Visual Basic6 网游登录器样式窗体

可以用双层窗体做叠加

form1的窗口代码，可以加在load里

Option Explicit
Dim od As New opacityDraw

Private Sub Form_Load()
    od.initi me,App.path & "\bg.png"
End Sub

Option Explicit

Private Const ULW_OPAQUE = &H4
Private Const ULW_COLORKEY = &H1
Private Const ULW_ALPHA = &H2
Private Const BI_RGB As Long = 0&
Private Const DIB_RGB_COLORS As Long = 0
Private Const AC_SRC_ALPHA As Long = &H1
Private Const AC_SRC_OVER = &H0
Private Const WS_EX_LAYERED = &H80000
Private Const GWL_STYLE As Long = -16
Private Const GWL_EXSTYLE As Long = -20
Private Const HWND_TOPMOST As Long = -1
Private Const SWP_NOMOVE As Long = &H2
Private Const SWP_NOSIZE As Long = &H1

Private Type BLENDFUNCTION
    BlendOp As Byte
    BlendFlags As Byte
    SourceConstantAlpha As Byte
    AlphaFormat As Byte
End Type

Private Type size
    cx As Long
    cy As Long
End Type

Private Type POINTAPI
    X As Long
    Y As Long
End Type

Private Type RGBQUAD
    rgbBlue As Byte
    rgbGreen As Byte
    rgbRed As Byte
    rgbReserved As Byte
End Type

Private 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

Private Type BITMAPINFO
    bmiHeader As BITMAPINFOHEADER
    bmiColors As RGBQUAD
End Type


Private Declare Function GdipCreateFromHDC Lib "gdiplus" (ByVal hdc As Long, graphics As Long) As GpStatus
Private Declare Function GdipCreateFromHWND Lib "gdiplus" (ByVal hwnd As Long, graphics As Long) As GpStatus
Private Declare Function GdipDeleteGraphics Lib "gdiplus" (ByVal graphics As Long) As GpStatus
Private Declare Function GdipGetDC Lib "gdiplus" (ByVal graphics As Long, hdc As Long) As GpStatus
Private Declare Function GdipReleaseDC Lib "gdiplus" (ByVal graphics As Long, ByVal hdc As Long) As GpStatus
Private Declare Function GdipDrawImageRect Lib "gdiplus" (ByVal graphics As Long, ByVal image As Long, ByVal X As Single, ByVal Y As Single, ByVal Width As Single, ByVal Height As Single) As GpStatus
Private Declare Function GdipLoadImageFromFile Lib "gdiplus" (ByVal FileName As String, image As Long) As GpStatus
Private Declare Function GdipCloneImage Lib "gdiplus" (ByVal image As Long, cloneImage As Long) As GpStatus
Private Declare Function GdipGetImageWidth Lib "gdiplus" (ByVal image As Long, Width As Long) As GpStatus
Private Declare Function GdipGetImageHeight Lib "gdiplus" (ByVal image As Long, Height As Long) As GpStatus
Private Declare Function GdipCreateBitmapFromHBITMAP Lib "gdiplus" (ByVal hbm As Long, ByVal hpal As Long, bitmap As Long) As GpStatus
Private Declare Function GdipBitmapGetPixel Lib "gdiplus" (ByVal bitmap As Long, ByVal X As Long, ByVal Y As Long, color As Long) As GpStatus
Private Declare Function GdipBitmapSetPixel Lib "gdiplus" (ByVal bitmap As Long, ByVal X As Long, ByVal Y As Long, ByVal color As Long) As GpStatus
Private Declare Function GdipDisposeImage Lib "gdiplus" (ByVal image As Long) As GpStatus
Private Declare Function GdipCreateBitmapFromFile Lib "gdiplus" (ByVal FileName As Long, bitmap As Long) As GpStatus

Private Declare Function ReleaseCapture Lib "user32" () As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long

Private Const HTCAPTION = 2
Private Const WM_NCLBUTTONDOWN = &HA1
Private Const WM_SYSCOMMAND = &H112

Private Type GdiplusStartupInput
    GdiplusVersion As Long
    DebugEventCallback As Long
    SuppressBackgroundThread As Long
    SuppressExternalCodecs As Long
End Type

Private Declare Function GdiplusStartup Lib "gdiplus" (token As Long, inputbuf As GdiplusStartupInput, Optional ByVal outputbuf As Long = 0) As GpStatus
Private Declare Sub GdiplusShutdown Lib "gdiplus" (ByVal token As Long)

Private Enum GpStatus
    Ok = 0
    GenericError = 1
    InvalidParameter = 2
    OutOfMemory = 3
    ObjectBusy = 4
    InsufficientBuffer = 5
    NotImplemented = 6
    Win32Error = 7
    WrongState = 8
    Aborted = 9
    FileNotFound = 10
    ValueOverflow = 11
    AccessDenied = 12
    UnknownImageFormat = 13
    FontFamilyNotFound = 14
    FontStyleNotFound = 15
    NotTrueTypeFont = 16
    UnsupportedGdiplusVersion = 17
    GdiplusNotInitialized = 18
    PropertyNotFound = 19
    PropertyNotSupported = 20
End Enum

