Additional scroll options...

Option for whether or not to load next file after reaching the start/end when using key based scrolling
Configurable delay before loading the next file after reaching the end with auto-scroll

src/pyj/read_book/flow_mode.pyj

@@ -51,9 +51,9 @@ def add_small_scroll(amt):
 
 
 def report_human_scroll(amt):
-    if amt > 0:
+    if abs(amt) > 0:
         h = scroll_viewport.height()
-        is_large_scroll = (amt / h) >= 0.5
+        is_large_scroll = (abs(amt) / h) >= 0.5
         if is_large_scroll:
             clear_small_scrolls()
             get_boss().report_human_scroll(amt / document_height())
@@ -180,10 +180,19 @@ def handle_shortcut(sc_name, evt):
 
 
 def layout(is_single_page):
-    cancel_scroll()
+    scroll_animator.wait = False
+    scroll_animator.sync()
     set_css(document.body, margin='0', border_width='0', padding='0')
     line_height.doc_style = window.getComputedStyle(document.body)
 
+# Pause auto-scroll while minimized
+document.addEventListener("visibilitychange", def():
+    if (document.visibilityState is 'visible'):
+        scroll_animator.sync()
+    else:
+        scroll_animator.pause()
+)
+
 def cancel_scroll():
     scroll_animator.stop()
 
@@ -202,16 +211,22 @@ class ScrollAnimator:
         return self.animation_id != None
 
     def start(self, direction, auto):
+        if self.wait:
+            return
+
         now = performance.now()
         self.end_time = now + self.DURATION
+        clearTimeout(self.auto_timer)
 
         if !self.is_running() or direction != self.direction or auto != self.auto:
-            self.paused = self.direction if self.auto and not auto else False
+            if self.auto and not auto:
+                self.pause()
             self.stop()
             self.auto = auto
             self.direction = direction
             self.start_time = now
             self.start_offset = window.pageYOffset
+            self.csi_idx = current_spine_item().index
             self.animation_id = window.requestAnimationFrame(self.auto_scroll if auto else self.smooth_scroll)
 
     def smooth_scroll(self, ts):
@@ -221,18 +236,22 @@ class ScrollAnimator:
         scroll_target += Math.trunc(self.direction * progress * duration * line_height() * opts.lines_per_sec_smooth) / 1000
 
         window.scrollTo(0, scroll_target)
+        amt = window.pageYOffset - self.start_offset
 
-        if progress < 1:
+        if is_scroll_end(scroll_target) and (not opts.scroll_stop_boundaries or (abs(amt) < 3 and duration is self.DURATION)):
+            # "Turn the page" if stop at boundaries option is false or
+            # this is a new scroll action and we were already at the end
+            self.animation_id = None
+            self.wait = True
+            report_human_scroll(amt)
+            get_boss().send_message('next_spine_item', previous=self.direction is DIRECTION.Up)
+        elif progress < 1:
             self.animation_id = window.requestAnimationFrame(self.smooth_scroll)
+        elif self.paused:
+            self.resume()
         else:
-            amt = window.pageYOffset - self.start_offset
+            self.animation_id = None
-            if abs(amt) < 3 and duration is self.DURATION and is_scroll_end(scroll_target):
+            report_human_scroll(amt)
-                get_boss().send_message('next_spine_item', previous=self.direction is DIRECTION.Up)
-            elif self.paused:
-                self.start(self.paused, True)
-            else:
-                self.animation_id = None
-                report_human_scroll(amt)
 
     def auto_scroll(self, ts):
         elapsed = max(0, ts - self.start_time) # max to account for jitter
@@ -247,24 +266,45 @@ class ScrollAnimator:
             self.sync(ts)
 
         if scroll_finished:
-            self.stop()
+            self.pause()
+            if opts.scroll_auto_boundary_delay:
+                self.auto_timer = setTimeout(def(): get_boss().send_message('next_spine_item', previous=self.direction is DIRECTION.Up);, opts.scroll_auto_boundary_delay * 1000)
         else:
             self.animation_id = window.requestAnimationFrame(self.auto_scroll)
 
+    def report(self):
+        amt = window.pageYOffset - self.start_offset
+        if abs(amt) > 0 and self.csi_idx is current_spine_item().index:
+            report_human_scroll(amt)
+
     def sync(self, ts):
         if self.auto:
-            report_human_scroll(window.pageYOffset - self.start_offset)
+            self.report()
+            self.csi_idx = current_spine_item().index
             self.start_time = ts or performance.now()
             self.start_offset = window.pageYOffset
+        else:
+            self.resume()
 
     def stop(self):
         self.auto = False
         if self.animation_id is not None:
             window.cancelAnimationFrame(self.animation_id)
             self.animation_id = None
-            amt = window.pageYOffset - self.start_offset
+            self.report()
-            if amt > 0:
+
-                report_human_scroll(amt)
+    def pause(self):
+        if self.auto:
+            self.paused = self.direction
+            self.stop()
+        else:
+            self.paused = False
+
+    # Resume auto-scroll
+    def resume(self):
+        if self.paused:
+            self.start(self.paused, True)
+            self.paused = False
 
 scroll_animator = ScrollAnimator()
 

