Mega update: Auto layout, code cleanup, api change.

Basically half a rewrite.

11 files changed, 605 insertions, 228 deletions

diff --git a/button.lua b/button.lua
index b55f35c..fd0cff4 100644
--- a/button.lua
+++ b/button.lua
@@ -23,31 +23,55 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ]]--
-local core = require((...):match("(.-)[^%.]+$") .. 'core')
+local BASE = (...):match("(.-)[^%.]+$")
+local core     = require(BASE .. 'core')
+local group    = require(BASE .. 'group')
+local mouse    = require(BASE .. 'mouse')
+local keyboard = require(BASE .. 'keyboard')
 
 -- the widget
-return function(title, x,y, w,h, widgetHit, draw)
+-- {text = text, pos = {x, y}, size={w, h}, widgetHit=widgetHit, draw=draw}
+return function(w)
+	assert(type(w) == "table" and w.text, "Invalid argument")
+
+	-- if tight fit requested, compute the size according to text size
+	-- have a 2px margin around the text
+	local tight = w.size and (w.size[1] == 'tight' or w.size[2] == 'tight')
+	if tight then
+		local f = assert(love.graphics.getFont())
+		if w.size[1] == 'tight' then
+			w.size[1] = f:getWidth(w.text) + 4
+		end
+		if w.size[2] == 'tight' then
+			w.size[2] = f:getHeight(w.text) + 4
+		end
+	end
+
 	-- Generate unique identifier for gui state update and querying.
 	local id = core.generateID()
 
+	-- group.getRect determines the position and size of the widget according
+	-- to the currently active group. Both arguments may be omitted.
+	local pos, size = group.getRect(w.pos, w.size)
+
+	-- mouse.updateWidget(id, {x,y}, {w,h}, widgetHit) updates the state for this widget.
+	-- widgetHit may be nil, in which case mouse.widgetHit will be used.
 	-- The widget mouse-state can be:
 	--   hot (mouse over widget),
 	--   active (mouse pressed on widget) or
 	--   normal (mouse not on widget and not pressed on widget).
-	--
-	-- core.mouse.updateState(id, widgetHit, x,y,w,h) updates the state for this widget.
-	core.mouse.updateState(id, widgetHit or core.style.widgetHit, x,y,w,h)
+	mouse.updateWidget(id, pos, size, w.widgetHit)
 
-	-- core.makeCyclable makes the item focus on tab or whatever binding is
+	-- keyboard.makeCyclable makes the item focus on tab or whatever binding is
 	-- in place (see core.keyboard.cycle). Cycle order is determied by the
 	-- order you call the widget functions.
-	core.makeCyclable(id)
+	keyboard.makeCyclable(id)
 
 	-- core.registerDraw(id, drawfunction, drawfunction-arguments...)
 	-- shows widget when core.draw() is called.
-	core.registerDraw(id, draw or core.style.Button, title,x,y,w,h)
+	core.registerDraw(id, w.draw or core.style.Button,
+		w.text, pos[1],pos[2], size[1],size[2])
 
-	return core.mouse.releasedOn(id) or
-	       (core.keyboard.key == 'return' and core.hasKeyFocus(id))
+	return mouse.releasedOn(id) or (keyboard.key == 'return' and keyboard.hasFocus(id))
 end
 
diff --git a/checkbox.lua b/checkbox.lua
index 22c325a..e04f6a6 100644
--- a/checkbox.lua
+++ b/checkbox.lua
@@ -23,22 +23,46 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ]]--
-local core = require((...):match("(.-)[^%.]+$") .. 'core')
+local BASE = (...):match("(.-)[^%.]+$")
+local core     = require(BASE .. 'core')
+local group    = require(BASE .. 'group')
+local mouse    = require(BASE .. 'mouse')
+local keyboard = require(BASE .. 'keyboard')
+
+-- {info = {checked = status, label = "", algin = "left"}, pos = {x, y}, size={w, h}, widgetHit=widgetHit, draw=draw}
+return function(w)
+	assert(type(w) == "table")
+	w.info.label = w.info.label or ""
+
+	local tight = w.size and (w.size[1] == 'tight' or w.size[2] == 'tight')
+	if tight then
+		local f = assert(love.graphics.getFont())
+		if w.size[1] == 'tight' then
+			w.size[1] = f:getWidth(w.info.label)
+		end
+		if w.size[2] == 'tight' then
+			w.size[2] = f:getHeight(w.info.label)
+		end
+		-- account for the checkbox
+		local bw = math.min(w.size[1] or group.size[1], w.size[2] or group.size[2])
+		w.size[1] = w.size[1] + bw + 4
+	end
 
