E-book viewer: Add a new option under scrolling behavior to control horizontal mouse wheel events jumping to next section

src/pyj/read_book/paged_mode.pyj

@@ -679,43 +679,63 @@ def is_return():
     return fsd and fsd.cols_per_screen is cols_per_screen and fsd.spine_index is csi.index and fsd.spine_name is csi.name
 
 
-class HandleWheel:
-
-    def __init__(self):
-        self.reset()
+class WheelState:
+    last_event_mode = 'page'
+    last_event_at = -10000
+    last_event_backwards = False
+    accumulated_scroll = 0
 
     def reset(self):
-        self.last_event_mode = 'page'
-        self.last_event_at = -10000
-        self.last_event_backwards = False
-        self.accumulated_scroll = 0
+        self.last_event_mode = WheelState.last_event_mode
+        self.last_event_at = WheelState.last_event_at
+        self.last_event_backwards = WheelState.last_event_backwards
+        self.accumulated_scroll = WheelState.accumulated_scroll
 
-    def onwheel(self, evt):
-        if not (evt.deltaY or evt.deltaX):
-            return
-        if evt.deltaY:
-            backward = evt.deltaY < 0
-            if evt.deltaMode is window.WheelEvent.DOM_DELTA_PIXEL:
-                self.add_pixel_scroll(backward, Math.abs(evt.deltaY))
-            else:
-                self.do_scroll(backward)
-        if evt.deltaX:
-            backward = evt.deltaX < 0
-            self.do_section_jump(backward)
-
-    def add_pixel_scroll(self, backward, deltaY):
+    def add_pixel_scroll(self, backward, delta, scroll_func):
         now = window.performance.now()
         if now - self.last_event_at > 1000 or self.last_event_backwards is not backward or self.last_event_mode is not 'pixel':
             self.accumulated_scroll = 0
         self.last_event_mode = 'pixel'
         self.last_event_at = now
         self.last_event_backwards = backward
-        self.accumulated_scroll += deltaY
+        self.accumulated_scroll += delta
         if self.accumulated_scroll > opts.paged_pixel_scroll_threshold:
+            self.reset()
+            scroll_func(backward)
+
+
+class HandleWheel:
+
+    def __init__(self):
+        self.vertical_state = WheelState()
+        self.horizontal_state = WheelState()
+
+    def onwheel(self, evt):
+        if not (evt.deltaY or evt.deltaX):
+            return
+        major_axis_vertical = True
+        if evt.deltaY:
+            if evt.deltaX:
+                major_axis_vertical = Math.abs(evt.deltaY) >= Math.abs(evt.deltaX)
+        else:
+            major_axis_vertical = False
+        if major_axis_vertical:
+            backward = evt.deltaY < 0
+            if evt.deltaMode is window.WheelEvent.DOM_DELTA_PIXEL:
+                self.vertical_state.add_pixel_scroll(backward, Math.abs(evt.deltaY), self.do_scroll)
+            else:
+                self.vertical_state.reset()
                 self.do_scroll(backward)
+        else:
+            if opts.paged_wheel_section_jumps:
+                backward = evt.deltaX < 0
+                if evt.deltaMode is window.WheelEvent.DOM_DELTA_PIXEL:
+                    self.horizontal_state.add_pixel_scroll(backward, Math.abs(evt.deltaX), self.do_section_jump)
+                else:
+                    self.horizontal_state.reset()
+                    self.do_section_jump(backward)
 
     def do_scroll(self, backward):
-        self.reset()
         if opts.paged_wheel_scrolls_by_screen:
             pos = previous_screen_location() if backward else next_screen_location()
         else:
@@ -726,7 +746,6 @@ class HandleWheel:
             scroll_to_pos(pos)
 
     def do_section_jump(self, backward):
-        self.reset()
         get_boss().send_message('next_section', forward=not backward)
 
 wheel_handler = HandleWheel()

src/pyj/read_book/prefs/scrolling.pyj

@@ -67,6 +67,8 @@ def create_scrolling_panel(container, apply_func, cancel_func):
     container.appendChild(E.div(style='margin-left: 1rem'))
     container.lastChild.appendChild(cb(
         'paged_wheel_scrolls_by_screen', _('Mouse wheel scrolls by screen fulls instead of pages')))
+    container.lastChild.appendChild(cb(
+        'paged_wheel_section_jumps', _('Horizontal mouse wheel jumps to next/previous section')))
     container.lastChild.appendChild(cb(
         'paged_margin_clicks_scroll_by_screen', _('Clicking on the margins scrolls by screen fulls instead of pages')))
     container.lastChild.appendChild(

src/pyj/read_book/settings.pyj

@@ -26,6 +26,7 @@ def update_settings(settings):
     opts.margin_bottom = max(0, settings.margin_bottom)
     opts.override_book_colors = settings.override_book_colors
     opts.paged_wheel_scrolls_by_screen = v'!!settings.paged_wheel_scrolls_by_screen'
+    opts.paged_wheel_section_jumps = v'!!settings.paged_wheel_section_jumps'
     opts.paged_pixel_scroll_threshold = settings.paged_pixel_scroll_threshold
     opts.scroll_auto_boundary_delay = settings.scroll_auto_boundary_delay
     opts.scroll_stop_boundaries = v'!!settings.scroll_stop_boundaries'

src/pyj/read_book/view.pyj

@@ -1018,6 +1018,7 @@ class View:
             'hide_tooltips': sd.get('hide_tooltips'),
             'cover_preserve_aspect_ratio': sd.get('cover_preserve_aspect_ratio'),
             'paged_wheel_scrolls_by_screen': sd.get('paged_wheel_scrolls_by_screen'),
+            'paged_wheel_section_jumps': sd.get('paged_wheel_section_jumps'),
             'paged_pixel_scroll_threshold': sd.get('paged_pixel_scroll_threshold'),
             'lines_per_sec_auto': sd.get('lines_per_sec_auto'),
             'lines_per_sec_smooth': sd.get('lines_per_sec_smooth'),

src/pyj/session.pyj

@@ -53,6 +53,7 @@ defaults = {
     'override_book_colors': 'never',
     'paged_margin_clicks_scroll_by_screen': True,
     'paged_wheel_scrolls_by_screen': False,
+    'paged_wheel_section_jumps': True,
     'paged_pixel_scroll_threshold': 60,
     'read_mode': 'paged',
     'scroll_auto_boundary_delay': 5,