vb.net窗体椭圆代码 vb中窗体是什么意思
vb.net中绘制圆的代码是什么?
Dim myGraphics As Graphics = Me.CreateGraphics '声明并创建一个Graphics对象
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Dim myPen As Pen = New Pen(Drawing.Color.Black, 3) '声明一个画笔,并设定颜色和粗细
myPen.DashStyle = Drawing.Drawing2D.DashStyle.Solid '线型,Solid是实线
myGraphics.DrawEllipse(myPen, 200, 200, 100, 100) '画圆,数值依次是:横坐标、纵坐标、宽度和高度(宽高相同为正圆,否则为椭圆)
myGraphics.Dispose() '释放Graphics占用的资源
怎么用vb制作圆形窗体?
这是代码:Private Declare Function CreateEllipticRgn Lib "gdi32" (ByVal X1 As Long, _
ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function SetWindowRgn Lib "user32" (ByVal hWnd As Long, _
ByVal hRgn As Long, ByVal bRedraw As Long) As LongPrivate Sub Form_Load()
Dim a, b As Long
Dim w, h As Long
w = Form1.Width / Screen.TwipsPerPixelX
h = Form1.Height / Screen.TwipsPerPixelY
a = CreateEllipticRgn(0, 0, w, h)
b = SetWindowRgn(Me.hWnd, a, True) '设置椭圆形窗体
End Sub
Private Sub Form_Activate()
Picture1(0).Visible = True
End SubPrivate Sub Label1_MouseMove(Index As Integer, Button As Integer, Shift As Integer, X As Single, Y As Single)
Picture1(0).Visible = False
Picture1(1).Visible = False
Picture1(2).Visible = False
Picture1(3).Visible = False
Select Case Index
Case Is = 0
Picture1(0).Visible = True '鼠标所在位置图形突起
Case Is = 1
Picture1(1).Visible = True '鼠标所在位置图形突起
Case Is = 2
Picture1(2).Visible = True '鼠标所在位置图形突起
Case Is = 3
Picture1(3).Visible = True '鼠标所在位置图形突起
End Select
End SubPrivate Sub Picture1_Click(Index As Integer)
End
End Sub
如何用VB.NET画同心圆
窗体上添加一个按钮,在该按钮的单击事件里编写代码如下:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'声明窗体的Me.CreateGraphics对象
Dim MyGraphics As Graphics = Me.CreateGraphics
Dim Cx As Integer = 150 '圆心的X坐标
Dim Cy As Integer = 150 '圆心的Y坐标
Dim R As Integer '圆的半径
'绘制半径为R的圆
For R = 5 To 100 Step 5
MyGraphics.DrawEllipse(Pens.Black, New Rectangle(Cx - R, Cy - R, 2 * R, 2 * R))
Next
End Sub
‘用黑色画笔绘制一组同心圆,半径从5开始,增量为5。
说明:
DrawEllipse是VB.Net的Graphics类的绘制椭圆的方法;他有几种格式,上面使用的是一种;
DrawEllipse(画笔的颜色,绘制椭圆所需要的矩形区域)
其中:绘制椭圆所需要的矩形区域,如果被定义为正方形,就演变成绘制圆,定义该区域由死个数值确定,第1个数值,确定该区域左上角的X坐标,第2个数值,确定该区域左上角的Y坐标,第3个数值,确定该区域的宽度,第4个数值,确定该区域的高度。
例如1:
DrawEllipse(Pens.Black, New Rectangle(150, 150, 50, 50))
就是以圆心坐标为(100,100),绘制半径为50 的圆。其实在VB.NET中,是告诉系统在以左上角坐标(150,150),边长为50的正方形里绘制内切圆。理解了是在正方形里绘制内切圆,就可以通过数学计算,知道如何绘制了。
同理例如2:
DrawEllipse(Pens.Black, New Rectangle(150, 150, 100, 50))
就是以圆心坐标为(100,100),绘制半径为50 的圆。其实在VB.NET中,是告诉系统在以左上角坐标(150,150),长轴为100,短轴为50的内切椭圆。
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