#63 numeric spinbox element

graphics/element.lua

@@ -87,6 +87,11 @@ function element.new(args)
     function protected.on_update(...)
     end
 
+    -- get control value
+    function protected.get_value()
+        return nil
+    end
+
     ---@class graphics_element
     local public = {}
 
@@ -117,6 +122,11 @@ function element.new(args)
         protected.on_update(...)
     end
 
+    -- get the control value reading
+    function public.get_value()
+        return protected.get_value()
+    end
+
     -- show the element
     function public.show()
         protected.window.setVisible(true)

graphics/elements/spinbox_numeric.lua

@@ -0,0 +1,90 @@
+-- Spinbox Numeric Graphics Element
+
+local element = require("graphics.element")
+local util    = require("scada-common.util")
+
+---@class spinbox_args
+---@field default? number default value, defaults to 0.0
+---@field whole_num_precision integer number of whole number digits
+---@field fractional_precision integer number of fractional digits
+---@field arrow_fg_bg cpair arrow foreground/background colors
+---@field parent graphics_element
+---@field x? integer 1 if omitted
+---@field y? integer 1 if omitted
+---@field fg_bg cpair foreground/background colors
+
+-- new spinbox control
+---@param args spinbox_args
+local function spinbox(args)
+    -- properties
+    local value = args.default or 0.0
+    local digits = {}
+    local wn_prec = args.whole_num_precision
+    local fr_prec = args.fractional_precision
+    local dec_point_x = args.whole_num_precision + 1
+
+    assert(util.is_int(wn_prec), "graphics.element.spinbox_numeric: whole number precision must be an integer")
+    assert(util.is_int(fr_prec), "graphics.element.spinbox_numeric: fractional precision must be an integer")
+
+    local initial_str = util.sprintf("%" .. wn_prec .. "." .. fr_prec .. "f", value)
+
+---@diagnostic disable-next-line: discard-returns
+    initial_str:gsub("%d", function(char) table.insert(digits, char) end)
+
+    -- determine widths
+    args.width = wn_prec + fr_prec + util.trinary(fr_prec > 0, 1, 0)
+    args.height = 3
+
+    -- create new graphics element base object
+    local e = element.new(args)
+
+    -- draw the arrows
+    e.window.setBackgroundColor(args.arrow_fg_bg.bkg)
+    e.window.setTextColor(args.arrow_fg_bg.fgd)
+    e.window.setCursorPos(1, 1)
+    e.window.write(util.strrep("\x1e", wn_prec))
+    e.window.setCursorPos(1, 3)
+    e.window.write(util.strrep("\x1f", wn_prec))
+    if fr_prec > 0 then
+        e.window.setCursorPos(1, 1)
+        e.window.write(" " .. util.strrep("\x1e", fr_prec))
+        e.window.setCursorPos(1, 3)
+        e.window.write(" " .. util.strrep("\x1f", fr_prec))
+    end
+
+    -- handle touch
+    ---@param event monitor_touch monitor touch event
+    function e.handle_touch(event)
+        -- only handle if on an increment or decrement arrow
+        if event.x ~= dec_point_x then
+            local idx = util.trinary(event.x > dec_point_x, event.x - 1, event.x)
+            if event.y == 1 then
+                -- increment
+                digits[idx] = digits[idx] + 1
+            elseif event.y == 3 then
+                -- decrement
+                digits[idx] = digits[idx] - 1
+            end
+
+            -- update value
+            value = 0
+            for i = 1, #digits do
+                if i <= wn_prec then
+                    local pow = wn_prec - i
+                    value = value + (digits[i] * (10 ^ pow))
+                else
+                    local pow = i - wn_prec
+                    value = value + (digits[i] * (10 ^ -pow))
+                end
+            end
+        end
+    end
+
+    -- get current value
+    ---@return number|integer
+    function e.get_value() return value end
+
+    return e.get()
+end
+
+return spinbox