如何在vb6中将bmp转换为jpg?
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'Convert BMP to JPG with this code. (Note: Requires vic32.dll available from 'http://www.catenary.com/) 'PLACE ALL THIS IN A NEW MODULE Declare Function bmpinfo Lib "VIC32.DLL" (ByVal Fname As String,bdat As BITMAPINFOHEADER) As Long Declare Function allocimage Lib "VIC32.DLL" (image As imgdes,ByVal wid As Long,ByVal leng As Long,ByVal BPPixel As Long) As Long Declare Function loadbmp Lib "VIC32.DLL" (ByVal Fname As String,desimg As imgdes) As Long Declare Sub freeimage Lib "VIC32.DLL" (image As imgdes) Declare Function convert1bitto8bit Lib "VIC32.DLL" (srcimg As imgdes,desimg As imgdes) As Long Declare Sub copyimgdes Lib "VIC32.DLL" (srcimg As imgdes,desimg As imgdes) Declare Function savejpg Lib "VIC32.DLL" (ByVal Fname As String,srcimg As imgdes,ByVal quality As Long) As Long ' Image descriptor Type imgdes ibuff As Long stx As Long sty As Long endx As Long endy As Long buffwidth As Long palette As Long colors As Long imgtype As Long bmh As Long hBitmap As Long End Type Type BITMAPINFOHEADER biSize As Long biWidth As Long biHeight As Long biPlanes As Integer biBitCount As Integer biCompression As Long biSizeImage As Long biXPelsPerMeter As Long biYPelsPerMeter As Long biClrUsed As Long biClrImportant As Long End Type 'PLACE THIS IN YOUR FORM DECLERATIONS Private Sub ConvertToJPEG(bmp_fname As String,jpg_fname As String,Optional quality As Long) Dim tmpimage As imgdes ' Image descriptors Dim tmp2image As imgdes Dim rcode As Long 'Dim quality As Long Dim vbitcount As Long Dim bdat As BITMAPINFOHEADER ' Reserve space for BMP struct 'Dim bmp_fname As String 'Dim jpg_fname As String 'bmp_fname = "test.bmp" 'jpg_fname = "test.jpg" If quality = 0 Then quality = 75 ' Get info on the file we're to load rcode = bmpinfo(bmp_fname,bdat) If (rcode <> NO_ERROR) Then msgBox "error: Unable to get file info" Exit Sub End If vbitcount = bdat.biBitCount If (vbitcount >= 16) Then ' 16-,24-,or 32-bit image is loaded into 24-bit buffer vbitcount = 24 End If ' Allocate space for an image rcode = allocimage(tmpimage,bdat.biWidth,bdat.biHeight,vbitcount) If (rcode <> NO_ERROR) Then msgBox "error: Not enough memory" Exit Sub End If ' Load image rcode = loadbmp(bmp_fname,tmpimage) If (rcode <> NO_ERROR) Then freeimage tmpimage ' Free image on error msgBox "error: Cannot load file" Exit Sub End If If (vbitcount = 1) Then ' If we loaded a 1-bit image,convert to 8-bit grayscale ' because jpeg only supports 8-bit grayscale or 24-bit color images rcode = allocimage(tmp2image,8) If (rcode = NO_ERROR) Then rcode = convert1bitto8bit(tmpimage,tmp2image) freeimage tmpimage ' Replace 1-bit image with grayscale image copyimgdes tmp2image,tmpimage End If End If ' Save image rcode = savejpg(jpg_fname,tmpimage,quality) freeimage tmpimage Kill bmp_fname msgBox "picture saved: " & jpg_fname End Sub