by Chris Wilson (9 Submissions)
Category: Graphics
Compatability: VB 6.0
Difficulty: Unknown Difficulty
Originally Published: Sat 14th April 2001
Date Added: Mon 8th February 2021
Rating: 
(1 Votes)
Convert BMP to JPG with this easy to use code. (Note: Requires vic32.dll available from https://www.catenary.com/)
API Declarations
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
VBcoders
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, bdat.biWidth, bdat.biHeight, 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
No comments have been posted about Convert BMP to JPG with this easy to use code. (Note: Requires vic32.dll available from http://www.. Why not be the first to post a comment about Convert BMP to JPG with this easy to use code. (Note: Requires vic32.dll available from http://www..
