gtween for Corona

The GTween library, originally created by Grant Skinner, ported from ActionScript to Lua for Ansca's Corona SDK by Josh Tynjala.

Usage

For those familiar with Corona, usage is very similar to transition.to(), but gtween offers a variety of useful features that go beyond Corona's built-in transitions. If you've used GTween in ActionScript, then gtween.lua should look very familiar.

local gtween = require("gtween")

local redSquare = display.newRect( 0, 0, 100, 100 )
redSquare:setFillColor( 255, 0, 0 )
redSquare.x = 60
redSquare.y = 60

local blueSquare = display.newRect( 0, 0, 100, 100 )
blueSquare:setFillColor( 0, 0, 255 )
blueSquare.x = 170
blueSquare.y = 60
blueSquare.alpha = 0

local function redSquareMove_onChange( tween )
	blueSquare.x = redSquare.x + 150
	blueSquare.y = redSquare.y
	blueSquare.alpha = 1 - redSquare.alpha
end

--[[
	gtween.new
	Parameters:
	1. target
	2. duration in seconds
	3. table of end values
	4. table of gtween properties (separate from tweened values to avoid collisions)
]]--	
gtween.new(redSquare, 1.5,
{
	x = 260,
	y = 260,
	alpha = 0
},
{
	transitionEase = easing.outQuad,        -- transition-style easing function
	--ease = gtween.easing.outQuadratic,    -- gtween-style easing function
	repeatCount = math.huge,                -- repeat forever!
	reflect = true,                         -- yoyo
	onChange = redSquareMove_onChange       -- called after every update
})

Easing

Corona uses a different signature for its built-in easing functions than the ones that come with gtween, but gtween can use them with the @transitionEase@ property (see the example above) to tell gtween.lua to use one of the easing functions designed for use with Corona's transitions. Use @ease@ (same as ActionScript) to use one of gtween's easing functions.

The following easing functions are included in gtween.lua, and should be used with the @ease@ property. Some overlap Corona's easing functions, while others are new.

• @gtween.easing.inBack@
• @gtween.easing.outBack@
• @gtween.easing.inOutBack@
• @gtween.easing.inBounce@
• @gtween.easing.outBounce@
• @gtween.easing.inOutBounce@
• @gtween.easing.inCircular@
• @gtween.easing.outCircular@
• @gtween.easing.inOutCircular@
• @gtween.easing.inCubic@
• @gtween.easing.outCubic@
• @gtween.easing.inOutCubic@
• @gtween.easing.inElastic@
• @gtween.easing.outElastic@
• @gtween.easing.inOutElastic@
• @gtween.easing.inExponential@
• @gtween.easing.outExponential@
• @gtween.easing.inOutExponential@
• @gtween.easing.noneLinear@
• @gtween.easing.inQuadratic@
• @gtween.easing.outQuadratic@
• @gtween.easing.inOutQuadratic@
• @gtween.easing.inQuartic@
• @gtween.easing.outQuartic@
• @gtween.easing.inOutQuartic@
• @gtween.easing.inQuintic@
• @gtween.easing.outQuintic@
• @gtween.easing.inOutQuintic@
• @gtween.easing.inSine@
• @gtween.easing.outSine@
• @gtween.easing.inOutSine@

Unsupported features

The following features from the original ActionScript GTween are not included in this port. They may or may not be added in the future.

• GTweenTimeline
• Plugins