最近的項目中也要用到一個局部圖片放大的功能,園子裏面一搜,發現(菩提下的楊過)楊大俠已經實現了。html
請參見這裏:http://www.cnblogs.com/yjmyzz/archive/2009/12/03/1615988.html後端
楊大俠已經給出了原理、知識要點、尺寸要點及後端主要代碼,但遺憾的是沒有給出xaml的代碼。按照楊大俠文中的提示,動手用WPF實踐了一下,花了一個小時,終於搞出來了。這篇文章也就算是一個補充吧。this
界面以下圖所示:spa
實現的原理和用到的知識點請點擊上面的連接,楊大俠已經說的很清楚了。這裏主要強調的就是尺寸要點:code
爲了簡單起見,咱們把尺寸固定死(實際上是能夠搞成活的),這裏僅爲了演示,如下尺寸知足上面的條件。orm
準備一張原圖:dog.jpg 分辨率:1920 * 1080xml
左側小圖片顯示區域:用Canvas 顯示,尺寸:320 * 180htm
半透明矩形框尺寸:50*50blog
右側大圖顯示區域:用Canvas顯示,尺寸:300 * 300圖片
如下是XAML代碼:
<Window x:Class="WpfZoom.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="WPF局部放大效果" Height="370" Width="700"> <Canvas x:Name="RootCanvas"> <!--左側小圖--> <Canvas x:Name="SmallBox" Width="320" Height="180" Canvas.Left="20" Canvas.Top="20"> <Canvas.Background> <ImageBrush ImageSource="Images/dog.jpg" Stretch="UniformToFill" /> </Canvas.Background> <!--半透明矩形框--> <Rectangle x:Name="MoveRect" Fill="White" Opacity="0.3" Stroke="Red" Width="50" Height="50" Canvas.Top="78" Canvas.Left="202" MouseMove="MoveRect_MouseMove" MouseLeftButtonDown="MoveRect_MouseLeftButtonDown" MouseLeftButtonUp="MoveRect_MouseLeftButtonUp"/> </Canvas> <!--右側大圖--> <Canvas x:Name="BigBox" Width="300" Height="300" Canvas.Left="360" Canvas.Top="20"> <!--右側原圖片 注意尺寸--> <Image x:Name="bigImg" Width="1920" Height="1080" Canvas.Left="0" Canvas.Top="-780" Source="Images/dog.jpg" /> <Canvas.Clip> <RectangleGeometry Rect="0,0,300,300" /> </Canvas.Clip> </Canvas> </Canvas> </Window>
cs 代碼:
using System; using System.Windows; using System.Windows.Controls; using System.Windows.Input; namespace WpfZoom { /// <summary> /// MainWindow.xaml 的交互邏輯 /// </summary> public partial class MainWindow : Window { //移動標誌 bool trackingMouseMove = false; //鼠標按下去的位置 Point mousePosition; public MainWindow() { InitializeComponent(); this.Loaded += new RoutedEventHandler(MainWindow_Loaded); } void MainWindow_Loaded(object sender, RoutedEventArgs e) { AdjustBigImage(); } /// <summary> /// 半透明矩形框鼠標左鍵按下 /// </summary> private void MoveRect_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { FrameworkElement element = sender as FrameworkElement; mousePosition = e.GetPosition(element); trackingMouseMove = true; if (null != element) { //強制獲取此元素 element.CaptureMouse(); element.Cursor = Cursors.Hand; } } /// <summary> /// 半透明矩形框鼠標左鍵彈起 /// </summary> private void MoveRect_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) { FrameworkElement element = sender as FrameworkElement; trackingMouseMove = false; element.ReleaseMouseCapture(); mousePosition.X = mousePosition.Y = 0; element.Cursor = null; } /// <summary> /// 半透明矩形框移動 /// </summary> private void MoveRect_MouseMove(object sender, MouseEventArgs e) { FrameworkElement element = sender as FrameworkElement; if (trackingMouseMove) { //計算鼠標在X軸的移動距離 double deltaV = e.GetPosition(element).Y - mousePosition.Y; //計算鼠標在Y軸的移動距離 double deltaH = e.GetPosition(element).X - mousePosition.X; //獲得圖片Top新位置 double newTop = deltaV + (double)element.GetValue(Canvas.TopProperty); //獲得圖片Left新位置 double newLeft = deltaH + (double)element.GetValue(Canvas.LeftProperty); //邊界的判斷 if (newLeft <= 0) { newLeft = 0; } //左側圖片框寬度 - 半透明矩形框寬度 if (newLeft >= (this.SmallBox.Width - this.MoveRect.Width)) { newLeft = this.SmallBox.Width - this.MoveRect.Width; } if (newTop <= 0) { newTop = 0; } //左側圖片框高度度 - 半透明矩形框高度度 if (newTop >= this.SmallBox.Height - this.MoveRect.Height) { newTop = this.SmallBox.Height - this.MoveRect.Height; } element.SetValue(Canvas.TopProperty, newTop); element.SetValue(Canvas.LeftProperty, newLeft); AdjustBigImage(); if (mousePosition.X <= 0 || mousePosition.Y <= 0) { return; } } } /// <summary> /// 調整右側大圖的位置 /// </summary> void AdjustBigImage() { //獲取右側大圖框與透明矩形框的尺寸比率 double n = this.BigBox.Width / this.MoveRect.Width; //獲取半透明矩形框在左側小圖中的位置 double left = (double)this.MoveRect.GetValue(Canvas.LeftProperty); double top = (double)this.MoveRect.GetValue(Canvas.TopProperty); //計算和設置原圖在右側大圖框中的Canvas.Left 和 Canvas.Top double newLeft = -left * n; double newTop = -top * n; bigImg.SetValue(Canvas.LeftProperty, newLeft); bigImg.SetValue(Canvas.TopProperty, newTop); } } }