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| 在VB中利用Windows的API函数可以实现很多的VB无法实现的扩展功能，下面的程序介绍的是如何通过调用Windows中的API函数实现文本旋转显示的特级效果。 首先建立一个工程文件，然后选菜单中的Project | Add Class Module 加入一个新的类文件，并将这个类的Name属性改变为APIFont，然后在类的代码窗口中加入以下的代码： Option Explicit Private Declare Function SelectClipRgn Lib “gdi32”(ByVal hdc As Long, ByVal hRgn As _ Long) As Long Private Declare Function CreateRectRgn Lib “gdi32”(ByVal X1 As Long, ByVal Y1 As _ Long, ByVal X2 As Long, ByVal Y2 As Long) As Long Private Declare Function SetTextColor Lib “gdi32”(ByVal hdc As Long, ByVal crColor As _ Long) As Long Private Declare Function DeleteObject Lib “gdi32”(ByVal hObject As Long) As Long Private Declare Function CreateFontIndirect Lib “gdi32” Alias “CreateFontIndirectA” _ (lpLogFont As LOGFONT) As Long Private Declare Function SelectObject Lib “gdi32”(ByVal hdc As Long, ByVal hObject As _ Long) As Long Private Declare Function TextOut Lib “gdi32” Alias “TextOutA” (ByVal hdc As Long, _ ByVal X As Long, ByVal Y As Long, ByVal lpString As String, ByVal nCount As _ Long) As Long Private Declare Function SetTextAlign Lib “gdi32”(ByVal hdc As Long, ByVal wFlags _ As Long) As Long Private Type RECT Left As Long Top As Long Right As Long Bottom As Long End Type Private Const TA_LEFT = 0 Private Const TA_RIGHT = 2 Private Const TA_CENTER = 6 Private Const TA_TOP = 0 Private Const TA_BOTTOM = 8 Private Const TA_BASELINE = 24 Private Type LOGFONT lfHeight As Long lfWidth As Long lfEscapement As Long lfOrientation As Long lfWeight As Long lfItalic As Byte lfUnderline As Byte lfStrikeOut As Byte lfCharSet As Byte lfOutPrecision As Byte lfClipPrecision As Byte lfQuality As Byte lfPitchAndFamily As Byte lfFaceName As String ＊ 50 End Type Private m_LF As LOGFONT Private NewFont As Long Private OrgFont As Long Public Sub CharPlace(o As Object, txt＄, X, Y) Dim Throw As Long Dim hregion As Long Dim R As RECT R.Left = X R.Right = X ＋ o.TextWidth(txt＄) ＊ 2 R.Top = Y R.Bottom = Y ＋ o.TextHeight(txt＄) ＊ 2 hregion = CreateRectRgn(R.Left, R.Top, R.Right, R.Bottom) Throw = SelectClipRgn(o.hdc, hregion) Throw = TextOut(o.hdc, X, Y, txt＄, Len(txt＄)) DeleteObject (hregion) End Sub Public Sub SetAlign(o As Object, Top, BaseLine, Bottom, Left, Center, Right) Dim Vert As Long Dim Horz As Long If Top = True Then Vert = TA_TOP If BaseLine = True Then Vert = TA_BASELINE If Bottom = True Then Vert = TA_BOTTOM If Left = True Then Horz = TA_LEFT If Center = True Then Horz = TA_CENTER If Right = True Then Horz = TA_RIGHT SetTextAlign o.hdc, Vert Or Horz End Sub Public Sub setcolor(o As Object, Cvalue As Long) Dim Throw As Long Throw = SetTextColor(o.hdc, Cvalue) End Sub Public Sub SelectOrg(o As Object) Dim Throw As Long NewFont = SelectObject(o.hdc, OrgFont) Throw = DeleteObject(NewFont) End Sub Public Sub SelectFont(o As Object) NewFont = CreateFontIndirect(m_LF) OrgFont = SelectObject(o.hdc, NewFont) End Sub Public Sub FontOut(text＄, o As Control, XX, YY) Dim Throw As Long Throw = TextOut(o.hdc, XX, YY, text＄, Len(text＄)) End Sub Public Property Get Width() As Long Width = m_LF.lfWidth End Property Public Property Let Width(ByVal W As Long) m_LF.lfWidth = W End Property Public Property Get Height() As Long Height = m_LF.lfHeight End Property Public Property Let Height(ByVal vNewValue As Long) m_LF.lfHeight = vNewValue End Property Public Property Get Escapement() As Long Escapement = m_LF.lfEscapement End Property Public Property Let Escapement(ByVal vNewValue As Long) m_LF.lfEscapement = vNewValue End Property Public Property Get Weight() As Long Weight = m_LF.lfWeight End Property Public Property Let Weight(ByVal vNewValue As Long) m_LF.lfWeight = vNewValue End Property Public Property Get Italic() As Byte Italic = m_LF.lfItalic End Property Public Property Let Italic(ByVal vNewValue As Byte) m_LF.lfItalic = vNewValue End Property Public Property Get UnderLine() As Byte UnderLine = m_LF.lfUnderline End Property Public Property Let UnderLine(ByVal vNewValue As Byte) m_LF.lfUnderline = vNewValue End Property Public Property Get StrikeOut() As Byte StrikeOut = m_LF.lfStrikeOut End Property Public Property Let StrikeOut(ByVal vNewValue As Byte) m_LF.lfStrikeOut = vNewValue End Property Public Property Get FaceName() As String FaceName = m_LF.lfFaceName End Property Public Property Let FaceName(ByVal vNewValue As String) m_LF.lfFaceName = vNewValue End Property Private Sub Class_Initialize() m_LF.lfHeight = 30 m_LF.lfWidth = 10 m_LF.lfEscapement = 0 m_LF.lfWeight = 400 m_LF.lfItalic = 0 m_LF.lfUnderline = 0 m_LF.lfStrikeOut = 0 m_LF.lfOutPrecision = 0 m_LF.lfClipPrecision = 0 m_LF.lfQuality = 0 m_LF.lfPitchAndFamily = 0 m_LF.lfCharSet = 0 m_LF.lfFaceName = "Arial" ＋ Chr(0) End Sub 在工程文件的Form1中加入一个PictureBox和一个CommandButton控件，然后在Form1的代码窗口中加入以下的代码： Option Explicit Dim AF As APIFont Dim X, Y As Integer Private Sub Command1_Click() Dim I As Integer Set AF = Nothing Set AF = New APIFont Picture2.Cls For I = 0 To 3600 Step 360 AF.Escapement = I AF.SelectFont Picture2 X = Picture2.ScaleWidth / 2 Y = Picture2.ScaleHeight / 2 '在字符串后面要加入7个空格 AF.FontOut “电脑商情报第42期 ”, Picture2, X, Y AF.SelectOrg Picture2 Next I End Sub Private Sub Form_Load() Picture2.ScaleMode = 3 End Sub 运行程序，点击Form上的Command1按钮，在窗口的图片框就会出现旋转的文本显示，程序的效果如图所示： 值得注意的问题是，由于Windows的动态连接库的中英文版本的关系，在一些系统中显示中文可能会有一些问题，大家可能看到，上面程序中的语句：AF.FontOut “脑商情报第42期”，Picture2, X, Y中的字符串后面有7个空格，这是对于“电脑商情报第42期”中的7个中文字符，中文系统计算的是7个字符，但是实际它们占据的是14个字节的空间，所以在输出时要在后面添加7个空格做“替身”。上面的程序在中文Win98，VB6下运行通过。(长沙 陈锐) |
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