Keyboard: properly handle keyboard layout height change

The japanese keyboard being taller than the others, when
switching to/from it from/to another layout:
- re-init InputDialog for proper sizing and positionning
- refresh the whole screen, to remove any trace of
  a previous taller keyboard

Also add calls to :free() here and there to free keyboard
keys' TextWidgets' XText C objects without waiting for GC.

frontend/ui/widget/inputdialog.lua

@@ -288,6 +288,15 @@ function InputDialog:init()
         self.button_table,
     }
 
+    -- Remember provided text_height if any (to restore it on keyboard height change)
+    if self.orig_text_height == nil then
+        if self.text_height then
+            self.orig_text_height = self.text_height
+        else
+            self.orig_text_height = false
+        end
+    end
+
     -- InputText
     if not self.text_height or self.fullscreen then
         -- We need to find the best height to avoid screen overflow
@@ -306,7 +315,7 @@ function InputDialog:init()
         if not self.keyboard_hidden then
             keyboard_height = input_widget:getKeyboardDimen().h
         end
-        input_widget:free()
+        input_widget:onCloseWidget() -- free() textboxwidget and keyboard
         -- Find out available height
         local available_height = Screen:getHeight()
                                     - 2*self.border_size
@@ -471,6 +480,21 @@ function InputDialog:onShowKeyboard(ignore_first_hold_release)
     end
 end
 
+function InputDialog:onKeyboardHeightChanged()
+    self.input = self:getInputText() -- re-init with up-to-date text
+    self:onClose() -- will close keyboard and save view position
+    self._input_widget:onCloseWidget() -- proper cleanup of InputText and its keyboard
+    self:free()
+    -- Restore original text_height (or reset it if none to force recomputing it)
+    self.text_height = self.orig_text_height or nil
+    self:init()
+    if not self.keyboard_hidden then
+        self:onShowKeyboard()
+    end
+    -- Our position on screen has probably changed, so have the full screen refreshed
+    UIManager:setDirty("all", "flashui")
+end
+
 function InputDialog:onClose()
     -- Remember current view & position in case of re-init
     self._top_line_num = self._input_widget.top_line_num

frontend/ui/widget/inputtext.lua

@@ -406,6 +406,13 @@ function InputText:onCloseKeyboard()
     UIManager:close(self.keyboard)
 end
 
+function InputText:onCloseWidget()
+    if self.keyboard then
+        self.keyboard:free()
+    end
+    self:free()
+end
+
 function InputText:getTextHeight()
     return self.text_widget:getTextHeight()
 end

frontend/ui/widget/virtualkeyboard.lua

@@ -148,7 +148,7 @@ function VirtualKey:init()
             file = self.icon,
             scale_factor = 0, -- keep icon aspect ratio
             height = icon_height,
-            width = icon_height * 100, -- to fit height when ensuring a/r
+            width = self.width - 2*self.bordersize,
         }
     else
         label_widget = TextWidget:new{
@@ -394,6 +394,7 @@ function VirtualKeyPopup:onClose()
 end
 
 function VirtualKeyPopup:onCloseWidget()
+    self:free()
     UIManager:setDirty(nil, function()
         return "ui", self[1][1].dimen
     end)
@@ -698,9 +699,18 @@ function VirtualKeyboard:getKeyboardLayout()
 end
 
 function VirtualKeyboard:setKeyboardLayout(layout)
+    local prev_keyboard_height = self.dimen and self.dimen.h
     G_reader_settings:saveSetting("keyboard_layout", layout)
     self:init()
-    self:_refresh(true)
+    if prev_keyboard_height and self.dimen.h ~= prev_keyboard_height then
+        self:_refresh(true, true)
+        -- Keyboard height change: notify parent (InputDialog)
+        if self.inputbox and self.inputbox.parent and self.inputbox.parent.onKeyboardHeightChanged then
+            self.inputbox.parent:onKeyboardHeightChanged()
+        end
+    else
+        self:_refresh(true)
+    end
 end
 
 function VirtualKeyboard:onClose()
@@ -713,11 +723,15 @@ function VirtualKeyboard:onPressKey()
     return true
 end
 
-function VirtualKeyboard:_refresh(want_flash)
+function VirtualKeyboard:_refresh(want_flash, fullscreen)
     local refresh_type = "ui"
     if want_flash then
         refresh_type = "flashui"
     end
+    if fullscreen then
+        UIManager:setDirty("all", refresh_type)
+        return
+    end
     UIManager:setDirty(self, function()
         return refresh_type, self[1][1].dimen
     end)
@@ -757,6 +771,7 @@ function VirtualKeyboard:initLayer(layer)
 end
 
 function VirtualKeyboard:addKeys()
+    self:free() -- free previous keys' TextWidgets
     self.layout = {}
     local base_key_width = math.floor((self.width - (#self.KEYS[1] + 1)*self.key_padding - 2*self.padding)/#self.KEYS[1])
     local base_key_height = math.floor((self.height - (#self.KEYS + 1)*self.key_padding - 2*self.padding)/#self.KEYS)