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August 11, 2016 03:46
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| // Written by Chris Johnson | |
| // 2013-07-21 | |
| // Assumes jQuery is available as `$` | |
| /* | |
| * USAGE | |
| * spritify($(element), { //should already have spritesheet set as background | |
| * spriteSheetWidth: 300, //width of spritesheet | |
| * spriteSheetHeight: 150, //height of spritesheet | |
| * offsetX: 0, //offset applied to each frame | |
| * offsetY: 50, //offset applied to each frame | |
| * numFrames: 6, | |
| * frameRate: 40, | |
| * mouseTarget: $(hoverTarget) //advances animation while hovering / reverses while unhovered | |
| * }); | |
| */ | |
| var spritify = function(el, options) { | |
| if ( typeof el === 'undefined' || | |
| typeof options === 'undefined' || | |
| typeof options.spriteSheetWidth === 'undefined' || isNaN(options.spriteSheetWidth) || | |
| typeof options.spriteSheetHeight === 'undefined' || isNaN(options.spriteSheetHeight) | |
| ) { | |
| return false; | |
| } | |
| if (typeof options === 'undefined') { | |
| options = {}; | |
| } | |
| //set defaults | |
| if (typeof options.offsetX === 'undefined' || isNaN(options.offsetX)) { | |
| options.offsetX = 0; | |
| } | |
| if (typeof options.offsetY === 'undefined' || isNaN(options.offsetY)) { | |
| options.offsetY = 0; | |
| } | |
| if (typeof options.frameWidth === 'undefined' || isNaN(options.frameWidth)) { | |
| options.frameWidth = $(el).outerWidth(); | |
| } | |
| if (typeof options.frameHeight === 'undefined' || isNaN(options.frameHeight)) { | |
| options.frameHeight = $(el).outerHeight(); | |
| } | |
| if (typeof options.numFrames === 'undefined' || isNaN(options.numFrames)) { | |
| options.numFrames = Math.floor((options.spriteSheetWidth - options.offsetX) / options.frameWidth) * Math.floor((options.spriteSheetHeight - options.offsetY) / options.frameHeight); | |
| } | |
| if (typeof options.frameRate === 'undefined' || isNaN(options.frameRate)) { | |
| options.frameRate = 30; | |
| } | |
| if (typeof options.mouseTarget === 'undefined') { | |
| options.mouseTarget = $(el); | |
| } | |
| //init sprite | |
| if (typeof options.spriteSheetPath !== 'undefined') { | |
| $(el).css('background-image', "url("+options.spriteSheetPath+")"); | |
| } | |
| var currentFrame = 1; | |
| var numCols = (options.spriteSheetWidth - options.offsetX) / options.frameWidth; | |
| var numRows = (options.spriteSheetHeight - options.offsetY) / options.frameHeight; | |
| var interval = null; | |
| update(); | |
| //utility functions | |
| function update() { | |
| var x = (options.frameWidth * ((currentFrame - 1) % numCols)) + options.offsetX; | |
| var y = (options.frameHeight * Math.floor((currentFrame -1 ) / numCols)) + options.offsetY; | |
| $(el).css('background-position', ("" + (-x) + "px " + (-y) + "px") ); | |
| } | |
| function unsetActiveInterval() { | |
| if (interval) { | |
| interval = clearInterval(interval); | |
| } | |
| } | |
| var hoverMethod = function() { | |
| unsetActiveInterval(); | |
| interval = setInterval(function() { | |
| if (currentFrame < options.numFrames) { | |
| currentFrame += 1; | |
| update(); | |
| } else { | |
| unsetActiveInterval(); | |
| } | |
| }, 1000/options.frameRate); | |
| }; | |
| var unhoverMethod = function() { | |
| unsetActiveInterval(); | |
| interval = setInterval(function() { | |
| if (currentFrame > 1) { | |
| currentFrame -= 1; | |
| update(); | |
| } else { | |
| unsetActiveInterval(); | |
| } | |
| }, 1000/options.frameRate); | |
| }; | |
| $(options.mouseTarget).hover(hoverMethod, unhoverMethod); | |
| }; |
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