There is a GDI+ library for (current) FreePascal and Delphi for over 20 years written by Dave Jewell and published in PC Pro even before MS officially released it. (together with XP)
There is another one that I forgot the author from except that he is from the Wallonië part of Belgium and is more complete and powerful..
So this is re-inventing wheels again.
Also note that adding {$mode delphi} to units does not count as a "port". (because that is all what is needed)
If you changed any code - I won't even look at it - you are on the wrong path.
(I wrote a KOL version of my old programmer friend Dave Jewell's code in 2001...., correction, just checked, early 2003)
Can you please explain what your code adds to the 2001 ports?
Also note the whole shebang is likely to be deprecated sooner or later.