Mouse

program Mouse;
uses GraphWPF;
const
  width = 720;
  height = 720;
  cx = width/2;
  cy = height/2;
  pen_width = 2.5;
var
  tx,ty: real;
procedure Prepare();
begin
  Window.Title := 'Мышка WPF';
  Window.SetSize(WIDTH, HEIGHT);
  Window.CenterOnScreen;
  Window.IsFixedSize := true;
  FillRectangle(0,0,WIDTH+10, HEIGHT+10, Colors.SeaShell);
  //Window.Clear(Colors.LightGreen);
end;
procedure MouseDown(mx,my: real; mousebutton: integer);
begin
  var dx := mx - tx;
  var dy := my - ty;
  var a := System.Math.Atan2(dy, dx);
  var dist := Sqrt(dx**2 + dy**2);
  var x := tx + dist*Cos(a);
  var y := ty+dist*Sin(a);
  // запоминаем новые координаты:
  tx := x;
  ty := y;
  // вперёд!
  LineTo(x,y);
end;

begin
  Prepare;
  Pen.Width := 2;
  Pen.Color := Colors.Green;
  MoveTo(cx,cy);
  tx := cx;
  ty := cy;
  OnMouseDown := MouseDown;
end.