Can You Extract Pixel Colors from an HTML Canvas?

Retrieving Pixel Values from HTML Canvas

Can the contents of an HTML Canvas be queried to retrieve the color of a specific pixel?

Answer:

Unquestionably! The W3C documentation provides detailed information on pixel manipulation. Here's an example to demonstrate the inversion of an image using pixel manipulation:

<code class="javascript">var context = document.getElementById('myCanvas').getContext('2d');

// Get pixel data from specified coordinates and dimensions.
var imgd = context.getImageData(x, y, width, height);
var pix = imgd.data;

// Invert the colors of each pixel.
for (var i = 0, n = pix.length; i < n; i += 4) {
    pix[i  ] = 255 - pix[i  ]; // Red
    pix[i+1] = 255 - pix[i+1]; // Green
    pix[i+2] = 255 - pix[i+2]; // Blue
    // i+3 is alpha (fourth element)
}

// Display the modified pixel data at specified coordinates.
context.putImageData(imgd, x, y);</code>

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