70(1).txt

VB文章集（含API、窗口、数据库、多媒体、系统、文件、等等）

　　 Pict(0, Y) = 0
　　 Pict(639, Y) = 0
　　 Next
　　 For X = 0 To 639
　　 Pict(X, 477) = Rnd ＊ 220 ＋ 35
　　 Pict(X, 478) = Rnd ＊ 220 ＋ 35
　　 Pict(X, 479) = Rnd ＊ 220 ＋ 35
　　 Next
　　 Accum = 0
　　 For X = 1 To 638
　　 For Y = 0 To 477
　　 Accum = (Accum ＋ Pict(X, Y ＋ 1) _
　　 ＋ Pict(X, Y ＋ 2) _
　　 ＋ Pict(X ＋ 1, Y ＋ 1) _
　　 ＋ Pict(X － 1, Y ＋ 1)) \ 5
　　 If Accum < 0 Then
　　 Accum = 0
　　 ElseIf Accum > 255 Then
　　 Accum = 255
　　 End If
　　 Pict(X, Y) = Accum
　　 Next
　　 Next
　　 For X = 0 To 639
　　 Pict(X, 0) = 0
　　 Pict(X, 1) = 0
　　 Next
　　 X = Rnd ＊ 639
　　 For Y = 50 To 439
　　 Next
　　 DDSBack.Unlock AlphaRect
　　If DX.TickCount() － lastTime > wait Then
　　 If Counter = 0 Then
　　 bDrawText = True
　　 Counter = 1
　　 XPos = Rnd ＊ 200
　　 YPos = 300 ＋ Rnd ＊ 140
　　 wait = 400
　　 ElseIf Counter = 1 Then
　　 MsgIndex = MsgIndex ＋ 1
　　 If MsgIndex > 5 Then MsgIndex = 0
　　 bDrawText = False
　　 Counter = 0
　　 wait = 2000
　　 End If
　　 lastTime = DX.TickCount
　　 End If
　　 If bDrawText Then
　　 On Error Resume Next
　　 DDSBack.DrawText XPos, YPos, Msg(MsgIndex), False
　　 On Error GoTo 0
　　 End If
　　 MainForm.Form_Paint
　　 Wend
　　 TerminateDX
　　 End
　　End Sub
　　Function ExModeActive() As Boolean
　　 Dim TestCoopRes As Long
　　TestCoopRes = DDraw.TestCooperativeLevel
　　 Select Case TestCoopRes
　　 Case DDERR_NOEXCLUSIVEMODE
　　 ExModeActive = False
　　 Case DD_OK
　　 ExModeActive = True
　　 End Select
　　End Function
　　Public Sub InitializeDX()
　　MainForm.Left = 0
　　MainForm.Top = 0
　　MainForm.Height =640 ＊ Screen.TwipsPerPixelY
　　MainForm.Width = 480 ＊ Screen.TwipsPerPixelX
　　MainForm.Show
　　 '建立DirectDraw对象
　　 Set DDraw = DX.DirectDrawCreate(“”)
　　 '设定DirectDraw对象的协作层
　　 DDraw.SetCooperativeLevel MainForm.hWnd, DDSCL_EXCLUSIVE Or DDSCL_FULLSCREEN ' DDSCL_NORMAL
　　 '设定显示模式位640×480×8位颜色
　　 DDraw.SetDisplayMode 640, 480, 8, 0, DDSDM_DEFAULT
　　 '设定DDSFrontDesc为主平面
　　 With DDSFrontDesc
　　.lFlags = DDSD_CAPS
　　.ddsCaps.lCaps = DDSCAPS_PRIMARYSURFACE 'Or DDSCAPS_SYSTEMMEMORY
　　 End With
　　 '设定DDSBackDesc为后台缓冲平面
　　 With DDSBackDesc
　　.ddsCaps.lCaps = DDSCAPS_SYSTEMMEMORY
　　.lFlags = DDSD_CAPS Or DDSD_WIDTH Or DDSD_HEIGHT
　　.lWidth = 640
　　.lHeight = 480
　　 End With
　　 '建立平面
　　 Set DDSFront = DDraw.CreateSurface(DDSFrontDesc)
　　 Set DDSBack = DDraw.CreateSurface(DDSBackDesc)
　　 Set Clipper = DDraw.CreateClipper(0)
　　 Clipper.SetHWnd MainForm.hWnd
　　 DDSFront.SetClipper Clipper
　　 DDSBack.SetClipper Clipper
　　 DoEvents
　　 Exit Sub
　　ERRoUT:
　　 If Not (DDraw Is Nothing) Then
　　 DDraw.RestoreDisplayMode
　　 DDraw.SetCooperativeLevel MainForm.hWnd, DDSCL_NORMAL
　　 DoEvents
　　 End If
　　 MsgBox “无法对DirectDraw进行初始化 ”＋Chr(13)＋“也许你的显示卡不支持 640×480×8 显示模式 ”
　　 End
　　End Sub
　　Public Sub TerminateDX()
　　 '子程序TerminateDX回复原来的显示模式并且释放所有的DirectDraw有关对象