Private Declare Function BitBlt Lib "gdi32.dll" (ByVal hDestDC As Long, ByVal X As Long, ByVal Y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function AlphaBlend Lib "Msimg32.dll" (ByVal hdcDest As Long, ByVal nXOriginDest As Long, ByVal lnYOriginDest As Long, ByVal nWidthDest As Long, ByVal nHeightDest As Long, ByVal hdcSrc As Long, ByVal nXOriginSrc As Long, ByVal nYOriginSrc As Long, ByVal nWidthSrc As Long, ByVal nHeightSrc As Long, ByVal bf As Long) As Boolean
Private Declare Function UpdateLayeredWindow Lib "user32.dll" (ByVal hwnd As Long, ByVal hdcDst As Long, pptDst As Any, psize As Any, ByVal hdcSrc As Long, pptSrc As Any, ByVal crKey As Long, ByRef pblend As BLENDFUNCTION, ByVal dwFlags As Long) As Long
Private Declare Function CreateDIBSection Lib "gdi32.dll" (ByVal hdc As Long, pBitmapInfo As BITMAPINFO, ByVal un As Long, ByRef lplpVoid As Any, ByVal handle As Long, ByVal dw As Long) As Long
Private Declare Function GetDIBits Lib "gdi32.dll" (ByVal aHDC As Long, ByVal hBitmap As Long, ByVal nStartScan As Long, ByVal nNumScans As Long, lpBits As Any, lpBI As BITMAPINFO, ByVal wUsage As Long) As Long
Private Declare Function SetDIBits Lib "gdi32.dll" (ByVal hdc As Long, ByVal hBitmap As Long, ByVal nStartScan As Long, ByVal nNumScans As Long, lpBits As Any, lpBI As BITMAPINFO, ByVal wUsage As Long) As Long
Private Declare Function CreateCompatibleDC Lib "gdi32.dll" (ByVal hdc As Long) As Long
Private Declare Function SelectObject Lib "gdi32.dll" (ByVal hdc As Long, ByVal hObject As Long) As Long
Private Declare Function DeleteDC Lib "gdi32.dll" (ByVal hdc As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Private Declare Function SetWindowPos Lib "user32.dll" (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal X As Long, ByVal Y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long) As Long
Private Declare Function GetWindowLong Lib "user32.dll" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function GetDC Lib "user32.dll" (ByVal hwnd As Long) As Long

Dim mDC As Long
Dim mainBitmap As Long
Dim blendFunc32bpp As BLENDFUNCTION
Dim token As Long
Dim oldBitmap As Long

Dim frm As Form
Public Sub initi(hwnd As Form, picPath As String)
    Set frm = hwnd
    Dim GpInput As GdiplusStartupInput
    GpInput.GdiplusVersion = 1
    
    If GdiplusStartup(token, GpInput) <> 0 Then
        Exit Sub
    End If
    
    MakeTrans picPath
End Sub

Private Function MakeTrans(pngPath As String) As Boolean
    
    Dim tempBI As BITMAPINFO
    Dim tempBlend As BLENDFUNCTION
    Dim lngHeight As Long, lngWidth As Long
    Dim curWinLong As Long
    Dim img As Long
    Dim graphics As Long
    Dim winSize As size
    Dim srcPoint As POINTAPI
    
    With tempBI.bmiHeader
        .biSize = Len(tempBI.bmiHeader)
        .biBitCount = 32
        .biHeight = frm.ScaleHeight
        .biWidth = frm.ScaleWidth
        .biPlanes = 1
        .biSizeImage = .biWidth * .biHeight * (.biBitCount / 8)
    End With
    mDC = CreateCompatibleDC(frm.hdc)
    mainBitmap = CreateDIBSection(mDC, tempBI, DIB_RGB_COLORS, ByVal 0, 0, 0)
    oldBitmap = SelectObject(mDC, mainBitmap)
    
    Call GdipCreateFromHDC(mDC, graphics)
    Call GdipLoadImageFromFile(StrConv(pngPath, vbUnicode), img)
    Call GdipGetImageHeight(img, lngHeight)
    Call GdipGetImageWidth(img, lngWidth)
    Call GdipDrawImageRect(graphics, img, 0, 0, lngWidth, lngHeight)
    
    curWinLong = GetWindowLong(frm.hwnd, GWL_EXSTYLE)
    
    SetWindowLong frm.hwnd, GWL_EXSTYLE, curWinLong Or WS_EX_LAYERED
    
    srcPoint.X = 0
    srcPoint.Y = 0
    winSize.cx = frm.ScaleWidth
    winSize.cy = frm.ScaleHeight
    
    With blendFunc32bpp
        .AlphaFormat = AC_SRC_ALPHA
        .BlendFlags = 0
        .BlendOp = AC_SRC_OVER
        .SourceConstantAlpha = 255
    End With
    
    Call GdipDisposeImage(img)
    Call GdipDeleteGraphics(graphics)
    Call UpdateLayeredWindow(frm.hwnd, frm.hdc, ByVal 0&, winSize, mDC, srcPoint, 0, blendFunc32bpp, ULW_ALPHA)
    
End Function

Private Sub Class_Terminate()
    On Error Resume Next
    
    Call GdiplusShutdown(token)
    SelectObject mDC, oldBitmap
    DeleteObject mainBitmap
    DeleteObject oldBitmap
    DeleteDC mDC
End Sub