-return function(info, x,y, w,h, widgetHit, draw)
 	local id = core.generateID()
+	local pos, size = group.getRect(w.pos, w.size)
 
-	core.mouse.updateState(id, widgetHit or core.style.widgetHit, x,y,w,h)
-	core.makeCyclable(id)
-	core.registerDraw(id, draw or core.style.Checkbox, info.checked,x,y,w,h)
+	mouse.updateWidget(id, pos, size, w.widgetHit)
+	keyboard.makeCyclable(id)
 
-	local checked = info.checked
-	local key = core.keyboard.key
-	if core.mouse.releasedOn(id) or
-		(core.hasKeyFocus(id) and key == 'return' or key == ' ') then
-		info.checked = not info.checked
+	local checked = w.info.checked
+	local key = keyboard.key
+	if mouse.releasedOn(id) or ((key == 'return' or key == ' ') and keyboard.hasFocus(id)) then
+		w.info.checked = not w.info.checked
 	end
 
-	return info.checked ~= checked
+	core.registerDraw(id, w.draw or core.style.Checkbox,
+		w.info.checked, w.info.label, w.info.align or 'left', pos[1], pos[2], size[1], size[2])
+
+	return w.info.checked ~= checked
 end
 
diff --git a/core.lua b/core.lua
index 74aebfb..371b114 100644
--- a/core.lua
+++ b/core.lua
@@ -24,81 +24,17 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ]]--
 
--- state
-local context = {maxid = 0}
-local draw_items = {n = 0}
 local NO_WIDGET = function()end
+local BASE = (...):match("(.-)[^%.]+$")
+local group    = require(BASE .. 'group')
+local mouse    = require(BASE .. 'mouse')
+local keyboard = require(BASE .. 'keyboard')
 
-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
-
-local function disableKeyFocus() return setKeyFocus{} end
-local function clearKeyFocus() return setKeyFocus(nil) end
-
--- input
-local mouse = {x = 0, y = 0, down = false}
-local keyboard = {key = nil, code = -1}
-keyboard.cycle = {
-	-- binding = {key = key, modifier1, modifier2, ...} XXX: modifiers are OR-ed!
-	prev = {key = 'tab', 'lshift', 'rshift'},
-	next = {key = 'tab'},
-}
-
-function mouse.updateState(id, widgetHit, ...)
-	if widgetHit(mouse.x, mouse.y, ...) 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
-		setKeyFocus(id)
-	end
-end
-
-function keyboard.isBindingDown(bind)
-	local modifiersDown = #bind == 0 or love.keyboard.isDown(unpack(bind))
-	return keyboard.key == bind.key and modifiersDown
-end
+--
+-- Helper functions
+--
 
-local function makeCyclable(id)
-	keyboard.tryGrab(id)
-	if hasKeyFocus(id) then
-		if keyboard.isBindingDown(keyboard.cycle.prev) then
-			setKeyFocus(context.lastwidget)
-			keyboard.key = nil
-		elseif keyboard.isBindingDown(keyboard.cycle.next) then
-			setKeyFocus(nil)
-			keyboard.key = nil
-		end
-	end
-	context.lastwidget = id
-end
-
--- helper functions
+-- evaluates all arguments
 local function strictAnd(...)
 	local n = select("#", ...)
 	local ret = true
@@ -124,66 +60,76 @@ local function save_unpack(t, i)
 	return t[i], save_unpack(t, i+1)
 end
 
+--
+-- Widget ID
+--
+local maxid = 0
+local function generateID()
+	maxid = maxid + 1
+	return maxid
+end
+
+--
+-- Drawing / Frame update
+--
+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 font = love.graphics.getFont()
+
 	local state = 'normal'
-	if isHot(id) or hasKeyFocus(id) then
-		state = isActive(id) and 'active' or 'hot'
+	if mouse.isHot(id) or keyboard.hasFocus(id) then
+		state = mouse.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
+	draw_items[draw_items.n] = function()
+		if font then love.graphics.setFont(font) end
+		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
+	keyboard.endFrame()
+	mouse.endFrame()
+	group.endFrame()
+
+	-- save graphics state
+	local c = {love.graphics.getColor()}
+	local f = love.graphics.getFont()
+	local lw = love.graphics.getLineWidth()
+	local ls = love.graphics.getLineStyle()
 
 	for i = 1,draw_items.n do draw_items[i]() end
 
-	-- prepare for next frame
-	draw_items.n = 0
-	context.maxid = 0
+	-- restore graphics state
+	love.graphics.setLine(lw, ls)
+	if f then love.graphics.setFont(f) end
+	love.graphics.setColor(c)
 
