mousewheel - Delphi Mouse wheel event in component -

i'm wanting write component uses mouse wheel zoom similar google earth.

i have component using onmousewheel , have properties maxzoom minzoom , zoom there better option stretchdraw bitmap i'm trying location of components area in form

what understand have find each parent until find tcustomform , add component's top , components left objects location find objects location. there better way

once have location can zoom map mouse cursor location if mouse on object , zoom from.

has 1 seen code please

it depends on kind of content going zoom ; post here how how long wheel has moved

on private declaration

private { private declarations } procedure formmousewheel(sender: tobject; shift: tshiftstate; wheeldelta: integer; mousepos: tpoint; var handled: boolean); 

on create or other starting procedure

onmousewheel := formmousewheel; // depends on  

the formmousewheel comes this

procedure formmousewheel(sender: tobject; shift: tshiftstate; wheeldelta: integer; mousepos: tpoint; var handled: boolean); begin // code here  // wheeldelta returns - or + values (in computer -120 , + 120 ;  // depends on control panel mouse wheel settings)  //   if font make font size bigger or  // if image   // strech := true; //  increase width , height of timage //and put them inside scrollbox //  end; 

i checked using vcl form (not inside component ), if want zoom post kind of content want zoom