feat: add editbox

asset/gameplay/ui.dl

@@ -51,4 +51,6 @@ cardlist :
 editbox :
 	cursor_speed : 20
 	cursor_color : 0x0000ff
+	line_height : 22
+	selection_color : 0x664f7dff
 	preedit_color : 0x000000

core/editbox.lua

@@ -0,0 +1,384 @@
+local utf8 = utf8
+local table = table
+
+global setmetatable
+
+local editbox = {}
+
+local KEY_BACKSPACE <const> = 259
+local KEY_DELETE <const> = 261
+local KEY_RIGHT <const> = 262
+local KEY_LEFT <const> = 263
+local KEY_HOME <const> = 268
+local KEY_END <const> = 269
+local KEYSTATE_PRESS <const> = 1
+local KEYSTATE_REPEAT <const> = 2
+local MODIFIER_SHIFT <const> = 0x1
+local HISTORY_LIMIT <const> = 100
+
+local remove = table.remove
+
+local Editor = {}
+Editor.__index = Editor
+
+local function text_len(text)
+	return utf8.len(text or "") or 0
+end
+
+local function clamp_position(text, position)
+	local len = text_len(text)
+	position = position or len
+	if position < 0 then
+		return 0
+	elseif position > len then
+		return len
+	end
+	return position
+end
+
+local function byte_offset(text, position)
+	if position <= 0 then
+		return 1
+	end
+	local len = text_len(text)
+	if position >= len then
+		return #text + 1
+	end
+	return utf8.offset(text, position + 1) or (#text + 1)
+end
+
+local function is_control_codepoint(codepoint)
+	return codepoint < 32 or (codepoint >= 127 and codepoint <= 159)
+end
+
+local function clean_text(text)
+	if not text or text == "" then
+		return ""
+	end
+	local out
+	local last = 1
+	for offset, codepoint in utf8.codes(text) do
+		if is_control_codepoint(codepoint) then
+			out = out or {}
+			if offset > last then
+				out[#out + 1] = text:sub(last, offset - 1)
+			end
+			last = offset + #utf8.char(codepoint)
+		end
+	end
+	if not out then
+		return text
+	end
+	if last <= #text then
+		out[#out + 1] = text:sub(last)
+	end
+	return table.concat(out)
+end
+
+local function snapshot(self)
+	return {
+		text = self._text,
+		cursor = self._cursor,
+		selection_anchor = self._selection_anchor,
+		selection_focus = self._selection_focus,
+	}
+end
+
+local function same_snapshot(a, b)
+	return a
+		and b
+		and a.text == b.text
+		and a.cursor == b.cursor
+		and a.selection_anchor == b.selection_anchor
+		and a.selection_focus == b.selection_focus
+end
+
+local function push_snapshot(stack, value)
+	if same_snapshot(stack[#stack], value) then
+		return
+	end
+	stack[#stack + 1] = value
+	if #stack > HISTORY_LIMIT then
+		remove(stack, 1)
+	end
+end
+
+local function clear_selection(self)
+	self._selection_anchor = nil
+	self._selection_focus = nil
+end
+
+local function restore_snapshot(self, value)
+	self._text = value.text or ""
+	self._cursor = clamp_position(self._text, value.cursor)
+	self._selection_anchor = value.selection_anchor
+	self._selection_focus = value.selection_focus
+end
+
+local function record_undo(self)
+	push_snapshot(self._undo, snapshot(self))
+	self._redo = {}
+end
+
+local function selection_range(self)
+	local anchor = self._selection_anchor
+	local focus = self._selection_focus
+	if not anchor or not focus then
+		return
+	end
+	local text = self._text
+	local start = clamp_position(text, anchor)
+	local finish = clamp_position(text, focus)
+	if finish < start then
+		start, finish = finish, start
+	end
+	if start == finish then
+		return
+	end
+	return start, finish
+end
+
+local function delete_selection(self)
+	local start, finish = selection_range(self)
+	if not start then
+		return false
+	end
+	local text = self._text
+	record_undo(self)
+	self._text = text:sub(1, byte_offset(text, start) - 1) .. text:sub(byte_offset(text, finish))
+	self._cursor = start
+	clear_selection(self)
+	return true
+end
+
+local function set_cursor(self, position, select)
+	local cursor = clamp_position(self._text, position)
+	local changed = self._cursor ~= cursor
+	if self._selection_anchor or self._selection_focus then
+		changed = true
+	end
+	if select then
+		if not self._selection_anchor then
+			self._selection_anchor = clamp_position(self._text, self._cursor)
+		end
+		self._selection_focus = cursor
+	else
+		clear_selection(self)
+	end
+	self._cursor = cursor
+	return changed
+end
+
+local function move_cursor_by(self, delta, select)
+	if not select then
+		local start, finish = selection_range(self)
+		if start then
+			if delta < 0 then
+				return set_cursor(self, start, false)
+			end
+			return set_cursor(self, finish, false)
+		end
+	end
+	return set_cursor(self, self._cursor + delta, select)
+end
+
+local function shift_modifier(modifiers)
+	return (modifiers or 0) & MODIFIER_SHIFT ~= 0
+end
+
+function editbox.new(text)
+	text = clean_text(text or "")
+	return setmetatable({
+		_text = text,
+		_cursor = text_len(text),