-	-- update mouse status
-	setHot(nil)
-	mouse.x, mouse.y = love.mouse.getPosition()
-	mouse.down = love.mouse.isDown('l')
+	draw_items.n = 0
+	maxid = 0
 
-	keyboard.key, keyboard.code = nil, -1
+	group.beginFrame()
+	mouse.beginFrame()
+	keyboard.beginFrame()
 end
 
+--
+-- The Module
+--
 return {
-	mouse           = mouse,
-	keyboard        = keyboard,
-
-	generateID      = generateID,
-	setHot          = setHot,
-	setActive       = setActive,
-	setKeyFocus     = setKeyFocus,
-	isHot           = isHot,
-	isActive        = isActive,
-	hasKeyFocus     = hasKeyFocus,
-
-	disableKeyFocus = disableKeyFocus,
-	enableKeyFocus  = clearKeyFocus,
-	clearKeyFocus   = clearKeyFocus,
-	makeCyclable    = makeCyclable,
-
-	style           = require((...):match("(.-)[^%.]+$") .. '.style-default'),
-	color           = color,
-	registerDraw    = registerDraw,
-	draw            = draw,
-
-	strictAnd       = strictAnd,
-	strictOr        = strictOr,
-	save_pack       = save_pack,
-	save_unpack     = save_unpack,
+	generateID   = generateID,
+
+	style        = require((...):match("(.-)[^%.]+$") .. 'style-default'),
+	registerDraw = registerDraw,
+	draw         = draw,
+
+	strictAnd    = strictAnd,
+	strictOr     = strictOr,
+	save_pack    = save_pack,
+	save_unpack  = save_unpack,
 }
diff --git a/group.lua b/group.lua
new file mode 100644
index 0000000..50e413e
--- /dev/null
+++ b/group.lua
@@ -0,0 +1,143 @@
+--[[
+Copyright (c) 2012 Matthias Richter
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+Except as contained in this notice, the name(s) of the above copyright holders
+shall not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+]]--
+
+local stack = {n = 0}
+local default = {
+	pos = {0,0},
+	grow = {0,0},
+	spacing = 2,
+	size = {100, 30},
+	upper_left  = {0,0},
+	lower_right = {0,0},
+}
+local current = default
+
+local Grow = {
+	none  = { 0,  0},
+	up    = { 0, -1},
+	down  = { 0,  1},
+	left  = {-1,  0},
+	right = { 1,  0}
+}
+
+-- {grow = grow, spacing = spacing, size = size, pos = pos}
+local function push(info)
+	local grow    = info.grow    or "none"
+	local spacing = info.spacing or default.spacing
+
+	local size = {
+		info.size and info.size[1] or current.size[1],
+		info.size and info.size[2] or current.size[2]
+	}
+
+	local pos = {current.pos[1], current.pos[2]}
+	if info.pos then
+		pos[1] = pos[1] + (info.pos[1] or 0)
+		pos[2] = pos[2] + (info.pos[2] or 0)
+	end
+
+	assert(size, "Size neither specified nor derivable from parent group.")
+	assert(pos, "Position neither specified nor derivable from parent group.")
+	grow = assert(Grow[grow], "Invalid grow: " .. tostring(grow))
+
+	current = {
+		pos         = pos,
+		grow        = grow,
+		size        = size,
+		spacing     = spacing,
+		upper_left  = { math.huge,  math.huge},
+		lower_right = {-math.huge, -math.huge},
+	}
+	stack.n = stack.n + 1
+	stack[stack.n] = current
+end
+
+local function advance(pos, size)
+	current.upper_left[1]  = math.min(current.upper_left[1], pos[1])
+	current.upper_left[2]  = math.min(current.upper_left[2], pos[2])
+	current.lower_right[1] = math.max(current.lower_right[1], pos[1] + size[1])
+	current.lower_right[2] = math.max(current.lower_right[2], pos[2] + size[2])
+
+	if current.grow[1] ~= 0 then
+		current.pos[1] = pos[1] + current.grow[1] * (size[1] + current.spacing)
+	end
+	if current.grow[2] ~= 0 then
+		current.pos[2] = pos[2] + current.grow[2] * (size[2] + current.spacing)
+	end
+	return pos, size
+end
+
+local function getRect(pos, size)
+	pos  = {pos  and pos[1]  or 0,               pos  and pos[2]  or 0}
+	size = {size and size[1] or current.size[1], size and size[2] or current.size[2]}
+
+	-- growing left/up: update current position to account for differnt size
+	if current.grow[1] < 0 and current.size[1] ~= size[1] then
+		current.pos[1] = current.pos[1] + (current.size[1] - size[1])
+	end
+	if current.grow[2] < 0 and current.size[2] ~= size[2] then
+		current.pos[2] = current.pos[2] - (current.size[2] - size[2])
+	end
+
+	pos[1] = pos[1] + current.pos[1]
+	pos[2] = pos[2] + current.pos[2]
+
+	return advance(pos, size)
+end
+
+local function pop()
+	assert(stack.n > 0, "Group stack is empty.")
+	stack.n = stack.n - 1
+	local child = current
+	current = stack[stack.n] or default
+
+	local size = {
+		child.lower_right[1] - math.max(child.upper_left[1], current.pos[1]),
+		child.lower_right[2] - math.max(child.upper_left[2], current.pos[2])
+	}
+	advance(current.pos, size)
+end
+
+local function beginFrame()
+	current = default
+	stack.n = 0
+end
+
+local function endFrame()
+	-- future use?
+end
+
+return setmetatable({
+	push       = push,
+	pop        = pop,
+	getRect    = getRect,
+	advance    = advance,
+	beginFrame = beginFrame,
+	endFrame   = endFrame,
+	default    = default,
+}, {__index = function(_,k) 
+	return ({size = current.size, pos = current.pos})[k]
+end})
diff --git a/init.lua b/init.lua
index c122ee5..11c5e92 100644
--- a/init.lua
+++ b/init.lua
@@ -29,6 +29,9 @@ assert(not BASE:match('%.init%.$'), "Invalid require path `"..(...).."' (drop th
 
