使用这个问题的样本后，我制作了完整版本的缩放应用程序，并且相对于鼠标指针进行正确的缩放。所有平移和缩放代码已经移动到名为ZoomBorder的单独类中。
ZoomBorder.cs
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
namespace PanAndZoom
{
public class ZoomBorder : Border
{
private UIElement child = null;
private Point origin;
private Point start;
private TranslateTransform GetTranslateTransform(UIElement element)
{
return (TranslateTransform)((TransformGroup)element.RenderTransform)
.Children.First(tr => tr is TranslateTransform);
}
private ScaleTransform GetScaleTransform(UIElement element)
{
return (ScaleTransform)((TransformGroup)element.RenderTransform)
.Children.First(tr => tr is ScaleTransform);
}
public override UIElement Child
{
get { return base.Child; }
set
{
if (value != null && value != this.Child)
this.Initialize(value);
base.Child = value;
}
}
public void Initialize(UIElement element)
{
this.child = element;
if (child != null)
{
TransformGroup group = new TransformGroup();
ScaleTransform st = new ScaleTransform();
group.Children.Add(st);
TranslateTransform tt = new TranslateTransform();
group.Children.Add(tt);
child.RenderTransform = group;
child.RenderTransformOrigin = new Point(0.0, 0.0);
this.MouseWheel += child_MouseWheel;
this.MouseLeftButtonDown += child_MouseLeftButtonDown;
this.MouseLeftButtonUp += child_MouseLeftButtonUp;
this.MouseMove += child_MouseMove;
this.PreviewMouseRightButtonDown += new MouseButtonEventHandler(
child_PreviewMouseRightButtonDown);
}
}
public void Reset()
{
if (child != null)
{
// reset zoom
var st = GetScaleTransform(child);
st.ScaleX = 1.0;
st.ScaleY = 1.0;
// reset pan
var tt = GetTranslateTransform(child);
tt.X = 0.0;
tt.Y = 0.0;
}
}
#region Child Events
private void child_MouseWheel(object sender, MouseWheelEventArgs e)
{
if (child != null)
{
var st = GetScaleTransform(child);
var tt = GetTranslateTransform(child);
double zoom = e.Delta > 0 ? .2 : -.2;
if (!(e.Delta > 0) && (st.ScaleX < .4 || st.ScaleY < .4))
return;
Point relative = e.GetPosition(child);
double absoluteX;
double absoluteY;
absoluteX = relative.X * st.ScaleX + tt.X;
absoluteY = relative.Y * st.ScaleY + tt.Y;
st.ScaleX += zoom;
st.ScaleY += zoom;
tt.X = absoluteX - relative.X * st.ScaleX;
tt.Y = absoluteY - relative.Y * st.ScaleY;
}
}
private void child_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if (child != null)
{
var tt = GetTranslateTransform(child);
start = e.GetPosition(this);
origin = new Point(tt.X, tt.Y);
this.Cursor = Cursors.Hand;
child.CaptureMouse();
}
}
private void child_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
if (child != null)
{
child.ReleaseMouseCapture();
this.Cursor = Cursors.Arrow;
}
}
void child_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
this.Reset();
}
private void child_MouseMove(object sender, MouseEventArgs e)
{
if (child != null)
{
if (child.IsMouseCaptured)
{
var tt = GetTranslateTransform(child);
Vector v = start - e.GetPosition(this);
tt.X = origin.X - v.X;
tt.Y = origin.Y - v.Y;
}
}
}
#endregion
}
}
MainWindow.xaml
<Window x:Class="PanAndZoom.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:PanAndZoom"
Title="PanAndZoom" Height="600" Width="900" WindowStartupLocation="CenterScreen">
<Grid>
<local:ZoomBorder x:Name="border" ClipToBounds="True" Background="Gray">
<Image Source="image.jpg"/>
</local:ZoomBorder>
</Grid>
</Window>
