CorelDRAW X3计算封闭曲线长度和面积

作为世界最优秀的矢量图形设计软件CorelDRAW X3(最新版）居然没有查询图形周长、面积的功能，然而作为矢量图形设计软件，查询图形几何属性是必不可少的，还好有VBA，给了我们扩展 CorelDRAW X3功能的无限空间，以下就是查询矢量图形几何信息的VBA过程。如果你有Corel Designer 12,   可以在里面找到此功能，将其中的窗体，模块，类模块，导出，再到 CorelDRAW X3 VBA中，把它们导过来，运行“宏”就可以在CorelDRAW X3中运行了，如果没有请看下面宏代码编写过程。

1、启动CorelDRAW X3,新建“图形1”，按“Alt+F11”打开Visual Basic编辑器，添加如下图所示用户窗体，名称为“frmGeometric”：2、为窗体编写VBA代码，窗体代码全部如下：

Option Explicit

Private CurUnit As Long
Private Lang As New clsLang
Private bPerimeter As Boolean
Private bValidSelection As Boolean
Private bValidArea As Boolean
Private vDepth As Double

Private vLength As Double
Private vArea As Double

Private WithEvents cPrecision As clsIntSpin

Private Sub OnUnitChange(ByVal Unit As Long)
    Dim strLength As String
    Dim strArea As String
    Dim strVolume As String
   
    vDepth = Application.ConvertUnits(vDepth, GetAppUnits(CurUnit), GetAppUnits(Unit))
    CurUnit = Unit
    UpdateDepth
   
    strLength = GetCurUnitString()
    lblUnitLength.Caption = strLength
    lblUnitArea.Caption = strLength & GetSquare(False)
    lblUnitDepth.Caption = strLength
    lblUnitVolume.Caption = strLength & GetCube(False)
   
    UpdateValues
End Sub

Private Sub UpdateDepth()
    Updating = Updating + 1
    txtDepth.Text = CStr(vDepth)
    Updating = Updating - 1
End Sub

Private Function GetCurUnitString() As String
    Dim strLength As String
    Select Case CurUnit
        Case 0
            strLength = Lang.GetString(eUnitInch)
        Case 1
            strLength = Lang.GetString(eUnitMM)
        Case 2
            strLength = Lang.GetString(eUnitCM)
        Case 3
            strLength = Lang.GetString(eUnitM)
    End Select
    GetCurUnitString = strLength
End Function

Private Function GetSquare(ByVal bUnicode As Boolean) As String
    Dim s As String
    s = ChrW$(178)
    If Not bUnicode And Asc(s) = 63 Then
        s = "2"
    End If
    GetSquare = s
End Function

Private Function GetCube(ByVal bUnicode As Boolean) As String
    Dim s As String
    s = ChrW$(179)
    If Not bUnicode And Asc(s) = 63 Then
        s = "3"
    End If
    GetCube = s
End Function

Private Sub cArea_Click()
    UpdateControls
End Sub

Private Sub cboUnits_Change()
    OnUnitChange cboUnits.ListIndex
End Sub

Private Sub cLength_Click()
    UpdateControls
End Sub

Private Sub cmClose_Click()
    Unload Me
End Sub

Private Sub cmCopy_Click()
    Dim sData As String
    Dim oData As New DataObject

    sData = GetDataString(False)
    If sData <> "" Then
        oData.SetText sData
        oData.PutInClipboard
    End If
End Sub

Private Sub cmCreateText_Click()
    Const TextSize As Double = 24 ' 24 pt text
    Dim lr As Layer
    Dim sData As String
    Dim sr As ShapeRange
    Dim x As Double, y As Double, w As Double, h As Double
    sData = GetDataString(True)
    Updating = Updating + 1
    If Not ActiveShape Is Nothing And sData <> "" Then
        Set sr = ActiveSelectionRange
        ActiveShape.GetBoundingBox x, y, w, h
        x = x + w / 2
        y = y - ActiveDocument.ToUnits(TextSize, cdrPoint)
        Set lr = ActiveShape.Layer
        If lr.Editable Then Set lr = ActiveLayer
        lr.CreateArtisticText x, y, sData, cdrEnglishUS, , "Times New Roman", 24, cdrTrue, cdrTrue, , cdrLeftAlignment
        sr.CreateSelection
    End If
    Updating = Updating - 1
End Sub

Private Sub cmRefresh_Click()
    RefreshForm
End Sub

Private Sub cmReset_Click()
    vDepth = 0
    UpdateDepth
    UpdateValues
End Sub

