#342 added element focusing feature to graphics library

graphics/elements/form/number_field.lua

@@ -0,0 +1,136 @@
+-- Numeric Value Entry Graphics Element
+
+local util    = require("scada-common.util")
+
+local core    = require("graphics.core")
+local element = require("graphics.element")
+
+local KEY_CLICK = core.events.KEY_CLICK
+
+---@class number_field_args
+---@field default? number default value, defaults to 0
+---@field min? number minimum, forced on unfocus
+---@field max? number maximum, forced on unfocus
+---@field max_digits? integer maximum number of digits, defaults to width
+---@field allow_decimal? boolean true to allow decimals
+---@field allow_negative? boolean true to allow negative numbers
+---@field parent graphics_element
+---@field id? string element id
+---@field x? integer 1 if omitted
+---@field y? integer auto incremented if omitted
+---@field width? integer parent width if omitted
+---@field fg_bg? cpair foreground/background colors
+---@field hidden? boolean true to hide on initial draw
+
+-- new numeric form field
+---@param args number_field_args
+---@return graphics_element element, element_id id
+local function number_field(args)
+    args.height = 1
+    args.can_focus = true
+
+    -- create new graphics element base object
+    local e = element.new(args)
+
+    local has_decimal = false
+
+    args.max_digits = args.max_digits or e.frame.w
+
+    -- set initial value
+    e.value = "" .. (args.default or 0)
+
+    local function show()
+        -- clear and print
+        e.w_set_cur(1, 1)
+        e.w_write(string.rep(" ", e.frame.w))
+        e.w_set_cur(1, 1)
+        e.w_set_fgd(colors.black)
+        e.w_write(e.value)
+        if e.is_focused() then
+            e.w_set_fgd(colors.lightGray)
+            e.w_write("_")
+        end
+    end
+
+    -- handle mouse interaction
+    ---@param event mouse_interaction mouse event
+    function e.handle_mouse(event)
+        -- only handle if on an increment or decrement arrow
+        if e.enabled and core.events.was_clicked(event.type) then
+            e.req_focus()
+        end
+    end
+
+    -- handle keyboard interaction
+    ---@param event key_interaction key event
+    function e.handle_key(event)
+        if event.type == KEY_CLICK.CHAR and string.len(e.value) < args.max_digits then
+            if tonumber(event.name) then
+                e.value = util.trinary(e.value == "0", "", e.value) .. tonumber(event.name)
+            end
+
+            show()
+        elseif event.type == KEY_CLICK.DOWN then
+            if (event.key == keys.backspace or event.key == keys.delete) and (string.len(e.value) > 0) then
+                e.value = string.sub(e.value, 1, string.len(e.value) - 1)
+                has_decimal = string.find(e.value, "%.") ~= nil
+                show()
+            elseif (event.key == keys.period or event.key == keys.numPadDecimal) and (not has_decimal) and args.allow_decimal then
+                e.value = e.value .. "."
+                has_decimal = true
+                show()
+            elseif (event.key == keys.minus or event.key == keys.numPadSubtract) and (string.len(e.value) == 0) and args.allow_negative then
+                e.value = "-"
+                show()
+            end
+        end
+    end
+
+    -- set the value
+    ---@param val number number to show
+    function e.set_value(val) e.value = val end
+
+    -- set minimum input value
+    ---@param min integer minimum allowed value
+    function e.set_min(min) args.min = min end
+
+    -- set maximum input value
+    ---@param max integer maximum allowed value
+    function e.set_max(max) args.max = max end
+
+    -- handle focus change
+    e.on_focused = show
+
+    function e.on_unfocused()
+        local val = tonumber(e.value)
+        local max = tonumber(args.max)
+        local min = tonumber(args.min)
+
+        if type(val) == "number" then
+            if type(args.max) == "number" and val > max then
+                e.value = "" .. max
+            elseif type(args.min) == "number" and val < min then
+                e.value = "" .. min
+            end
+        else
+            e.value = ""
+        end
+
+        show()
+    end
+
+    -- enable this input
+    function e.enable()
+    end
+
+    -- disable this input
+    function e.disable()
+    end
+
+    -- initial draw
+    show()
+
+    return e.complete()
+end
+
+return number_field