fix(encoder): use floor() for explicit truncation in MaskUtil

[vlakoff]

This PR addresses issue #131.

In PHP 8.1+, implicit float-to-int conversion raises precision loss warnings. The current implementation in MaskUtil.php:

$fixedPercentVariances = (int) (abs($darkRatio - 0.5) * 20);

produces warnings when the result is a non-integer float (e.g., 19.666...).

The QR code specification requires explicit truncation at this step. This PR replaces the cast-only approach with floor() to ensure correct behavior and avoid precision loss warnings:

$fixedPercentVariances = (int) floor(abs($darkRatio - 0.5) * 20);

This change makes truncation explicit, aligns with the specification, and removes PHP 8.1+ warnings.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.81%. Comparing base (38d3c55) to head (8ad2573).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main     #211   +/-   ##
=========================================
  Coverage     70.81%   70.81%           
  Complexity      994      994           
=========================================
  Files            49       49           
  Lines          3169     3169           
=========================================
  Hits           2244     2244           
  Misses          925      925           

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[vlakoff]

By the way, this code path doesn’t appear to be covered by unit tests, since the tests didn’t flag the issue.

[DASPRiD]

LGTM! And yeah, we don't have 100% code coverage, only the critical code paths are covered.

[TimWolla]

I'm confused by this change. The explicit (int) cast will not emit a warning with or without a floor().

https://3v4l.org/OM0LP#veol

[vlakoff]

Thank you for pointing this out. You seem to be right — now I’m puzzled as well.

(That being said, the explicit floor may still be nice for code clarity.)

Issue #131 was encountered on the old version 1.0.2 — see line 223 at that time:

BaconQrCode/src/BaconQrCode/Encoder/MaskUtil.php

Line 223 in 8cac918

$intermediate = (BitUtils::unsignedRightShift($y, 1) + ($x / 3)) & 0x1;

(I had already done some “history digging” when figuring out #131, but I don’t know how I ended up on an unrelated line.)

[vlakoff]

I've fed the code of MaskUtil::getDataMaskBit() into my AI slave, and it yelled a lot of warnings at me. This function definitely needs some reviewing.