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'ofd 是打开文件对话框

Dim img As Bitmap
Dim iscmyk As Boolean
Dim i As String
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click


    ofd.Filter = "Jpg Image(*.jpg)|*.jpg"
    If ofd.ShowDialog = Windows.Forms.DialogResult.OK Then
        img = Bitmap.FromFile(ofd.FileName)
        iscmyk = ((DirectCast(img.Flags, Imaging.ImageFlags) And Imaging.ImageFlags.ColorSpaceCmyk) = Imaging.ImageFlags.ColorSpaceCmyk)
    End If
    img = New Bitmap(img, New Size(120, 190))
    MsgBox("cmyk = " & iscmyk)
    PictureBox1.Image = img
End Sub

我需要检查图像是 cmyk 还是 rgb 如果它的 cmyk 然后 iscmyk 返回 true 如果它不是 cmyk 然后 iscmyk 在我的 Windows 7 pc 中返回 false 它为每个图像返回 false 但在 XP 中它返回完美的答案

为什么它不能在我的其他 win7 电脑上工作？？？

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1 回答 1

2
  • 首先，抱歉这么晚才回复...
  • 其次，实际上我不知道为什么你会在不同的操作系统版本上得到不同的结果。

无论如何，这是一个低级（且丑陋）的解决方法。它专为 JPEG 图像而设计：

Public Shared Function GetJpegBpp(FileName As String) As Integer
    Dim len As Integer
    Dim fp As FileStream = Nothing
    Dim marker(1) As Byte
    Dim data(15) As Byte
    Dim components As Byte = 0

    GetJpegBpp = -2
    Try
        fp = New FileStream(FileName, FileMode.Open, FileAccess.Read)
        GetJpegBpp = -1
        If fp.Read(marker, 0, 2) < 2 OrElse marker(0) <> &HFF OrElse marker(1) <> &HD8 Then Exit Function
        Do
            If fp.Read(marker, 0, 2) < 2 OrElse marker(0) <> &HFF OrElse (marker(1) > 1 And marker(1) < &HC0) Then Exit Function
            If (marker(1) < &HD0 Or marker(1) > &HD9) AndAlso marker(1) > 1 Then
                If fp.Read(data, 0, 2) < 2 Then Exit Function
                len = (CInt(data(0)) << 8) Or data(1)
                len -= 2
                If len < 0 Then Exit Function
                If (marker(1) >= &HC0) And (marker(1) <= &HC3) Then
                    If len < 9 OrElse fp.Read(data, 0, 6) < 6 Then Exit Function
                    components = data(5)
                    If components = 0 OrElse components = 2 OrElse components > 4 OrElse (components * 3 + 6) <> len Then Exit Function
                    len -= 6
                ElseIf marker(1) = &HDA Then
                    If len < (4 + 2 * components) Or (fp.ReadByte() <> components) Then Exit Function
                    len -= 1
                End If
                fp.Position += len
            End If
        Loop Until marker(1) = &HDA Or marker(1) = &HD9
        If components = 0 OrElse marker(1) = &HD9 OrElse (fp.Length - fp.Position) < 3 Then Exit Function
    Catch
        Exit Function
    Finally
        If Not fp Is Nothing Then fp.Close()
    End Try
    GetJpegBpp = components * 8
End Function

您需要替换此行

iscmyk = ((DirectCast(img.Flags, Imaging.ImageFlags) And Imaging.ImageFlags.ColorSpaceCmyk) = Imaging.ImageFlags.ColorSpaceCmyk)

有了这个：

iscmyk = (GetJpegBpp(ofd.FileName) = 32)

最后，我还没有用 CMYK JPEG 图像测试过这段代码，但我想它应该可以工作......

于 2012-10-30T05:45:34.070 回答