渐变颜色LinearGradientBrush

LinearGradientBrush是用来渐变效果的，使用的初始化参数是矩形区域，开始颜色，结束颜色，颜色变化方向，它能够形成比较统一的渐变效果，对比PathGradientBrush的渐变，它的特点是它与周围的颜色渐变频率是一样的，设置LinearGradientBrush的区域大小时，可以想象一个大的有渐变色的长方形，压在多边形上面，并根据多边形的边界裁剪。

效果图

源码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;

namespace Graphic
{
    public partial class Demo_UseLinearGradientBrush : Form
    {
        public Demo_UseLinearGradientBrush()
        {
            InitializeComponent();

           
        }

        private void b_start_color_Click(object sender, EventArgs e)
        {
            ColorDialog clr = new ColorDialog();

            clr.ShowDialog();

            this.p_start_color.BackColor = clr.Color;
        
        }

        private void b_end_color_Click(object sender, EventArgs e)
        {
            ColorDialog clr = new ColorDialog();

            clr.ShowDialog();

            this.p_end_color.BackColor = clr.Color;

          
        }

        private void p_drawpic_Paint(object sender, PaintEventArgs e)
        {
               drawpic(this.p_start_color.BackColor, this.p_end_color.BackColor);
              
        }

        //绘图方法
        private void drawpic(Color start, Color end)
        {

            LinearGradientBrush br =
             new LinearGradientBrush(this.ClientRectangle, start, end, LinearGradientMode.ForwardDiagonal);

            Graphics g = this.p_drawpic.CreateGraphics();//为控件创建Graphics
            g.Clear(this.BackColor);
            g.FillRectangle(br,this.ClientRectangle);

            Font font = new Font("隶书", 50, FontStyle.Bold);
            g.DrawString("测试", font, br, new PointF(100, 50));

          
            g.Dispose();

        }

    }
}