WPF程序设计指南第二章例子CircleTheRainbow效果

源码如下：

添加brush.GradientOrigin = new Point(.25, .25)及

添加brush.GradientOrigin = new Point(.75, .75)的代码我不小心删了

这里是书中的代码，需要的自己添加就行了

//-------------------------------------------------

// CircleTheRainbow.cs (c) 2006 by Charles Petzold

//-------------------------------------------------

using System;

using System.Windows;

using System.Windows.Input;

using System.Windows.Media;

namespace Petzold.CircleTheRainbow

{

public class CircleTheRainbow : Window

{

[STAThread]

public static void Main()

{

Application app = new Application();

app.Run(new CircleTheRainbow());

}

public CircleTheRainbow()

{

Title = "Circle the Rainbow";

RadialGradientBrush brush = new RadialGradientBrush();

Background = brush;

// Rainbow mnemonic is the name Roy G. Biv.

brush.GradientStops.Add(new GradientStop(Colors.Red, 0));

brush.GradientStops.Add(new GradientStop(Colors.Orange, .17));

brush.GradientStops.Add(new GradientStop(Colors.Yellow, .33));

brush.GradientStops.Add(new GradientStop(Colors.Green, .5));

brush.GradientStops.Add(new GradientStop(Colors.Blue, .67));

brush.GradientStops.Add(new GradientStop(Colors.Indigo, .84));

brush.GradientStops.Add(new GradientStop(Colors.Violet, 1));

}

}

}