MainWindow.xaml.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace PanAndZoom
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
}
}
double zoomCorrected = zoom*st.ScaleX; st.ScaleX += zoomCorrected; st.ScaleY += zoomCorrected; - DELUXEnizedprivate void image_MouseWheel(object sender, MouseWheelEventArgs e)
{
var st = (ScaleTransform)image.RenderTransform;
double zoom = e.Delta > 0 ? .2 : -.2;
st.ScaleX += zoom;
st.ScaleY += zoom;
}
为了处理平移，我首先处理了图像上的MouseLeftButtonDown事件，以捕获鼠标并记录其位置，我还存储了TranslateTransform的当前值，这是更新以实现平移的内容。
Point start;
Point origin;
private void image_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
image.CaptureMouse();
var tt = (TranslateTransform)((TransformGroup)image.RenderTransform)
.Children.First(tr => tr is TranslateTransform);
start = e.GetPosition(border);
origin = new Point(tt.X, tt.Y);
}
然后我处理了MouseMove事件来更新TranslateTransform。
private void image_MouseMove(object sender, MouseEventArgs e)
{
if (image.IsMouseCaptured)
{
var tt = (TranslateTransform)((TransformGroup)image.RenderTransform)
.Children.First(tr => tr is TranslateTransform);
Vector v = start - e.GetPosition(border);
tt.X = origin.X - v.X;
tt.Y = origin.Y - v.Y;
}
}
最后别忘了释放鼠标捕获。
private void image_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
image.ReleaseMouseCapture();
}
关于调整大小的选择手柄，可以使用装饰器来完成，详细信息请参见此文章。
上面已经发布了答案，但不完整。这是完整版本：
XAML
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="MapTest.Window1"
x:Name="Window"
Title="Window1"
Width="1950" Height="1546" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:Controls="clr-namespace:WPFExtensions.Controls;assembly=WPFExtensions" mc:Ignorable="d" Background="#FF000000">
<Grid x:Name="LayoutRoot">
<Grid.RowDefinitions>
<RowDefinition Height="52.92"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Border Grid.Row="1" Name="border">
<Image Name="image" Source="map3-2.png" Opacity="1" RenderTransformOrigin="0.5,0.5" />
</Border>
</Grid>
后台代码
using System.Linq;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media;
namespace MapTest
{
public partial class Window1 : Window
{
private Point origin;
private Point start;
public Window1()
{
InitializeComponent();
TransformGroup group = new TransformGroup();
ScaleTransform xform = new ScaleTransform();
group.Children.Add(xform);
TranslateTransform tt = new TranslateTransform();
group.Children.Add(tt);
image.RenderTransform = group;
image.MouseWheel += image_MouseWheel;
image.MouseLeftButtonDown += image_MouseLeftButtonDown;
image.MouseLeftButtonUp += image_MouseLeftButtonUp;
image.MouseMove += image_MouseMove;
}
private void image_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
image.ReleaseMouseCapture();
}
private void image_MouseMove(object sender, MouseEventArgs e)
{
if (!image.IsMouseCaptured) return;
var tt = (TranslateTransform) ((TransformGroup) image.RenderTransform).Children.First(tr => tr is TranslateTransform);
Vector v = start - e.GetPosition(border);
tt.X = origin.X - v.X;
tt.Y = origin.Y - v.Y;
}
private void image_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
image.CaptureMouse();
var tt = (TranslateTransform) ((TransformGroup) image.RenderTransform).Children.First(tr => tr is TranslateTransform);
start = e.GetPosition(border);
origin = new Point(tt.X, tt.Y);
}
private void image_MouseWheel(object sender, MouseWheelEventArgs e)