Private Sub cPrecision_Change()
    UpdateValues
End Sub

Private Sub cVolume_Click()
    UpdateControls
End Sub

Private Sub txtDepth_Change()
    Dim s As String
   
    If Updating Then Exit Sub
   
    s = Trim$(txtDepth.Text)
    If s <> "" Then
        vDepth = Val(Replace(s, ",", "."))
    Else
        vDepth = 0
    End If
    UpdateValues
End Sub

Private Sub UserForm_Initialize()
    Updating = 0
    vDepth = 0
   
    Set cPrecision = New clsIntSpin
    cPrecision.Init txtPrecision, spnPrecision, 3, lblPrecision, 0, 5, 1
   
    Me.Caption = Lang.GetString(eFormCaption)
   
    grpLength.Caption = Lang.GetString(eCapPerimeter)
    cLength.Caption = Lang.GetString(eCapPerimeter) & ":"
    bPerimeter = True
   
    grpArea.Caption = Lang.GetString(eCapArea)
    cArea.Caption = Lang.GetString(eCapArea) & ":"
   
    grpVolume.Caption = Lang.GetString(eCapVolume)
    lblDepth.Caption = Lang.GetString(eCapDepth) & ":"
    cmReset.Caption = Lang.GetString(eBtnReset)
    cVolume.Caption = Lang.GetString(eCapVolume) & ":"
   
    cmCreateText.Caption = Lang.GetString(eBtnCreateText)
    cmCopy.Caption = Lang.GetString(eBtnCopy)
    cmClose.Caption = Lang.GetString(eBtnClose)
    cmRefresh.Caption = Lang.GetString(eBtnRefresh)
    lblUnits.Caption = Lang.GetString(eCapUnits) & ":"
    lblPrecision.Caption = Lang.GetString(eCapPrecision) & ":"
  
    cboUnits.Clear
    cboUnits.AddItem Lang.GetString(eStrInch)
    cboUnits.AddItem Lang.GetString(eStrMM)
    cboUnits.AddItem Lang.GetString(eStrCM)
    cboUnits.AddItem Lang.GetString(eStrM)
    cboUnits.ListIndex = IIf(Lang.IsMetric(), 1, 0)
   
    RefreshForm
    MacroRunning = True
End Sub

Sub RefreshForm()
    Dim nSelCount As Long
   
    bValidSelection = False
    bValidArea = False
   
    Updating = Updating + 1
   
    On Error GoTo ErrHandler
   
    If Not ActiveDocument Is Nothing Then
        nSelCount = ActiveDocument.Selection.Shapes.Count
        Select Case nSelCount
            Case 0
                ShowStatusMessage Lang.GetString(eStrNoSelection)
               
            Case 1
                ProcessSelection ActiveShape
               
            Case Else
                ShowStatusMessage Lang.GetString(eStrGroupSelected)
        End Select
    Else
        ShowStatusMessage Lang.GetString(eStrNoSelection)
    End If
   
ExitSub:
    UpdateControls
    Updating = Updating - 1
    Exit Sub
   
ErrHandler:
    ShowStatusMessage Lang.GetString(eStrError) & ": " & Err.Description
    Resume ExitSub
End Sub

Private Sub EnableTextControl(ByVal Txt As TextBox, ByVal bState As Boolean)
    Txt.Enabled = bState
    Txt.BackColor = IIf(bState, vbWindowBackground, vbButtonFace)
End Sub

Private Sub UpdateControls()
    Dim bEnabled As Boolean
   
    cLength.Enabled = bValidSelection
    EnableTextControl txtLength, bValidSelection
    lblUnitLength.Enabled = bValidSelection

    cArea.Enabled = bValidArea
    EnableTextControl txtArea, bValidArea
    lblUnitArea.Enabled = bValidArea
   
    lblDepth.Enabled = bValidArea
    EnableTextControl txtDepth, bValidArea
    lblUnitDepth.Enabled = bValidArea
    cmReset.Enabled = bValidArea
    cVolume.Enabled = bValidArea
    EnableTextControl txtVolume, bValidArea
    lblUnitVolume.Enabled = bValidArea
   
    bEnabled = bValidSelection
    If bEnabled Then
        bEnabled = cLength.Value <> 0
        If bValidArea And Not bEnabled Then
            bEnabled = cArea.Value <> 0 Or cVolume.Value <> 0
        End If
    End If
    cmCreateText.Enabled = bEnabled
    cmCopy.Enabled = bEnabled
End Sub

