Can We Stretch Images in the Browser Without Antialiasing?

Stretching Images Without Antialiasing in the Browser

Enhancing pixel art often involves stretching images to enlarge individual pixels. However, traditional techniques like CSS and JavaScript typically introduce unwanted blurring (antialiasing). This article addresses the question of whether it's possible to stretch images in the browser without antialiasing.

Despite exploration using CSS, JavaScript, and HTML, the author initially encountered unsuccessful attempts due to antialiasing. CSS techniques like image-rendering: crisp-edges proved effective in modern browsers but were inconsistent and unsupported in Internet Explorer 9 and earlier versions.

The solution presented involves utilizing a canvas element to manipulate image data pixel by pixel. A source canvas receives the original image and a destination canvas is created to scale and draw the individual pixels.

<code class="javascript">var img = new Image();
img.src = ...;
img.onload = function() {

    var scale = 8;

    var src_canvas = document.createElement('canvas');
    src_canvas.width = this.width;
    src_canvas.height = this.height;

    var src_ctx = src_canvas.getContext('2d');
    src_ctx.drawImage(this, 0, 0);
    var src_data = src_ctx.getImageData(0, 0, this.width, this.height).data;

    var dst_canvas = document.getElementById('canvas');
    dst_canvas.width = this.width * scale;
    dst_canvas.height = this.height * scale;
    var dst_ctx = dst_canvas.getContext('2d');

    var offset = 0;
    for (var y = 0; y < this.height; ++y) {
        for (var x = 0; x < this.width; ++x) {
            var r = src_data[offset++];
            var g = src_data[offset++];
            var b = src_data[offset++];
            var a = src_data[offset++] / 100.0;
            dst_ctx.fillStyle = 'rgba(' + [r, g, b, a].join(',') + ')';
            dst_ctx.fillRect(x * scale, y * scale, scale, scale);
        }
    }
};</code>

This method provides a workaround for the antialiasing issue, enabling pixel-perfect scaling without any blurring. However, it is worth noting that support for image-rendering properties may vary across browsers and versions.

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