C#简单画图程序源代码

private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            xValueLabel.Text = e.X.ToString();
            yValueLabel.Text = e.Y.ToString();
            if (CanMove == true)
            {
                Pen pen = new Pen(col, 3);
                Graphics g = this.CreateGraphics();
                endpt.X = e.X;
                endpt.Y = e.Y;
                if (ComVar.drawType != ComVar.DrawTypes.line)
                    g.Clear(Color.White);
                switch (ComVar.drawType)
                {
                    case ComVar.DrawTypes.line:
                        g.DrawLine(pen, middlept, endpt);
                        break;
                    case ComVar.DrawTypes.rect:
                        min.X = Math.Min(startpt.X, middlept.X);
                        min.Y = Math.Min(startpt.Y, middlept.Y);
                        wide = Math.Abs(middlept.X - startpt.X);
                        high = Math.Abs(middlept.Y - startpt.Y);
                        g.DrawRectangle(pen, min.X, min.Y, wide, high);
                        break;
                    case ComVar.DrawTypes.ellipse:
                        g.DrawEllipse(pen, startpt.X, startpt.Y, middlept.X - startpt.X, middlept.Y - startpt.Y);
                        break;
                }
                middlept = endpt;
            }
        }