pocket signal bars

graphics/elements/indicators/signal.lua

@@ -0,0 +1,72 @@
+-- Signal Bars Graphics Element
+
+local util    = require("scada-common.util")
+
+local element = require("graphics.element")
+
+---@class signal_bar_args
+---@field colors_low_med? cpair color a for low signal quality, color b for medium signal quality
+---@field disconnect_color? color color for the 'x' on disconnect
+---@field parent graphics_element
+---@field id? string element id
+---@field x? integer 1 if omitted
+---@field y? integer auto incremented if omitted
+---@field fg_bg? cpair foreground/background colors (foreground is used for high signal quality)
+---@field hidden? boolean true to hide on initial draw
+
+-- new signal bar
+---@nodiscard
+---@param args signal_bar_args
+---@return graphics_element element, element_id id
+local function signal_bar(args)
+    args.height = 1
+    args.width = 2
+
+    -- create new graphics element base object
+    local e = element.new(args)
+
+    e.value = 0
+
+    local blit_bkg = args.fg_bg.blit_bkg
+    local blit_0, blit_1, blit_2, blit_3 = args.fg_bg.blit_fgd, args.fg_bg.blit_fgd, args.fg_bg.blit_fgd, args.fg_bg.blit_fgd
+
+    if type(args.colors_low_med) == "table" then
+        blit_1 = args.colors_low_med.blit_a or blit_1
+        blit_2 = args.colors_low_med.blit_b or blit_2
+    end
+
+    if util.is_int(args.disconnect_color) then blit_0 = colors.toBlit(args.disconnect_color) end
+
+    -- on state change (0 = offline, 1 through 3 = low to high signal)
+    ---@param new_state integer signal state
+    function e.on_update(new_state)
+        e.value = new_state
+        e.redraw()
+    end
+
+    -- set signal state (0 = offline, 1 through 3 = low to high signal)
+    ---@param val integer signal state
+    function e.set_value(val) e.on_update(val) end
+
+    -- draw label and signal bar
+    function e.redraw()
+        e.w_set_cur(1, 1)
+
+        if e.value == 1 then
+            e.w_blit("\x9f ", blit_bkg .. blit_bkg, blit_1 .. blit_bkg)
+        elseif e.value == 2 then
+            e.w_blit("\x9f\x94", blit_bkg .. blit_2, blit_2 .. blit_bkg)
+        elseif e.value == 3 then
+            e.w_blit("\x9f\x81", blit_bkg .. blit_bkg, blit_3 .. blit_3)
+        else
+            e.w_blit(" x", blit_0 .. blit_0, blit_bkg .. blit_bkg)
+        end
+    end
+
+    -- initial draw
+    e.redraw()
+
+    return e.complete()
+end
+
+return signal_bar