Graphics用来绘图。
用draw来划线。vb.net没有画点的功能。
可以画直接、矩形、椭圆、Bezier、弧、饼(封闭的弧线)。
要注意的是:弧、饼用的是度数(不是弧度),且是顺时间转的角度。
- Imports System.Drawing
- Imports System.Math
- Public Class Form1
- Const pi As Double = 3.14159
-
- '画点(用一个像素的矩形或两个像素的直接来模拟
- Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
- Dim gr As Graphics = PictureBox1.CreateGraphics
- Dim j As Int32 = 50
- For i As Int32 = 10 To 150
- gr.DrawLine(Pens.Red, i, j, i + 1, j + 1)
- j += 1
- Next
- End Sub
-
- '用直线构成图
- Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
- PictureBox1.Refresh() '清除
-
- Dim gr As Graphics = PictureBox1.CreateGraphics
- Dim x1, y1, x2, y2, d As Short '起点终点、基准距离
- Dim b, c As Double '真实距离
-
- d = 60
- For a = 0 To 2 * pi Step pi / 360
- b = d * (1 + 1 / 4 * Cos(12 * a))
- c = b * (1 + Sin(4 * a))
- x1 = 150 + Int(c * Cos(a)) '(150,180)中心点
- y1 = 180 + Int(c * Sin(a))
- x2 = 150 + Int(c * Cos(a + pi / 5))
- y2 = 180 + Int(c * Sin(a + pi / 5))
- gr.DrawLine(Pens.BlueViolet, x1, y1, x2, y2)
- Next
- End Sub
-
- '椭圆或圆
- Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
- PictureBox1.Refresh()
- Dim gr As Graphics = PictureBox1.CreateGraphics
- gr.DrawEllipse(Pens.Red, New Rectangle(0, 0, 100, 80))
- gr.DrawEllipse(Pens.Aqua, New Rectangle(120, 120, 80, 80))
- End Sub
-
- '椭圆弧 或圆弧 (是对上面椭圆的部分提取)
- '注意:开始和结束角度是以度为单位,且顺时针方向,下面是从30度到120度
- Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
- PictureBox1.Refresh()
- Dim gr As Graphics = PictureBox1.CreateGraphics
- gr.DrawArc(Pens.Red, New Rectangle(20, 20, 150, 200), 30, 120)
- End Sub
-
- '封闭椭圆弧线,即饼图
- '参数与arc同,只是成图时是封闭的
- Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
- PictureBox1.Refresh()
- Dim gr As Graphics = PictureBox1.CreateGraphics
- gr.DrawPie(Pens.Red, New Rectangle(20, 20, 150, 200), 30, 120)
- End Sub
-
- '贝赛尔曲线 Bezier
- '它由四个点:起点、两个中间点(控制)、终点 组成
- Private Sub Button6_Click(sender As Object, e As EventArgs) Handles Button6.Click
- PictureBox1.Refresh()
- Dim gr As Graphics = PictureBox1.CreateGraphics
- gr.DrawBezier(Pens.Brown, 10, 20, 140, 40, 40, 240, 200, 270)
- gr.DrawRectangle(Pens.Red, New Rectangle(200, 40, 80, 170))
- End Sub
-
- '多边形--不规则形状
- '由多个点来决定,多个点用Points()数组来表达
- Private Sub Button7_Click(sender As Object, e As EventArgs) Handles Button7.Click
- PictureBox1.Refresh()
- Dim gr As Graphics = PictureBox1.CreateGraphics
- Dim p(2) As System.Drawing.Point
-
- p(0).X = 30 : p(0).Y = 30
- p(1).X = 100 : p(1).Y = 100
- p(2).X = 50 : p(2).Y = 250
- gr.DrawPolygon(Pens.DarkGreen, p)
- End Sub
- End Class
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