Refactor scroll viewport handling

src/pyj/read_book/cfi.pyj

@@ -21,7 +21,7 @@ from __python__ import hash_literals
 #    scroll_to(cfi): which scrolls the browser to a point corresponding to the
 #                    given cfi, and returns the x and y co-ordinates of the point.
 
-from read_book.globals import scroll_viewport
+from read_book.viewport import scroll_viewport
 
 # CFI escaping {{{
 escape_pat = /[\[\],^();~@!-]/g

src/pyj/read_book/flow_mode.pyj

@@ -1,12 +1,14 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
-from __python__ import hash_literals, bound_methods
+from __python__ import bound_methods, hash_literals
 
 from dom import set_css
-from read_book.globals import get_boss, scroll_viewport
 from keycodes import get_key
+from read_book.globals import get_boss
+from read_book.viewport import scroll_viewport
 from utils import document_height, document_width, viewport_to_document
 
+
 def flow_to_scroll_fraction(frac):
     scroll_viewport.scroll_to(0, document_height() * frac)
 

src/pyj/read_book/globals.pyj

@@ -5,7 +5,6 @@ from __python__ import hash_literals
 from aes import GCM, random_bytes
 from encodings import hexlify
 from gettext import gettext as _, register_callback, gettext as gt
-from utils import is_ios
 
 _boss = None
 
@@ -39,97 +38,11 @@ class Messenger:
 messenger = Messenger()
 iframe_id = 'read-book-iframe'
 uid = 'calibre-' + hexlify(random_bytes(12))
-scroll_viewport = {}
-
-def flow_viewport_x():
-    return window.pageXOffset
-
-def flow_viewport_y():
-    return window.pageYOffset
-
-def flow_viewport_scroll_to(x, y):
-    window.scrollTo(x, y)
-
-def flow_viewport_scroll_into_view(elem):
-    elem.scrollIntoView()
-
-def flow_reset_globals():
-    pass
-
-def flow_reset_transforms():
-    pass
-
-def paged_viewport_y():
-    return 0
-
-scroll_viewport.x = flow_viewport_x
-scroll_viewport.y = flow_viewport_y
-scroll_viewport.scroll_to = flow_viewport_scroll_to
-scroll_viewport.scroll_into_view = flow_viewport_scroll_into_view
-scroll_viewport.reset_globals = flow_reset_globals
-scroll_viewport.reset_transforms = flow_reset_transforms
-
-if is_ios:
-    window_width = def ():
-        return window_width.from_parent or window.innerWidth
-    window_height = def():
-        return window_height.from_parent or window.innerHeight
-    paged_viewport_scroll_to = def (x, y):
-        if x is 0:
-            document.documentElement.style.transform = 'none'
-        else:
-            x *= -1
-            document.documentElement.style.transform = f'translateX({x}px)'
-        boss = get_boss()
-        if boss:
-            boss.onscroll()
-    paged_viewport_x = def():
-        raw = document.documentElement.style.transform
-        if not raw or raw is 'none':
-            return 0
-        raw = raw[raw.indexOf('(') + 1:]
-        ans = parseInt(raw)
-        if isNaN(ans):
-            return 0
-        ans *= -1
-        return ans
-    paged_viewport_scroll_into_view = def(elem):
-        left = elem.offsetLeft
-        if left is None:
-            return  # element has display: none
-        elem.scrollIntoView()
-        window.scrollTo(0, 0)
-        p = elem.offsetParent
-        while p:
-            left += p.offsetLeft
-            p = p.offsetParent
-        # left -= window_width() // 2
-        paged_viewport_scroll_to(max(0, left), 0)
-    paged_content_width = def():
-        return document.documentElement.scrollWidth
-    paged_reset_transforms = def():
-        document.documentElement.style.transform = 'none'
-    paged_reset_globals = def():
-        paged_reset_transforms()
-
-else:
-    window_width = def():
-        return window.innerWidth
-    window_height = def():
-        return window.innerHeight
-    paged_viewport_scroll_to = flow_viewport_scroll_to
-    paged_viewport_x = flow_viewport_x
-    paged_viewport_scroll_into_view = flow_viewport_scroll_into_view
-    paged_reset_globals = flow_reset_globals
-    paged_content_width = def():
-        return document.documentElement.scrollWidth
-    paged_reset_transforms = def():
-        pass
-
-scroll_viewport.width = window_width
-scroll_viewport.height = window_height
-scroll_viewport.paged_content_width = paged_content_width
 
