Abused id parameter to not break compatibility

button.lua

@@ -69,7 +69,7 @@ return function(w)
 
 	-- core.registerDraw(id, drawfunction, drawfunction-arguments...)
 	-- shows widget when core.draw() is called.
-	core.registerDraw(id, w.draw or core.style.Button, false,
+	core.registerDraw(id, w.draw or core.style.Button,
 		w.text, pos[1],pos[2], size[1],size[2])
 
 	return mouse.releasedOn(id) or keyboard.pressedOn(id, 'return')

checkbox.lua

@@ -60,7 +60,7 @@ return function(w)
 		w.checked = not w.checked
 	end
 
-	core.registerDraw(id, w.draw or core.style.Checkbox, false,
+	core.registerDraw(id, w.draw or core.style.Checkbox,
 		w.checked, w.text, w.align or 'left', pos[1], pos[2], size[1], size[2])
 
 	return w.checked ~= checked

core.lua

@@ -66,7 +66,7 @@ end
 -- Drawing / Frame update
 --
 local draw_items = {n = 0}
-local function registerDraw(id, f, isGroup, ...)
+local function registerDraw(id, f, ...)
 	assert(type(f) == 'function' or (getmetatable(f) or {}).__call,
 	       'Drawing function is not a callable type!')
 
@@ -80,7 +80,7 @@ local function registerDraw(id, f, isGroup, ...)
 	draw_items.n = draw_items.n + 1
     
     local targetindex = draw_items.n
-    if isGroup then targetindex = 1 end
+    if id == "group_draw" then targetindex = 1 end
     
 	table.insert(draw_items, targetindex, function()
 		if font then love.graphics.setFont(font) end

group.lua

@@ -80,9 +80,6 @@ local function push(info)
 	assert(pos, "Position neither specified nor derivable from parent group.")
 	grow = assert(Grow[grow], "Invalid grow: " .. tostring(grow))
 	
-	local id = info.id
-	if not id then id = core.generateID() end
-    
 	current = {
 		pos         = pos,
 		grow        = grow,
@@ -92,7 +89,6 @@ local function push(info)
 		border      = info.border,
 		bkg         = info.bkg,
 		draw        = info.draw,
-        id          = id,
 		upper_left  = { math.huge,  math.huge},
 		lower_right = {-math.huge, -math.huge},
 	}
@@ -154,8 +150,9 @@ local function pop()
 	}
 	advance(current.pos, size)
     
+	-- skip the draw call if we don't need it
 	if child.bkg or child.border then
-		core.registerDraw(child.id, child.draw or core.style.Group, true,
+		core.registerDraw("group_draw", child.draw or core.style.Group,
 		child.bkg, child.border, child.upper_left[1], child.upper_left[2], child.lower_right[1] - child.upper_left[1], child.lower_right[2] - child.upper_left[2])
 	end
 end

input.lua

@@ -73,7 +73,7 @@ return function(w)
 		w.info.cursor = w.info.cursor + 1
 	end
 
-	core.registerDraw(id, w.draw or core.style.Input, false,
+	core.registerDraw(id, w.draw or core.style.Input,
 		w.info.text, w.info.cursor, pos[1],pos[2], size[1],size[2])
 
 	return mouse.releasedOn(id) or keyboard.pressedOn(id, 'return')

label.lua

@@ -53,7 +53,7 @@ return function(w)
 		keyboard.clearFocus()
 	end
 
-	core.registerDraw(id, w.draw or core.style.Label, false,
+	core.registerDraw(id, w.draw or core.style.Label,
 		w.text, w.align, pos[1],pos[2], size[1],size[2])
 
 	return mouse.releasedOn(id)

slider.lua

@@ -72,7 +72,7 @@ return function(w)
 		end
 	end
 
-	core.registerDraw(id, w.draw or core.style.Slider, false,
+	core.registerDraw(id, w.draw or core.style.Slider,
 		fraction, w.vertical, pos[1],pos[2], size[1],size[2])
 
 	return changed

slider2d.lua

@@ -92,7 +92,7 @@ return function(w)
 		end
 	end
 
-	core.registerDraw(id, w.draw or core.style.Slider2D, false,
+	core.registerDraw(id, w.draw or core.style.Slider2D,
 		fraction, pos[1],pos[2], size[1],size[2])
 
 	return changed