src/pyj/read_book/iframe.pyj

@@ -270,7 +270,6 @@ class IframeBoss:
         self.last_window_width, self.last_window_height = scroll_viewport.width(), scroll_viewport.height()
         apply_settings()
         fix_fullscreen_svg_images()
-        self.do_layout(self.is_titlepage)
         if self.mathjax:
             return apply_mathjax(self.mathjax, self.book.manifest.link_uid, self.content_loaded_stage2)
         # window.setTimeout(self.content_loaded_stage2, 1000)
@@ -307,6 +306,7 @@ class IframeBoss:
                 if si:
                     self.length_before += files[si]?.length or 0
         self.onscroll()
+        self.do_layout(self.is_titlepage)
         self.send_message('content_loaded', progress_frac=self.calculate_progress_frac(), file_progress_frac=progress_frac())
         self.last_cfi = None
         window.setTimeout(self.update_cfi, 0)

src/pyj/read_book/prefs/scrolling.pyj

@@ -16,6 +16,9 @@ CONTAINER = unique_id('standalone-scrolling-settings')
 MIN_SCROLL_SPEED_AUTO = 0.25
 MAX_SCROLL_SPEED_AUTO = 5
 
+MIN_SCROLL_AUTO_DELAY = 0
+MAX_SCROLL_AUTO_DELAY = 10
+
 MIN_SCROLL_SPEED_SMOOTH = 10
 MAX_SCROLL_SPEED_SMOOTH = 50
 
@@ -57,7 +60,7 @@ def create_scrolling_panel(container, apply_func, cancel_func):
         ans = E.input(type='number', name=name, id=name)
         for key, val in Object.entries(kwargs):
             ans[key] = val
-        ans.valueAsNumber = sd.get(name) or defaults[name]
+        ans.valueAsNumber = sd.get(name, defaults[name])
         return E.label("for"=name, text), ans
 
     container.appendChild(E.div(style='margin-top:1ex', _('Control how mouse based scrolling works in paged mode')))
@@ -68,8 +71,12 @@ def create_scrolling_panel(container, apply_func, cancel_func):
 
     container.appendChild(E.hr())
     container.appendChild(E.div(style='margin-top:1ex', _('Control how smooth scrolling works in flow mode')))
+    container.appendChild(cb(
+        'scroll_stop_boundaries',
+        _('Stop at file boundaries when continuous scrolling while holding down the scroll key')
+    ))
     container.appendChild(
-        E.div(style='display:grid;margin-top:1ex;align-items:center;grid-template-columns:auto auto;grid-gap:1ex;justify-content:flex-start;',
+        E.div(style='display:grid;margin-top:1ex;align-items:center;grid-template-columns:25em min-content;grid-gap:1ex',
             *spinner(
                 'lines_per_sec_smooth',
                 _('Smooth scrolling speed in lines/sec'),
@@ -83,6 +90,13 @@ def create_scrolling_panel(container, apply_func, cancel_func):
                 step=MIN_SCROLL_SPEED_AUTO,
                 min=MIN_SCROLL_SPEED_AUTO,
                 max=MAX_SCROLL_SPEED_AUTO
+            ),
+            *spinner(
+                'scroll_auto_boundary_delay',
+                _('Seconds to wait before loading the next file after auto-scroll reaches the end; 0 to disable'),
+                step=0.25,
+                min=MIN_SCROLL_AUTO_DELAY,
+                max=MAX_SCROLL_AUTO_DELAY
             )
         )
     )

src/pyj/read_book/settings.pyj

@@ -23,6 +23,8 @@ def update_settings(settings):
     opts.margin_right = max(0, settings.margin_right)
     opts.override_book_colors = settings.override_book_colors
     opts.paged_wheel_scrolls_by_screen = v'!!settings.paged_wheel_scrolls_by_screen'
+    opts.scroll_auto_boundary_delay = settings.scroll_auto_boundary_delay
+    opts.scroll_stop_boundaries = v'!!settings.scroll_stop_boundaries'
     opts.user_stylesheet = settings.user_stylesheet
 
 update_settings()

src/pyj/read_book/view.pyj

@@ -712,6 +712,8 @@ class View:
             'paged_wheel_scrolls_by_screen': sd.get('paged_wheel_scrolls_by_screen'),
             'lines_per_sec_auto': sd.get('lines_per_sec_auto'),
             'lines_per_sec_smooth': sd.get('lines_per_sec_smooth'),
+            'scroll_auto_boundary_delay': sd.get('scroll_auto_boundary_delay'),
+            'scroll_stop_boundaries': sd.get('scroll_stop_boundaries'),
         }
 
     def show_name(self, name, initial_position=None):

src/pyj/session.pyj

@@ -49,6 +49,8 @@ defaults = {
     'paged_margin_clicks_scroll_by_screen': True,
     'paged_wheel_scrolls_by_screen': False,
     'read_mode': 'paged',
+    'scroll_auto_boundary_delay': 5,
+    'scroll_stop_boundaries': False,
     'standalone_font_settings': {},
     'standalone_misc_settings': {},
     'standalone_recently_opened': v'[]',
@@ -75,6 +77,8 @@ is_local_setting = {
     'max_text_width': True,
     'override_book_colors': True,
     'read_mode': 'paged',
+    'scroll_auto_boundary_delay': True,
+    'scroll_stop_boundaries': True,
     'standalone_font_settings': True,
     'standalone_misc_settings': True,
     'standalone_recently_opened': True,