 return {
 	core     = require(BASE .. 'core'),
+	group    = require(BASE .. 'group'),
+	mouse    = require(BASE .. 'mouse'),
+	keyboard = require(BASE .. 'keyboard'),
 	Button   = require(BASE .. 'button'),
 	Slider   = require(BASE .. 'slider'),
 	Slider2D = require(BASE .. 'slider2d'),
diff --git a/input.lua b/input.lua
index 3e83988..64f2ced 100644
--- a/input.lua
+++ b/input.lua
@@ -24,47 +24,56 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ]]--
 
-local core = require((...):match("(.-)[^%.]+$") .. 'core')
+local BASE = (...):match("(.-)[^%.]+$")
+local core     = require(BASE .. 'core')
+local group    = require(BASE .. 'group')
+local mouse    = require(BASE .. 'mouse')
+local keyboard = require(BASE .. 'keyboard')
 
-return function(info, x,y,w,h, widgetHit, draw)
-	info.text = info.text or ""
-	info.cursor = math.min(info.cursor or info.text:len(), info.text:len())
+-- {info = {text = "", cursor = text:len()}, pos = {x, y}, size={w, h}, widgetHit=widgetHit, draw=draw}
+return function(w)
+	assert(type(w) == "table" and type(w.info) == "table", "Invalid argument")
+	w.info.text = w.info.text or ""
+	w.info.cursor = math.min(w.info.cursor or w.info.text:len(), w.info.text:len())
 
 	local id = core.generateID()
-	core.mouse.updateState(id, widgetHit or core.style.widgetHit, x,y,w,h)
-	core.makeCyclable(id)
-	if core.isActive(id) then core.setKeyFocus(id) end
-
-	core.registerDraw(id, draw or core.style.Input, info.text, info.cursor, x,y,w,h)
-	if not core.hasKeyFocus(id) then return false end
+	local pos, size = group.getRect(w.pos, w.size)
+	mouse.updateWidget(id, pos, size, w.widgetHit)
+	keyboard.makeCyclable(id)
+	if mouse.isActive(id) then keyboard.setFocus(id) end
 
