[UX] Add keyboard swipes (#4884)

Only the `e` and `E` are added in this initial commit.

frontend/ui/data/keyboardlayouts/std.lua

@@ -1,3 +1,28 @@
+local _E_ = {
+    "E",
+    north = "Ë",
+    northeast = "É",
+    northwest = "È",
+    east = "Ê",
+    west = "Ẽ",
+    south = "Ę",
+    southeast = "€",
+    southwest = "Ė",
+    "Ē",
+}
+local _e_ = {
+    "e",
+    north = "ë",
+    northeast = "é",
+    northwest = "è",
+    east = "ê",
+    west = "ẽ",
+    south = "ę",
+    southeast = "€",
+    southwest = "ė",
+    "ē",
+}
+
 return {
     shiftmode_keys = {["Shift"] = true},
     symbolmode_keys = {["Sym"] = true, ["ABC"] = true},
@@ -8,7 +33,7 @@ return {
         {  --  1           2       3       4       5       6       7       8       9       10      11      12
             { "Q",        "q",    "„",    "0",    "Й",    "й",    "?",    "!",    "Å",    "å",    "1",    "ª", },
             { "W",        "w",    "!",    "1",    "Ц",    "ц",    "(",    "1",    "Ä",    "ä",    "2",    "º", },
-            { "E",        "e",    "@",    "2",    "У",    "у",    ")",    "2",    "Ö",    "ö",    "3",    "¡", },
+            { _E_,        _e_,    "@",    "2",    "У",    "у",    ")",    "2",    "Ö",    "ö",    "3",    "¡", },
             { "R",        "r",    "#",    "3",    "К",    "к",    "~",    "3",    "ß",    "ß",    "4",    "¿", },
             { "T",        "t",    "+",    "=",    "Е",    "е",    "Ә",    "ә",    "À",    "à",    "5",    "¼", },
             { "Y",        "y",    "€",    "(",    "Н",    "н",    "І",    "і",    "Â",    "â",    "6",    "½", },

frontend/ui/widget/virtualkeyboard.lua

@@ -66,6 +66,9 @@ function VirtualKey:init()
         self.callback = function() self.keyboard:downLine() end
     else
         self.callback = function () self.keyboard:addChar(self.key) end
+        self.swipe_callback = function(ges)
+            self.keyboard:addChar(self.key_chars[ges.direction])
+        end
     end
 
     local label_widget
@@ -118,6 +121,12 @@ function VirtualKey:init()
                     range = self.dimen,
                 },
             },
+            SwipeKey = {
+                GestureRange:new{
+                    ges = "swipe",
+                    range = self.dimen,
+                },
+            },
         }
     end
     self.flash_keyboard = G_reader_settings:readSetting("flash_keyboard") ~= false
@@ -184,6 +193,22 @@ function VirtualKey:onHoldSelect()
     return true
 end
 
+function VirtualKey:onSwipeKey(arg, ges)
+    if self.flash_keyboard and not self.skipswipe then
+        self[1].inner_bordersize = self.focused_bordersize
+        self:update_keyboard(false, true)
+        if self.swipe_callback then
+            self.swipe_callback(ges)
+        end
+        UIManager:tickAfterNext(function() self:invert(false, true) end)
+    else
+        if self.swipe_callback then
+            self.swipe_callback(ges)
+        end
+    end
+    return true
+end
+
 function VirtualKey:invert(invert, hold)
     if invert then
         self[1].inner_bordersize = self.focused_bordersize
@@ -311,21 +336,33 @@ function VirtualKeyboard:addKeys()
         local horizontal_group = HorizontalGroup:new{}
         local layout_horizontal = {}
         for j = 1, #self.KEYS[i] do
+            local key
+            local key_chars = self.KEYS[i][j][self.keyboard_layout]
+            if type(key_chars) == "table" then
+                key = key_chars[1]
+            else
+                key = key_chars
+                key_chars = nil
+            end
             local width_factor = self.KEYS[i][j].width or 1.0
             local key_width = math.floor((base_key_width + self.key_padding) * width_factor)
                             - self.key_padding
             local key_height = base_key_height
-            local label = self.KEYS[i][j].label or self.KEYS[i][j][self.keyboard_layout]
-            local key = VirtualKey:new{
-                key = self.KEYS[i][j][self.keyboard_layout],
+            local label = self.KEYS[i][j].label or key
+            local virtual_key = VirtualKey:new{
+                key = key,
+                key_chars = key_chars,
                 icon = self.KEYS[i][j].icon,
                 label = label,
                 keyboard = self,
                 width = key_width,
                 height = key_height,
             }
-            table.insert(horizontal_group, key)
-            table.insert(layout_horizontal, key)
+            if not key_chars then
+                virtual_key.swipe_callback = nil
+            end
+            table.insert(horizontal_group, virtual_key)
+            table.insert(layout_horizontal, virtual_key)
             if j ~= #self.KEYS[i] then
                 table.insert(horizontal_group, h_key_padding)
             end