Private Sub ProcessSelection(ByVal s As Shape)
    If s.Type = cdrGroupShape Then
        ShowStatusMessage Lang.GetString(eStrGroupSelected)
    ElseIf s.IsSimpleShape And s.Type <> cdrTextShape Then
        ProcessCurve s.DisplayCurve
    Else
        ShowStatusMessage Lang.GetString(eStrInvalidObject)
    End If
End Sub

Private Function CheckSubpaths(ByVal crv As Curve) As Boolean
    Dim bRet As Boolean
    Dim n As Long
    bRet = True
    If crv.SubPaths.Count <> 1 Then
        For n = 2 To crv.SubPaths.Count
            If crv.SubPaths(n).Nodes.Count > 1 Then
                bRet = False
                Exit For
            End If
        Next n
    End If
    CheckSubpaths = bRet
End Function

Private Sub ProcessCurve(ByVal crv As Curve)
    Dim v As Double
    Dim bClearStatus As Boolean
    Dim bClosed As Boolean
   
    bClosed = crv.SubPaths(1).Closed
    bClearStatus = True
    bValidArea = bClosed And CheckSubpaths(crv)
    If bValidArea Then
        grpLength.Caption = Lang.GetString(eCapPerimeter)
        cLength.Caption = Lang.GetString(eCapPerimeter) & ":"
        bPerimeter = True
    Else
        grpLength.Caption = Lang.GetString(eCapLength)
        cLength.Caption = Lang.GetString(eCapLength) & ":"
        bPerimeter = False
    End If
   
    bValidSelection = True
    vLength = crv.Length
   
    If bValidArea Then
        vArea = calcShapeArea(crv.SubPaths(1))
    Else
        vArea = 0
        If bClosed Then
            ShowStatusMessage Lang.GetString(eStrMultipathCurve)
        Else
            ShowStatusMessage Lang.GetString(eStrCurveOpen)
        End If
        bClearStatus = False
    End If
   
    If bClearStatus Then ClearStatusMessage
    UpdateValues
End Sub

Private Sub UpdateValues()
    Dim v As Double
    txtLength.Text = FormatValue(GetLength(vLength))
   
    If bValidArea Then
        v = GetArea(vArea)
        txtArea.Text = FormatValue(v)
        txtVolume.Text = FormatValue(v * vDepth)
    Else
        txtArea.Text = ""
        txtVolume.Text = ""
    End If
End Sub

Private Function FormatValue(ByVal v As Double) As String
    Dim sFormat As String
    sFormat = "0"
    If cPrecision.GetValue() > 0 Then
        sFormat = "0." & String$(cPrecision.GetValue(), "0")
    End If
    FormatValue = Format$(v, sFormat)
End Function

Private Function GetAppUnits(ByVal vUnit As Long) As cdrUnit
    Dim tUnit As cdrUnit
    Select Case CurUnit
        Case 1
            tUnit = cdrMillimeter
        Case 2
            tUnit = cdrCentimeter
        Case 3
            tUnit = cdrMeter
        Case Else
            tUnit = cdrInch
    End Select
    GetAppUnits = tUnit
End Function

Private Function GetLength(ByVal v As Double) As Double
    If ActiveDocument Is Nothing Then
        GetLength = 0
    Else
        GetLength = ActiveDocument.FromUnits(v, GetAppUnits(CurUnit)) * ActiveDocument.WorldScale
    End If
End Function

Private Function GetArea(ByVal v As Double) As Double
    GetArea = GetLength(GetLength(v))
End Function

Private Function calcShapeArea(ByVal sp As SubPath) As Double
    Dim cx As New Collection
    Dim cy As New Collection
    Dim seg As Segment
    Dim n As Long
    Dim x As Double, y As Double
    Dim Area As Double
    Dim nPts As Long
   
    sp.StartNode.GetPosition x, y
   
    cx.Add x
    cy.Add y
   
    For Each seg In sp.Segments
        If seg.Type = cdrCurveSegment Then
            For n = 1 To 49
                seg.GetPointPositionAt x, y, n / 50
                cx.Add x
                cy.Add y
            Next n
        End If
        seg.EndNode.GetPosition x, y
        cx.Add x
        cy.Add y
    Next seg
   
    Area = 0
    For n = 1 To cx.Count - 1
        Area = Area + cx(n) * cy(n + 1) - cy(n) * cx(n + 1)
    Next
   
    calcShapeArea = Abs(Area / 2)
End Function

Private Sub ShowStatusMessage(ByVal msg As String)
    lblStatusBar.Caption = msg
End Sub

