/
create.js
144 lines (109 loc) · 3.35 KB
/
create.js
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var Canvas = require('canvas')
, Image = Canvas.Image
, fs = require('fs')
, counter = 0
, startingscr = process.argv[2]
, name = __dirname + '/' + startingscr.split('.')[0];
function downscale(filenamein, filenameout, resdrop, cb){
var img = new Image;
img.onerror = function(err){throw err;};
img.onload = function(){
var w = img.width / resdrop
, h = img.height / resdrop
, canvas = new Canvas(w, h)
, ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0, w, h);
var out = fs.createWriteStream(filenameout);
var stream = canvas.createJPEGStream({
bufsize : 2048,
quality : 80
});
out.on('close', function(){
if(cb) cb();
});
stream.pipe(out);
};
img.src = filenamein;
}
function createDiffImg(imgsrc1, imgsrc2, outsrc, cb){
/*
Create a differece jpeg, where imgscr1 should be the higher resolution image
*/
var img1 = new Image
, img2 = new Image;
img1.onerror = function(err){throw err;};
img2.onerror = function(err){throw err;};
img1.onload = function(){
var w = img1.width
, h = img1.height
, canvas = new Canvas(w,h)
, ctx = canvas.getContext('2d');
ctx.drawImage(img1, 0, 0, w, h);
var data1 = ctx.getImageData(0,0,w,h);
img2.onload = function(){
ctx.drawImage(img2,0,0,w,h);
var data2 = ctx.getImageData(0,0,w,h);
// make the diff, leveled at 127 and mod 256 (ignoring alpha channel)
for(var i=0;i<img1.width*img1.height;i++){
for(var j=0;j<3;j++){
data1.data[4*i+j] = Math.min(255,Math.max(0,(data1.data[4*i+j]-data2.data[4*i+j])+127));
}
}
ctx.putImageData(data1,0,0);
var out = fs.createWriteStream(outsrc);
var stream = canvas.createJPEGStream({
bufsize : 2048,
quality : 80
});
out.on('close', function(){
if(cb) cb();
});
stream.pipe(out);
}
img2.src = imgsrc2;
}
img1.src = imgsrc1;
}
function testDecode(imgsrc1, imgsrc2, cb){
var img1 = new Image()
, img2 = new Image();
img1.onload = function(){
img2.onload = function(){
var w = img2.width
, h = img2.height
, canvas = new Canvas(w,h)
, ctx = canvas.getContext('2d');
ctx.drawImage(img1,0,0,w,h);
data1 = ctx.getImageData(0,0,w,h);
ctx.drawImage(img2,0,0,w,h);
data2 = ctx.getImageData(0,0,w,h);
// Use the diff
for(var i=0;i<img2.width*img2.height;i++){
for(var j=0;j<3;j++){
data1.data[4*i+j] = Math.min(255,Math.max(0,(data1.data[4*i+j]+((data2.data[4*i+j]-127) || 0))));
}
}
ctx.putImageData(data1,0,0);
if(cb) {
cb(ctx.canvas.toDataURL());
}
};
img2.src = imgsrc2;
};
img1.src = imgsrc1;
}
counter = 0;
function phaseTwo(){
counter++;
if(counter==2) {
// images made - make the diffs
createDiffImg(name+'_med.jpg',name+'_low.jpg',name+'_low_to_med_diff.jpg', function(){
testDecode(name+'_low.jpg',name+'_low_to_med_diff.jpg',function(medsrc){
createDiffImg(__dirname + '/' + startingscr,medsrc,name+'_med_to_full_diff.jpg');
});
});
}
}
// make the images
downscale(__dirname + '/' + startingscr, name+'_low.jpg', 4, phaseTwo);
downscale(__dirname + '/' + startingscr, name+'_med.jpg', 2, phaseTwo);