Rounded Corners SVG QR Code in PHP

gistfile1.php

<?php

/**
 * This code generates an SVG QR code with rounded corners. It uses a round rect for each square and then additional
 * paths to fill in the gap where squares are next to each other. Adjacent squares overlap - to almost completely
 * eliminate hairline antialias "cracks" that tend to appear when two SVG paths are exactly adjacent to each other.
 *
 * composer require chillerlan/php-qrcode (tested with version v5 dev-main)
 */

use chillerlan\QRCode\Common\EccLevel;
use chillerlan\QRCode\Data\QRMatrix;
use chillerlan\QRCode\Output\QRMarkupSVG;
use chillerlan\QRCode\{QRCode, QROptions};

require_once __DIR__.'/../vendor/autoload.php';

class RoundedCornerSVGQRCodeOutput extends QRMarkupSVG{

	// this constant may be added to QRMatrix
	protected const neighbours = [
		0b00000001 => [-1, -1],
		0b00000010 => [ 0, -1],
		0b00000100 => [ 1, -1],
		0b00001000 => [ 1,  0],
		0b00010000 => [ 1,  1],
		0b00100000 => [ 0,  1],
		0b01000000 => [-1,  1],
		0b10000000 => [-1,  0]
	];

	/**
	 * Checks the status neighbouring modules of the given module at ($x, $y) and returns a bitmask with the results.
	 *
	 * The 8 flags of the bitmask represent the status of each of the neighbouring fields,
	 * starting with the lowest bit for top left, going clockwise:
	 *
	 *   1 2 3
	 *   8 # 4
	 *   7 6 5
	 *
	 * @todo: when $M_TYPE_VALUE is given, it should check for the same $M_TYPE while igrnoring the IS_DARK flag
	 *
	 * (this method may be added to QRMatrix as direct array access is faster than method calls)
	 */
	protected function checkNeighbours(int $x, int $y, int $M_TYPE_VALUE):int{
		$bits = 0;

		foreach($this::neighbours as $bit => $coord){
			if($this->matrix->check($x + $coord[0], $y + $coord[1])){
				$bits |= $bit;
			}
		}

		return $bits;
	}


	protected function paths():string{
		// main square with rounded corners
		$svg = $this->symbolWithPath('s', ['M0,0 m0,0.3 v0.4 q0,0.3 0.3,0.3 h0.4 q0.3,0 0.3,-0.3 v-0.4 q0,-0.3 -0.3,-0.3 h-0.4 q-0.3,0 -0.3,0.3Z']);

		// "plus" to invert the corner radius
		$svg .= $this->symbolWithPath('p', [
			// a curved plus, radius slightly righter than the main square
			'M0.3 0.6 Q0.58,0.58 0.6,0.3 Q0.62,0.58 0.9,0.6 Q0.62,0.62 0.6,0.9 Q0.58,0.61 0.3,0.6 Z',
			// a sharp plus (with points further out logner than the curved one)
			'M0.6 0 L0.61 0.59 L1.2 0.6 L0.61 0.61 L0.6 1.2 L0.59 0.61 L0 0.6 L0.59 0.59 Z'
		]);

		// top/left/bottom/right triangles fill in edges
		$svg .= $this->symbolWithPath('t', ['M0 0.3 L0.6 0.3 L0.3 0.9 Z']);
		$svg .= $this->symbolWithPath('l', ['M0.6 0 L0 0.3 L0.6 0.6 Z']);
		$svg .= $this->symbolWithPath('b', ['M0 0.6 L0.6 0.6 L0.3 0 Z']);
		$svg .= $this->symbolWithPath('r', ['M0.3 0 L1.2 0.3 L0.3 0.6 Z']);

		// a daimond to fill in block areas
		$svg .= $this->symbolWithPath('d', ['M0.6 0 L1.2 0.6 L0.6 1.2 L0 0.6 Z']);

		foreach($this->matrix->matrix() as $y => $row){
			foreach($row as $x => $val){

				if(($val & QRMatrix::IS_DARK) !== QRMatrix::IS_DARK){
					continue;
				}

				$bits  = $this->checkNeighbours($x, $y, $val);
				$check = fn(int $mask):bool => ($bits & $mask) === $mask;

				// main square block
				$svg .= $this->use('s', $x, $y);

				// top left corner
				if($check(0b10000011)){
					$svg .= $this->use('d', $x - 0.6, $y - 0.6);
				}
				elseif($check(0b10000001)){
					$svg .= $this->use('p', $x - 0.6, $y - 0.6);
				}
				elseif($check(0b00000011)){
					$svg .= $this->use('p', $x - 0.6, $y - 0.6);
				}
				elseif($check(0b00000010)){
					$svg .= $this->use('r', $x - 0.3, $y - 0.3);
				}
				elseif($check(0b10000000)){
					$svg .= $this->use('t', $x - 0.3, $y - 0.3);
				}

				// bottom right corner
#				if($check(0b00111000)){
					// already done
#				} else
				if($check(0b00011000)){
					$svg .= $this->use('p', $x + 1 - 0.6, $y + 1 - 0.6);
				}
				elseif($check(0b00110000)){
					$svg .= $this->use('p', $x + 1 - 0.6, $y + 1 - 0.6);
				}
				elseif($check(0b00100000)){
					$svg .= $this->use('l', $x + 1 - 0.6, $y + 1 - 0.3);
				}
				elseif($check(0b00001000)){
					$svg .= $this->use('b', $x + 1 - 0.3, $y + 1 - 0.6);
				}

				// top right corner
#				if($check(0b00001110)){
					// already done
#				} else
				if($check(0b00001100)){
					$svg .= $this->use('p', $x + 1 - 0.6, $y - 0.6);
				}
				elseif($check(0b00000110)){
					$svg .= $this->use('p', $x + 1 - 0.6, $y - 0.6);
				}

			}
		}

		return $svg;
	}

	protected function use($node, $x, $y){
		return "<use href=\"#$node\" x=\"$x\" y=\"$y\" />\n";
	}

	protected function symbolWithPath($id, $paths, $fill = null){
		$fillOutput = $fill === null ? '' : " fill=\"$fill\"";
		$output     = "<symbol id=\"$id\"$fillOutput>";

		foreach($paths as $path){
			$output .= "<path d=\"$path\"  class=\"dark\" shape-rendering=\"geometricPrecision\" />"; //
		}

		$output .= "</symbol>\n";

		return $output;
	}

}

$url = 'https://github.com/chillerlan/php-qrcode/issues/127';

$options = new QROptions([
	'eccLevel'        => EccLevel::L,
	'imageBase64'     => false,
	'addQuietzone'    => true,
	'outputType'      => QRCode::OUTPUT_CUSTOM,
	'outputInterface' => RoundedCornerSVGQRCodeOutput::class,
]);

header('content-type: image/svg+xml');
echo (new QRCode($options))->render($url);