Private Sub ClearStatusMessage()
    lblStatusBar.Caption = ""
End Sub

Private Sub UserForm_Terminate()
    MacroRunning = False
End Sub

Private Function GetDataString(ByVal bUnicode As Boolean)
    Dim s As String
    s = ""
    If bValidSelection Then
        If cLength.Value Then
            If bPerimeter Then
                s = Lang.GetString(eCapPerimeter)
            Else
                s = Lang.GetString(eCapLength)
            End If
            s = s & " = " & txtLength.Text & " " & GetCurUnitString()
        End If
       
        If bValidArea Then
            If cArea.Value Then
                If s <> "" Then s = s & vbCrLf
                s = s & Lang.GetString(eCapArea) & " = " & txtArea.Text & " " & GetCurUnitString() & GetSquare(bUnicode)
            End If
           
            If cVolume.Value Then
                If s <> "" Then s = s & vbCrLf
                s = s & Lang.GetString(eCapVolume) & " = " & txtVolume.Text & " " & GetCurUnitString() & GetCube(bUnicode)
            End If
        End If
    End If
    GetDataString = s
End Function

3、添加模块，名称为“Information”，代码如下：

Option Explicit

Public MacroRunning As Boolean
Public Updating As Long

Public Sub Dialog()
    EventsEnabled = True
    frmGeoMetric.Show vbModeless
End Sub

4、添加三个类模块：

  （1）名称为clsIntSpin，代码如下：

Option Explicit

Public Event Change()

'================= Private Data =================
Private WithEvents cTxt As TextBox
Private WithEvents cSpin As SpinButton
Private Updating As Long
Private Value As Long
Private lLabel As Label
Private Digits As Long

'================= Interface ================
Public Sub Init(Txt As TextBox, Spin As SpinButton, ByVal v As Long, Optional CtlLabel As Label, Optional ByVal nMin As Long = 0, Optional ByVal nMax As Long = 2147483647, Optional ByVal nStep As Long = 1, Optional ByVal NumDigits As Long)
    If v < nMin Then v = nMin
    If v > nMax Then v = nMax
    Value = v
    Set cTxt = Txt
    Set cSpin = Spin
    Set lLabel = CtlLabel
    BeginUpdate
    If NumDigits > 0 Then
        Digits = NumDigits
    Else
        Digits = 1
    End If
   
    cTxt.Value = FormatValue(Value)
    With cSpin
        .Min = nMin
        .Max = nMax
        .SmallChange = nStep
        .Value = Value
    End With
   
    EndUpdate
End Sub

Public Function OnTextExit() As Boolean
    Dim n As Long
    OnTextExit = False
    If Updating = 0 Then
        n = GetTextValue()
        BeginUpdate
        If cSpin.Value <> n Then
            cSpin.Value = n
            Value = n
            OnTextExit = True
            RaiseEvent Change
        Else
            cTxt.Value = FormatValue(n)
        End If
        EndUpdate
    End If
End Function

Public Sub SetValue(ByVal nVal As Long)
    BeginUpdate
    With cSpin
        If nVal < .Min Then nVal = .Min
        If nVal > .Max Then nVal = .Max
        .Value = nVal
    End With
    Value = nVal
    cTxt.Value = FormatValue(nVal)
    EndUpdate
End Sub

Public Function GetValue() As Long
    GetValue = Value
End Function

Public Sub Enable(ByVal bState As Boolean)
    If Not lLabel Is Nothing Then lLabel.Enabled = bState
    cTxt.Locked = Not bState
    cTxt.TabStop = bState
    cTxt.BackColor = IIf(bState, vbWindowBackground, vbButtonFace)
    cTxt.ForeColor = IIf(bState, vbWindowText, vbButtonShadow)
    cSpin.Enabled = bState
End Sub

Public Sub SetMaxRange(ByVal nVal)
    BeginUpdate
    If Value > nVal Then
        Value = nVal
        cSpin.Value = nVal
        cTxt.Value = FormatValue(nVal)
    End If
    cSpin.Max = nVal
    EndUpdate
End Sub

Public Sub SetMinRange(ByVal nVal)
    BeginUpdate
    If Value < nVal Then
        Value = nVal
        cSpin.Value = nVal
        cTxt.Value = FormatValue(nVal)
    End If
    cSpin.Min = nVal
    EndUpdate
End Sub

