cgelement.vb

苏金明编写的《用VB.NET和VC#.NET开发交互式CAD系统》一书的源代码

'图元基类

Public MustInherit Class CGElement

    '绘图方式
    Public Enum geDrawMode
        Normal = 1
        Selec = 2
        Drag = 3
        Delete = 4
    End Enum

    '图元的线型
    Public Enum geStyle
        Solid = 1
        Dash = 2
        Dot = 3
        DashDot = 4
        DashDotDot = 5
    End Enum

    Private m_Color, m_Style, m_Width As Integer

    '颜色属性
    Public Property Color() As Integer
        Get
            Return m_Color
        End Get
        Set(ByVal Value As Integer)
            m_Color = Value
        End Set
    End Property

    '线型属性
    Public Property Style() As Integer
        Get
            Return m_Style
        End Get
        Set(ByVal Value As Integer)
            m_Style = Value
        End Set
    End Property

    '线宽属性
    Public Property Width() As Integer
        Get
            Return m_Width
        End Get
        Set(ByVal Value As Integer)
            m_Width = Value
        End Set
    End Property

    '构造函数
    Public Sub New()
        Init()
    End Sub

    '初始化图元
    Protected Sub Init()
        m_Style = 0
        m_Width = 1
        m_Color = RGB(0, 0, 0)
    End Sub

    '绘制图元
    Public MustOverride Sub Draw(ByVal g As Graphics, _
        ByVal aGrawMode As geDrawMode)

    '获取图元的包围矩形
    Public MustOverride Function GetBox() As CBox

    '拾取图元
    Public MustOverride Function Pick(ByVal aPos As PointF) As Boolean

    '根据不同的绘图模式设置不同的绘图参数
    Public Function DrawSettings(ByVal hdc As IntPtr, _
        ByVal aDrawMode As geDrawMode) As Integer()
        Dim penPara(2) As Integer
        Select Case aDrawMode
            Case geDrawMode.Normal
                Win32API.SetROP2(hdc, 13)
                m_Style = 0
                m_Width = 1
                m_Color = RGB(0, 0, 0)
            Case geDrawMode.Selec
                Win32API.SetROP2(hdc, 13)
                m_Style = 1
                m_Width = 1
                m_Color = RGB(255, 0, 0)
            Case geDrawMode.Drag
                Win32API.SetROP2(hdc, 10)
                m_Style = 0
                m_Width = 1
                m_Color = RGB(0, 0, 255)
            Case geDrawMode.Delete
                Win32API.SetROP2(hdc, 13)
                m_Style = 0
                m_Width = 1
                m_Color = RGB(255, 255, 255)
        End Select

        penPara(0) = m_Style
        penPara(1) = m_Width
        penPara(2) = m_Color

        Return penPara
    End Function

End Class