　　 DDraw.RestoreDisplayMode
　　 DDraw.SetCooperativeLevel MainForm.hWnd, DDSCL_NORMAL
　　 DoEvents
　　 Set Clipper = Nothing
　　 Set DDSBack = Nothing
　　 Set DDSFront = Nothing
　　 Set DDraw = Nothing
　　 Set DX = Nothing
　　End Sub
　　在工程文件中再加入一个Module，这个Module主要定义与图像保存相关的操作，在建立的Module中加入以下代码：
　　 Option Explicit
　　Option Base 0
　　Private Type PALETTEENTRY
　　 peRed As Byte
　　 peGreen As Byte
　　 peBlue As Byte
　　 peFlags As Byte
　　End Type
　　
　　Private Type LOGPALETTE
　　 palVersion As Integer
　　 palNumEntries As Integer
　　 palPalEntry(255) As PALETTEENTRY
　　End Type
　　
　　Private Type GUID
　　 Data1 As Long
　　 Data2 As Integer
　　 Data3 As Integer
　　 Data4(7) As Byte
　　End Type
　　Private Const RASTERCAPS As Long = 38
　　Private Const RC_PALETTE As Long = ＆H100
　　Private Const SIZEPALETTE As Long = 104
　　Private Declare Function CreateCompatibleDC Lib “GDI32” (ByVal hDC As Long) As Long
　　Private Declare Function CreateCompatibleBitmap Lib “GDI32” (ByVal hDC As Long, ByVal nWidth As Long, ByVal nHeight As Long) As Long
　　Private Declare Function GetDeviceCaps Lib “GDI32” (ByVal hDC As Long, ByVal iCapabilitiy As Long) As Long
　　Private Declare Function GetSystemPaletteEntries Lib “GDI32” (ByVal hDC As Long, ByVal wStartIndex As Long, ByVal wNumEntries As Long, lpPaletteEntries As PALETTEENTRY) As Long
　　Private Declare Function CreatePalette Lib “GDI32”(lpLogPalette As LOGPALETTE) As Long
　　Private Declare Function SelectObject Lib “GDI32”(ByVal hDC As Long, ByVal hObject As Long) As Long
　　Private Declare Function BitBlt Lib “GDI32”(ByVal hDCDest As Long, ByVal XDest As Long, ByVal YDest As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hdcSrc As Long, ByVal XSrc As Long, ByVal YSrc As Long, ByVal dwRop As Long) As Long
　　Private Declare Function DeleteDC Lib “GDI32”(ByVal hDC As Long) As Long
　　Private Declare Function GetForegroundWindow Lib “USER32” () As Long
　　Private Declare Function SelectPalette Lib “GDI32”(ByVal hDC As Long, ByVal hPalette As Long, ByVal bForceBackground As Long) As Long
　　Private Declare Function RealizePalette Lib “GDI32” (ByVal hDC As Long) As Long
　　Private Declare Function GetWindowDC Lib “USER32” (ByVal hWnd As Long) As Long
　　Private Declare Function GetDC Lib “USER32"(ByVal hWnd As Long) As Long
　　Private Declare Function GetWindowRect Lib “USER32”(ByVal hWnd As Long, lpRect As RECT) As Long
　　Private Declare Function ReleaseDC Lib “USER32”(ByVal hWnd As Long, ByVal hDC As Long) As Long
　　Private Declare Function GetDesktopWindow Lib “{USER32"() As Long
　　
　　Private Type PicBmp
　　 Size As Long
　　 Type As Long
　　 hBmp As Long
　　 hPal As Long
　　 Reserved As Long
　　End Type
　　Private Declare Function OleCreatePictureIndirect Lib “olepro32.dll” (PicDesc As PicBmp, RefIID As GUID, ByVal fPictureOwnsHandle As Long, IPic As IPicture) As Long
