fix(Rect): Modify to use saturating ops to prevent arith overflow

[HeeillWang]

Fix arithmetic overflow reported on #517 #520

[codecov]

Codecov Report

Merging #523 (8af31e3) into main (c9b8e7c) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #523   +/-   ##
=======================================
  Coverage   90.00%   90.01%           
=======================================
  Files          40       40           
  Lines       11190    11193    +3     
=======================================
+ Hits        10072    10075    +3     
  Misses       1118     1118           

Files Changed	Coverage Δ
src/layout.rs	98.38% <100.00%> (+<0.01%)	⬆️

[joshka]

Hi, thanks for the PR. Would you mind signing your commit with GPG?
See https://docs.github.com/articles/about-gpg/ for more info.

[HeeillWang]

Hi, thanks for the PR. Would you mind signing your commit with GPG? See https://docs.github.com/articles/about-gpg/ for more info.

Opps, didn't knew that amending to signed commit also needs another signing...
Signed again, should be no problem now

[joshka]

Thanks for the PR. I modified the commit message a little and merged.