+		_undo = {},
+		_redo = {},
+	}, Editor)
+end
+
+function Editor:text()
+	return self._text
+end
+
+function Editor:set_text(text)
+	self._text = clean_text(text or "")
+	self._cursor = text_len(self._text)
+	clear_selection(self)
+	self._undo = {}
+	self._redo = {}
+end
+
+function Editor:cursor_position()
+	return clamp_position(self._text, self._cursor)
+end
+
+function Editor:selection()
+	local cursor = self:cursor_position()
+	local start, finish = selection_range(self)
+	return {
+		start = start or cursor,
+		finish = finish or cursor,
+		anchor = self._selection_anchor or cursor,
+		focus = self._selection_focus or cursor,
+	}
+end
+
+function Editor:selected_text()
+	local start, finish = selection_range(self)
+	if not start then
+		return
+	end
+	local text = self._text
+	return text:sub(byte_offset(text, start), byte_offset(text, finish) - 1)
+end
+
+function Editor:select_all()
+	local len = text_len(self._text)
+	if len == 0 then
+		clear_selection(self)
+		return false
+	end
+	self._selection_anchor = 0
+	self._selection_focus = len
+	self._cursor = len
+	return true
+end
+
+function Editor:insert_text(text)
+	text = clean_text(text)
+	if text == "" then
+		return false
+	end
+	record_undo(self)
+	local start, finish = selection_range(self)
+	local position = clamp_position(self._text, self._cursor)
+	local current = self._text
+	if start then
+		self._text = current:sub(1, byte_offset(current, start) - 1) .. text .. current:sub(byte_offset(current, finish))
+		position = start
+	else
+		self._text = current:sub(1, byte_offset(current, position) - 1) ..
+			text .. current:sub(byte_offset(current, position))
+	end
+	self._cursor = position + text_len(text)
+	clear_selection(self)
+	return true
+end
+
+function Editor:backspace()
+	if delete_selection(self) then
+		return true
+	end
+	local text = self._text
+	local cursor = clamp_position(text, self._cursor)
+	if text == "" or cursor == 0 then
+		return false
+	end
+	record_undo(self)
+	self._text = text:sub(1, byte_offset(text, cursor - 1) - 1) .. text:sub(byte_offset(text, cursor))
+	self._cursor = cursor - 1
+	return true
+end
+
+function Editor:delete_forward()
+	if delete_selection(self) then
+		return true
+	end
+	local text = self._text
+	local cursor = clamp_position(text, self._cursor)
+	if cursor >= text_len(text) then
+		return false
+	end
+	record_undo(self)
+	self._text = text:sub(1, byte_offset(text, cursor) - 1) .. text:sub(byte_offset(text, cursor + 1))
+	self._cursor = cursor
+	return true
+end
+
+function Editor:copy()
+	return self:selected_text()
+end
+
+function Editor:cut()
+	local value = self:selected_text()
+	if not value then
+		return
+	end
+	delete_selection(self)
+	return value
+end
+
+function Editor:paste(text)
+	return self:insert_text(text)
+end
+
+function Editor:begin_selection(position)
+	local cursor = clamp_position(self._text, position)
+	local changed = self._cursor ~= cursor or self._selection_anchor ~= cursor or self._selection_focus ~= cursor
+	self._cursor = cursor
+	self._selection_anchor = cursor
+	self._selection_focus = cursor
+	return changed
+end
+
+function Editor:update_selection(position)
+	local cursor = clamp_position(self._text, position)
+	if not self._selection_anchor then
+		self._selection_anchor = clamp_position(self._text, self._cursor)
+	end
+	local changed = self._cursor ~= cursor or self._selection_focus ~= cursor
+	self._cursor = cursor
+	self._selection_focus = cursor
+	return changed
+end
+
+function Editor:finish_selection()
+	if self._selection_anchor == self._selection_focus then
+		clear_selection(self)
+		return true
+	end
+	return false
+end
+
+function Editor:undo()
+	local value = remove(self._undo)
+	if not value then
+		return false
+	end
+	push_snapshot(self._redo, snapshot(self))
+	restore_snapshot(self, value)
+	return true
+end
+
+function Editor:redo()
+	local value = remove(self._redo)
+	if not value then
+		return false
+	end
+	push_snapshot(self._undo, snapshot(self))
+	restore_snapshot(self, value)
+	return true
+end
+
+function Editor:key(keycode, key_state, modifiers)
+	if key_state ~= KEYSTATE_PRESS and key_state ~= KEYSTATE_REPEAT then
+		return false
+	end
+	local select = shift_modifier(modifiers)
+	if keycode == KEY_BACKSPACE then
+		return self:backspace()
+	elseif keycode == KEY_DELETE then
+		return self:delete_forward()
+	elseif keycode == KEY_LEFT then
+		return move_cursor_by(self, -1, select)
+	elseif keycode == KEY_RIGHT then
+		return move_cursor_by(self, 1, select)
+	elseif keycode == KEY_HOME then
+		return set_cursor(self, 0, select)
+	elseif keycode == KEY_END then
+		return set_cursor(self, text_len(self._text), select)
+	end
+	return false
+end
+
+return editbox