在WPF下实现以鼠标为中心图片缩放范例-技术开发专区

在WPF下实现以鼠标为中心图片缩放范例

作者：IT168技术频道整理编辑：胡铭娅 2009-10-31 01:00 来源：IT168�

　　Window1.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;

using System.Diagnostics;

namespace MouseMove

{

    /// <summary>

    /// Interaction logic for Window1.xaml

    /// </summary>

    public partial class Window1 : Window

    {

        private bool m_IsMouseLeftButtonDown;

        public Window1()

        {

            InitializeComponent();

        }

        private void MasterImage_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)

        {

            Rectangle rectangle = sender as Rectangle;

            if (rectangle == null)

                return;

            rectangle.ReleaseMouseCapture();

            m_IsMouseLeftButtonDown = false;

        }

        private Point m_PreviousMousePoint;

        private void MasterImage_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)

        {

            Rectangle rectangle = sender as Rectangle;

            if (rectangle == null)

                return;

            rectangle.CaptureMouse();

            m_IsMouseLeftButtonDown = true;

            m_PreviousMousePoint = e.GetPosition(rectangle);

        }

        private void MasterImage_MouseMove(object sender, MouseEventArgs e)

        {

            Rectangle rectangle = sender as Rectangle;

            if (rectangle == null)

                return;

            if (m_IsMouseLeftButtonDown)

                DoImageMove(rectangle, e);

        }

        private void DoImageMove(Rectangle rectangle, MouseEventArgs e)

        {

            //Debug.Assert(e.LeftButton == MouseButtonState.Pressed);

            if (e.LeftButton != MouseButtonState.Pressed)

                return;

            TransformGroup group = MainPanel.FindResource("ImageTransformResource") as TransformGroup;

            Debug.Assert(group != null);

            TranslateTransform transform = group.Children[1] as TranslateTransform;

            Point position = e.GetPosition(rectangle);

            transform.X += position.X - m_PreviousMousePoint.X;

            transform.Y += position.Y - m_PreviousMousePoint.Y;

            m_PreviousMousePoint = position;

        }

        private void MasterImage_MouseWheel(object sender, MouseWheelEventArgs e)

        {

            TransformGroup group = MainPanel.FindResource("ImageTransformResource") as TransformGroup;

            Debug.Assert(group != null);

            ScaleTransform transform = group.Children[0] as ScaleTransform;

            transform.ScaleX += e.Delta * 0.001;

            transform.ScaleY += e.Delta * 0.001;

        }

    }

}

　　实现了以图片中心为基点的缩放拖拽之后，又想实现以图片焦点为基点的缩放拖拽。下面让一起通过实例来进行学习吧。

第1页：在WPF下实现以鼠标为中心图片缩放范例第2页：以图片中心为基准点进行缩放第3页：Window1.xaml.cs代码第4页：以鼠标为基点进行缩放第5页：关键代码

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