Create Lua frontend UI code

builtin/ui/window.lua

@@ -0,0 +1,190 @@
+-- Luanti
+-- SPDX-License-Identifier: LGPL-2.1-or-later
+-- Copyright (C) 2023 v-rob, Vincent Robinson <robinsonvincent89@gmail.com>
+
+ui.Window = core.class()
+
+ui._window_types = {
+	filter = 0,
+	mask = 1,
+	hud = 2,
+	chat = 3,
+	gui = 4,
+}
+
+function ui.Window:new(param)
+	local function make_window(props)
+		self:_init(ui._req(props, "table"))
+		return self
+	end
+
+	self._type = ui._req_enum(param, ui._window_types)
+	return make_window
+end
+
+function ui.Window:_init(props)
+	self._theme = ui._opt(props.theme, ui.Style, ui.get_default_theme())
+	self._styles = ui._opt_array(props.styles, ui.Style, props)
+
+	self._root = ui._req(props.root, ui.Root)
+
+	self._context = nil -- Set by ui.Context
+
+	self._elems = self._root:_get_flat()
+	self._elems_by_id = {}
+
+	for _, elem in ipairs(self._elems) do
+		local id = elem._id
+
+		assert(not self._elems_by_id[id], "Element has duplicate ID: '" .. id .. "'")
+		self._elems_by_id[id] = elem
+
+		assert(elem._window == nil, "Element '" .. elem._id .. "' already has a window")
+		elem._window = self
+	end
+
+	for _, item in ipairs(props) do
+		ui._req(item, ui.Style)
+	end
+end
+
+function ui.Window:_encode(player, opening)
+	local enc_styles = self:_encode_styles()
+	local enc_elems = self:_encode_elems()
+
+	local data = ui._encode("ZzZ", enc_elems, self._root._id, enc_styles)
+	if opening then
+		data = ui._encode("ZB", data, ui._window_types[self._type])
+	end
+
+	return data
+end
+
+function ui.Window:_encode_styles()
+	-- Clear out all the boxes in every element.
+	for _, elem in ipairs(self._elems) do
+		for box in pairs(elem._boxes) do
+			elem._boxes[box] = {n = 0}
+		end
+	end
+
+	-- Get a cascaded and flattened list of all the styles for this window.
+	local styles = self:_get_full_style():_get_flat()
+
+	-- Take each style and apply its properties to every box and state matched
+	-- by its selector.
+	self:_apply_styles(styles)
+
+	-- Take the styled boxes and encode their styles into a single table,
+	-- replacing the boxes' style property tables with indices into this table.
+	local enc_styles = self:_index_styles()
+
+	return ui._encode_array("Z", enc_styles)
+end
+
+function ui.Window:_get_full_style()
+	-- The full style contains the theme, global styles, and local element
+	-- styles as sub-styles, in that order, to ensure the correct precedence.
+	local styles = table.merge({self._theme}, self._styles)
+
+	for _, elem in ipairs(self._elems) do
+		-- Cascade the inline style with the element's ID, ensuring that the
+		-- inline style globally refers to this element only.
+		local local_style = ui.Style("#" .. elem._id) {
+			props = elem._props,
+			nested = elem._styles,
+		}
+		table.insert(styles, local_style)
+	end
+
+	-- Return all these styles wrapped up into a single style.
+	return ui.Style {nested = styles}
+end
+
+local function apply_style(elem, boxes, style)
+	-- Loop through each box, applying the styles accordingly. The table of
+	-- boxes may be empty, in which case nothing happens.
+	for _, box in pairs(boxes) do
+		local name = box.name or "main"
+
+		-- If this style resets all properties, find all states that are a
+		-- subset of the state being styled and clear their property tables.
+		if style._reset then
+			for i = ui._STATE_NONE, ui._NUM_STATES - 1 do
+				if bit.band(box.states, i) == box.states then
+					elem._boxes[name][i] = nil
+				end
+			end
+		end
+
+		-- Get the existing style property table for this box if it exists.
+		local props = elem._boxes[name][box.states] or {}
+
+		-- Cascade the properties from this style onto the box.
+		elem._boxes[name][box.states] = ui._cascade_props(style._props, props)
+	end
+end
+
+function ui.Window:_apply_styles(styles)
+	-- Loop through each style and element and see if the style properties can
+	-- be applied to any boxes.
+	for _, style in ipairs(styles) do
+		for _, elem in ipairs(self._elems) do
+			-- Check if the selector for this style. If it matches, apply the
+			-- style to each of the applicable boxes.
+			local matches, boxes = style._sel(elem)
+			if matches then
+				apply_style(elem, boxes, style)
+			end
+		end
+	end
+end
+
+local function index_style(box, i, style_indices, enc_styles)
+	-- If we have a style for this state, serialize it to a string. Identical
+	-- styles have identical strings, so we use this to our advantage.
+	local enc = ui._encode_props(box[i])
+
+	-- If we haven't serialized a style identical to this one before, store
+	-- this as the latest index in the list of style strings.
+	if not style_indices[enc] then
+		style_indices[enc] = #enc_styles
+		table.insert(enc_styles, enc)
+	end
+
+	-- Set the index of our state to the index of its style string, and keep
+	-- count of how many states with valid indices we have for this box so far.
+	box[i] = style_indices[enc]
+	box.n = box.n + 1
+end
+
+function ui.Window:_index_styles()
+	local style_indices = {}
+	local enc_styles = {}
+
+	for _, elem in ipairs(self._elems) do
+		for _, box in pairs(elem._boxes) do
+			for i = ui._STATE_NONE, ui._NUM_STATES - 1 do
+				if box[i] then
+					-- If this box has a style, encode and index it.
+					index_style(box, i, style_indices, enc_styles)
+				else
+					-- Otherwise, this state has no style, so set it as such.
+					box[i] = ui._NO_STYLE
+				end
+			end
+		end
+	end
+
+	return enc_styles
+end
+
+function ui.Window:_encode_elems()
+	local enc_elems = {}
+
+	for _, elem in ipairs(self._elems) do
+		table.insert(enc_elems, elem:_encode())
+	end
+
+	return ui._encode_array("Z", enc_elems)
+end