Viewer: Add a setting to control how many pixels a scroll wheel should generate before triggering a page turn

src/pyj/read_book/paged_mode.pyj

@@ -567,8 +567,7 @@ class HandleWheel:
         self.last_event_at = now
         self.last_event_backwards = backward
         self.accumulated_scroll += deltaY
-        lh = line_height()
-        if self.accumulated_scroll > 5 * lh:
+        if self.accumulated_scroll > opts.paged_pixel_scroll_threshold:
             self.do_scroll(backward)
 
     def do_scroll(self, backward):

src/pyj/read_book/prefs/scrolling.pyj

@@ -70,6 +70,17 @@ def create_scrolling_panel(container, apply_func, cancel_func):
         'paged_margin_clicks_scroll_by_screen', _('Clicking on the margins scrolls by screen fulls instead of pages')))
     container.appendChild(cb(
         'paged_taps_scroll_by_screen', _('Tapping scrolls by screen fulls instead of pages')))
+    container.appendChild(
+        E.div(style='display:grid;margin-top:1ex;align-items:center;grid-template-columns:auto min-content;grid-gap:1ex; max-width: 30em',
+            *spinner(
+                'paged_pixel_scroll_threshold',
+    _('Pixel scroll threshold:'),
+                title=_('When using a touchpad or mouse wheel that produces scroll events in pixels, set the number of pixels before a page turn is triggered'),
+                step=5,
+                min=0,
+                max=1000
+            ),
+    ))
 
     container.appendChild(E.hr())
     container.appendChild(E.div(style='margin-top:1ex', _('Control how smooth scrolling works in flow mode')))

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_pixel_scroll_threshold = settings.paged_pixel_scroll_threshold
     opts.paged_taps_scroll_by_screen = v'!!settings.paged_taps_scroll_by_screen'
     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

@@ -854,6 +854,7 @@ 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_pixel_scroll_threshold': sd.get('paged_pixel_scroll_threshold'),
             'paged_taps_scroll_by_screen': sd.get('paged_taps_scroll_by_screen'),
             'lines_per_sec_auto': sd.get('lines_per_sec_auto'),
             'lines_per_sec_smooth': sd.get('lines_per_sec_smooth'),

src/pyj/session.pyj

@@ -51,6 +51,7 @@ defaults = {
     'paged_margin_clicks_scroll_by_screen': True,
     'paged_wheel_scrolls_by_screen': False,
     'paged_taps_scroll_by_screen': False,
+    'paged_pixel_scroll_threshold': 60,
     'read_mode': 'paged',
     'scroll_auto_boundary_delay': 5,
     'scroll_stop_boundaries': False,