assembly/encode_decode.html at master · ibeeger/assembly · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>图片</title>
	<style>
		img{ max-width: 100%; max-height: 100%;}
		section{
			display: flex;
			width: 90%;
			padding: 30px 0;
			margin: 0 auto;
			align-items: center;
			align-content: space-between;
		}
		canvas{
			max-height: 100%;
			max-width: 100%;
		}
		section>div{
			width: 50%;
		}
	</style>
</head>
<body>

	<section>
		<div>
			<img src="" id="photo" alt="">
		</div>
		<div>
			<img src="" id="photo2" alt="">
			<!-- <canvas></canvas> -->
		</div>
	</section>

	<input type="file" id="bbb">

	<script>

		const box = {}

		async function encodeImage(box) {
			// const cs = document.querySelector('canvas');
			const cs = document.createElement('canvas');
			const ctx = cs.getContext('2d');
			const img = document.getElementById('photo');
			cs.width = img.naturalWidth;
			cs.height = img.naturalHeight;
			let sw =box.sw, sh=box.sh, x = box.x, y=box.y;
			ctx.drawImage(img,0,0);
			let imgdataList = [], list=box.randomlist;
			for(let i=0; i<y; i++) {
				for(let j=0; j<x; j++) {
					imgdataList.push(ctx.getImageData(j*sw,i*sh,sw,sh));
				}
			};
			ctx.fillRect(0,0,cs.width,cs.height);
			for(let i=0, j=0; i<list.length; i++) {
				if(i >= x && (i%x) == 0) {
					j++;
				}
				ctx.putImageData(imgdataList[list[i]], sw*(i%x),sh*j);
			}

			cs.toBlob(function(blob){
		    	var urlCreator = window.URL || window.webkitURL;
				var imageUrl = urlCreator.createObjectURL(blob);
		    	var img = document.querySelector("#photo2");
		    	img.src= imageUrl
			},"image/png")
			// await showImage(arr, '#photo2')
		}

		function decodeImage() {

		}

		//计算打乱顺序
		function calculateRandomRule(imgsize){
			let sw=0, sh=0;
			let x,y; //xy轴划分
			let randomlist = []
			for(let i=4; i<Math.max(imgsize.w,imgsize.h); i++) {
				if(imgsize.w%i == 0) {
					sw = imgsize.w/i;
					x = i;
					if(sh){break}
				}
				if(imgsize.h%i == 0) {
					sh = imgsize.h/i;
					y = i;
					if(sw){break}
				}
			};

			for(let i=0; i<x*y; i++) {
				randomlist.push(i);
			}
			randomlist = randomlist.sort(() =>  0.4 - Math.random())
			return {
				sw,
				sh,
				x,
				y,
				randomlist
			}
		}


		function getImageSize(bf) {
			var blob = new Blob( [ bf ], { type: "image/png" } );
		    var urlCreator = window.URL || window.webkitURL;
		    var imageUrl = urlCreator.createObjectURL( blob );
		    var img = new Image();
		    return new Promise(function(resolve){
		    	img.onload = function(){
		    		resolve({w:img.naturalWidth, h:img.naturalHeight});
		    	};
		    	img.src = imageUrl;
		    })
		}


		function showLocal(file,callback) {
			var fileReader = new FileReader();
			fileReader.onload = function(e) {
				fileContent = e.target.result;
				callback(fileContent);
			}
			fileReader.readAsArrayBuffer(file);
		}


		document.getElementById('bbb').addEventListener('change',  function(e){
			showLocal(e.target.files[0], async function(m){
				let imgsize = await getImageSize(m);
				let randomObj = calculateRandomRule(imgsize);
				let arr = new Int8Array(m);
				console.log(arr);
				let boxabf = new ArrayBuffer(m.byteLength/50);
				let newarr = new Int8Array(arr.length+randomObj.randomlist.length+1);
				let boxarr = new Int8Array(boxabf.byteLength);
				for(let i =0; i<newarr.length; i++){
					if(i>=arr.length){
						if(i=== arr.length+randomObj.randomlist.length){
							newarr[i] = randomObj.randomlist.length;
						} else{
							newarr[i] = randomObj.randomlist[i-arr.length];
						}
					} else {
						newarr[i] = arr[i]
						boxarr[i] = arr[i]
						// if(i>= (arr.length - boxarr.length) ) {
						// 	boxarr[i-(arr.length-boxarr.length)] = arr[i];
						// }
					};

				}


				//打乱原始数据
				// arr = arr.sort(() => .4 - Math.random());
				console.log(arr.length, randomObj.randomlist.length, newarr.length);
				await showImage(boxarr, '#photo');
				encodeImage(randomObj)
			})
		}, false)


		async function loadImage() {
		 const res = await fetch('./images/demo.jpg');
		 const ares = await res.arrayBuffer();
		 const oldit = new Int8Array(ares);
		 let ke = await showImage(oldit, '#photo');
		 encodeImage();
		}

		async function showImage(bf, id){
			var blob = new Blob( [ bf ], { type: "image/png" } );
		    var urlCreator = window.URL || window.webkitURL;
		    var imageUrl = urlCreator.createObjectURL( blob );
		    var img = document.querySelector( id || "#photo" );
		    return new Promise(function(resolve){
		    	img.onload = resolve;
		    	img.src = imageUrl;
		    })
		}

		// loadImage()

	</script>
</body>
</html>