{
TransformGroup transformGroup = (TransformGroup) image.RenderTransform;
ScaleTransform transform = (ScaleTransform) transformGroup.Children[0];
double zoom = e.Delta > 0 ? .2 : -.2;
transform.ScaleX += zoom;
transform.ScaleY += zoom;
}
}
}
我有一些演示此功能的源代码，显示在Jot the sticky note app中。
请尝试使用这个缩放控件：http://wpfextensions.codeplex.com
这个控件的使用非常简单，只需要引用wpfextensions程序集即可：
<wpfext:ZoomControl>
<Image Source="..."/>
</wpfext:ZoomControl>
目前不支持滚动条。(在接下来的版本中将会支持，预计一到两周内发布)。
@Anothen 和 @Number8 - Vector 类在 Silverlight 中不可用，因此为了使其工作，我们只需要记录上一次调用 MouseMove 事件时看到的最后一个位置，并比较这两个点找到差异；然后调整转换。
XAML：
<Border Name="viewboxBackground" Background="Black">
<Viewbox Name="viewboxMain">
<!--contents go here-->
</Viewbox>
</Border>
代码后台：
public Point _mouseClickPos;
public bool bMoving;
public MainPage()
{
InitializeComponent();
viewboxMain.RenderTransform = new CompositeTransform();
}
void MouseMoveHandler(object sender, MouseEventArgs e)
{
if (bMoving)
{
//get current transform
CompositeTransform transform = viewboxMain.RenderTransform as CompositeTransform;
Point currentPos = e.GetPosition(viewboxBackground);
transform.TranslateX += (currentPos.X - _mouseClickPos.X) ;
transform.TranslateY += (currentPos.Y - _mouseClickPos.Y) ;
viewboxMain.RenderTransform = transform;
_mouseClickPos = currentPos;
}
}
void MouseClickHandler(object sender, MouseButtonEventArgs e)
{
_mouseClickPos = e.GetPosition(viewboxBackground);
bMoving = true;
}
void MouseReleaseHandler(object sender, MouseButtonEventArgs e)
{
bMoving = false;
}
我也尝试了这个答案，但对结果并不完全满意。我继续搜索，最终在2021年找到了一个Nuget包，帮助我实现了想要的效果。我想与Stack Overflow的前任开发人员分享。
我使用了这个Nuget包Gu.WPF.Geometry，通过这个Github存储库发现。所有开发的功劳应归给Johan Larsson，该包的所有者。
我如何使用它？我想在缩放框下方将命令作为按钮显示，就像在MachineLayoutControl.xaml中所示。
<UserControl
x:Class="MyLib.MachineLayoutControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:csmachinelayoutdrawlib="clr-namespace:CSMachineLayoutDrawLib"
xmlns:effects="http://gu.se/Geometry">
<UserControl.Resources>
<ResourceDictionary Source="Resources/ResourceDictionaries/AllResourceDictionariesCombined.xaml" />
</UserControl.Resources>
<Grid Margin="0">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Border
Grid.Row="0"
Margin="0,0"
Padding="0"
BorderThickness="1"
Style="{StaticResource Border_Head}"
Visibility="Visible">
<effects:Zoombox
x:Name="ImageBox"
IsManipulationEnabled="True"
MaxZoom="10"
MinZoom="0.1"
Visibility="{Binding Zoombox_Visibility}">
<ContentControl Content="{Binding Viewing_Canvas}" />
</effects:Zoombox>
</Border>
<StackPanel
Grid.Column="1"
Margin="10"
HorizontalAlignment="Right"
Orientation="Horizontal">
<Button
Command="effects:ZoomCommands.Increase"
CommandParameter="2.0"
CommandTarget="{Binding ElementName=ImageBox}"
Content="Zoom In"
Style="{StaticResource StyleForResizeButtons}" />
<Button
Command="effects:ZoomCommands.Decrease"
CommandParameter="2.0"
CommandTarget="{Binding ElementName=ImageBox}"
Content="Zoom Out"
Style="{StaticResource StyleForResizeButtons}" />
<Button
Command="effects:ZoomCommands.Uniform"
CommandTarget="{Binding ElementName=ImageBox}"
Content="See Full Machine"
Style="{StaticResource StyleForResizeButtons}" />
<Button
Command="effects:ZoomCommands.UniformToFill"
CommandTarget="{Binding ElementName=ImageBox}"
Content="Zoom To Machine Width"
Style="{StaticResource StyleForResizeButtons}" />