 	local changed = false
+	if not keyboard.hasFocus(id) then
+		--[[nothing]]
 	-- editing
-	if core.keyboard.key == 'backspace' then
-		info.text = info.text:sub(1,info.cursor-1) .. info.text:sub(info.cursor+1)
-		info.cursor = math.max(0, info.cursor-1)
+	elseif keyboard.key == 'backspace' then
+		w.info.text = w.info.text:sub(1,w.info.cursor-1) .. w.info.text:sub(w.info.cursor+1)
+		w.info.cursor = math.max(0, w.info.cursor-1)
 		changed = true
-	elseif core.keyboard.key == 'delete' then
-		info.text = info.text:sub(1,info.cursor) .. info.text:sub(info.cursor+2)
-		info.cursor = math.min(info.text:len(), info.cursor)
+	elseif keyboard.key == 'delete' then
+		w.info.text = w.info.text:sub(1,w.info.cursor) .. w.info.text:sub(w.info.cursor+2)
+		w.info.cursor = math.min(w.info.text:len(), w.info.cursor)
 		changed = true
 	-- movement
-	elseif core.keyboard.key == 'left' then
-		info.cursor = math.max(0, info.cursor-1)
-	elseif core.keyboard.key == 'right' then
-		info.cursor = math.min(info.text:len(), info.cursor+1)
-	elseif core.keyboard.key == 'home' then
-		info.cursor = 0
-	elseif core.keyboard.key == 'end' then
-		info.cursor = info.text:len()
-	-- input
-	elseif core.keyboard.code >= 32 and core.keyboard.code < 127 then
-		local left = info.text:sub(1,info.cursor)
-		local right =  info.text:sub(info.cursor+1)
-		info.text = table.concat{left, string.char(core.keyboard.code), right}
-		info.cursor = info.cursor + 1
+	elseif keyboard.key == 'left' then
+		w.info.cursor = math.max(0, w.info.cursor-1)
+	elseif keyboard.key == 'right' then
+		w.info.cursor = math.min(w.info.text:len(), w.info.cursor+1)
+	elseif keyboard.key == 'home' then
+		w.info.cursor = 0
+	elseif keyboard.key == 'end' then
+		w.info.cursor = w.info.text:len()
+	-- info
+	elseif keyboard.code >= 32 and keyboard.code < 127 then
+		local left = w.info.text:sub(1,w.info.cursor)
+		local right =  w.info.text:sub(w.info.cursor+1)
+		w.info.text = table.concat{left, string.char(keyboard.code), right}
+		w.info.cursor = w.info.cursor + 1
 		changed = true
 	end
 
+	core.registerDraw(id, w.draw or core.style.Input,
+		w.info.text, w.info.cursor, pos[1],pos[2], size[1],size[2])
+
 	return changed
 end
diff --git a/keyboard.lua b/keyboard.lua
new file mode 100644
index 0000000..0b20570
--- /dev/null
+++ b/keyboard.lua
@@ -0,0 +1,89 @@
+--[[
+Copyright (c) 2012 Matthias Richter
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+Except as contained in this notice, the name(s) of the above copyright holders
+shall not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+]]--
+
+local key,code = nil, -1
+local focus, lastwidget
+
+local cycle = {
+	-- binding = {key = key, modifier1, modifier2, ...} XXX: modifiers are OR-ed!
+	prev = {key = 'tab', 'lshift', 'rshift'},
+	next = {key = 'tab'},
+}
+
+local function pressed(...)   key, code = ... end
+local function setFocus(id)   focus = id end
+local function disableFocus() focus = NO_WIDGET end
+local function clearFocus()   focus = nil end
+local function hasFocus(id)   return id == focus end
+
+local function tryGrab(id)
+	if not focus then
+		setFocus(id)
+	end
+end
+
+local function isBindingDown(bind)
+	local modifiersDown = #bind == 0 or love.keyboard.isDown(unpack(bind))
+	return key == bind.key and modifiersDown
+end
+
+local function makeCyclable(id)
+	tryGrab(id)
+	if hasFocus(id) then
+		if isBindingDown(cycle.prev) then
+			setFocus(lastwidget)
+			key = nil
+		elseif isBindingDown(cycle.next) then
+			setFocus(nil)
+			key = nil
+		end
+	end
+	lastwidget = id
+end
+
+local function beginFrame()
+	-- for future use?
+end
+
+local function endFrame()
+	key, code = nil, -1
+end
+
+return setmetatable({
+	cycle         = cycle,
+	pressed       = pressed,
+	tryGrab       = tryGrab,
+	isBindingDown = isBindingDown,
+	setFocus      = setFocus,
+	disableFocus  = disableFocus,
+	enableFocus   = clearFocus,
+	clearFocus    = clearFocus,
+	hasFocus      = hasFocus,
+	makeCyclable  = makeCyclable,
+
+	beginFrame   = beginFrame,
+	endFrame     = endFrame,
+}, {__index = function(_,k) return ({key = key, code = code})[k] end})
diff --git a/label.lua b/label.lua
index ed7ad80..62b3950 100644
--- a/label.lua
+++ b/label.lua
@@ -24,12 +24,38 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ]]--
 
