vb点虐 鼠标画圆 vbcircle画圆

在VB.Net中如何画实心的圆

在游罩拦PictureBox1上神胡画红色的实闷首心圆：

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Private Sub DrawCircle(ByVal cp As Point, ByVal radius As Integer, ByVal color As Brush)

Dim gr As Graphics

gr = PictureBox1.CreateGraphics

Dim rect As Rectangle = New Rectangle(cp.X - radius, cp.Y - radius, 2 * radius, 2 * radius)

gr.DrawEllipse(Pens.Black, rect)

gr.FillEllipse(color, rect)

End Sub

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click

DrawCircle(New Point(120, 100), 80, Brushes.Red)

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 '圆正哪心的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，绘制椭圆所需要闷清碰的矩形区域）

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，确定蚂谈该区域左上角的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。

vb点虐 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

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：横坐标孝源、纵坐标巧配态、宽度和高度（宽高卖缺相同为正圆，否则为椭圆）

myGraphics.Dispose() '释放Graphics占用的资源

怎样用VB实现:用鼠标拖动绘制实圆与多种虚线圆

Dim

s

As

Boolean,

ci

As

Integer,

xianxing

As

Integer,

xiankuan

As

Integer

Dim

x0

As

Single,

y0

As

Single

Private

Sub

Command1_Click()

s

=

True

Command1.Enabled

=

False

End

Sub

Private

Sub

Form_Load()

Dim

b

b

=

Array("茄耐透明",

"实线",

"虚线",

"点线",

"点划线",

"双点划线")

Frame1.Move

100,

100,

1300,

3500

Frame1.Caption

=

"线型"

Frame2.Move

Width

-

1500,

100,

1300,

3500

Frame2.Caption

=

"线宽"

For

i

=

To

5

Option1(i).Move

100,

300

+

i

*

500,

1100,

300

Option1(i).Caption

=

b(i)

Option2(i).Move

100,

500

+

i

*

500,

800,

300

Option2(i).Caption

=

i

+

1

"点宽"

Next

i

Shape1(0).Visible

=

False

Shape1(1).Visible

=

False

s

=

ci

=

-1

Command1.Caption

=

"开始画圆"

Command1.ToolTipText

=

"点击按钮后在窗体内按下鼠标知数左键处为圆心，拖到半径处松开鼠标左键即可"

End

Sub

Private

Sub

Form_MouseDown(Button

As

Integer,

Shift

As

Integer,

X

As

Single,

Y

As

Single)

If

s

And

Button

=

1

Then

x0

=

X

y0

=

Y

ci

=

ci

+

1

If

ci

1

Then

Load

Shape1(ci)

Shape1(ci).Visible

=

True

Shape1(ci).BorderStyle

=

xianxing

Shape1(ci).Move

x0,

y0,

0,

Shape1(ci).Shape

=

3

Shape1(ci).BorderWidth

=

xiankuan

End

If

End

Sub

Private

Sub

Form_MouseMove(Button

As

Integer,

Shift

As

Integer,

X

As

Single,

Y

As

Single)

If

s

And

Button

=

1

Then

banjing

=

Sqr((x0

-

X)

*

(x0

-

X)

+

(y0

-

Y)

*

(y0

-

Y))

Shape1(ci).Move

x0

-

banjing,

y0

-

banjing,

2

*

banjing,

2

*

banjing

End

If

End

Sub

Private

Sub

Form_MouseUp(Button

As

Integer,

Shift

As

Integer,

X

As

Single,

Y

As

Single)

Command1.Enabled

=

True

s

=

False

End

Sub

Private

Sub

Option1_Click(Index

As

Integer)

For

i

=

To

5

If

Option1(i)

Then

xianxing

=

i

Next

i

If

i

=

1

Then

Frame2.Enabled

=

True

Else

Frame2.Enabled

=

False

xiankuan

=

1

End

If

End

Sub

Private

Sub

Option2_Click(Index

As

Integer)

For

i

=

To

5

If

Option2(i)

Then

xiankuan

=

1

+

i

Next

i

End

Sub

界面稍微复杂了点：

一个按钮，两个框架，第一框架上option1共六个，第二个框架上option2也是六个颤猛春。