silverlight图片局部放大效果

很多购物平台中(比如京东购物)，浏览产品详情时都有这种效果，前几天看到有朋友问SL能不能实现，当然可以

代码:by 菩提树下的杨过 http://www.cnblogs.com/yjmyzz
using System.Windows;

using System.Windows.Controls;

using System.Windows.Input;

namespace PartMagnifier

{

public partial class MainPage : UserControl

{

bool trackingMouseMove = false;

Point mousePosition;

public MainPage()

{

// 为初始化变量所必需

InitializeComponent();

}

private void LayoutRoot_Loaded(object sender, System.Windows.RoutedEventArgs e)

{

Adjust();

}

private void Rectangle_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)

{

FrameworkElement element = sender as FrameworkElement;

mousePosition = e.GetPosition(element);

trackingMouseMove = true;

if (null != element)

{

element.CaptureMouse();

element.Cursor = Cursors.Hand;

}

Adjust();

Debug();

sb.Begin();//标题动画，可去掉

}

private void Rectangle_MouseMove(object sender, MouseEventArgs e)

{

FrameworkElement element = sender as FrameworkElement;

if (trackingMouseMove)

{

double deltaV = e.GetPosition(element).Y - mousePosition.Y;

double deltaH = e.GetPosition(element).X - mousePosition.X;

double newTop = deltaV + (double)element.GetValue(Canvas.TopProperty);

double newLeft = deltaH + (double)element.GetValue(Canvas.LeftProperty);

if (newLeft <= 10)

{

newLeft = 10;

}

if (newLeft >= 130)

{

newLeft = 130;

}

if (newTop <= 10) { newTop = 10; }

if (newTop >= 85) { newTop = 85; }

element.SetValue(Canvas.TopProperty, newTop);

element.SetValue(Canvas.LeftProperty, newLeft);

mousePosition = e.GetPosition(element);

Adjust();

if (mousePosition.X <= 0 || mousePosition.Y <= 0) { return; }

Debug();

}

}

private void Rectangle_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)

{

FrameworkElement element = sender as FrameworkElement;

trackingMouseMove = false;

element.ReleaseMouseCapture();

mousePosition.X = mousePosition.Y = 0;

element.Cursor = null;

}

/// <summary>

/// 调试信息

/// </summary>

void Debug()

{

txtResult.Text = "鼠标相对坐标：" + mousePosition.ToString() + "\n小框left：" + rect.GetValue(Canvas.LeftProperty) + ",小框top：" + rect.GetValue(Canvas.TopProperty) + "\n大图left：" + ((double)img.GetValue(Canvas.LeftProperty)).ToString("F0") + ",大图right：" + ((double)img.GetValue(Canvas.TopProperty)).ToString("F0");

}

/// <summary>

/// 调整右侧大图的位置

/// </summary>

void Adjust()

{

double n = cBig.Width / rect.Width;

double left = (double)rect.GetValue(Canvas.LeftProperty) - 10;

double top = (double)rect.GetValue(Canvas.TopProperty) - 10;

double newLeft = -left * n;

double newTop = -top * n;

img.SetValue(Canvas.LeftProperty, newLeft);

img.SetValue(Canvas.TopProperty, newTop);

}

}

}