meshenger/web/photostuff.js

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JavaScript
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/*
* PHOTO STUFF
*/
var imgDim = 200;
var canvas1;
var context1;
var canvas2;
var context2;
var imgObj;
var fileReader;
var rotation = 0;
var sourceImage = document.getElementById('sourceImage'); // get reference to img
var fileInput = document.getElementById('fileInput'); // get reference to file select
var progressEl = document.getElementById('progress');
var totalEl = document.getElementById('total');
function initPhotoStuff(){
canvas1 = document.getElementById('canvas1');
context1 = canvas1.getContext('2d');
canvas2 = document.getElementById('canvas2');
context2 = canvas2.getContext('2d');
canvas3 = document.getElementById('canvas3');
context3 = canvas3.getContext('2d');
initCanvas(context1);
initCanvas(context2);
initCanvas(context3);
fileInput.onchange = onFileInputChange;
document.getElementById('rot-left').onclick = onRotateLeft;
document.getElementById('rot-right').onclick = onRotateRight;
document.getElementById('submit-photo').onclick = submitImage;
}
function submitImage(){
var image = new Image(); //create new image holder
var canvas = document.getElementById('canvas3'); // choose canvas element to convert
var dataURL = canvas.toDataURL(); // convert cabvas to data url we can handle
image.src = dataURL;
image.className = 'photo-message';
if ( !image.src || image.src === "data:image/png;base64,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" ) { /* prevent sending of empty messages (data url of blank, thus white, canvas)*/
return false;
}
var namm = document.getElementById('photo-name').value;
if( !namm || namm == "" ){
namm = "anonymous";
}
addOutboxItem( namm, image.outerHTML );
showOverview();
return false;
}
function initCanvas(context){
// Debug filling
context.fillStyle ="#dbbd7a";
context.fill();
context.beginPath();
context.rect(0,0, imgDim, imgDim);
context.fillStyle = 'white';
context.fill();
// context.lineWidth = 7;
// context.strokeStyle = 'black';
// context.stroke();
}
// create file reader
function onFileInputChange(){
var file = fileInput.files[0]; // get selected file (camera capture)
fileReader = new FileReader();
fileReader.onload = onFileReaderLoad; // add onload listener
fileReader.onprogress = onFileReaderProgress; // add progress listener
fileReader.readAsDataURL( file ); // get captured image as data URI
}
function onFileReaderProgress(e) {
if (e.lengthComputable) {
var progress = parseInt( ((e.loaded / e.total) * 100), 10 );
console.log(progress);
progressEl.innerHTML = e.loaded;
totalEl.innerHTML = e.total;
}
}
function onFileReaderLoad() {
imgObj = new Image();
imgObj.src = fileReader.result;
imgObj.onload = onImageLoad;
//for debugging: show image on screen, will be squashed
sourceImage.src = fileReader.result;
}
function onImageLoad() {
var w,h;
var xOffset = 0;
var yOffset = 0;
if ( imgObj.width > imgObj.height ) {
h = imgDim;
w = imgDim * imgObj.width / imgObj.height;
xOffset = (imgDim - w) / 2;
} else {
w = imgDim;
h = imgDim * imgObj.height / imgObj.width;
yOffset = (imgDim - h) / 2;
}
context1.drawImage(imgObj, xOffset, yOffset, w, h);
var imageData = context1.getImageData( 0, 0, canvas1.width, canvas1.height);
context2.putImageData( monochrome(imageData,128,"atkinson"), 0, 0);
drawRotated();
}
function onRotateRight(){
rotation += 90;
drawRotated();
}
function onRotateLeft(){
rotation -= 90;
drawRotated();
}
function drawRotated(){
context3.clearRect(0,0,canvas3.width,canvas3.height);
context3.save();
context3.translate(canvas3.width/2,canvas3.height/2);
context3.rotate(rotation * Math.PI / 180);
context3.translate(-canvas3.width/2,-canvas3.height/2);
context3.drawImage( canvas2, 0, 0 );
context3.restore();
}
var bayerThresholdMap = [
[ 15, 135, 45, 165 ],
[ 195, 75, 225, 105 ],
[ 60, 180, 30, 150 ],
[ 240, 120, 210, 90 ]
];
var lumR = [];
var lumG = [];
var lumB = [];
for (var i=0; i<256; i++) {
lumR[i] = i*0.299;
lumG[i] = i*0.587;
lumB[i] = i*0.114;
}
function monochrome(imageData, threshold, type){
var imageDataLength = imageData.data.length;
// Greyscale luminance (sets r pixels to luminance of rgb)
for (var i = 0; i <= imageDataLength; i += 4) {
imageData.data[i] = Math.floor(lumR[imageData.data[i]] + lumG[imageData.data[i+1]] + lumB[imageData.data[i+2]]);
}
var w = imageData.width;
var newPixel, err;
for (var currentPixel = 0; currentPixel <= imageDataLength; currentPixel+=4) {
if (type === "none") {
// No dithering
imageData.data[currentPixel] = imageData.data[currentPixel] < threshold ? 0 : 255;
} else if (type === "bayer") {
// 4x4 Bayer ordered dithering algorithm
var x = currentPixel/4 % w;
var y = Math.floor(currentPixel/4 / w);
var map = Math.floor( (imageData.data[currentPixel] + bayerThresholdMap[x%4][y%4]) / 2 );
imageData.data[currentPixel] = (map < threshold) ? 0 : 255;
} else if (type === "floydsteinberg") {
// FloydSteinberg dithering algorithm
newPixel = imageData.data[currentPixel] < 129 ? 0 : 255;
err = Math.floor((imageData.data[currentPixel] - newPixel) / 16);
imageData.data[currentPixel] = newPixel;
imageData.data[currentPixel + 4 ] += err*7;
imageData.data[currentPixel + 4*w - 4 ] += err*3;
imageData.data[currentPixel + 4*w ] += err*5;
imageData.data[currentPixel + 4*w + 4 ] += err*1;
} else {
// Bill Atkinson's dithering algorithm
newPixel = imageData.data[currentPixel] < 129 ? 0 : 255;
err = Math.floor((imageData.data[currentPixel] - newPixel) / 8);
imageData.data[currentPixel] = newPixel;
imageData.data[currentPixel + 4 ] += err;
imageData.data[currentPixel + 8 ] += err;
imageData.data[currentPixel + 4*w - 4 ] += err;
imageData.data[currentPixel + 4*w ] += err;
imageData.data[currentPixel + 4*w + 4 ] += err;
imageData.data[currentPixel + 8*w ] += err;
}
// Set g and b pixels equal to r
imageData.data[currentPixel + 1] = imageData.data[currentPixel + 2] = imageData.data[currentPixel];
}
// Alpha: make white pixels transparent!
var newColor = {r:0,g:0,b:0, a:0};
for ( i = 0, n = imageData.data.length; i <n; i += 4) {
var r = imageData.data[i],
g = imageData.data[i+1],
b = imageData.data[i+2];
// If its white, or close to white then change it
if(r >=200 && g >= 200 && b >= 200){
// Change the white to whatever.
imageData.data[i] = newColor.r;
imageData.data[i+1] = newColor.g;
imageData.data[i+2] = newColor.b;
imageData.data[i+3] = newColor.a;
}
}
return imageData;
}