unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics,
  Controls, Forms, Dialogs, imageenview, ieview, ComCtrls;

type
  TForm1 = class(TForm)
    ImageEnView1: TImageEnView;
    StatusBar1: TStatusBar;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  protected
    { Protected declarations }
    procedure WMDropFiles(var Message: TWMDropFiles); message WM_DROPFILES;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses ShellAPI, hyieutils, imageenio;

procedure TForm1.FormCreate(Sender: TObject);
begin
  { Activate accepting files from the Windows shell }
  DragAcceptFiles(Self.Handle, True);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  { Deactivate accepting files from the Windows shell }
  DragAcceptFiles(Self.Handle, False);
end;

procedure TForm1.WMDropFiles(var Message: TWMDropFiles);
{ Handle dropping files to the form from Windows Explorer }
var
  i: Integer;
  iFilename: array [0 .. 256] of char;
  iNumberOfFiles: Integer;
  DropInfo: HDROP;
begin
  Screen.Cursor := crHourGlass;
  try
    try
      iNumberOfFiles := DragQueryFile(message.Drop, $FFFFFFFF, nil, 0);
      if iNumberOfFiles = 1 then
      begin
        DragQueryFile(message.Drop, 0, iFilename, SizeOf(iFilename));
        if (FileExists(iFilename)) and (IsKnownFormat(iFilename)) then
        begin
          ImageEnView1.IO.LoadFromFile(iFilename);
          ImageEnView1.Proc.ClearAllUndo;
          ImageEnView1.Proc.ClearAllRedo;
          ImageEnView1.MouseInteract := [];
          StatusBar1.Panels[0].Text := ExtractFileDir(iFilename);
          StatusBar1.Panels[1].Text := ExtractFileName(iFilename);
        end
        else
        begin
          MessageBox(0, 'The file is not supported.', 'Warning',
            MB_ICONWARNING or MB_OK);
        end;
      end
      else
        MessageBox(0,
          'This application only allows dropping one file at a time.',
          'Warning', MB_ICONWARNING or MB_OK);
    finally
      DragFinish(message.Drop);
    end;
    inherited;
  finally
    Screen.Cursor := crDefault;
  end;
end;

end.