crotate.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

'旋转变换
Public Class CRotate
    Implements ICommand

    Private m_Step As Integer
    Private m_basePos, m_desPos As PointF

    '单击鼠标左键时的绘图行为
    Public Sub LButtonDown(ByVal g As Graphics, ByVal aPos As PointF) Implements ICommand.LButtonDown
        Dim i As Integer

        '鼠标单击次数加1
        m_Step += 1

        Select Case m_Step
            Case 1
                m_basePos = aPos
                m_desPos = aPos
            Case 2
                '清除最后一条橡皮线
                Dim tempLine As New CLine(m_basePos, m_desPos)
                tempLine.Draw(g, CGElement.geDrawMode.Drag)
                tempLine = Nothing

                '如果选择集中的图元个数大于0
                If geSels.Count > 0 Then
                    Dim aAngle As Single
                    '计算旋转角度
                    aAngle = GetAngle(m_basePos, m_desPos)
                    For i = 0 To geSels.Count - 1
                        '清除图元在当前位置的图形
                        geSels(i).Draw(g, CGElement.geDrawMode.Delete)
                        '将所有被选中的图元旋转到目标位置并进行绘制
                        geSels(i).Rotate(g, m_basePos, aAngle)
                        geSels(i).Draw(g, CGElement.geDrawMode.Selec)
                    Next i
                End If

                m_Step = 0
        End Select
    End Sub

    '移动鼠标时的绘图行为
    Public Sub MouseMove(ByVal g As Graphics, ByVal aPos As PointF) Implements ICommand.MouseMove
        Select Case m_Step
            Case 1
                Dim prePos As New PointF()
                Dim curPos As New PointF()

                prePos = m_desPos
                curPos = aPos

                '清除上一条橡皮线
                Dim tempLine1 As New CLine(m_basePos, prePos)
                tempLine1.Draw(g, CGElement.geDrawMode.Drag)
                tempLine1 = Nothing

                '绘当前位置的橡皮线
                Dim tempLine2 As New CLine(m_basePos, curPos)
                tempLine2.Draw(g, CGElement.geDrawMode.Drag)
                tempLine2 = Nothing

                m_desPos = aPos
        End Select
    End Sub

    '单击鼠标右键时的绘图行为
    Public Sub RButtonDown(ByVal g As Graphics, ByVal aPos As PointF) Implements ICommand.RButtonDown
        If m_Step = 1 Then
            '清除上一条橡皮线
            Dim tempLine As New CLine(m_basePos, m_desPos)
            tempLine.Draw(g, CGElement.geDrawMode.Drag)
            tempLine = Nothing
        End If
    End Sub

End Class