Add option to specify the amount of selectable units in preference menu

[SimoneStarace]

Since war1gus has this option I found weird that wargus doesn't have this option.

Basically I have added a new variable in the table of default preferences and in the option menu a new drop down menu has been added to specify the number of possible selectable units.

Here are the screenshots for the changes

[Jarod42]

Sad to duplicate list.
int<->string conversion can be done on the fly IMO.

Textfield/spinbox is another option. Not sure we have validator though.

[SimoneStarace]

The conversion from int to string and vice versa is easy, that's true.
I was thinking this change

local maxSelectableUnitsList = {"9", "12", "18", "50", "100", "200"}
   menu:addLabel(_("Selectable units:"),  225, 28 + 19 * 8 + 5, Fonts["game"], false)
   local maxSelectableUnitsListDD = menu:addDropDown(maxSelectableUnitsList, 225, 28 + 19 * 9 + 5, function(dd) end)
   -- Get the index of the MaxSelectableUnits from list
   local idx_msu = 0
   for i,v in ipairs(maxSelectableUnitsList) do
      if tonumber(v) == wc2.preferences.MaxSelectableUnits then
         idx_msu = i - 1
         break
      end
   end
   maxSelectableUnitsListDD:setSelected(idx_msu)
   maxSelectableUnitsListDD:setActionCallback(
      function()
         Preference.MaxSelectableUnits = tonumber(maxSelectableUnitsListDD:getSelected())
      end
   )
   maxSelectableUnitsListDD:setSize(40, 16)

The problem I have is the dropDown function getSelected() doesn't return the value from the list but the index of it. For example if I select 18 the function will return 2 and not 18.
I cannot find the function that actually returns the value I want and not the index from it.

[Jarod42]

ImageDropDownWidget has std::string getSelectedItem() (in trunk, not in 3.3.2).
Else capture the table maxSelectableUnitsList

[SimoneStarace]

I forgot to mention that I did already test that

maxSelectableUnitsListDD:setActionCallback(
      function()
         Preference.MaxSelectableUnits = maxSelectableUnitsListDD:getSelectedItem()
      end
   )

But I got this error
[string "/home/not_important/.stratagus/data.Wargus/scripts..."]:410: attempt to call method 'getSelectedItem' (a nil value)

Is this function added recently?
Because I'm testing the changes on the stable version (3.3.2)

[Jarod42]

Indeed, not present in 3.3.2
Was added by Wargus/stratagus@425fa26
so 1 year and some days.

[SimoneStarace]

By the way I have solved with this code:

maxSelectableUnitsListDD:setActionCallback(
      function()
         Preference.MaxSelectableUnits = tonumber(maxSelectableUnitsList[maxSelectableUnitsListDD:getSelected() + 1])
      end
   )