+def viewport_mode_changer(val):
+    if val:
+        viewport_mode_changer.val = val
+    return viewport_mode_changer.val
 
 def current_layout_mode():
     return current_layout_mode.value
@@ -137,20 +50,7 @@ current_layout_mode.value = 'flow'
 
 def set_layout_mode(val):
     current_layout_mode.value = val
-    if val is 'flow':
+    viewport_mode_changer()(val)
-        scroll_viewport.x = flow_viewport_x
-        scroll_viewport.y = flow_viewport_y
-        scroll_viewport.scroll_to = flow_viewport_scroll_to
-        scroll_viewport.scroll_into_view = flow_viewport_scroll_into_view
-        scroll_viewport.reset_globals = flow_reset_globals
-        scroll_viewport.reset_transforms = flow_reset_transforms
-    else:
-        scroll_viewport.x = paged_viewport_x
-        scroll_viewport.y = paged_viewport_y
-        scroll_viewport.scroll_to = paged_viewport_scroll_to
-        scroll_viewport.scroll_into_view = paged_viewport_scroll_into_view
-        scroll_viewport.reset_globals = paged_reset_globals
-        scroll_viewport.reset_transforms = paged_reset_transforms
 
 def current_spine_item():
     return current_spine_item.value

src/pyj/read_book/iframe.pyj

@@ -13,8 +13,8 @@ from read_book.flow_mode import (
     layout as flow_layout, scroll_by_page as flow_scroll_by_page
 )
 from read_book.globals import (
-    current_book, current_layout_mode, current_spine_item, scroll_viewport, set_boss,
+    current_book, current_layout_mode, current_spine_item, set_boss,
-    set_current_spine_item, set_layout_mode, window_height, window_width
+    set_current_spine_item, set_layout_mode
 )
 from read_book.mathjax import apply_mathjax
 from read_book.paged_mode import (
@@ -28,6 +28,7 @@ from read_book.resources import finalize_resources, unserialize_html
 from read_book.settings import apply_settings, opts
 from read_book.toc import update_visible_toc_anchors
 from read_book.touch import create_handlers as create_touch_handlers
+from read_book.viewport import scroll_viewport
 from utils import debounce, html_escape, is_ios
 
 FORCE_FLOW_MODE = False
@@ -118,7 +119,7 @@ class IframeBoss:
 
     def initialize(self, data):
         self.gcm_from_parent, self.gcm_to_parent = GCM(data.secret.subarray(0, 32)), GCM(data.secret.subarray(32))
-        window_width.from_parent, window_height.from_parent = data.width, data.height
+        scroll_viewport.update_window_size(data.width, data.height)
         if data.translations:
             install(data.translations)
         window.onerror = self.onerror
@@ -224,7 +225,7 @@ class IframeBoss:
         # document.body.appendChild(
         #     E.style()  # TODO: User style sheet
         # )
-        self.last_window_width, self.last_window_height = window_width(), window_height()
+        self.last_window_width, self.last_window_height = scroll_viewport.width(), scroll_viewport.height()
         self.apply_colors()
         self.apply_font_size()
         self.do_layout()
@@ -313,10 +314,10 @@ class IframeBoss:
             self.onresize_stage2()
 
     def onresize_stage2(self):
-        if window_width() is self.last_window_width and window_height() is self.last_window_height:
+        if scroll_viewport.width() is self.last_window_width and scroll_viewport.height() is self.last_window_height:
             # Safari at least, generates lots of spurious resize events
             return
-        self.last_window_width, self.last_window_height = window_width(), window_height()
+        self.last_window_width, self.last_window_height = scroll_viewport.width(), scroll_viewport.height()
         if current_layout_mode() is not 'flow':
             self.do_layout()
         if self.last_cfi:
@@ -327,7 +328,7 @@ class IframeBoss:
         self.update_toc_position()
 
     def received_window_size(self, data):
-        window_width.from_parent, window_height.from_parent = data.width, data.height
+        scroll_viewport.update_window_size(data.width, data.height)
         if self.content_ready:
             self.onresize_stage2()
 

src/pyj/read_book/paged_mode.pyj

@@ -2,14 +2,20 @@
 # License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 from __python__ import hash_literals
 