</StackPanel>
</Grid>
</UserControl>
public Visibility Zoombox_Visibility { get => movZoombox_Visibility; set { movZoombox_Visibility = value; OnPropertyChanged(nameof(Zoombox_Visibility)); } }
public Canvas Viewing_Canvas { get => mdvViewing_Canvas; private set => mdvViewing_Canvas = value; }
public partial class MachineLayoutControl : UserControl
{
#region Constructors
public MachineLayoutControl()
{
InitializeComponent();
Loaded += MyWindow_Loaded;
}
#endregion Constructors
#region EventHandlers
private void MyWindow_Loaded(object sender, RoutedEventArgs e)
{
Application.Current.Dispatcher.BeginInvoke(
DispatcherPriority.ApplicationIdle,
new Action(() =>
{
ZoomCommands.Uniform.Execute(null, ImageBox);
((MachineLayoutControlViewModel)DataContext).Zoombox_Visibility = Visibility.Visible;
}));
}
#endregion EventHandlers
}
var position = e.GetPosition(image1);
image1.RenderTransformOrigin = new Point(position.X / image1.ActualWidth, position.Y / image1.ActualHeight);
@ Merk
您可以使用以下代码来替代lambda表达式：
//var tt = (TranslateTransform)((TransformGroup)image.RenderTransform).Children.First(tr => tr is TranslateTransform);
TranslateTransform tt = null;
TransformGroup transformGroup = (TransformGroup)grid.RenderTransform;
for (int i = 0; i < transformGroup.Children.Count; i++)
{
if (transformGroup.Children[i] is TranslateTransform)
tt = (TranslateTransform)transformGroup.Children[i];
}
这段代码可以直接在 .Net Framework 3.0 或 2.0 中使用。
希望对您有所帮助 :-)
这是同种类型控件的另一版本，与其他控件具有相似的功能，但增加了以下功能：
使用方法很简单：
<Controls:ImageViewControl ImagePath="{Binding ...}" />
代码如下：
public class ImageViewControl : Border
{
private Point origin;
private Point start;
private Image image;
public ImageViewControl()
{
ClipToBounds = true;
Loaded += OnLoaded;
}
#region ImagePath
/// <summary>
/// ImagePath Dependency Property
/// </summary>
public static readonly DependencyProperty ImagePathProperty = DependencyProperty.Register("ImagePath", typeof (string), typeof (ImageViewControl), new FrameworkPropertyMetadata(string.Empty, OnImagePathChanged));
/// <summary>
/// Gets or sets the ImagePath property. This dependency property
/// indicates the path to the image file.
/// </summary>
public string ImagePath
{
get { return (string) GetValue(ImagePathProperty); }
set { SetValue(ImagePathProperty, value); }
}
/// <summary>
/// Handles changes to the ImagePath property.
/// </summary>
private static void OnImagePathChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var target = (ImageViewControl) d;
var oldImagePath = (string) e.OldValue;
var newImagePath = target.ImagePath;
target.ReloadImage(newImagePath);
target.OnImagePathChanged(oldImagePath, newImagePath);
}
/// <summary>
/// Provides derived classes an opportunity to handle changes to the ImagePath property.
/// </summary>
protected virtual void OnImagePathChanged(string oldImagePath, string newImagePath)
{
}
#endregion
private void OnLoaded(object sender, RoutedEventArgs routedEventArgs)
{
image = new Image {
//IsManipulationEnabled = true,
RenderTransformOrigin = new Point(0.5, 0.5),
RenderTransform = new TransformGroup {
Children = new TransformCollection {
new ScaleTransform(),
new TranslateTransform()
}
}
};
// NOTE I use a border as the first child, to which I add the image. I do this so the panned image doesn't partly obscure the control's border.
