从图像文件中提取属性

Question

有没有什么办法从vb 6.0中提取图像文件的属性？我想浏览特定的照片，然后从任何图像格式中提取如下属性。

Answer 1

如果安装WIA 2.0（需要XP SP1，在Vista和Windows 7预安装），你可以这样做：

Private Sub Command1_Click() 
    Dim imfSubject As WIA.ImageFile 
    Dim vecProperty As WIA.Vector 
    Dim propEach As WIA.Property 

    With CommonDialog1 
     .CancelError = True 
     .DialogTitle = "Select JPEG Image" 
     .Filter = "JPEG Image (*.jpg, *.jpeg)|*.jpg;*.jpeg|" _ 
       & "GIF Image (*.gif)|*.gif|" _ 
       & "PNG Image (*.png)|*.png" 
     .FilterIndex = 1 
     .Flags = cdlOFNExplorer _ 
       Or cdlOFNFileMustExist _ 
       Or cdlOFNLongNames _ 
       Or cdlOFNPathMustExist _ 
       Or cdlOFNShareAware 
     .InitDir = strStartDir 
     On Error Resume Next 
     .ShowOpen 
     If Err.Number = cdlCancel Then Exit Sub 
     On Error GoTo 0 

     Log "Photo " & .FileName, ClearLog:=True 
     Log 
    End With 

    Set imfSubject = New WIA.ImageFile 
    With imfSubject 
     On Error Resume Next 
     .LoadFile (CommonDialog1.FileName) 
     If Err.Number <> 0 Then 
      Log "Error &H" & Hex$(Err.Number) & " (" & CStr(Err.Number) & ") in " _ 
       & Err.Source 
      Log Err.Description 
      Err.Clear 
      Exit Sub 
     End If 

     Log "Width = " & .Width 
     Log "Height = " & .Height 
     Log "Depth = " & .PixelDepth 
     Log "HorizontalResolution = " & .HorizontalResolution 
     Log "VerticalResolution = " & .VerticalResolution 
     Log "FrameCount = " & .FrameCount 

     If .IsIndexedPixelFormat Then 
      Log "Pixel data contains palette indexes" 
     End If 

     If .IsAlphaPixelFormat Then 
      Log "Pixel data has alpha information" 
     End If 

     If .IsExtendedPixelFormat Then 
      Log "Pixel data has extended color information (16 bit/channel)" 
     End If 

     If .IsAnimated Then 
      Log "Image is animated" 
     End If 

     For Each propEach In .Properties 
      Select Case propEach.Name 
       Case "40091" 
        Set vecProperty = propEach.Value 
        Log "Title = " & vecProperty.String 

       Case "40092" 
        Set vecProperty = propEach.Value 
        Log "Comment = " & vecProperty.String 

       Case "40093" 
        Set vecProperty = propEach.Value 
        Log "Author = " & vecProperty.String 

       Case "40094" 
        Set vecProperty = propEach.Value 
        Log "Keywords = " & vecProperty.String 

       Case "40095" 
        Set vecProperty = propEach.Value 
        Log "Subject = " & vecProperty.String 

       Case Else 
        Log propEach.Name & " = " & CStr(propEach.Value) 
      End Select 
     Next 
    End With 
End Sub 

代码假设strStartDir是一个全球性的字符串设定为起始文件夹用于浏览并且记录结果有Log子）。它生产基于图像文件中的信息，例如结果：

Photo C:\Users\George\Pictures\Phone\IMAG0005.jpg 

Width = 1600 
Height = 1200 
Depth = 24 
HorizontalResolution = 96 
VerticalResolution = 96 
FrameCount = 1 
EquipMake = HTC 
EquipModel = VOGU100 
XResolution = 72 
YResolution = 72 
ResolutionUnit = 2 
DateTime = 2010:05:17 11:54:38 
Artist = Bob Riemersma 
ExifDTOrig = 2010:05:17 11:54:38 
ExifFlash = 0 
ExifPixXDim = 1600 
ExifPixYDim = 1200 
ExifColorSpace = -1 
ExifDTDigitized = 2010:05:17 11:54:38 
ThumbnailImageWidth = 160 
ThumbnailImageHeight = 120 
ThumbnailCompression = 6 
JPEGInterFormat = 368 

您也可以使用命令对象检索的Windows值的属性对话框中的值，但是这可能是有风险的，因为不同的Windows版本，把他们涉及收集的不同点。