.top_margin, opts.bottom_margin
         self.show_controls = opts.show_controls
@@ -291,12 +292,14 @@ class Document(QWebPage):  # {{{
     def switch_to_paged_mode(self, onresize=False, last_loaded_path=None):
         if onresize and not self.loaded_javascript:
             return
+        cols_per_screen = self.cols_per_screen_portrait if self.is_portrait else self.cols_per_screen_landscape
+        cols_per_screen = max(1, min(5, cols_per_screen))
         self.javascript('''
             window.paged_display.use_document_margins = %s;
             window.paged_display.set_geometry(%d, %d, %d, %d);
             '''%(
             ('true' if self.use_book_margins else 'false'),
-            self.cols_per_screen, self.top_margin, self.side_margin,
+            cols_per_screen, self.top_margin, self.side_margin,
             self.bottom_margin
             ))
         force_fullscreen_layout = bool(getattr(last_loaded_path,
@@ -448,6 +451,10 @@ class Document(QWebPage):  # {{{
     def window_width(self):
         return self.javascript('window.innerWidth', 'int')
 
+    @property
+    def is_portrait(self):
+        return self.window_width < self.window_height
+
     @property
     def xpos(self):
         return self.mainFrame().scrollPosition().x()