How to resolve the algorithm Image noise step by step in the JavaScript programming language

Published on 12 May 2024 09:40 PM
#Javascript

How to resolve the algorithm Image noise step by step in the JavaScript programming language

Table of Contents

Problem Statement

Generate a random black and white   320x240   image continuously, showing FPS (frames per second).

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Image noise step by step in the JavaScript programming language

This code is a JavaScript program that runs in a web browser and animates a canvas element. The canvas element is a rectangular region in the browser window that can be used to create and display graphics. The code first sets up the canvas element by getting a reference to it by its id, which is 'c'. It then sets the width and height of the canvas to 320 and 240 pixels, respectively. Next, the code creates a new context object for the canvas, which is used to draw on the canvas. The context object is used to set the font, which is 'normal 400 24px/2 Unknown Font, sans-serif' and create an image data object, which is used to store the pixels of the canvas. The code initializes the image data object by setting all of the alpha channel values to 255, which makes the canvas opaque. The animate function is then defined, which is called repeatedly to create the animation. The animate function first sets the index to 0, which is the index of the first pixel in the image data object. The animate function then iterates over each pixel in the canvas, setting the red, green, and blue values to either 255 or 0, depending on the output of the Math.random() function. The alpha channel value is constant and is set to 255. The animate function then uses the putImageData() method of the context object to draw the image data object to the canvas. The frame count is then incremented and if it is divisible by 50, the frames per second (FPS) is calculated and displayed in the status bar of the browser. The setTimeout() function is called to schedule the next call to the animate function, which occurs after a delay of 0 milliseconds. The animate function is called once initially to start the animation.

Source code in the javascript programming language

<body>
<canvas id='c'></canvas>

<script>
var canvas = document.getElementById('c');
var ctx = canvas.getContext('2d');

var w = canvas.width = 320;
var h = canvas.height = 240;
var t1 = new Date().getTime();
var frame_count = 0;
ctx.font = 'normal 400 24px/2 Unknown Font, sans-serif';
var img = ctx.createImageData(w, h);

var index_init = 0;
for (var x = 0; x < w; x++) {
    for (var y = 0; y < h; y++) {
        img.data[index_init + 3] = 255; // alpha
        index_init += 4;
    }
}

function animate() {
    var index = 0;
    for (var x = 0; x < w; x++) {
        for (var y = 0; y < h; y++) {
            var value = (Math.random() > 0.5) ? 255 : 0;
            img.data[index    ] = value;
            img.data[index + 1] = value;
            img.data[index + 2] = value;
            // alpha channel is constant
            index += 4;
        }
    }

    ctx.putImageData(img, 0, 0);

    frame_count++;
    if (frame_count % 50 == 0) {
        var fps = frame_count / (new Date().getTime() - t1) * 1000;
        window.status = fps.toFixed(2) + " fps";
    }

    setTimeout(animate, 0);
}

animate();
</script>
</body>

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