-local core = require((...):match("(.-)[^%.]+$") .. 'core')
+local BASE = (...):match("(.-)[^%.]+$")
+local core     = require(BASE .. 'core')
+local group    = require(BASE .. 'group')
+local mouse    = require(BASE .. 'mouse')
+local keyboard = require(BASE .. 'keyboard')
+
+-- {text = text, align = align,  pos = {x, y}, size={w, h}, widgetHit=widgetHit, draw=draw}
+return function(w)
+	assert(type(w) == "table" and w.text, "Invalid argument")
+	w.align = w.align or 'left'
+
+	local tight = w.size and (w.size[1] == 'tight' or w.size[2] == 'tight')
+	if tight then
+		local f = assert(love.graphics.getFont())
+		if w.size[1] == 'tight' then
+			w.size[1] = f:getWidth(w.text)
+		end
+		if w.size[2] == 'tight' then
+			w.size[2] = f:getHeight(w.text)
+		end
+	end
 
-return function(text, x,y,w,h,align, draw)
 	local id = core.generateID()
-	w, h, align = w or 0, h or 0, align or 'left'
-	core.registerDraw(id, draw or core.style.Label,  text,x,y,w,h,align)
-	return false
+	local pos, size = group.getRect(w.pos, w.size)
+
+	if keyboard.hasFocus(id) then
+		keyboard.clearFocus()
+	end
+
+	core.registerDraw(id, draw or core.style.Label,
+		w.text, w.align, pos[1],pos[2], size[1],size[2])
+
+	return mouse.releasedOn(id)
 end
 
diff --git a/mouse.lua b/mouse.lua
new file mode 100644
index 0000000..eac46f5
--- /dev/null
+++ b/mouse.lua
@@ -0,0 +1,86 @@
+--[[
+Copyright (c) 2012 Matthias Richter
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+Except as contained in this notice, the name(s) of the above copyright holders
+shall not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+]]--
+
+local _M -- holds the module. needed to make widgetHit overridable
+
+local x,y = 0,0
+local down = false
+local hot, active = nil, nil
+
+local function widgetHit(mouse, pos, size)
+	return mouse[1] >= pos[1] and mouse[1] <= pos[1] + size[1] and
+	       mouse[2] >= pos[2] and mouse[2] <= pos[2] + size[2]
+end
+
+local function setHot(id)    hot = id end
+local function setActive(id) active = id end
+local function isHot(id)     return id == hot end
+local function isActive(id)  return id == active end
+
+local function updateWidget(id, pos, size, hit)
+	hit = hit or _M.widgetHit
+
+	if hit({x,y}, pos, size) then
+		setHot(id)
+		if not active and down then
+			setActive(id)
+		end
+	end
+end
+
+local function releasedOn(id)
+	return not down and isHot(id) and isActive(id)
+end
+
+local function beginFrame()
+	hot = nil
+	x,y = love.mouse.getPosition()
+	down = love.mouse.isDown('l')
+end
+
+local function endFrame()
+	if not down then -- released
+		setActive(nil)
+	elseif not active then -- clicked outside
+		setActive(NO_WIDGET)
+	end
+end
+
+_M = {
+	widgetHit    = widgetHit,
+	setHot       = setHot,
+	setActive    = setActive,
+	isHot        = isHot,
+	isActive     = isActive,
+	updateWidget = updateWidget,
+	releasedOn   = releasedOn,
+
+	beginFrame   = beginFrame,
+	endFrame     = endFrame,
+}
+
+-- metatable provides getters to x, y and down
+return setmetatable(_M, {__index = function(_,k) return ({x = x, y = y, down = down})[k] end})
diff --git a/slider.lua b/slider.lua
index 4a88515..4561d4a 100644
--- a/slider.lua
+++ b/slider.lua
@@ -24,47 +24,56 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ]]--
 
-local core = require((...):match("(.-)[^%.]+$") .. 'core')
+local BASE = (...):match("(.-)[^%.]+$")
+local core     = require(BASE .. 'core')
+local group    = require(BASE .. 'group')
+local mouse    = require(BASE .. 'mouse')
+local keyboard = require(BASE .. 'keyboard')
 
