feat(color): allow all UI controls for widgets when full screen

[philmoz]

Extends the Lua LVGL API to allow buttons, text and number edit, sliders etc to be used on widgets when the widget is in full screen mode.

Example widget script:

local opts = {
}

local wgt
local exitApp = false

local function create(zone, opts)
  wgt = { zone=zone, opts=opts }
  return wgt
end

local function update(wgt, opts)
  wgt.opts = opts
  exitApp = false

  if lvgl == nil then return end

  lvgl.clear()

  local lyt

  if (lvgl.isFullscreen()) then
    lyt = {
      {type="button", text="Close", x=100, y=100,
          press=(
              function()
                  lvgl.confirm({title="Exit", message="Really exit?",
                      confirm=(function() exitApp = true end)
                  })
              end)},
    }
  else
    lyt = {
      {type="label", text="Enter full screen for UI", x=100, y=100},
    }
  end

  lvgl.build(lyt)
end

local function background(wgt)
end

local function refresh(wgt, event, touchState)
  if (exitApp) then
    lcd.exitFullScreen()
  end

  if lvgl == nil then
    lcd.drawText(0, 0, "Lvgl support required", COLOR_THEME_WARNING)
  end
end

return { name="Lvgl App", options=opts, create=create, update=update, refresh=refresh, background=background, useLvgl=true }