Janilabo | TPAExtractPoints()

{==============================================================================]
  Explanation: Extracts all points from a given TPointArray TPA
               by removing all points that fall outside extractPoints.
[==============================================================================}
procedure TPAExtractPoints(var TPA: TPointArray; extractPoints: TPointArray);
var
  tmp: TPointArray;
begin
  if (Length(TPA) > 0) then
    if (Length(extractPoints) > 0) then
    begin
      tmp := CopyTPA(TPA);
      TPAFilterPoints(tmp, extractPoints);
      if (Length(tmp) > 0) then
      begin
        TPAFilterPoints(TPA, tmp);
        SetLength(tmp, 0);
      end;
    end else
      SetLength(TPA, 0);
end;

var
  tmp, TPA: TPointArray;

begin
  TPA := [Point(1, 1), Point(1, 2), Point(2, 1), Point(2, 2)];
  TPAExtractPoints(TPA, tmp);
  WriteLn(TPAToStr(TPA));
  SetLength(TPA, 0);
end.