四、使用GDI+画曲线

DrawBezier(Pen,Point,Point,Point,Point)

DrawBezier(Pen,PointF,PointF,PointF,PointF)

DrawBezier(Pen,Single,Single,Single,Single,Single,Single,Single,Single)

DrawCurve(Pen,Point[])

DrawCurve(Pen,PointF[])

DrawCurve(Pen,Point[],Single)

DrawCurve(Pen,PointF[],Int32,Int32)

DrawCurve(Pen,Point[],Int32,Int32,Single)

DrawCurve(Pen,PointF[],Int32,Int32,Single)

private void Form1_Paint(object sender, PaintEventArgs e)
{    
    //创建画板从Paint事件中的直接引用Graphics对象
    Graphics graphics = e.Graphics;

    graphics.Clear(Color.Black);

    //定义画笔
    Pen pen = new Pen(Color.White, 3.0f);
    Pen thickPen = new Pen(Color.White,2.0f);
    Pen thick = new Pen(Color.Red, 2.0f);

    //Rectangle是椭圆的一部分,Rectangle结构
    //第一个-60是指与X轴的角度，顺时针，第二个弧线结束点到开始的角度
    Point start = new Point(100, 100);
    Point control1 = new Point(200, 400);
    Point control2 = new Point(400, 400);
    Point end = new Point(500, 100);
    graphics.DrawBezier(pen, start, control1, control2, end);

}

在上次坐标的基础上继续画曲线

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            //创建画板从Paint事件中的直接引用Graphics对象
            Graphics graphics = e.Graphics;

            graphics.Clear(Color.Black);

            //定义画笔
            Pen pen = new Pen(Color.White, 3.0f);
            Pen thickPen = new Pen(Color.White, 2.0f);
            Pen thick = new Pen(Color.Red, 2.0f);

            //画横坐标
            Point pointFirstX = new Point(0, this.ClientRectangle.Height / 2);
            Point pointFirstY = new Point(this.ClientRectangle.Width, this.ClientRectangle.Height / 2);
            Point pointSecondX = new Point(this.ClientRectangle.Width / 2, 0);
            Point pointSecondY = new Point(this.ClientRectangle.Width / 2, this.ClientRectangle.Height);
            graphics.DrawLine(pen, pointFirstX, pointFirstY);
            graphics.DrawLine(pen, pointSecondX, pointSecondY);

            //画箭头
            Point PointUpLeftX = new Point(this.ClientRectangle.Width / 2, 0);
            Point PointUpLeftY = new Point(this.ClientRectangle.Width / 2 - 10, 10);
            Point PointUpRightY = new Point(this.ClientRectangle.Width / 2 + 10, 10);
            Point PointRightUpX = new Point(this.ClientRectangle.Width, this.ClientRectangle.Height / 2);
            Point PointRightUpY = new Point(this.ClientRectangle.Width - 10, this.ClientRectangle.Height / 2 - 10);
            Point PointRightDownY = new Point(this.ClientRectangle.Width - 10, this.ClientRectangle.Height / 2 + 10);
            graphics.DrawLine(pen, PointUpLeftX, PointUpLeftY);
            graphics.DrawLine(pen, PointUpLeftX, PointUpRightY);
            graphics.DrawLine(pen, PointRightUpX, PointRightUpY);
            graphics.DrawLine(pen, PointRightUpX, PointRightDownY);

            //画原点
            PointF centre = new PointF(this.ClientRectangle.Width / 2, this.ClientRectangle.Height / 2);
            Font font = new Font("黑体", 14.0f);
            Brush brush = Brushes.White;
            graphics.DrawString("0", font, brush, centre);

