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(function(){
var canvases = document.getElementsByTagName("canvas")
if (canvases.length == 0) { alert("no canvas found"); return; }
var source = canvases[0]
var encoder = new GifEncoder()
encoder.on("encoded-frame", encoded_frame)
encoder.on("rendered", rendered_bytes)
encoder.on("rendered-url", rendered_url)
var w, h, x, y;
var last_t, frame_t, count, delay, done;
var frames = []
var curtain, outline
var dragging = false
var lastGif
init()
function init(){
document.body.style.width = "100%"
document.body.style.height = "100%"
document.body.parentNode.style.width = "100%"
document.body.parentNode.style.height = "100%"
var template = document.getElementById("template").innerHTML
var el = document.createElement("div")
el.innerHTML = template
document.body.appendChild(el)
bind()
}
function bind(){
curtain = document.getElementById("curtain")
outline = document.getElementById("outline")
controls = document.getElementById("outline")
document.getElementById("record").addEventListener("click", record, false)
document.getElementById("save").addEventListener("click", save, false)
curtain.addEventListener("mousedown", box_start, false)
curtain.addEventListener("mousemove", box_size, false)
curtain.addEventListener("mouseup", box_end, false)
outline.style.display = "none"
controls.style.display = "none"
}
function box_start(e){
x = e.pageX
y = e.pageY
w = 1
h = 1
dragging = true
outline.style.left = px(x-1)
outline.style.top = px(y-1)
outline.style.width = px(w)
outline.style.height = px(h)
outline.style.display = "block"
}
function box_size(e){
if (! dragging) return
w = e.pageX - x
h = e.pageY - y
outline.style.width = px(w)
outline.style.height = px(h)
}
function box_end(e){
dragging = false
controls.style.display = "block"
enable("record")
document.getElementById("record").focus()
}
function enable(id){ document.getElementById(id).removeAttribute("disabled") }
function disable(id){ document.getElementById(id).setAttribute("disabled","disabled") }
function px(n){ return n + "px" }
function record(){
count = parseInt(document.getElementById("framecount").value)
delay = parseFloat(document.getElementById("framedelay").value) * 1000
done = 0
frame_t = 0
build()
capture()
last_t = +new Date()
requestAnimationFrame(recordloop)
status("recording")
disable("record")
}
function recordloop(){
var canvas = document.createElement("canvas")
var t = +new Date()
frame_t += t - last_t
last_t = t
if (frame_t > delay) {
frame_t -= delay
capture()
}
if (done == count) {
render()
}
else {
requestAnimationFrame(recordloop)
}
}
function build(){
frames = new Array(count)
for (var i = 0; i < count; i++){
frames[i] = document.createElement("canvas")
frames[i].height = h
frames[i].width = w
}
}
function capture(){
var frame = frames[done++]
var ctx = frame.getContext('2d')
ctx.fillStyle = document.body.backgroundColor
ctx.fillRect(0,0,w,h)
ctx.drawImage(source, x, y, w, h, 0, 0, w, h)
}
function render(){
encoder.reset()
encoder.addFrames(frames, delay)
status("encoding")
try {
encoder.encode()
}
catch (e) {
rendering = false
status(e)
throw e
}
}
function status(s){
document.getElementById("status").innerHTML = s
}
function encoded_frame(done,count){
status("encoded " + done + " / " + count)
}
function rendered_bytes(bytes){
status(filesize(bytes.length))
}
function rendered_url(url){
var image = new Image ()
lastGif = image.src = url
document.getElementById("preview").innerHTML = ""
document.getElementById("preview").appendChild(image)
rendering = false
enable("record")
enable("save")
}
function save (){
if (! lastGif) return;
var filename = (window.location.host + window.location.pathname).replace(/[^a-zA-Z0-9]/g,"-").replace(/-+/,"-")
var blob = dataUriToBlob(lastGif)
saveAs(blob, filename + "-" + (+new Date()) + ".gif");
}
function filesize(n) {
if (n < 1e3) return n + " bytes"
if (n < 1e6) return decimalString(n/1e3) + " kb"
if (n < 1e9) return decimalString(n/1e6) + " mb"
return "WAY TOO BIG DUDE"
}
function decimalString(n){
var m = Math.floor(n);
return m + "." + Math.round((n-m)*10)
}
})()
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