Title: Find intersectionpoint of two lines
Question: How to calculate the crosspoint of two lines
Answer:
If you want to know if 2 Lines crossing each other, you can use this function below. The lines are given in with the beginning- and end-points.
You will find the Coordinates of the Crosspoint in Cross, if the Function anwers
True = we did found a crossing;
function GetCrossPointOfLines(pA1, pA2, pB1, pB2: TPoint; var Cross : TPoint): Boolean;
var h, i, j, k, l, m : Integer; o, p: Extended;
begin
k:= pB1.Y- pA1.Y;
l:= pA2.Y- pA1.Y;
m:= pB2.Y- pB1.Y;
h:= pA2.X- pA1.X;
i:= pB1.X- pA1.X;
j:= pB2.X- pB1.x;
Result:=false;
if Abs(j*l - m*h) 0 then
begin
p:= (k*h - i*l) / (j*l - m*h);
o:= (k*j - i*m) / (j*l - m*h);
if (o=0.0) and (o=0.0) and (p begin
Cross.X:= Round(pA1.X + o* h);
Cross.Y:= Round(pA1.Y + o* l);
Result:= True;
end;
end;
end;