Complex curved line

program new;
{$I SRL/OSR.simba}

var
  BMP: TMufasaBitmap;

function GenSubPoints(A,B:Vector2; count: Int32): array of Vector2;
var
  t,d,r,rx,ry,step: Double;
  i,j,k: Int32;
  vec: Vector2;
  v,tmp: array of Vector2;
begin
  d := Hypot(A.x-B.x, B.y-B.y) / count;
  SetLength(v, count);
  v[0] := A;
  r := srl.SkewedRand(d, 0, d*2);
  for i:=1 to count-1 do
  begin
    t := Random(-0.7, 2.5)*0.8 + srl.SkewedRand(0.5,-0.7,2.5)*0.2;
    v[i].x := ((1-t)*v[i-1].x + t*B.x) + Random()*d-r;
    v[i].y := ((1-t)*v[i-1].y + t*B.y) + Random()*d-r;
  end;
  v[count-1] := B;

  step := Max(0.01, 1/Sqr(count));
  t := 0;
  while t <= 1 do
  begin
    tmp := Copy(v);
    for i:=High(tmp) downto 1 do
      for k:=0 to i-1 do
      begin
        tmp[k].x := tmp[k].x + (tmp[k+1].x - tmp[k].x) * t;
        tmp[k].y := tmp[k].y + (tmp[k+1].y - tmp[k].y) * t;
      end;
    vec := tmp[0];
    Result += vec;
    t += step;
  end;
  Result += B;
end;


function SmoothLine(src, dst: Vector2; Gravity, NoiseLevel, maxStep: Double; Sharpness:Int32; targetArea:Double): TPointArray;
var
  t,noiseX,noiseY,dist,xstep,ystep,len,newDist,rmaxStep,rNoise,rGravity: Single;
  i: Int32;
  prev,tmp: TPoint;
  line: TPointArray;
  v: array of Vector2;
const
  PI2 := PI/2;
begin
  v := GenSubPoints(src,dst, sharpness);
  //for i:=0 to High(v) do
  //  BMP.DrawCircle(v[i].ToPoint, 3, $FF);

  noiseX := Random();
  noiseY := Random();

  Result += src.ToPoint;
  prev := src.ToPoint;

  rMaxStep := maxStep;
  rNoise   := NoiseLevel;
  rGravity := Gravity;

  i := 1;
  dst := v[i];
  dist := Hypot(src.x - dst.x, src.y - dst.y);
  while (Hypot(src.x - v[High(v)].x, src.y - v[High(v)].y) > 1) do
  begin
    if (dist < targetArea) then
    begin
      if (i = High(v)) then
      begin
        if (rMaxStep > 1) then rMaxStep /= Sqrt(2)
      end else
      begin
        dst := v[Inc(i)];
        rMaxStep := Max(Sqrt(2), Min(MaxStep, Hypot(src.x - v[i].x, src.y - v[i].y)));

        if rMaxStep >= Sqrt(5) then
        begin
          rNoise   := NoiseLevel;
          rGravity := Gravity;
        end else
        begin
          rNoise := 0;
          rGravity := 1;
        end;
      end;
    end;

    noiseX := noiseX * 2/3 + (2*Random()-1) * rNoise * 1/3;
    noiseY := noiseY * 2/3 + (2*Random()-1) * rNoise * 1/3;
    xstep := noiseX + rGravity * (dst.x-src.x) / dist;
    ystep := noiseY + rGravity * (dst.y-src.y) / dist;
    len := Hypot(xstep, ystep);

    if (len > rMaxStep) then
    begin
      newDist := 1+Random() * rMaxStep;
      xstep := (xstep / len) * newDist;
      ystep := (ystep / len) * newDist;
    end;

    src.x += xstep;
    src.y += ystep;
    tmp.x := Round(src.x);
    tmp.y := Round(src.y);

    if (tmp <> prev) then
    begin
      if len <= Sqrt(2) then
        result += tmp
      else
      begin
        line := TPAFromLine(prev.x,prev.y,tmp.x,tmp.y);
        result += line;
      end;
    end;

    dist := Hypot(src.x - dst.x, src.y - dst.y);
    prev := tmp;
  end;
end;


var
  p: TPoint;
  a: TPoint=[50,50];
  b: TPoint=[430,380];
  i,c: Int32;
begin
  bmp := GetMufasaBitmap(CreateBitmap(500,500));
  bmp.Debug();

  while True do
  begin
    bmp.Clear();
    bmp.DrawTPA(TPAFromLine(a.x,a.y,b.x,b.y), $FFFFFF);

    for p in SmoothLine([a.x,a.y], [b.x,b.y],  9, 2.5, 10, 7, 50) do
    try
      if InRange(p.x, 0,bmp.GetWidth-1) and InRange(p.y, 0,bmp.GetHeight-1) then
        bmp.SetPixel(p.x,p.y, $FF00FF);

      Inc(i);
      if i mod 4 = 0 then bmp.Debug();
    except end;
    bmp.Debug();
    Wait(500);
  end;
  bmp.Debug();
end.