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encode.js
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encode.js
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window.onload = function () {
console.log('>>image_processing::active');
/*-------------------------------------------- */
const canvas_container = document.getElementById('_canvas_container');
const _canvas_original = document.getElementById('_input_image');
const _canvas_processed = document.getElementById("_encrypted_image");
const _message = document.getElementById("_input_msg");
const hide_msg_button = document.getElementById('hide_msg');
const image_upload = document.getElementById('_image_upload');
const ctx_original = _canvas_original.getContext('2d');
const ctx_processed = _canvas_processed.getContext('2d');
/*creating a new image object */
var imageOBJ = new Image();
imageOBJ.onload = function () {
let w = _canvas_original.width;
let n_h = imageOBJ.naturalHeight;
let n_w = imageOBJ.naturalWidth;
//finding aspect ratio
let aspect_ratio = n_w / n_h;
let h = w / aspect_ratio;
_canvas_original.height = h;
//drawing image to canvas
ctx_original.drawImage(imageOBJ, 0, 0, w, h);
}
/*when file is uploaded */
image_upload.addEventListener('change', function (event) {
image_src = URL.createObjectURL(event.target.files[0]);
imageOBJ.src = image_src;
if (canvas_container.style.display === "none") {
canvas_container.style.display = "block";
}
});
/* download canvas image when canvas is clicked*/
_canvas_processed.addEventListener('click',(e)=>{
//get canvas data
var image = _canvas_processed.toDataURL();
//create temporary link
var tmpLink = document.createElement( 'a' );
tmpLink.download = 'processedImage.png';
//set the name of the download file
tmpLink.href = image;
//temporarily add link to body and initiate the download
document.body.appendChild( tmpLink );
tmpLink.click();
document.body.removeChild( tmpLink );
});
/*hide msg button in clicked */
hide_msg_button.addEventListener('click', function (e) {
if(_message.value.length<=0){
alert("please enter the message");
return false;
}
if(image_upload.files.length<=0){
alert("please upload an image");
return false;
}
/*processing message*/
var _msgData=Tools.encode_message(_message.value).bits;
/*process image*/
var _imgData=ctx_original.getImageData(0,0,_canvas_original.width,_canvas_original.height);
/*check whether msg can be hidden in image or not */
if(_msgData.length>_imgData.data.length){
console.log("need a large size image to accomodate the msg,\n go open an issue on gitHub, what else can you do?");
return false;
}
/*superimpose image and messgae*/
var _processed_data=Tools.superimpose(_imgData.data,_msgData);
_imgData.data=_processed_data;
/*setting up canvas dimentions */
_canvas_processed.width=_canvas_original.width;
_canvas_processed.height=_canvas_original.height;
/*drawing in canvas */
ctx_processed.putImageData(_imgData,0,0);
var after_info=document.getElementById('after_info');
if(after_info.style.display==="none"){
after_info.style.display="block";
}
});
}