Update modules/game_textwindow/textwindow.lua

Improved behavior
- Up / Down will move the whole screen 1 line up / down
- If scrollbar is at the end and Up / Down is pressed it will move the cursor in the right direction
- You can't change the line by using Left / Right key (to remove bugs with scrollbar)

Bugs:
When editing the text (adding new lines / removing line) the scrollbar doesn't update

modules/game_textwindow/textwindow.lua

@@ -22,6 +22,8 @@ function destroy()
 end
 
 function getCursorPosByNewLine(str, count)
+  if count <= 1 then return 0 end
+  
   local i = 0
   for n = 1, count-1 do
     local tPos = string.find(str, '\n', i)
@@ -33,6 +35,32 @@ function getCursorPosByNewLine(str, count)
   return i - 1
 end
 
+function getLineByCursorPos(str, pos, maxLine)
+  for i = 1, maxLine do
+    if pos <= getCursorPosByNewLine(str, i) then
+      return i
+    end
+  end
+  
+  return maxLine + 1
+end
+
+
+function getLineSizeByCursorPos(str, pos, maxLine)
+  for i = 1, maxLine + 1 do
+    if pos < getCursorPosByNewLine(str, i) then
+      return {minPos = getCursorPosByNewLine(str, i-1), maxPos = (getCursorPosByNewLine(str, i) - 1)}
+    end
+  end
+  
+  return {minPos = getCursorPosByNewLine(str, maxLine + 1), maxPos = str:len()}
+end
+
+function string.count(str, pattern)
+  local _, _count = string.gsub(str, pattern, pattern)
+  return _count
+end
+
 function onGameEditText(id, itemId, maxLength, text, writter, time)
   if textWindow then return end
   textWindow = g_ui.createWidget('TextWindow', rootWidget)
@@ -89,35 +117,76 @@ function onGameEditText(id, itemId, maxLength, text, writter, time)
     destroy()
   end
   
-  local _, newLineCount = string.gsub(text, '\n', '\n')
+  local newLineCount = string.count(textEdit:getText(), '\n')
   if(newLineCount >= 9) then
     textScroll:setMaximum(newLineCount-9)
   end
     
-  local _prev, _next, _current = 0, 11, 0
-  local onValueChange = function()
-  local diff = textScroll:getValue() - _current
+  local _prev, _next = 0, 11
+  local scrollOnValueChange = function(widget, value, delta)
+    local line = getLineByCursorPos(textEdit:getText(), textEdit:getCursorPos(), newLineCount)
+    if(delta > 0) then
+      textEdit:setCursorPos(getCursorPosByNewLine(textEdit:getText(), _next + delta - 1))
+      if writeable then textEdit:setCursorPos(getCursorPosByNewLine(textEdit:getText(), line + delta)) end
+    else
+      textEdit:setCursorPos(getCursorPosByNewLine(textEdit:getText(), _prev + delta + 1))
+      if writeable then textEdit:setCursorPos(getCursorPosByNewLine(textEdit:getText(), line + delta)) end
+    end
   
-  if(diff > 0) then
-    textEdit:setCursorPos(getCursorPosByNewLine(text, _next+(diff-1)))
-  else
-    textEdit:setCursorPos(getCursorPosByNewLine(text, _prev+(diff+1)))
+    _next = _next + delta
+    _prev = _prev + delta
   end
   
-  _current = textScroll:getValue()
-  _next = _next + diff
-  _prev = _prev + diff
+  textScroll.onValueChange = scrollOnValueChange
+  
+  local navigateVertical = function(up)   -- Pressing Up / Down when scrollbar is at min / max value
+    local line = getLineByCursorPos(textEdit:getText(), textEdit:getCursorPos(), newLineCount)
+    if up and textScroll:getValue() == textScroll:getMinimum() then
+      textEdit:setCursorPos(getCursorPosByNewLine(textEdit:getText(), line - 1))
+    elseif not up and textScroll:getValue() == textScroll:getMaximum() then
+      textEdit:setCursorPos(getCursorPosByNewLine(textEdit:getText(), line + 1))
+    end
   end
   
-  textScroll.onValueChange = onValueChange
-  g_keyboard.bindKeyPress("Up", function() textScroll:setValue(textScroll:getValue()-1) end, textWindow, 400)
-  g_keyboard.bindKeyPress("Down", function() textScroll:setValue(textScroll:getValue()+1) end, textWindow, 400)
+  local navigateHorizontal = function(right)  -- Pressing Left / Right to navigate in a line
+    local currentCursor = textEdit:getCursorPos()
+    local lineSize = getLineSizeByCursorPos(textEdit:getText(), currentCursor, newLineCount)
+    if right and currentCursor < lineSize.maxPos then
+      textEdit:setCursorPos(currentCursor+1)
+    elseif not right and currentCursor > lineSize.minPos then
+      textEdit:setCursorPos(currentCursor-1)
+    end
+  end
+  
+  local onKeyPress = function(widget, keyCode, keyModifiers)
+    if keyModifiers ~= 0 then
+      return false
+    end
+
+    if keyCode == 16 or keyCode == 17 then  -- Left / Right
+      navigateHorizontal((keyCode == 17))  
+      return true
+    elseif keyCode == 14 or keyCode == 15 then -- Up / Down
+      local up = (keyCode == 14)
+      navigateVertical(up)
+      
+      if up then
+        textScroll:setValue(textScroll:getValue() - 1)
+      else
+        textScroll:setValue(textScroll:getValue() + 1)
+      end
+      return true
+    end
+    return false
+  end
   
   if(not writeable) then
     textEdit:setCursorPos(0)
+    textWindow.onKeyPress = onKeyPress  -- textEdit won't receive focus
   else
     textScroll:setValue(textScroll:getMaximum())
     textEdit:setCursorPos(text:len())
+    textEdit.onKeyPress = onKeyPress
   end
   
   okButton.onClick = doneFunc
@@ -175,4 +244,4 @@ function onGameEditList(id, doorId, text)
   okButton.onClick = doneFunc
   textWindow.onEnter = doneFunc
   textWindow.onEscape = destroy
-end
+end