Initial commit

1 files changed, 153 insertions, 0 deletions

diff --git a/core.lua b/core.lua
new file mode 100644
index 0000000..f57caa9
--- /dev/null
+++ b/core.lua
@@ -0,0 +1,153 @@
+-- state
+local context = {maxid = 0}
+local NO_WIDGET = function()end
+
+local function generateID()
+	context.maxid = context.maxid + 1
+	return context.maxid
+end
+
+local function setHot(id) context.hot = id end
+local function isHot(id)  return context.hot == id end
+
+local function setActive(id) context.active = id end
+local function isActive(id)  return context.active == id end
+
+local function setKeyFocus(id) context.keyfocus = id end
+local function hasKeyFocus(id) return context.keyfocus == id end
+
+-- input
+local mouse = {x = 0, y = 0, down = false}
+local keyboard = {key = nil, code = -1}
+
+function mouse.inRect(x,y,w,h)
+	return mouse.x >= x and mouse.x <= x+w and mouse.y >= y and mouse.y <= y+h
+end
+
+function mouse.updateState(id, x,y,w,h)
+	if mouse.inRect(x,y,w,h) then
+		setHot(id)
+		if not context.active and mouse.down then
+			setActive(id)
+		end
+	end
+end
+
+function mouse.releasedOn(id)
+	return not mouse.down and isHot(id) and isActive(id)
+end
+
+function keyboard.pressed(key, code)
+	keyboard.key = key
+	keyboard.code = code
+end
+
+function keyboard.tryGrab(id)
+	if not context.keyfocus then
+		context.keyfocus = id
+	end
+end
+
+local function makeTabable(id)
+	keyboard.tryGrab(id)
+	if hasKeyFocus(id) and keyboard.key == 'tab' then
+		if love.keyboard.isDown('rshift', 'lshift') then
+			setKeyFocus(context.lastwidget)
+		else
+			setKeyFocus(nil)
+		end
+		keyboard.key = nil
+	end
+	context.lastwidget = id
+end
+
+-- helper functions
+local function strictAnd(...)
+	local n = select("#", ...)
+	local ret = true
+	for i = 1,n do ret = select(i, ...) and ret end
+	return ret
+end
+
+local function strictOr(...)
+	local n = select("#", ...)
+	local ret = false
+	for i = 1,n do ret = select(i, ...) or ret end
+	return ret
+end
+
+-- allow packed nil
+local function save_pack(...)
+	return {n = select('#', ...), ...}
+end
+
+local function save_unpack(t, i)
+	i = i or 1
+	if i >= t.n then return t[i] end
+	return t[i], save_unpack(t, i+1)
+end
+
+local draw_items = {n = 0}
+local function registerDraw(id, f, ...)
+	assert(type(f) == 'function' or (getmetatable(f) or {}).__call,
+	       'Drawing function is not a callable type!')
+
+	local state = 'normal'
+	if isHot(id) or hasKeyFocus(id) then
+		state = isActive(id) and 'active' or 'hot'
+	end
+	local rest = save_pack(...)
+	draw_items.n = draw_items.n + 1
+	draw_items[draw_items.n] = function() f(state, save_unpack(rest)) end
+end
+
+-- actually update-and-draw
+local function draw()
+	-- close frame state
+	if not mouse.down then -- released
+		setActive(nil)
+	elseif not context.active then -- clicked outside
+		setActive(NO_WIDGET)
+	end
+
+	for i = 1,draw_items.n do draw_items[i]() end
+
+	-- prepare for next frame
+	draw_items.n = 0
+	context.maxid = 0
+
+	-- update mouse status
+	setHot(nil)
+	mouse.x, mouse.y = love.mouse.getPosition()
+	mouse.down = love.mouse.isDown('l')
+
+	-- clear keyboard focus if nobody wants it
+	if keyboard.key == 'tab' then
+		context.keyboardfocus = nil
+	end
+	keyboard.key, keyboard.code = nil, -1
+end
+
+return {
+	mouse        = mouse,
+	keyboard     = keyboard,
+
+	generateID   = generateID,
+	setHot       = setHot,
+	setActive    = setActive,
+	setKeyFocus  = setKeyFocus,
+	isHot        = isHot,
+	isActive     = isActive,
+	hasKeyFocus  = hasKeyFocus,
+	makeTabable  = makeTabable,
+
+	style        = require((...):match("^(.+)%.[^%.]+") .. '.style-default'),
+	color        = color,
+	registerDraw = registerDraw,
+	draw         = draw,
+
+	strictAnd    = strictAnd,
+	strictOr     = strictOr,
+	save_pack    = save_pack,
+	save_unpack  = save_unpack,
+}