[VB6] salvare immagine jpeg

[nik600]

ciao a tutti

sto utilizzando uil comando

savepicture (nomeoggetto,nomefile)

x salvare un'immagine jpeg, ho visto però (anche nella documentazione) che questo comando permette solo di salvare in formato bmp con conseguenze disastrose sulla dimensione del file!!

se io volessi salvare l'immagine utilizzando il formato jpeg, come posso fare?

grazie

[nik600]

ciao ci sono riuscito!

ho trovato questi script in internet che si basano sulla dll vic32.dll

che se non avete, dovete mettere nella cartella c:\%systemroot%\system

modulo della funzione:
Public Sub creajpeg(nomebmp As String, nomejpeg As String)
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"

bmp_fname = nomebmp
jpg_fname = nomejpeg

quality = 75
' Get info on the file we're to load
rcode = bmpinfo(bmp_fname, bdat)
If (rcode <> NO_ERROR) Then
MsgBox "Cannot find file", 0, "Error encountered!"
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

'prove di ridimensionamento
bdat.biWidth = 30
bdat.biHeight = 30

' Allocate space for an image
rcode = allocimage(tmpimage, bdat.biWidth, bdat.biHeight, vbitcount)
If (rcode <> NO_ERROR) Then
MsgBox "Not enough memory", 0, "Error encountered!"
Exit Sub
End If

' Load image
rcode = loadbmp(bmp_fname, tmpimage)
If (rcode <> NO_ERROR) Then
freeimage tmpimage ' Free image on error
MsgBox "Cannot load file", 0, "Error encountered!"
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

End Sub


modulo delle definizioni:

' 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

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




naturalmente potete apportare modifiche alla funzione che crea la jpeg, passandole ad esempio valori x definire dimensioni..qualità..ecc!


ciao e grazie( :gren: )