Display library, adding to and modifying the existing Corona display library.

displaylib.lua

-- display lib

local newShapeList = {
	"newCircle",
	"newContainer",
	"newEmbossedText",
	"newEmitter",
	"newGroup",
	"newImage",
	"newImageRect",
	"newLine",
	"newMesh",
	"newPolygon",
	"newRect",
	"newRoundedRect",
	"newSnapshot",
	"newSprite",
	"newText",
}

--[[
	Adds a property called 'type' to the returned display object created by
	every display.* library function which creates a display object.
	
	Example:
		local circle = display.newCircle( 10, 10, 100 )
		print( circle.type )
		-- This will print "newCircle" to the console.
]]--
local function addDisplayShapeNamings()
	for name,v in pairs(display) do
		if (string.starts( name, "new" ) and type(v) == "function" and name ~= "newGroups") then
			local oldFunc = display[ name ]
			display[ name ] = function( ... )
				local displayObj = oldFunc( unpack( arg ) )
				displayObj.type = name
				return displayObj
			end
		end
	end
end
addDisplayShapeNamings()

local function testAddDisplayShapeNamings()
	local group = display.newGroup()
	local circle = display.newCircle( 0, 0, 100 )
	local rect = display.newRect( 0, 0, 200, 100 )
	local roundedrect = display.newRoundedRect( 0, 0, 200, 100, 50 )
	
	print( group.type )
	print( circle.type )
	print( rect.type )
	print( roundedrect.type )
	
	group:removeSelf()
	circle:removeSelf()
	rect:removeSelf()
	roundedrect:removeSelf()
end
-- testAddDisplayShapeNamings()

local function addLocalToContentOverride( displayObj )
	local oldFunc = displayObj.contentToLocal
	
	displayObj.contentToLocal = function( x, y, rotation )
		local _x, _y = oldFunc( displayObj, x, y )
		-- perform rotation to local here
		return _x, _y
	end
end

local function addShapeOverrides()
	for i=1, #newShapeList do
		local funcName = newShapeList[i]
		local funcOld = display[ funcName ]
		
		local function funcNew( ... )
			local displayObj = oldFunc( unpack( arg ) )
			
			addLocalToContentOverride( displayObj )
			
			return object
		end
		
		display[ funcName ] = funcNew
	end
end
--addShapeOverrides()

function display.newRadialFillCircle( parent, x, y, r, c )
	local group = display.newGroup()
	group.x, group.y = x, y
	parent = parent or display.currentStage
	parent:insert( group )
	
	local ringinc = 100/(r/4)
	local a = 0
	for i=r, 2, -4 do
		local circle = display.newCircle( group, 0, 0, i-2 )
		circle.fill = {0,0,0,0}
		circle.strokeWidth = 4
		a = a + ringinc
		c[4] = a/100
		circle.stroke = c
	end
	
	return group
end

function display.newDonut( ... )
	local parent, x, y, width
	
	if (#arg == 3) then
		x, y, width = unpack( arg )
	elseif (#arg == 4) then
		parent, x, y, width = unpack( arg )
	end
	
	local g = display.newGroup()
	g.x, g.y = x, y
	
	if (parent) then
		parent:insert( g )
	end
	
	local b = display.newCircle( g, 0, 0, width/6+1 )
	b.fill = {1,1,1,0}
	b.stroke = {0,0,0,0}
	b.strokeWidth = 0
	
	local a = display.newCircle( g, 0, 0, math.floor(width/3) )
	a.fill = {0,0,0,0}
	a.stroke = {1,1,1}
	a.strokeWidth = (width/3)
	
	function g:setFill( r, g, _b, a )
		b.fill = { r, g, _b, a }
	end
	
	function g:setStroke( r, g, b, _a )
		a.stroke = { r, g, b, _a }
	end
	
	g.width, g.height = width, width
	
	return g
end

function display.newDonutRect( ... )
	local parent, x, y, width, height
	
	if (#arg == 4) then
		x, y, width, height = unpack( arg )
	elseif (#arg == 5) then
		parent, x, y, width, height = unpack( arg )
	end
	
	if (height > width) then
		height = width
	end
	
	local stroke = height/3
	local w, h = width-math.floor(stroke), height-math.floor(stroke)
	local r = h/2
	
	local g = display.newGroup()
	g.x, g.y = x, y
	
	if (parent) then
		parent:insert( g )
	end
	
	local fill = display.newRoundedRect( g, 0, 0, math.ceil(w-stroke)+2, math.ceil(h-stroke)+2, r )
	fill.fill = {1,1,1,0}
	fill.stroke = {0,0,0,0}
	fill.strokeWidth = 0
	
	local rect = display.newRoundedRect( g, 0, 0, math.floor(w), math.floor(h), math.floor(r) )
	rect.fill = {0,0,0,0}
	rect.stroke = {1,1,1,1}
	rect.strokeWidth = math.floor(stroke)
	
	function g:setFill( r, g, _b, a )
		fill.fill = { r, g, _b, a }
	end
	
	function g:setStroke( r, g, b, _a )
		rect.stroke = { r, g, b, _a }
	end
	
	g.width, g.height = width, height
	
	return g
end

function display.newHoleBar( ... )
	local parent, x, y, width, count
	
	if (#arg == 4) then
		x, y, width, count = unpack( arg )
	elseif (#arg == 5) then
		parent, x, y, width, count = unpack( arg )
	end
	
	local g = display.newGroup()
	g.x, g.y = x, y
	
	if (parent) then
		parent:insert( g )
	end
	
	local s = display.newDonutRect( g, 0, 0, width+(count-1)*((width/3)*2), width )
	
	s:setFill( 0,0,0,0 )
	s:setStroke( 1,1,1 )
	
	local d = display.newDonut( g, 0, 0, width )
	d.x, d.y = s.x-s.width/2+d.width/2, s.y
	d:setStroke( 1,1,1 )
	
	local step = (d.width/3)*2
	
	for i=2, count do
		local e = display.newDonut( g, 0, 0, width )
		e.x = g[i].x + step
		e:setStroke( 1,1,1 )
	end
	
	function g:setFill( r, _g, b, a )
		for i=1, g.numChildren do
			g[i]:setFill(r,_g,b,a)
		end
	end
	
	function g:setStroke( r, _g, b, a )
		for i=1, g.numChildren do
			g[i]:setStroke(r,_g,b,a)
		end
	end
	
	return g
end