added tri-state indicator light

graphics/elements/indicators/light.lua

@@ -1,7 +1,5 @@
 -- Indicator Light Graphics Element
 
-local util    = require("scada-common.util")
-
 local element = require("graphics.element")
 
 ---@class indicator_light_args

graphics/elements/indicators/trilight.lua

@@ -0,0 +1,65 @@
+-- Tri-State Indicator Light Graphics Element
+
+local element = require("graphics.element")
+
+---@class tristate_indicator_light_args
+---@field label string indicator label
+---@field c_off color color for off
+---@field c1 color color for state 1
+---@field c2 color color for state 2
+---@field c3 color color for state 3
+---@field min_label_width? integer label length if omitted
+---@field parent graphics_element
+---@field id? string element id
+---@field x? integer 1 if omitted
+---@field y? integer 1 if omitted
+---@field fg_bg? cpair foreground/background colors
+
+-- new indicator light
+---@param args tristate_indicator_light_args
+---@return graphics_element element, element_id id
+local function tristate_indicator_light(args)
+    assert(type(args.label) == "string", "graphics.elements.indicators.trilight: label is a required field")
+    assert(type(args.c_off) == "integer", "graphics.elements.indicators.trilight: c_off is a required field")
+    assert(type(args.c1) == "integer", "graphics.elements.indicators.trilight: c1 is a required field")
+    assert(type(args.c2) == "integer", "graphics.elements.indicators.trilight: c2 is a required field")
+    assert(type(args.c3) == "integer", "graphics.elements.indicators.trilight: c3 is a required field")
+
+    -- single line
+    args.height = 1
+
+    -- determine width
+    args.width = math.max(args.min_label_width or 1, string.len(args.label)) + 2
+
+    -- blit translations
+    local c_off colors.toBlit(args.c_off)
+    local c1 colors.toBlit(args.c1)
+    local c2 colors.toBlit(args.c2)
+    local c3 colors.toBlit(args.c3)
+
+    -- create new graphics element base object
+    local e = element.new(args)
+
+    -- on state change
+    ---@param new_state integer indicator state
+    function e.on_update(new_state)
+        e.window.setCursorPos(1, 1)
+        if new_state == 1 then
+            e.window.blit(" \x95", "0" .. c1, c1 .. e.fg_bg.blit_bkg)
+        elseif new_state == 2 then
+            e.window.blit(" \x95", "0" .. c2, c2 .. e.fg_bg.blit_bkg)
+        elseif new_state == 3 then
+            e.window.blit(" \x95", "0" .. c3, c3 .. e.fg_bg.blit_bkg)
+        else
+            e.window.blit(" \x95", "0" ..c_off, c_off .. e.fg_bg.blit_bkg)
+        end
+    end
+
+    -- write label and initial indicator light
+    e.on_update(0)
+    e.window.write(args.label)
+
+    return e.get()
+end
+
+return tristate_indicator_light