获得jpg文件的实际尺寸 -pc6资讯

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获得jpg文件的实际尺寸 时间：2004/11/7 4:11:00来源：本站整理作者：蓝点我要评论(0): bask

把它编译成组件就可以用了，还支持png

'I have released this source code into the public domain.  You may use it

'with no strings attached.

'Just call GetImageSize with a string containing the filename, and

'it will return a user defined type 'ImageSize'  (see below)

'Return values of 0 indicate an error of some sort.  The error handling

'in this module is limited.  There is *NO* error handling on the test

'form.  This routine is limited to X or Y sizes of 32767 pixels, but that

'should not be a problem.

'Check back at http://www.qtm.net/~davidc

'I may add support for more file types.

'supported in this version:

'JPEG

'GIF

'PNG

'This routine does not require any royalty fees for Unisys as it

'does nothing with the compressed part of GIF files.  It simply reads

'4 bytes to determine image size.

Option Explicit

Public WImg As Long

Public HImg As Long

Public Type ImageSize

    Width As Long

    Height As Long

End Type

Public Sub GetImageSize(sFileName As String)

    On Error Resume Next        'you'll want to change this

    Dim iFN As Integer

    Dim bTemp(3) As Byte

    Dim lFlen As Long

    Dim lPos As Long

    Dim bHmsb As Byte

    Dim bHlsb As Byte

    Dim bWmsb As Byte

    Dim bWlsb As Byte

    Dim bBuf(7) As Byte

    Dim bDone As Byte

    Dim iCount As Integer

    lFlen = FileLen(sFileName)

    iFN = FreeFile

    Open sFileName For Binary As iFN

    Get #iFN, 1, bTemp()



    'PNG file

    If bTemp(0) = &H89 And bTemp(1) = &H50 And bTemp(2) = &H4E _

    And bTemp(3) = &H47 Then

        Get #iFN, 19, bWmsb

        Get #iFN, 20, bWlsb

        Get #iFN, 23, bHmsb

        Get #iFN, 24, bHlsb

        'GetImageSize.Width = CombineBytes(bWlsb, bWmsb)

        'GetImageSize.Height = CombineBytes(bHlsb, bHmsb)

        WImg = CombineBytes(bWlsb, bWmsb)

        HImg = CombineBytes(bHlsb, bHmsb)

    End If



    'GIF file

    If bTemp(0) = &H47 And bTemp(1) = &H49 And bTemp(2) = &H46 _

    And bTemp(3) = &H38 Then

        Get #iFN, 7, bWlsb

        Get #iFN, 8, bWmsb

        Get #iFN, 9, bHlsb

        Get #iFN, 10, bHmsb

        'GetImageSize.Width = CombineBytes(bWlsb, bWmsb)

        'GetImageSize.Height = CombineBytes(bHlsb, bHmsb)

        WImg = CombineBytes(bWlsb, bWmsb)

        HImg = CombineBytes(bHlsb, bHmsb)

    End If





    'JPEG file

    If bTemp(0) = &HFF And bTemp(1) = &HD8 And bTemp(2) = &HFF Then

    Debug.Print "JPEG"

        lPos = 3

        Do

            Do

                Get #iFN, lPos, bBuf(1)

                Get #iFN, lPos + 1, bBuf(2)

                lPos = lPos + 1

            Loop Until (bBuf(1) = &HFF And bBuf(2) <> &HFF) Or lPos > lFlen



            For iCount = 0 To 7

                Get #iFN, lPos + iCount, bBuf(iCount)

            Next iCount

            If bBuf(0) >= &HC0 And bBuf(0) <= &HC3 Then

                bHmsb = bBuf(4)

                bHlsb = bBuf(5)

                bWmsb = bBuf(6)

                bWlsb = bBuf(7)

                bDone = 1

            Else

                lPos = lPos + (CombineBytes(bBuf(2), bBuf(1))) + 1

            End If

        Loop While lPos < lFlen And bDone = 0

        'GetImageSize.Width = CombineBytes(bWlsb, bWmsb)

        'GetImageSize.Height = CombineBytes(bHlsb, bHmsb)

        WImg = CombineBytes(bWlsb, bWmsb)

        HImg = CombineBytes(bHlsb, bHmsb)

    End If

    Close iFN



End Sub

Private Function CombineBytes(lsb As Byte, msb As Byte) As Long

    CombineBytes = CLng(lsb + (msb * 256))

End Function

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