-return function(info, x,y,w,h, widgetHit, draw)
-	assert(type(info) == 'table' and info.value, "Incomplete slider value info")
-	info.min = info.min or 0
-	info.max = info.max or math.max(info.value, 1)
-	info.step = info.step or (info.max - info.min) / 50
-	local fraction = (info.value - info.min) / (info.max - info.min)
+-- {info = {value = v, min = 0, max = 1, step = (max-min)/20}, vertical = boolean, pos = {x, y}, size={w, h}, widgetHit=widgetHit, draw=draw}
+return function(w)
+	assert(type(w) == 'table' and type(w.info) == "table" and w.info.value, "Invalid argument.")
+	w.info.min = w.info.min or 0
+	w.info.max = w.info.max or math.max(w.info.value, 1)
+	w.info.step = w.info.step or (w.info.max - w.info.min) / 20
+	local fraction = (w.info.value - w.info.min) / (w.info.max - w.info.min)
 
 	local id = core.generateID()
-	core.mouse.updateState(id, widgetHit or core.style.widgetHit, x,y,w,h)
-	core.makeCyclable(id)
-	core.registerDraw(id,draw or core.style.Slider, fraction, x,y,w,h, info.vertical)
+	local pos, size = group.getRect(w.pos, w.info.size)
+
+	mouse.updateWidget(id, pos, size, w.widgetHit)
+	keyboard.makeCyclable(id)
 
 	-- mouse update
-	if core.isActive(id) then
-		core.setKeyFocus(id)
-		if info.vertical then
-			fraction = math.min(1, math.max(0, (y - core.mouse.y + h) / h))
+	local changed = false
+	if mouse.isActive(id) then
+		keyboard.setFocus(id)
+		if w.vertical then
+			fraction = math.min(1, math.max(0, (pos[2] - mouse.y + size[2]) / size[2]))
 		else
-			fraction = math.min(1, math.max(0, (core.mouse.x - x) / w))
+			fraction = math.min(1, math.max(0, (mouse.x - pos[1]) / size[1]))
 		end
-		local v = fraction * (info.max - info.min) + info.min
-		if v ~= info.value then
-			info.value = v
-			return true
+		local v = fraction * (w.info.max - w.info.min) + w.info.min
+		if v ~= w.info.value then
+			w.info.value = v
+			changed = true
 		end
 	end
 
 	-- keyboard update
-	local changed = false
-	if core.hasKeyFocus(id) then
-		local keys = info.vertical and {'up', 'down'} or {'right', 'left'}
-		if core.keyboard.key == keys[1] then
-			info.value = math.min(info.max, info.value + info.step)
+	if keyboard.hasFocus(id) then
+		local keys = w.vertical and {'up', 'down'} or {'right', 'left'}
+		if keyboard.key == keys[1] then
+			w.info.value = math.min(w.info.max, w.info.value + w.info.step)
 			changed = true
-		elseif core.keyboard.key == keys[2] then
-			info.value = math.max(info.min, info.value - info.step)
+		elseif keyboard.key == keys[2] then
+			w.info.value = math.max(w.info.min, w.info.value - w.info.step)
 			changed = true
 		end
 	end
 
+	core.registerDraw(id, w.draw or core.style.Slider,
+		fraction, w.vertical, pos[1],pos[2], size[1],size[2])
+
 	return changed
 end
diff --git a/slider2d.lua b/slider2d.lua
index 20f063c..19abaf1 100644
--- a/slider2d.lua
+++ b/slider2d.lua
@@ -24,58 +24,76 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ]]--
 
-local core = require((...):match("(.-)[^%.]+$") .. 'core')
+local BASE = (...):match("(.-)[^%.]+$")
+local core     = require(BASE .. 'core')
+local group    = require(BASE .. 'group')
+local mouse    = require(BASE .. 'mouse')
+local keyboard = require(BASE .. 'keyboard')
+
+-- {info = {value = {x,y}, min = {0,0}, max = {1,1}, step = (max-min)/20}, pos = {x, y}, size={w, h}, widgetHit=widgetHit, draw=draw}
+return function(w)
+	assert(type(w) == 'table' and type(w.info) == "table" and w.info.value, "Invalid argument.")
+	w.info.min = {
+		w.info.min and w.info.min[1] or 0,
+		w.info.min and w.info.min[2] or 0,
+	}
+	w.info.max = {
+		w.info.max and w.info.max[1] or math.max(1, w.info.value[1]),
+		w.info.max and w.info.max[2] or math.max(1, w.info.value[2]),
+	}
+	w.info.step = {
+		w.info.step and w.info.step[1] or (w.info.max[1] - w.info.min[1]) / 20,
+		w.info.step and w.info.step[2] or (w.info.max[2] - w.info.min[2]) / 20,
+	}
 
