画圆画线

首先来个画背景的,写上偶的名字咧!嘿嘿 
  protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            
            e.Graphics.DrawString("yellowyu", new Font("Verdana", 14), Brushes.Black, new PointF(100, 100));
        }

接着画圆画方

            Graphics g = this.CreateGraphics();
            //消除锯齿,控制图像质量
            g.SmoothingMode = SmoothingMode.AntiAlias;

            Rectangle rect = new Rectangle(20, 20, 100, 100);
            Pen redPen = new Pen(Color.Red, 3);
            Pen blackPen = Pens.Black;

            //单色画笔,填充形状
            SolidBrush greenBrush = new SolidBrush(Color.Green);

            //画一个矩形
            g.DrawRectangle(redPen, rect);
            //填充一个矩形里的椭圆
            g.FillEllipse(greenBrush, rect);

            //画一条横线
            g.DrawLine(blackPen, 0, 250, this.Width, 250);

            //画一系列圆形
            g.FillEllipse(Brushes.Blue, 70, 220, 30, 30);
            g.FillEllipse(Brushes.SkyBlue, 100, 210, 40, 40);
            g.FillEllipse(Brushes.Green, 140, 200, 50, 50);
            g.FillEllipse(Brushes.Yellow, 190, 190, 60, 60);
            g.FillEllipse(Brushes.Violet, 250, 180, 70, 70);
            g.FillEllipse(Brushes.Red, 320, 170, 80, 80);

            //通过两点定一条直线
            Point pt = new Point(150, 150);
            Point newpt = Point.Empty;
            newpt.X = 200;
            newpt.Y = 300;
            Pen pn = new Pen(Color.Blue, 10);
            g.DrawLine(pn, pt, newpt);

            StringFormat drawFormat = new StringFormat();
            //文本cuizi对齐
            string DrawText = "Draw GDI+ BY YELLOWYU";
            drawFormat.FormatFlags = StringFormatFlags.DirectionVertical;

            g.DrawString(DrawText, new Font("Verdana", 14), Brushes.Aquamarine, 200.0F, 20.0F, drawFormat);
            g.DrawString(DrawText, new Font("Verdana", 14), Brushes.Aquamarine, 220.0F, 20.0F);

            greenBrush.Dispose();
            redPen.Dispose();
            g.Dispose();

接着画坐标,还有通过鼠标连线
 Graphics g = this.CreateGraphics();
            Font VertFont = new Font(strFontStyle, 10, FontStyle.Bold);
            Font horzFont = new Font(strFontStyle, 10, FontStyle.Bold);
            SolidBrush vertBrush = new SolidBrush(Color.Black);
            SolidBrush horzBrush = new SolidBrush(Color.Blue);
            Pen BlackPen = new Pen(Color.Black, 2);
            Pen BluePen = new Pen(Color.Blue, 2);
            g.DrawLine(BlackPen, 350, 520, 350, 225);
            g.DrawLine(BluePen, 350, 520, 550, 520);

            for (int i = 0; i < 11; i++)
            {
                g.DrawString(i.ToString(), horzFont, horzBrush, 350 + i * 20, 520);
            }

            //绘制文本

            StringFormat vertStrFormat = new StringFormat();
            vertStrFormat.FormatFlags = StringFormatFlags.DirectionVertical;

            for (int i = 1; i < 11; i++)
            {
                g.DrawString("-", horzFont, horzBrush, 350 + i * 20, 512, vertStrFormat);
                x = 350 + i * 20;
            }

            for (int i = 0; i < 10; i++)
            {
                g.DrawString((10 * (10 - i)).ToString() + "-", VertFont, vertBrush, 325, 310 + 20 * (i % 11));
                if (i == 0)
                {
                    y = 310 + 20 * (i % 11);
                }
            }

            Console.WriteLine("X:{0},Y:{1}", new object[] { x, y });

点击两点连线
 base.OnMouseDown(e);

            if (e.Button == MouseButtons.Left)
            {
                Graphics g1 = this.CreateGraphics();

                Pen linePen = new Pen(Color.Green, 1);
                Pen EllipsePen = new Pen(Color.Red, 1);

                startPoint = endPoint;
                endPoint = new Point(e.X, e.Y);

                g1.DrawLine(linePen, startPoint, endPoint);

                if (checkBox1.Checked)
                {
                    g1.DrawRectangle(EllipsePen, e.X - 2, e.Y - 2, 4, 4);

                }
                else
                {
                    g1.DrawEllipse(EllipsePen, e.X - 2, e.Y - 2, 4, 4);
                }

                linePen.Dispose();
                EllipsePen.Dispose();
                g1.Dispose();
            }

直接上效果图


最后即是刷新,其实这里面有个技巧,就是在刷的时候先把图取下来,刷完再往上盖
而Invalidate函数是使某块区域无效
比如吧!一个LISTVIEW切换一项,系统会先取得那一项的位置,还有改变后的位置,把这两个地方INVALIDATE掉,再画上该画的东西
startPoint = new Point(350, 520);
             endPoint = new Point(350, 520);
              t = new Rectangle(370, 310, 100, 100);
             this.Invalidate(t);

而这里面有太多性能上的问题,改天再说喽!打球去喽!夏天的上海,真热,还有一张饼图的,改天再补上