'================ Helper Functions ==============
Private Sub BeginUpdate()
    Updating = Updating + 1
End Sub

Private Sub EndUpdate()
    Updating = Updating - 1
End Sub

Private Function GetTextValue() As Long
    Dim v As Double
    v = 0
    If Trim$(cTxt.Text) <> "" Then v = Val(cTxt.Text)
    If v < CDbl(cSpin.Min) Then v = cSpin.Min
    If v > CDbl(cSpin.Max) Then v = cSpin.Max
    GetTextValue = CLng(v)
End Function

Private Function FormatValue(ByVal v As Long) As String
    Dim s As String
    Dim bNegative As Boolean
   
    bNegative = v < 0
    s = Trim$(str$(Abs(v)))
    If Len(s) < Digits Then
        s = Right$(String$(Digits, "0") & s, Digits)
    End If
   
    If bNegative Then s = "-" & s
    FormatValue = s
End Function

Private Sub Class_Initialize()
    Value = 0
End Sub

Private Sub cSpin_Change()
    If Updating = 0 Then
        BeginUpdate
        cTxt.Value = FormatValue(cSpin.Value)
        Value = cSpin.Value
        RaiseEvent Change
        EndUpdate
    End If
End Sub

Private Sub cTxt_Change()
    Dim n As Long
    If Updating = 0 Then
        n = GetTextValue()
        If cSpin.Value <> n Then
            BeginUpdate
            cSpin.Value = n
            Value = n
            EndUpdate
            RaiseEvent Change
        End If
    End If
End Sub

  （2）名称为clsLang，代码如下：

Option Explicit

Private colDict As New Collection
Private bMetric As Boolean

Private Sub Class_Initialize()
 
     AddString eFormCaption, "Geometric Information"
    AddString eBtnClose, "关闭"
    AddString eBtnCopy, "复制"
    AddString eBtnCreateText, "创建文本"
    AddString eBtnRefresh, "刷新"
    AddString eBtnReset, "清零"
    AddString eCapArea, "面积"
    AddString eCapLength, "长度"
    AddString eCapPerimeter, "周长"
    AddString eCapVolume, "体积"
    AddString eCapDepth, "高度"
    AddString eCapUnits, "单位"
    AddString eCapPrecision, "精度"
    AddString eUnitInch, "in"
    AddString eUnitMM, "mm"
    AddString eUnitCM, "cm"
    AddString eUnitM, "m"
    AddString eStrInch, "英寸 (in)"
   
    AddString eStrMM, "毫米 (mm)"
    AddString eStrCM, "厘米 (cm)"
    AddString eStrM, "米 (m)"
    AddString eStrError, "Error"
    AddString eStrNoSelection, "未选择任何图形"
    AddString eStrGroupSelected, "不支持群组图形，请选择单个图形"
    AddString eStrInvalidObject, "无效选择"
    AddString eStrCurveOpen, "非闭合图形无法计算面积和体积"
    AddString eStrMultipathCurve, "组合图形无法计算面积和体积"
End Sub

Private Sub AddString(ByVal eId As ELangStringID, ByVal s As String)
    Dim tPair As New clsLangPair
    tPair.eId = eId
    tPair.sDef = s
    colDict.Add tPair
End Sub

Public Function GetString(ByVal eId As ELangStringID) As String
    Dim tPair As clsLangPair
    Dim s As String
    s = "Str #" & eId
    For Each tPair In colDict
        If tPair.eId = eId Then
            s = tPair.sDef
            Exit For
        End If
    Next tPair
    GetString = s
End Function

Public Function IsMetric() As Boolean
    IsMetric = bMetric
End Function

  （3）名称为clsLangPair，代码如下：

Option Explicit

Public Enum ELangStringID
    eFormCaption
    eBtnClose
    eBtnCopy
    eBtnCreateText
    eBtnRefresh
    eBtnReset
    eCapArea
    eCapLength
    eCapPerimeter
    eCapVolume
    eCapDepth
    eCapUnits
    eCapPrecision
    eUnitInch
    eUnitMM
    eUnitCM
    eUnitM
    eStrInch
    eStrMM
    eStrCM
    eStrM
    eStrError
    eStrNoSelection
    eStrGroupSelected
    eStrInvalidObject
    eStrCurveOpen
    eStrMultipathCurve
End Enum

Public eId As ELangStringID
Public sDef As String

    现在一切编写完毕，按F5键运行吧，选中图形，点击程序中“刷新”，“面积”，“体积”等数据立即显示出来，程序运行效果如下图：