wpf实现图片拖动和缩放

1.wpf提供了
ScaleTransform，来进行缩放变换，提供了
TranslateTransform来进行位置变换(移动坐标)。
以下代码来自互联网，实现图片的缩放和平移。 也可以将图片改为其他元素。

2.xaml代码

 <Window x:Class="Manager.Window4" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="600" Width="800" WindowState="Maximized" >
    <Canvas Name="root">

        <Grid>
            <ScrollViewer Margin="100,100" HorizontalAlignment="Left" VerticalAlignment="Top">
                <Image Name="img" Source="/manager;component/bin/Release/123.png" MouseDown="img_MouseDown" MouseWheel="img_MouseWheel" MouseMove="img_MouseMove" MouseUp="img_MouseUp" MouseLeave="img_MouseLeave" Stretch="Uniform" RenderOptions.BitmapScalingMode="NearestNeighbor" Canvas.Left="109" Canvas.Top="103">

                        <Image.RenderTransform>
                            <TransformGroup>
                                <ScaleTransform x:Name="sfr" />
                                <TranslateTransform x:Name="tlt" />
                            </TransformGroup>
                        </Image.RenderTransform>
                    </Image>
            </ScrollViewer>
        </Grid>
    </Canvas>
</Window>

3.cs文件代码

 using System;
using System.Collections.Generic;
using System.Diagnostics;
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 Manager
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class Window4 : Window
    {
        private bool isMouseLeftButtonDown = false;
        Point previousMousePoint = new Point(0, 0);
        public Window4()
        {
            InitializeComponent();
        }

        private void img_MouseDown(object sender, MouseButtonEventArgs e)
        {
            isMouseLeftButtonDown = true;
            previousMousePoint = e.GetPosition(img);
        }

        private void img_MouseUp(object sender, MouseButtonEventArgs e)
        { 
            isMouseLeftButtonDown = false;
        }

        private void img_MouseLeave(object sender, MouseEventArgs e)
        {
            isMouseLeftButtonDown = false;
        }

        private void img_MouseMove(object sender, MouseEventArgs e)
        {
            if (isMouseLeftButtonDown == true)
            {
                Point position = e.GetPosition(img);
                tlt.X += position.X - this.previousMousePoint.X;
                tlt.Y += position.Y - this.previousMousePoint.Y;
            }
        }

        private void img_MouseWheel(object sender, MouseWheelEventArgs e)
        { 
            Point centerPoint = e.GetPosition(img);

            double val = (double)e.Delta / 2000;   //描述鼠标滑轮滚动
            if (sfr.ScaleX < 0.3 && sfr.ScaleY < 0.3 && e.Delta < 0)
            {
                return;
            }
            sfr.CenterX = centerPoint.X;
            sfr.CenterY = centerPoint.Y;

            sfr.ScaleX += val;
            sfr.ScaleY += val;
        } 

    }
}