Is the cycle correct for points in an area?

Question

Delphi

x:=StrToFloat(Edit1.Text);

y:=StrToFloat(Edit2.Text);
  if  ((x=0) and (y=-1)) or ((x=1) and (y=-1))
  then
  Label1.Caption:=' точка лежит в заштрихованной области'
  else if ((x=-1) or (y=-2)) or ((x=2) or (y=-2)) or ((x-y)=0) or ((x+y)=4)
  or ((x=2) and (y=-1))
   then
  Label1.Caption:=' точка лежит на границе заштрихованной области '
  else Label1.Caption:=' точка за пределами заштрихованной области '

A cycle was made to check the presence / absence of points in the figure. BUT I don't know if it works for all cases and what can be done to make it better?

Answer 1

Check first whether the point is in the triangle. Then into a rectangle.
Or you can try using Windows features

function PointInPolygon(Point: TPoint; const Polygon: array of TPoint): Boolean;
var
  rgn: HRGN;
begin
  rgn := CreatePolygonRgn(Polygon[0], Length(Polygon), WINDING);
  Result := PtInRegion(rgn, Point.X, Point.Y);
  DeleteObject(rgn);
end;

Использование
var Points: array of TPoint;
Points := [TPoint.Create(-1, 0), TPoint.Create(0, 0), ...];
if PointInPolygon(TPoint.Create(0, 0), Points) then <точка входит в область>

Or a separate implementation
https://wiki.freepascal.org/Geometry_in_Pascal

Answer 2

First, there is no cycle here.
Secondly, the check of finding a point inside the area is implemented incorrectly. Even from general considerations, it is clear that checking whether a point falls into an area cannot be performed by checking whether the coordinates of the point are equal to anything. There should be a check for more or less.
I did not check the long condition for checking if it hit the border, laziness. But something in it is suspiciously few logical AND (and). It is most likely incorrect.