[mattiasgeniar]

The encoder's inner loops look up the matrix row again for every cell: through ByteMatrix::get() and set() while embedding data bits, and through $array[$y][$x] in mask penalty rules 2 and 3 and in clear(). These three commits fetch each row once and index into it. The matrix and mask pattern are identical for 264 inputs across all four error-correction levels, and the test suite has the same result as main (the two GD tests error on both here, without the extension).

Benchmark (an otpauth:// URL, the usual 2FA QR code)	Before	After	% change
Encoder::encode()	4.37 ms	3.35 ms	−23.3%
Encoder::encode(), first call	4.95 ms	3.94 ms	−20.4%
Writer::writeString(), 400 px SVG	7.17 ms	6.26 ms	−12.7%

Median of 15 fresh PHP 8.5 processes per side, run interleaved, opcache on. "First call" is the first run in a new process.