-return function(info, x,y,w,h, widgetHit, draw)
-	assert(type(info) == 'table' and type(info.value) == "table", "Incomplete slider value info")
-	info.min = info.min or {x = 0, y = 0}
-	info.max = info.max or {x = math.max(info.value.x or 0, 1), y = math.max(info.value.y or 0, 1)}
-	info.step = info.step or {x = (info.max.x - info.min.x)/50, y = (info.max.y - info.min.y)/50}
 	local fraction = {
-		x = (info.value.x - info.min.x) / (info.max.x - info.min.x),
-		y = (info.value.y - info.min.y) / (info.max.y - info.min.y),
+		(w.info.value[1] - w.info.min[1]) / (w.info.max[1] - w.info.min[1]),
+		(w.info.value[2] - w.info.min[2]) / (w.info.max[2] - w.info.min[2]),
 	}
 
 	local id = core.generateID()
-	core.mouse.updateState(id, widgetHit or core.style.widgetHit, x,y,w,h)
-	core.makeCyclable(id)
-	core.registerDraw(id,draw or core.style.Slider2D, fraction, x,y,w,h)
+	local pos, size = group.getRect(w.pos, w.size)
+
+	mouse.updateWidget(id, pos, size, w.widgetHit)
+	keyboard.makeCyclable(id)
 
 	-- update value
-	if core.isActive(id) then
-		core.setKeyFocus(id)
+	local changed = false
+	if mouse.isActive(id) then
+		keyboard.setFocus(id)
 		fraction = {
-			x = (core.mouse.x - x) / w,
-			y = (core.mouse.y - y) / h,
+			math.min(1, math.max(0, (mouse.x - pos[1]) / size[1])),
+			math.min(1, math.max(0, (mouse.y - pos[2]) / size[2])),
 		}
-		fraction.x = math.min(1, math.max(0, fraction.x))
-		fraction.y = math.min(1, math.max(0, fraction.y))
 		local v = {
-			x = fraction.x * (info.max.x - info.min.x) + info.min.x,
-			y = fraction.y * (info.max.y - info.min.y) + info.min.y,
+			fraction[1] * (w.info.max[1] - w.info.min[1]) + w.info.min[1],
+			fraction[2] * (w.info.max[2] - w.info.min[2]) + w.info.min[2],
 		}
-		if v.x ~= info.value.x or v.y ~= info.value.y then
-			info.value = v
-			return true
+		if v[1] ~= w.info.value[1] or v[2] ~= w.info.value[2] then
+			w.info.value = v
+			changed = true
 		end
 	end
 
-	local changed = false
-	if core.hasKeyFocus(id) then
-		if core.keyboard.key == 'down' then
-			info.value.y = math.min(info.max.y, info.value.y + info.step.y)
+	if keyboard.hasFocus(id) then
+		if keyboard.key == 'down' then
+			w.info.value[2] = math.min(w.info.max[2], w.info.value[2] + w.info.step.y)
 			changed = true
-		elseif core.keyboard.key == 'up' then
-			info.value.y = math.max(info.min.y, info.value.y - info.step.y)
+		elseif keyboard.key == 'up' then
+			w.info.value[2] = math.max(w.info.min[2], w.info.value[2] - w.info.step.y)
 			changed = true
 		end
-		if core.keyboard.key == 'right' then
-			info.value.x = math.min(info.max.x, info.value.x + info.step.x)
+		if keyboard.key == 'right' then
+			w.info.value[1] = math.min(w.info.max[1], w.info.value[1] + w.info.step.x)
 			changed = true
-		elseif core.keyboard.key == 'left' then
-			info.value.x = math.max(info.min.x, info.value.x - info.step.x)
+		elseif keyboard.key == 'left' then
+			w.info.value[1] = math.max(w.info.min[1], w.info.value[1] - w.info.step.x)
 			changed = true
 		end
 	end
+
+	core.registerDraw(id, w.draw or core.style.Slider2D,
+		fraction, pos[1],pos[2], size[1],size[2])
+
 	return changed
 end