Created
December 18, 2014 17:24
GlitchText
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var randomChars = "jldfsifnJSODNBD~±§1234567890!@£$%^&*()-=_+,./<>?"; | |
function easeOut (t,d,p) { | |
return 1-Math.pow(1-(t/d),p); | |
} | |
function randomInt (min,max) { | |
return Math.floor(Math.random()*(max-min+1))+min; | |
} | |
function limit (value,min,max) { | |
return Math.min(max,Math.max(min,value)); | |
} | |
function GlitchText (text,el,charDuration,numCharSteps,onComplete) { | |
this.el = el; | |
this.origText = text; | |
this.duration = text.length * 80; | |
this.charDuration = charDuration; | |
this.numCharSteps = numCharSteps; | |
this.textLength = this.origText.length; | |
this.onComplete = onComplete; | |
this.el.innerHTML = ""; | |
this.running = true; | |
}; | |
GlitchText.prototype.start = function () { | |
this.lettersArray = []; | |
for ( var i=0; i<this.textLength; i++ ) { | |
var letter = new GlitchTextLetter(randomChars,this.charDuration,this.numCharSteps,this.origText.charAt(i)); | |
this.lettersArray.push(letter); | |
} | |
this.startTime = Date.now(); | |
requestAnimationFrame(this.step.bind(this)); | |
}; | |
GlitchText.prototype.stop = function () { | |
this.running = false; | |
}; | |
GlitchText.prototype.step = function (time) { | |
var pos = easeOut(Date.now()-this.startTime,this.duration,3); | |
var completeCount = 0; | |
var index = Math.round(this.lettersArray.length*pos); | |
var currString = ""; | |
for ( var i=0; i<this.textLength; i++ ) { | |
if ( i < index ) { | |
this.lettersArray[i].start(); | |
} | |
currString += this.lettersArray[i].getCurrChar(); | |
if ( this.lettersArray[i].isComplete() ) { | |
completeCount++; | |
} | |
} | |
this.el.innerHTML = currString; | |
if ( completeCount < this.textLength && this.running ) { | |
requestAnimationFrame(this.step.bind(this)); | |
} else { | |
if ( this.onComplete ) this.onComplete(); | |
} | |
}; | |
function GlitchTextLetter (randomChars,duration,numSteps,finalChar) { | |
this.value = ""; | |
this.started = false; | |
this.complete = false; | |
this.randomChars = randomChars; | |
this.duration = duration; | |
this.numSteps = numSteps; | |
this.finalChar = finalChar; | |
this.charArray = []; | |
for ( var i=0; i<this.numSteps; i++ ) { | |
this.charArray[i] = i === this.numSteps-1 ? this.finalChar : this.finalChar === " " ? " " : this.randomChars.charAt(randomInt(0,this.randomChars.length)); | |
} | |
}; | |
GlitchTextLetter.prototype.start = function () { | |
if ( this.started ) return; | |
this.started = true; | |
this.startTime = Date.now(); | |
requestAnimationFrame(this.step.bind(this)); | |
}; | |
GlitchTextLetter.prototype.step = function (time) { | |
var progress = Date.now()-this.startTime; | |
var pos = limit(easeOut(progress,this.duration,3),0,1); | |
var index = Math.round((this.charArray.length-1)*pos); | |
this.value = this.charArray[index]; | |
if ( progress < this.duration ) { | |
requestAnimationFrame(this.step.bind(this)); | |
} else { | |
this.complete = true; | |
this.value = this.finalChar; | |
} | |
}; | |
GlitchTextLetter.prototype.getCurrChar = function () { | |
return this.value; | |
}; | |
GlitchTextLetter.prototype.isComplete = function () { | |
return this.complete; | |
}; |
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