-from dom import set_css
-from elementmaker import E
-from keycodes import get_key
-from read_book.cfi import scroll_to as cfi_scroll_to, at_point as cfi_at_point, at_current as cfi_at_current
-from read_book.globals import get_boss, scroll_viewport
-from read_book.settings import opts
 import traceback
-from utils import get_elem_data, set_elem_data, viewport_to_document, document_width
+from elementmaker import E
+
+from dom import set_css
+from keycodes import get_key
+from read_book.cfi import (
+    at_current as cfi_at_current, at_point as cfi_at_point,
+    scroll_to as cfi_scroll_to
+)
+from read_book.globals import get_boss
+from read_book.settings import opts
+from read_book.viewport import scroll_viewport
+from utils import document_width, get_elem_data, set_elem_data, viewport_to_document
+
 
 def first_child(parent):
     c = parent.firstChild

src/pyj/read_book/toc.pyj

@@ -8,7 +8,8 @@ from elementmaker import E
 from gettext import gettext as _
 from modals import error_dialog
 from widgets import create_tree, find_text_in_tree, scroll_tree_item_into_view
-from read_book.globals import toc_anchor_map, set_toc_anchor_map, current_spine_item, current_layout_mode, current_book, scroll_viewport
+from read_book.globals import toc_anchor_map, set_toc_anchor_map, current_spine_item, current_layout_mode, current_book
+from read_book.viewport import scroll_viewport
 
 
 def update_visible_toc_nodes(visible_anchors):

src/pyj/read_book/touch.pyj

@@ -1,9 +1,10 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
-from __python__ import hash_literals, bound_methods
+from __python__ import bound_methods, hash_literals
 
-from read_book.globals import get_boss, scroll_viewport
 from book_list.globals import get_read_ui
+from read_book.globals import get_boss
+from read_book.viewport import scroll_viewport
 
 HOLD_THRESHOLD = 750  # milliseconds
 TAP_THRESHOLD = 5  # pixels

src/pyj/read_book/viewport.pyj

@@ -0,0 +1,115 @@
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2017, Kovid Goyal <kovid at kovidgoyal.net>
+from __python__ import bound_methods, hash_literals
+
+FUNCTIONS = 'x y scroll_to scroll_into_view reset_globals reset_transforms'.split(' ')
+
+from read_book.globals import get_boss, viewport_mode_changer
+from utils import is_ios
+
+class ScrollViewport:
+
+    def __init__(self):
+        self.set_mode('flow')
+        self.window_width_from_parent = self.window_height_from_parent = None
+
+    def set_mode(self, mode):
+        prefix = ('flow' if mode is 'flow' else 'paged') + '_'
+        for attr in FUNCTIONS:
+            self[attr] = self[prefix + attr]
+
+    def flow_x(self):
+        return window.pageXOffset
+
+    def flow_y(self):
+        return window.pageYOffset
+
+    def paged_y(self):
+        return 0
+
+    def flow_scroll_to(self, x, y):
+        window.scrollTo(x, y)
+
+    def flow_scroll_into_view(self, elem):
+        elem.scrollIntoView()
+
+    def flow_reset_globals(self):
+        pass
+
+    def flow_reset_transforms(self):
+        pass
+
+    def paged_content_width(self):
+        return document.documentElement.scrollWidth
+
+    def update_window_size(self, w, h):
+        self.window_width_from_parent = w
+        self.window_height_from_parent = h
+
+    def width(self):
+        return window.innerWidth
+
+    def height(self):
+        return window.innerHeight
+
+
+class IOSScrollViewport(ScrollViewport):
+
+    def width(self):
+        return self.window_width_from_parent or window.innerWidth
+
+    def height(self):
+        return self.window_height_from_parent or window.innerHeight
+
+    def _scroll_implementation(self, x):
+        if x is 0:
+            document.documentElement.style.transform = 'none'
+        else:
+            x *= -1
+            document.documentElement.style.transform = f'translateX({x}px)'
+
+    def paged_scroll_to(self, x, y):
+        self._scroll_implementation(x)
+        boss = get_boss()
+        if boss:
+            boss.onscroll()
+
+    def paged_x(self):
+        raw = document.documentElement.style.transform
+        if not raw or raw is 'none':
+            return 0
+        raw = raw[raw.indexOf('(') + 1:]
+        ans = parseInt(raw)
+        if isNaN(ans):
+            return 0
+        ans *= -1
+        return ans
+
+    def paged_scroll_into_view(self, elem):
+        left = elem.offsetLeft
+        if left is None:
+            return  # element has display: none
+        elem.scrollIntoView()
+        window.scrollTo(0, 0)
+        p = elem.offsetParent
+        while p:
+            left += p.offsetLeft
+            p = p.offsetParent
+        # left -= window_width() // 2
+        self._scroll_implementation(max(0, left))
+
+    def paged_reset_transforms(self):
+        document.documentElement.style.transform = 'none'
+
+    def paged_reset_globals(self):
+        self.paged_reset_transforms()
+
+
+if is_ios:
+    scroll_viewport = IOSScrollViewport()
+else:
+    scroll_viewport = ScrollViewport()
+for attr in FUNCTIONS:
+    if not scroll_viewport['paged_' + attr]:
+        scroll_viewport['paged_' + attr] = scroll_viewport[attr]
+viewport_mode_changer(scroll_viewport.set_mode)