cc-mek-scada/graphics/elements/listbox.lua
2023-07-09 23:42:44 -04:00

284 lines
11 KiB
Lua

-- Scroll-able List Box Display Graphics Element
local tcd = require("scada-common.tcd")
local core = require("graphics.core")
local element = require("graphics.element")
local CLICK_TYPE = core.events.CLICK_TYPE
---@class listbox_args
---@field scroll_height integer height of internal scrolling container (must fit all elements vertically tiled)
---@field item_pad? integer spacing (lines) between items in the list (default 0)
---@field nav_fg_bg? cpair foreground/background colors for scroll arrows and bar area
---@field nav_active? cpair active colors for bar held down or arrow held down
---@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 height? integer parent height if omitted
---@field gframe? graphics_frame frame instead of x/y/width/height
---@field fg_bg? cpair foreground/background colors
---@field hidden? boolean true to hide on initial draw
---@class listbox_item
---@field id string|integer element ID
---@field e graphics_element element
---@field y integer y position
---@field h integer element height
-- new listbox element
---@nodiscard
---@param args listbox_args
---@return graphics_element element, element_id id
local function listbox(args)
-- create new graphics element base object
local e = element.new(args)
-- create content window for child elements
local scroll_frame = window.create(e.window, 1, 1, e.frame.w - 1, args.scroll_height, false)
e.content_window = scroll_frame
-- item list and scroll management
local list = {}
local item_pad = args.item_pad or 0
local scroll_offset = 0
local content_height = 0
local max_down_scroll = 0
-- bar control/tracking variables
local max_bar_height = e.frame.h - 2
local bar_height = 0 -- full height of bar
local bar_bounds = { 0, 0 } -- top and bottom of bar
local bar_is_scaled = false -- if the scrollbar doesn't have a 1:1 ratio with lines
local holding_bar = false -- bar is being held by mouse
local bar_grip_pos = 0 -- where the bar was gripped by mouse down
local mouse_last_y = 0 -- last reported y coordinate of drag
-- draw scroll bar arrows, optionally showing one of them as pressed
---@param pressed_arrow? 1|0|-1 arrow to show as pressed (1 = scroll up, 0 = neither, -1 = scroll down)
local function draw_arrows(pressed_arrow)
local nav_fg_bg = args.nav_fg_bg or e.fg_bg
local active_fg_bg = args.nav_active or nav_fg_bg
-- draw up/down arrows
if pressed_arrow == 1 then
e.window.setTextColor(active_fg_bg.fgd)
e.window.setBackgroundColor(active_fg_bg.bkg)
e.window.setCursorPos(e.frame.w, 1)
e.window.write("\x1e")
e.window.setTextColor(nav_fg_bg.fgd)
e.window.setBackgroundColor(nav_fg_bg.bkg)
e.window.setCursorPos(e.frame.w, e.frame.h)
e.window.write("\x1f")
elseif pressed_arrow == -1 then
e.window.setTextColor(nav_fg_bg.fgd)
e.window.setBackgroundColor(nav_fg_bg.bkg)
e.window.setCursorPos(e.frame.w, 1)
e.window.write("\x1e")
e.window.setTextColor(active_fg_bg.fgd)
e.window.setBackgroundColor(active_fg_bg.bkg)
e.window.setCursorPos(e.frame.w, e.frame.h)
e.window.write("\x1f")
else
e.window.setTextColor(nav_fg_bg.fgd)
e.window.setBackgroundColor(nav_fg_bg.bkg)
e.window.setCursorPos(e.frame.w, 1)
e.window.write("\x1e")
e.window.setCursorPos(e.frame.w, e.frame.h)
e.window.write("\x1f")
end
e.window.setTextColor(e.fg_bg.fgd)
e.window.setBackgroundColor(e.fg_bg.bkg)
end
-- render the scroll bar and re-cacluate height & bounds
local function draw_bar()
local offset = 2 + math.abs(scroll_offset)
bar_height = math.min(max_bar_height + max_down_scroll, max_bar_height)
if bar_height < 1 then
bar_is_scaled = true
-- can't do a 1:1 ratio
-- use minimum size bar with scaled offset
local scroll_progress = scroll_offset / max_down_scroll
offset = 2 + math.floor(scroll_progress * (max_bar_height - 1))
bar_height = 1
else
bar_is_scaled = false
end
bar_bounds = { offset, (bar_height + offset) - 1 }
for i = 2, e.frame.h - 1 do
if (i >= offset and i < (bar_height + offset)) and (bar_height ~= max_bar_height) then
if args.nav_fg_bg ~= nil then
e.window.setBackgroundColor(args.nav_fg_bg.fgd)
else
e.window.setBackgroundColor(e.fg_bg.fgd)
