<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>MNIST with GGML</title>
<script src="mnist.js"></script>
</head>
<body>
<h2>MNIST digit recognizer with <a href="https://github.com/ggerganov/ggml">GGML</a></h2>
<p id="msg">Loading model and data set, please wait ...</p>
<canvas id="ggCanvas" width="364" height="364" style="border:2px solid #d3d3d3;">
Your browser does not support the HTML canvas tag.
</canvas>
<div>
<button id="clear" onclick="onClear()">Clear</button>
<button id="random" onclick="onRandom()" disabled>Random</button>
<button id="download" onclick="onDownload()">Download</button>
</div>
<div>
<p id="prediction"></p>
</div>
<script>
"use strict";
const DIGIT_SIZE = 28; // digits are 28x28 pixels
var canvas = document.getElementById("ggCanvas");
var ctx = canvas.getContext("2d", { alpha: false, willReadFrequently: true });
ctx.fillStyle = "white";
ctx.fillRect(0, 0, canvas.width, canvas.height);
var dragging = false;
var lastX, lastY;
function onClear(event) {
ctx.fillStyle = "white";
ctx.fillRect(0, 0, canvas.width, canvas.height);
document.getElementById("prediction").innerHTML = "";
}
function predict(digit) {
let buf = Module._malloc(digit.length);
if (buf == 0) {
console.log("failed to allocate memory");
return;
}
Module.HEAPU8.set(digit, buf);
let prediction = Module.ccall('wasm_eval', null, ['number'], [buf]);
Module._free(buf);
if (prediction >= 0) {
document.getElementById("prediction").innerHTML = "Predicted digit is <b>" + prediction + "</b>";
}
}
function onRandom(event) {
onClear();
const bufLength = DIGIT_SIZE*DIGIT_SIZE;
var buf = Module._malloc(bufLength);
if (buf == 0) {
console.log("failed to allocate memory");
return;
}
let ret = Module.ccall('wasm_random_digit', null, ['number'], [buf]);
let digit = new Uint8Array(Module.HEAPU8.buffer, buf, bufLength);
for (let i = 0; i < digit.length; i++) {
let x = i % DIGIT_SIZE;
let y = Math.floor(i / DIGIT_SIZE);
setPixel(x, y, digit[i]);
}
Module._free(buf);
predict(digit);
}
function onDownload(event) {
let digit = scaleCanvas();
let digitBlob = new Blob([new Uint8Array(digit)], {type: "application/octet-stream"});
let url = URL.createObjectURL(digitBlob);
let link = document.createElement('a');
link.href = url;
link.download = "image.raw";
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
}
// Get the position of the mouse relative to the canvas
function getMousePos(event) {
if (event.touches !== undefined && event.touches.length > 0) {
event = event.touches[0];
}
var rect = canvas.getBoundingClientRect();
return [Math.floor(event.clientX) - rect.left, Math.floor(event.clientY) - rect.top];
}
function setPixel(x, y, val) {
let canvasX = x * 13;
let canvasY = y * 13;
let color = 255 - val;
ctx.fillStyle = "#" + color.toString(16) + color.toString(16) + color.toString(16);
ctx.fillRect(canvasX, canvasY, 13, 13);
}
function onMouseDown(e) {
dragging = true;
[lastX, lastY] = getMousePos(e);
}
// scale the canvas to 28x28 pixels and return the pixel values as an array
function scaleCanvas() {
let imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
let tempCanvas = document.createElement('canvas');
tempCanvas.width = DIGIT_SIZE;
tempCanvas.height = DIGIT_SIZE;
let tempCtx = tempCanvas.getContext("2d");
tempCtx.drawImage(canvas, 0, 0, DIGIT_SIZE, DIGIT_SIZE);
let tempImgData = tempCtx.getImageData(0, 0, DIGIT_SIZE, DIGIT_SIZE);
let tempData = tempImgData.data;
let digit = new Array(DIGIT_SIZE*DIGIT_SIZE).fill(0);
for (let i = 0; i < tempData.length; i += 4) {
let val = 255 - tempData[i];
digit[i / 4] = val;
}
return digit;
}
function onMouseUp(e) {
dragging = false;
let digit = scaleCanvas();
predict(digit);
}
function onMouseMove(e) {
if (dragging) {
let [mouseX, mouseY] = getMousePos(e);
ctx.beginPath();
ctx.moveTo(lastX, lastY);
ctx.lineTo(mouseX, mouseY);
ctx.lineWidth = 20;
ctx.lineJoin = ctx.lineCap = 'round';
ctx.strokeStyle = "#000000";
ctx.stroke();
ctx.closePath();
lastX = mouseX;
lastY = mouseY;
}
}
// Prevent scrolling when touching the canvas
document.body.addEventListener("touchstart", function (e) {
if (e.target == canvas) {
e.preventDefault();
}
}, {passive: false});
document.body.addEventListener("touchend", function (e) {
if (e.target == canvas) {
e.preventDefault();
}
}, {passive: false});
document.body.addEventListener("touchmove", function (e) {
if (e.target == canvas) {
e.preventDefault();
}
}, {passive: false});
function onRuntimeInitialized() {
// Use the same handlers for mouse and touch events
canvas.onmousedown = onMouseDown;
canvas.onmouseup = onMouseUp;
canvas.onmousemove = onMouseMove;
canvas.ontouchstart = onMouseDown;
canvas.ontouchend = onMouseUp;
canvas.ontouchmove = onMouseMove;
document.getElementById("msg").innerHTML = "Draw a single digit on the canvas below:"
document.getElementById("random").disabled = false;
}
Module['onRuntimeInitialized'] = onRuntimeInitialized;
</script>
</body>
</html>