　　
　　Public Function SaveTohBmp(ByVal hdcSrc As Long, ByVal LeftSrc As Long, _
　　 ByVal TopSrc As Long, ByVal WidthSrc As Long, ByVal HeightSrc As Long) As Picture
　　 Dim hDCMemory As Long
　　 Dim hBmp As Long
　　 Dim hBmpPrev As Long
　　 Dim r As Long
　　 Dim hPal As Long
　　 Dim hPalPrev As Long
　　 Dim RasterCapsScrn As Long
　　 Dim HasPaletteScrn As Long
　　 Dim PaletteSizeScrn As Long
　　 Dim LogPal As LOOGPALETTE
　　 '建立一个内存图形设备句柄
　　hDCMemory=CreateCompatibleDC(hdcSrc)
　　'建立一个bitmap并保存到hDCMemory中
　　hBmp = CreateCompatibleBitmap(hdcSrc, WidthSrc, HeightSrc)
　　 hBmpPrev = SelectObject(hDCMemory, hBmp)
　　 RasterCapsScrn = GetDeviceCaps(hdcSrc, RASTE图CAPS) 'rRaste
　　 HasPaletteScrn = RasterCapsScrn And RC_PALtTTEic1 ' Palette
　　 PaletteSizeScrn = GetDeviceCaps(hdcSrc, SIZEPALETTE) ' Size of
　　 If HasPaletteScrn And (PaletteSizeScrn = 256) Then
　　 '建立系统调色板的拷贝
　　 LogPal.palVersion = ＆H300
　　 LogPal.palNumEntries = 256
　　 r = GetSystemPaletteEntries(hdcSrc, 0, 256, LogPal.palPalEntry(0))
　　 hPal = CreatePalette(LogPal)
　　 hPalPrev = SelectPalette(hDCMemory, hPal, 0)
　　 r = RealizePalette(hDCMemory)
　　 End If
　　 '将屏幕图形拷贝到内存图形设备句柄中
　　 r = BitBlt(hDCMemory, 0, 0, WidthSrc, HeightSrc, hdcSrc, LeftSrc, TopSrc, vbSrcCopy)
　　 hBmp = SelectObject(hDCMemory, hBmpPrev)
　　 If HasPaletteScrn And (PaletteSizeScrn = 256) Then
　　 hPal = SelectPalette(hDCMemory, hPalPrev, 0)
　　 End If
　　'释放图形设备句柄
　　 r = DeleteDC(hDCMemory)
　　 Debug.Print r
　　  '调用CreateBitmapPicture函数从指定的bitmap对象和调色板中建立一个picture对象
　　 Set SaveTohBmp = CreateBitmapPicture(hBmp, hPal)
　　End Function
　　Public Function CreateBitmapPicture(ByVal hBmp As Long, ByVal hPal As Long) As Picture
　　 Dim r As Long
　　 Dim Pic As PicBmp
　　 Dim IPic As IPicture
　　 Dim IID_IDispatch As GUID
　　 '填充IDispatch界面
　　 With IID_IDispatch
　　 .Data1 = ＆H20400
　　 .Data4(0) = ＆HC0
　　 .Data4(7) = ＆H46
　　 End With
　　 '填充Pic结构
　　 With Pic
　　 .Size = Len(Pic) ' Length of structure.
　　 .Type = vbPicTypeBitmap ' Type of Picture (bitmap).
　　 .hBmp = hBmp ' Handle to bitmap.
　　 .hPal = hPal ' Handle to palette (may be null).
　　 End With
　　 '建立Picture对象
　　 r = OleCreatePictureIndirect(Pic, IID_IDispatch, 1, IPic)
　　 '返回Picture对象
　　 Set CreateBitmapPicture = IPic
　　End Function
　　运行程序，在屏幕上会出现一些火焰字的特效，按Enter键可以将屏幕保存到“c:\a.bmp”中，按Esc键退出程序回到Windows。
　　在上面的程序中，程序首先建立一个DirectDraw对象，然后设置该对象的协作层为全屏协作模式，接下来设置显示模式为640×480×8位颜色，建立一个前台DirectDrawSurface对象和一个后台缓冲DirectDrawSurface对象，建立和设置DirectDrawClipper对象。
　　在主程序段中，程序首先对前台绘图平面的调色板（DirectDrawPalette
　　）对象进行操作以改变显示的文字的颜色，然后对后台缓冲绘图平面进行字节操作，以产生文字弥散的效果，然后再将后台缓冲绘图平面翻转到前台。当用户按下Enter键之后，程序获得与前台绘图平面相兼容的图形设备句柄，然后再调用Windows API函数将绘图平面内存中的内容保存到Windows位图文件中。
　　上面粗略地介绍了DirectX7 SDK的新特性以及初步的DirectDraw编程，希望对大家能有所帮助。以上的程序在Windows98、VB6.0下运行通过。