{
 The example below demonstrates creating custom caret:
}
unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
 ExtCtrls, StdCtrls;
type
 TForm1 = class(TForm)
  Memo1: TMemo;
  Image1: TImage;
  Edit1: TEdit;
  procedure Memo1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
  procedure Edit1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
 private
  { Private declarations }
 public
  { Public declarations }
 end;
var
 Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Memo1MouseDown(Sender: TObject; Button: TMouseButton;
 Shift: TShiftState; X, Y: Integer);
begin
 CreateCaret(Memo1.Handle, Image1.Picture.Bitmap.Handle, 0, 0);
 ShowCaret(Memo1.Handle);
end;
procedure TForm1.Edit1MouseDown(Sender: TObject; Button: TMouseButton;
 Shift: TShiftState; X, Y: Integer);
begin
 CreateCaret(Edit1.Handle, 0, 10, 4);
 ShowCaret(Edit1.Handle);
end;
end.

{The form file source (*.dfm) }
object Form1: TForm1
 Left = 192
  = 107
 Width = 544
 Height = 375
 Caption = 'Form1'
 Color = clBtnFace
 Font.Charset = DEFAULT_CHARSET
 Font.Color = clWindowText
 Font.Height = -11
 Font.Name = 'MS Sans Serif'
 Font.Style = []
 OldCreateOrder = False
 PixelsPerInch = 96
 TextHeight = 13
 object Image1: TImage
  Left = 12
   = 4
  Width = 16
  Height = 16
  AutoSize = True
  Picture.Data = {
  07544269746D6170B6020000424DB602000000000000B6000000280000001000
  0000100000000100100000000000000200000000000000000000100000000000
  000000000000000080000080000000808000800000008000800080800000C0C0
  C000808080000000FF0000FF000000FFFF00FF000000FF00FF00FFFF0000FFFF
  FF00000000000000000000000000000000000000000000000000000000000000
  0000000000000000000000000000000000000000000000000000000000000000
  000000000000FF7FFF7FFF7FFF7F000000000000FF7FFF7FFF7FFF7FFF7FFF7F
  00000000FF7FFF7FFF7FFF7F000000000000FF7FFF7FFF7FFF7FFF7FFF7F0000
  0000FF7FFF7FFF7FFF7FFF7F00000000FF7FFF7FFF7FFF7FFF7FFF7FFF7F0000
  000000000000FF7FFF7FFF7F0000000000000000FF7FFF7FFF7FFF7F00000000
  0000000000000000FF7FFF7FFF7FFF7FFF7FFF7FFF7FFF7FFF7FFF7F00000000
  0000000000000000FF7FFF7FFF7FFF7FFF7FFF7FFF7FFF7FFF7F000000000000
  0000000000000000FF7FFF7FFF7F00000000FF7FFF7FFF7FFF7F000000000000
  00000000000000000000FF7FFF7FFF7FFF7FFF7FFF7FFF7F0000000000000000
  00000000000000000000FF7FFF7FFF7FFF7FFF7FFF7FFF7F0000000000000000
  000000000000000000000000FF7FFF7FFF7FFF7FFF7FFF7F0000000000000000
  000000000000000000000000FF7FFF7FFF7FFF7FFF7F00000000000000000000
  0000000000000000000000000000FF7FFF7FFF7FFF7F00000000000000000000
  0000000000000000000000000000FF7FFF7FFF7F000000000000000000000000
  00000000000000000000000000000000FF7F0000000000000000000000000000
  0000}
 end
 object Memo1: TMemo
  Left = 12
   = 36
  Width = 149
  Height = 149
  Lines.Strings = ('Memo1')
  TabOrder = 0
  OnMouseDown = Memo1MouseDown
 end
 object Edit1: TEdit
  Left = 220
   = 60
  Width = 121
  Height = 21
  TabOrder = 1
  Text = 'Edit1'
  OnMouseDown = Edit1MouseDown
 end
end