[UX] Treat inverse_reading_order as a proper setting (#5284)

This is supported by ReaderPaging and ReaderRolling, but the menu entry was only shown in ReaderPaging.

Hold now sets the global default.

Fixes <https://github.com/koreader/koreader/issues/4983>.
Fixes <https://github.com/koreader/koreader/issues/4089>.

frontend/apps/reader/modules/readerpaging.lua

@@ -1,13 +1,14 @@
-local InputContainer = require("ui/widget/container/inputcontainer")
-local Geom = require("ui/geometry")
-local Input = require("device").input
+local ConfirmBox = require("ui/widget/confirmbox")
 local Device = require("device")
-local Screen = Device.screen
 local Event = require("ui/event")
-local UIManager = require("ui/uimanager")
+local Geom = require("ui/geometry")
+local InputContainer = require("ui/widget/container/inputcontainer")
 local Math = require("optmath")
+local UIManager = require("ui/uimanager")
 local logger = require("logger")
 local _ = require("gettext")
+local Input = Device.input
+local Screen = Device.screen
 
 
 local function copyPageState(page_state)
@@ -33,7 +34,7 @@ local ReaderPaging = InputContainer:new{
     show_overlap_enable = nil,
     overlap = Screen:scaleBySize(DOVERLAPPIXELS),
 
-    inverse_reading_order = false,
+    inverse_reading_order = nil,
     page_flipping_mode = false,
     bookmark_flipping_mode = false,
     flip_steps = {0,1,2,5,10,20,50,100}
@@ -178,7 +179,12 @@ function ReaderPaging:onReadSettings(config)
     end
     self.flipping_zoom_mode = config:readSetting("flipping_zoom_mode") or "page"
     self.flipping_scroll_mode = config:readSetting("flipping_scroll_mode") or false
-    self.inverse_reading_order = config:readSetting("inverse_reading_order") or false
+    self.inverse_reading_order = config:readSetting("inverse_reading_order")
+    if self.inverse_reading_order == nil and G_reader_settings:has("inverse_reading_order") then
+        self.inverse_reading_order = G_reader_settings:isTrue("inverse_reading_order")
+    else
+        self.inverse_reading_order = false
+    end
 end
 
 function ReaderPaging:onSaveSettings()
@@ -233,13 +239,25 @@ function ReaderPaging:addToMainMenu(menu_items)
         end,
         sub_item_table = page_overlap_menu,
     }
-    menu_items.read_from_right_to_left = {
-        text = _("Read from right to left"),
+    menu_items.invert_page_turn_gestures = {
+        text = _("Invert page turn taps and swipes"),
         checked_func = function() return self.inverse_reading_order end,
         callback = function()
             self.inverse_reading_order = not self.inverse_reading_order
             self:setupTapTouchZones()
         end,
+        hold_callback = function(touchmenu_instance)
+            UIManager:show(ConfirmBox:new{
+                text = self.inverse_reading_order and _("Enable right to left reading by default?")
+                    or _("Disable right to left reading by default?"),
+                ok_text = self.inverse_reading_order and _("Enable")
+                    or _("Disable"),
+                ok_callback = function()
+                    G_reader_settings:saveSetting("inverse_reading_order", self.inverse_reading_order)
+                    if touchmenu_instance then touchmenu_instance:updateItems() end
+                end,
+            })
+        end,
     }
 end
 

frontend/apps/reader/modules/readerrolling.lua

@@ -38,7 +38,7 @@ local ReaderRolling = InputContainer:new{
     old_doc_height = nil,
     old_page = nil,
     current_pos = 0,
-    inverse_reading_order = false,
+    inverse_reading_order = nil,
     -- only used for page view mode
     current_page= nil,
     xpointer = nil,
@@ -188,7 +188,12 @@ function ReaderRolling:onReadSettings(config)
     if self.show_overlap_enable == nil then
         self.show_overlap_enable = DSHOWOVERLAP
     end
-    self.inverse_reading_order = config:readSetting("inverse_reading_order") or false
+    self.inverse_reading_order = config:readSetting("inverse_reading_order")
+    if self.inverse_reading_order == nil and G_reader_settings:has("inverse_reading_order") then
+        self.inverse_reading_order = G_reader_settings:isTrue("inverse_reading_order")
+    else
+        self.inverse_reading_order = false
+    end
 
     -- This self.visible_pages may not be the current nb of visible pages
     -- as crengine may decide to not ensure that in some conditions.
@@ -343,6 +348,27 @@ function ReaderRolling:getLastProgress()
 end
 
 function ReaderRolling:addToMainMenu(menu_items)
+    --- @fixme Repeated code with ReaderPaging read from left to right.
+    menu_items.invert_page_turn_gestures = {
+        text = _("Invert page turn taps and swipes"),
+        checked_func = function() return self.inverse_reading_order end,
+        callback = function()
+            self.inverse_reading_order = not self.inverse_reading_order
+            self:setupTouchZones()
+        end,
+        hold_callback = function(touchmenu_instance)
+            UIManager:show(ConfirmBox:new{
+                text = self.inverse_reading_order and _("Enable right to left reading by default?")
+                    or _("Disable right to left reading by default?"),
+                ok_text = self.inverse_reading_order and _("Enable")
+                    or _("Disable"),
+                ok_callback = function()
+                    G_reader_settings:saveSetting("inverse_reading_order", self.inverse_reading_order)
+                    if touchmenu_instance then touchmenu_instance:updateItems() end
+                end,
+            })
+        end,
+    }
     --- @fixme repeated code with page overlap menu for readerpaging
     -- needs to keep only one copy of the logic as for the DRY principle.
     -- The difference between the two menus is only the enabled func.

frontend/ui/elements/reader_menu_order.lua

@@ -37,7 +37,6 @@ local order = {
         "highlight_options",
     },
     setting = {
-        "read_from_right_to_left",
         -- common settings
         -- those that don't exist will simply be skipped during menu gen
         "frontlight", -- if Device:hasFrontlight()
@@ -70,6 +69,7 @@ local order = {
         "enable_back_history",
         "android_volume_keys",
         "----------------------------",
+        "invert_page_turn_gestures",
         "invert_page_turn_buttons",
     },
     network = {