[ VB2010 ] - 繪製斜橢圓

[ VB2010 ] - 繪製斜橢圓

Imports System.Drawing.Drawing2D
Public Class Form1
    Dim bmp1 As Bitmap
    Dim g1 As Graphics
    Dim mymatrix As New Matrix
    Dim mypen As Pen
    Dim angle1 As Single = 0
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        bmp1 = New Bitmap(400, 300)
        g1 = Graphics.FromImage(bmp1)
        g1.Clear(Color.White)
        mypen = New Pen(Color.Red, 3)
        g1.DrawLine(Pens.Black, 0, 130, 399, 130)
        g1.DrawLine(Pens.Black, 200, 0, 200, 299)
        rotateEllipse(mymatrix, mypen, g1, angle1, 100, 80, 200, 100) '旋轉0度
        angle1 = 45
        rotateEllipse(mymatrix, mypen, g1, angle1, 100, 80, 200, 100) '旋轉45度。

        g1.DrawLine(Pens.LightSkyBlue, 0, 130, 399, 130)
        PictureBox1.Image = bmp1
    End Sub


    Public Sub rotateEllipse(ByVal mtr As Matrix, ByVal ps As Pen, ByVal rg As Graphics, ByVal a As Single, ByVal x As Integer, ByVal y As Integer, ByVal w As Integer, ByVal h As Integer)
        mtr.RotateAt(a, New PointF((w / 2) + x, (h / 2) + y))
        rg.Transform = mtr
        rg.DrawEllipse(ps, x, y, w, h)
    End Sub


    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        End
    End Sub

End Class