            //画坐标点    
            int iWidht = this.ClientRectangle.Width / 2;
            int iHeight = this.ClientRectangle.Height / 2;
            int j = 0;
            for (int i = iWidht; i < this.ClientRectangle.Width; i = i + 50)
            {
                Point tmpStart = new Point(i, iHeight);
                Point tmpEnd = new Point(i, iHeight - 8);
                graphics.DrawLine(thickPen, tmpStart, tmpEnd);
                if (j != 0)
                {
                    graphics.DrawString(j.ToString(), font, brush, new Point(tmpEnd.X - 7, tmpEnd.Y + 10));
                }
                j++;
            }

            int k = 0;
            for (int i = iWidht; i > 0; i = i - 50)
            {
                Point tmpStart = new Point(i, iHeight);
                Point tmpEnd = new Point(i, iHeight - 8);
                graphics.DrawLine(thickPen, tmpStart, tmpEnd);
                if (k != 0)
                {
                    graphics.DrawString("-" + k.ToString(), font, brush, new Point(tmpEnd.X - 7, tmpEnd.Y + 10));
                }
                k++;
            }
            int l = 0;
            for (int i = iHeight; i > 0; i = i - 50)
            {
                Point tmpStart = new Point(iWidht, i);
                Point tmpEnd = new Point(iWidht + 8, i);
                graphics.DrawLine(thickPen, tmpStart, tmpEnd);
                if (l != 0)
                {
                    graphics.DrawString(l.ToString(), font, brush, new Point(tmpEnd.X, tmpEnd.Y - 9));
                }
                l++;
            }

            int m = 0;
            for (int i = iHeight; i < this.ClientRectangle.Height; i = i + 50)
            {
                Point tmpStart = new Point(iWidht, i);
                Point tmpEnd = new Point(iWidht + 8, i);
                graphics.DrawLine(thickPen, tmpStart, tmpEnd);
                if (m != 0)
                {
                    graphics.DrawString("-" + m.ToString(), font, brush, new Point(tmpEnd.X, tmpEnd.Y - 9));
                }
                m++;
            }


            //定义坐标数组
            PointF[] points = { 
                        new PointF(105.0f,102.0f),
                        new PointF(106.0f,105.0f),
                        new PointF(200.0f,121.0f),
                        new PointF(220.0f,126.0f),
                        new PointF(230.0f,110.0f),
                        new PointF(300.0f,200.0f),
                        new PointF(320.0f,95.0f),
                        new PointF(343.0f,158.0f),
                        new PointF(360.0f,100.0f),
                        new PointF(450.0f,184.3f)
                    };

            //画折线
            graphics.DrawLines(thick, points);

            //画曲线
            Point beizerStart = new Point(200, 50);
            Point beizerControl1 = new Point(220, 287);
            Point beizerControl2 = new Point(460, 287);
            Point beizerEnd = new Point(500, 50);
            graphics.DrawBezier(thickPen, beizerStart, beizerControl1, beizerControl2, beizerEnd);
        }

使用DrawCurve绘制曲线

private void Form1_Paint(object sender, PaintEventArgs e)
{    
    //创建画板从Paint事件中的直接引用Graphics对象
    Graphics graphics = e.Graphics;

    graphics.Clear(Color.Black);

    //定义画笔
    Pen pen = new Pen(Color.White, 3.0f);
    Pen thickPen = new Pen(Color.White,2.0f);
    Pen thick = new Pen(Color.Red, 2.0f);

    //定义点坐标
    Point[] points = { 
                         new Point(50,50),
                         new Point(100,230),
                         new Point(150,50)
                     };
    graphics.DrawCurve(pen, points);

}

效果

使用它的重载DrawCurve(Pen,Point[],Single)画曲线

private void Form1_Paint(object sender, PaintEventArgs e)
{    
    //创建画板从Paint事件中的直接引用Graphics对象
    Graphics graphics = e.Graphics;

    graphics.Clear(Color.Black);

    //定义画笔
    Pen pen = new Pen(Color.White, 3.0f);
    Pen thickPen = new Pen(Color.White,2.0f);
    Pen thick = new Pen(Color.Red, 2.0f);

    //定义点坐标
    Point[] points = { 
                         new Point(50,50),
                         new Point(100,25),
                         new Point(200,5),
                         new Point(250,50),
                         new Point(300,100),
                         new Point(350,200),
                         new Point(250,250)
                     };    
    graphics.DrawCurve(pen, points,0.5f);

}

第三个参数是张力(平滑度)，如果等于0.0的话就是线段了，相当于DrawLines,越接近1.0越光滑。如果大于1.0的出现异常结果。

下面是从0.0,0.2,0.4,0.6,0.8,1.0的效果图

转载于:https://www.cnblogs.com/kiny/articles/2506715.html