怎样把图片保存为jpg格式
使用这个SavePicture,保存出来的图片是BMP格式
我怎样才可以保存为JPG格式的呢
[解决办法]
Saving images to JPG using GDI+
This function saves a StdPicture object to a file with JPG format using the GDI+ encoder. Just call the function passing the image object, the filename and, optionally, the image quality (from 1 to 100) .
' ----==== API Declarations ====----
Private Type GUID
Data1 As Long
Data2 As Integer
Data3 As Integer
Data4(0 To 7) As Byte
End Type
Private Type GdiplusStartupInput
GdiplusVersion As Long
DebugEventCallback As Long
SuppressBackgroundThread As Long
SuppressExternalCodecs As Long
End Type
Private Type EncoderParameter
GUID As GUID
NumberOfValues As Long
type As Long
Value As Long
End Type
Private Type EncoderParameters
Count As Long
Parameter As EncoderParameter
End Type
Private Declare Function GdiplusStartup Lib "GDIPlus" ( _
token As Long, _
inputbuf As GdiplusStartupInput, _
Optional ByVal outputbuf As Long = 0) As Long
Private Declare Function GdiplusShutdown Lib "GDIPlus" ( _
ByVal token As Long) As Long
Private Declare Function GdipCreateBitmapFromHBITMAP Lib "GDIPlus" ( _
ByVal hbm As Long, _
ByVal hpal As Long, _
Bitmap As Long) As Long
Private Declare Function GdipDisposeImage Lib "GDIPlus" ( _
ByVal Image As Long) As Long
Private Declare Function GdipSaveImageToFile Lib "GDIPlus" ( _
ByVal Image As Long, _
ByVal filename As Long, _
clsidEncoder As GUID, _
encoderParams As Any) As Long
Private Declare Function CLSIDFromString Lib "ole32" ( _
ByVal str As Long, _
id As GUID) As Long
' ----==== SaveJPG ====----
Public Sub SaveJPG( _
ByVal pict As StdPicture, _
ByVal filename As String, _
Optional ByVal quality As Byte = 80)
Dim tSI As GdiplusStartupInput
Dim lRes As Long
Dim lGDIP As Long
Dim lBitmap As Long
' Initialize GDI+
tSI.GdiplusVersion = 1
lRes = GdiplusStartup(lGDIP, tSI)
If lRes = 0 Then
' Create the GDI+ bitmap
' from the image handle
lRes = GdipCreateBitmapFromHBITMAP(pict.Handle, 0, lBitmap)
If lRes = 0 Then
Dim tJpgEncoder As GUID
Dim tParams As EncoderParameters
' Initialize the encoder GUID
CLSIDFromString StrPtr("{557CF401-1A04-11D3-9A73-0000F81EF32E}"), _
tJpgEncoder
' Initialize the encoder parameters
tParams.Count = 1
With tParams.Parameter ' Quality
' Set the Quality GUID
CLSIDFromString StrPtr("{1D5BE4B5-FA4A-452D-9CDD-5DB3505E7EB}"), .GUID
.NumberOfValues = 1
.type = 1
.Value = VarPtr(quality)
End With
' Save the image
lRes = GdipSaveImageToFile( _
lBitmap, _
StrPtr(filename), _
tJpgEncoder, _
tParams)
' Destroy the bitmap
GdipDisposeImage lBitmap
End If
' Shutdown GDI+
GdiplusShutdown lGDIP
End If
If lRes Then
Err.Raise 5, , "Cannot save the image. GDI+ Error:" & lRes
End If
End Sub