// In case you are going to use rounder corner's on this control, you may to update your clipping, as in this example:
// http://wpfspark.wordpress.com/2011/06/08/clipborder-a-wpf-border-that-clips/
var border = new Border {
IsManipulationEnabled = true,
ClipToBounds = true,
Child = image
};
Child = border;
image.MouseWheel += (s, e) =>
{
var zoom = e.Delta > 0
? .2
: -.2;
var position = e.GetPosition(image);
image.RenderTransformOrigin = new Point(position.X / image.ActualWidth, position.Y / image.ActualHeight);
var st = (ScaleTransform)((TransformGroup)image.RenderTransform).Children.First(tr => tr is ScaleTransform);
st.ScaleX += zoom;
st.ScaleY += zoom;
e.Handled = true;
};
image.MouseLeftButtonDown += (s, e) =>
{
if (e.ClickCount == 2)
ResetPanZoom();
else
{
image.CaptureMouse();
var tt = (TranslateTransform) ((TransformGroup) image.RenderTransform).Children.First(tr => tr is TranslateTransform);
start = e.GetPosition(this);
origin = new Point(tt.X, tt.Y);
}
e.Handled = true;
};
image.MouseMove += (s, e) =>
{
if (!image.IsMouseCaptured) return;
var tt = (TranslateTransform) ((TransformGroup) image.RenderTransform).Children.First(tr => tr is TranslateTransform);
var v = start - e.GetPosition(this);
tt.X = origin.X - v.X;
tt.Y = origin.Y - v.Y;
e.Handled = true;
};
image.MouseLeftButtonUp += (s, e) => image.ReleaseMouseCapture();
//NOTE I apply the manipulation to the border, and not to the image itself (which caused stability issues when translating)!
border.ManipulationDelta += (o, e) =>
{
var st = (ScaleTransform)((TransformGroup)image.RenderTransform).Children.First(tr => tr is ScaleTransform);
var tt = (TranslateTransform)((TransformGroup)image.RenderTransform).Children.First(tr => tr is TranslateTransform);
st.ScaleX *= e.DeltaManipulation.Scale.X;
st.ScaleY *= e.DeltaManipulation.Scale.X;
tt.X += e.DeltaManipulation.Translation.X;
tt.Y += e.DeltaManipulation.Translation.Y;
e.Handled = true;
};
}
private void ResetPanZoom()
{
var st = (ScaleTransform)((TransformGroup)image.RenderTransform).Children.First(tr => tr is ScaleTransform);
var tt = (TranslateTransform)((TransformGroup)image.RenderTransform).Children.First(tr => tr is TranslateTransform);
st.ScaleX = st.ScaleY = 1;
tt.X = tt.Y = 0;
image.RenderTransformOrigin = new Point(0.5, 0.5);
}
/// <summary>
/// Load the image (and do not keep a hold on it, so we can delete the image without problems)
/// </summary>
/// <see cref="http://blogs.vertigo.com/personal/ralph/Blog/Lists/Posts/Post.aspx?ID=18"/>
/// <param name="path"></param>
private void ReloadImage(string path)
{
try
{
ResetPanZoom();
// load the image, specify CacheOption so the file is not locked
var bitmapImage = new BitmapImage();
bitmapImage.BeginInit();
bitmapImage.CacheOption = BitmapCacheOption.OnLoad;
bitmapImage.UriSource = new Uri(path, UriKind.RelativeOrAbsolute);
bitmapImage.EndInit();
image.Source = bitmapImage;
}
catch (SystemException e)
{
Console.WriteLine(e.Message);
}
}
}
if (image.ActualWidth*(st.ScaleX + zoom) < 200 || image.ActualHeight*(st.ScaleY + zoom) < 200) //不要缩小得太小。 return;。 - huoxudong125