// Read the count of the images in a file
function GetPDFPageCount(const AFileName: String): Integer;
var
  iImageEnIO: TImageEnIO;
  iPages: Integer;
begin
  Result := -1;
  iImageEnIO := TImageEnIO.Create(nil);
  iImageEnIO.ParamsFromFile(AFileName);
  iPages := iImageEnIO.Params.ImageCount;
  Result := iPages;
  iImageEnIO.Free;
end;

procedure TForm1.Open1Click(Sender: TObject);
var
  i: Integer;
  iPageCount: Integer;
  iFilename: string;
begin
  if OpenPictureDialog1.Execute then
  begin
    if TIEMiscPluginsImageMagick.IsAvailable then
    begin
      ImageEnMView1.Clear;
      iFilename := OpenPictureDialog1.FileName;
      if FileExists(iFilename) then
      begin
        iPageCount := GetPDFPageCount(iFilename);
        for i := 0 to iPageCount - 1 do
          ImageEnMView1.AppendImage(iFilename + IEM_Path_Index_Delimiter +
            IntToStr(i));
        ImageEnView1.IO.Params.ImageIndex := 1;
        ImageEnView1.IO.Params.Dict.Insert('PDF:Density', 200);
        ImageEnView1.IO.LoadFromFile(iFilename);
        ImageEnView1.Fit;
        Caption := 'PDF- ' + iFilename;
        StatusBar1.Panels[0].Text := ExtractFileDir(iFilename);
        StatusBar1.Panels[1].Text := ExtractFileName(iFilename);
        StatusBar1.Panels[2].Text := IntToStr(iPageCount);
      end;
    end
    else
    begin
      MessageBox(0, 'Failed to load ImageMagick plugin.', 'Warning',
        MB_ICONWARNING or MB_OK);
    end;
  end;
end;