aspjpeg设置透明文字水印

<%
LocalFile="supidea.com.jpg"
TargetFile="supidea.jpg"
Dim Jpeg
Set Jpeg = Server.CreateObject("Persits.Jpeg")
If -2147221005=Err then
Response.write "没有这个组件，请安装!"             '检查是否安装AspJpeg组件
Response.End()
End If
Jpeg.Open Server.MapPath(LocalFile)                                           '打开图片
If err.number then
Response.write"打开图片失败,请检查路径！"
Response.End()
End if
Dim aa
aa=Jpeg.Binary                                                      '将原始数据赋给aa
Jpeg.Canvas.Font.Color = &Hfffffff                         '水印文字颜色
Jpeg.Canvas.Font.Family = Arial                            '字体
Jpeg.Canvas.Font.Bold = True                               '是否加粗
Jpeg.Canvas.Font.Size = 35                                   '字体大小
Jpeg.Canvas.Font.ShadowColor = &H000000        '阴影色彩
Jpeg.Canvas.Font.ShadowYOffset = 1 '阴影X轴偏移
Jpeg.Canvas.Font.ShadowXOffset = 1 ‘阴影Y轴偏移
Jpeg.Canvas.Brush.Solid = True ’文字加粗
Jpeg.Canvas.Font.Quality = 4                                '输出质量
Jpeg.Canvas.PrintText Jpeg.OriginalWidth/2-100,Jpeg.OriginalHeight/2+20, "www.supidea.com"    '水印位置及文字
bb=Jpeg.Binary                                                       '将文字水印处理后的值赋给bb，这时，文字水印没有不透明度

'============调整文字透明度================
Set MyJpeg = Server.CreateObject("Persits.Jpeg")
MyJpeg.OpenBinary aa
Set Logo = Server.CreateObject("Persits.Jpeg")
Logo.OpenBinary bb
MyJpeg.DrawImage 0,0, Logo, 0.2                           '0.2是透明度
cc=MyJpeg.Binary                                                    '将最终结果赋值给cc,这时也可以生成目标图片了
response.BinaryWrite cc                                          '将二进输出给浏览器
MyJpeg.Save (TargetFile)
set aa=nothing
set bb=nothing
set cc=nothing
Jpeg.close
MyJpeg.Close
Logo.Close   
%>