end
else
if args.nav_fg_bg ~= nil then
e.window.setBackgroundColor(args.nav_fg_bg.bkg)
else
e.window.setBackgroundColor(e.fg_bg.bkg)
end
end
e.window.setCursorPos(e.frame.w, i)
e.window.write(" ")
end
e.window.setBackgroundColor(e.fg_bg.bkg)
end
-- update item y positions and move elements
local function update_positions()
local next_y = 1
scroll_frame.setVisible(false)
scroll_frame.setBackgroundColor(e.fg_bg.bkg)
scroll_frame.setTextColor(e.fg_bg.fgd)
scroll_frame.clear()
for i = 1, #list do
local item = list[i] ---@type listbox_item
item.y = next_y
next_y = next_y + item.h + item_pad
item.e.reposition(1, item.y)
item.e.show()
end
content_height = next_y
max_down_scroll = math.min(-1 * (content_height - (e.frame.h + 1 + item_pad)), 0)
if scroll_offset < max_down_scroll then scroll_offset = max_down_scroll end
scroll_frame.reposition(1, 1 + scroll_offset)
scroll_frame.setVisible(true)
draw_bar()
end
-- determine where to scroll to based on a scrollbar being dragged without a 1:1 relationship
---@param direction -1|1 negative 1 to scroll up by one, positive 1 to scroll down by one
local function scaled_bar_scroll(direction)
local scroll_progress = scroll_offset / max_down_scroll
local bar_position = math.floor(scroll_progress * (max_bar_height - 1))
-- check what moving the scroll bar up or down would mean for the scroll progress
scroll_progress = (bar_position + direction) / (max_bar_height - 1)
return math.max(math.floor(scroll_progress * max_down_scroll), max_down_scroll)
end
-- scroll down the list
local function scroll_down(scaled)
if scroll_offset > max_down_scroll then
if scaled then
scroll_offset = scaled_bar_scroll(1)
else
scroll_offset = scroll_offset - 1
end
update_positions()
end
end
-- scroll up the list
local function scroll_up(scaled)
if scroll_offset < 0 then
if scaled then
scroll_offset = scaled_bar_scroll(-1)
else
scroll_offset = scroll_offset + 1
end
update_positions()
end
end
-- handle a child element having been added to the list
---@param id element_id element identifier
---@param child graphics_element child element
function e.on_added(id, child)
table.insert(list, { id = id, e = child, y = 0, h = child.get_height() })
update_positions()
end
-- handle a child element having been removed from the list
---@param id element_id element identifier
function e.on_removed(id)
for idx, elem in ipairs(list) do
if elem.id == id then
table.remove(list, idx)
update_positions()
return
end
end
end
-- handle mouse interaction
---@param event mouse_interaction mouse event
function e.handle_mouse(event)
if e.enabled then
if event.type == CLICK_TYPE.TAP then
if event.current.x == e.frame.w then
if event.current.y == 1 or event.current.y < bar_bounds[1] then
draw_arrows(1)
scroll_up()
if args.nav_active ~= nil then tcd.dispatch(0.25, function () draw_arrows(0) end) end
elseif event.current.y == e.frame.h or event.current.y > bar_bounds[2] then
draw_arrows(-1)
scroll_down()
if args.nav_active ~= nil then tcd.dispatch(0.25, function () draw_arrows(0) end) end
end
end
elseif event.type == CLICK_TYPE.DOWN then
if event.current.x == e.frame.w then
if event.current.y == 1 or event.current.y < bar_bounds[1] then
draw_arrows(1)
scroll_up()
elseif event.current.y == e.frame.h or event.current.y > bar_bounds[2] then
draw_arrows(-1)
scroll_down()
else
-- clicked on bar
holding_bar = true
bar_grip_pos = event.current.y - bar_bounds[1]
mouse_last_y = event.current.y
end
end
elseif event.type == CLICK_TYPE.UP then
holding_bar = false
draw_arrows(0)
elseif event.type == CLICK_TYPE.DRAG then
if holding_bar then
-- if mouse is within vertical frame, including the grip point
if event.current.y > (1 + bar_grip_pos) and event.current.y <= ((e.frame.h - bar_height) + bar_grip_pos) then
if event.current.y < mouse_last_y then
scroll_up(bar_is_scaled)
elseif event.current.y > mouse_last_y then
scroll_down(bar_is_scaled)
end
mouse_last_y = event.current.y
end
end
elseif event.type == CLICK_TYPE.SCROLL_DOWN then
scroll_down()
elseif event.type == CLICK_TYPE.SCROLL_UP then
scroll_up()
end
end
end
draw_arrows(0)
draw_bar()
return e.complete()
end
return listbox