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wpf 影象瀏覽(平移,縮放)

<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        x:Class="WpfApp2.MainWindow"
mc:Ignorable="d" Title="MainWindow" Height="800" Width="1000"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="*"/> <RowDefinition Height="40"/> </Grid.RowDefinitions> <Border x:Name="outside" Background
="Black" PreviewMouseDown="outsidewrapper_PreviewMouseDown" PreviewMouseMove="outsidewrapper_PreviewMouseMove" PreviewMouseUp="outside_PreviewMouseUp" PreviewMouseWheel="outside_PreviewMouseWheel" ClipToBounds="True">
<Canvas x:Name="inside" Width="{Binding ActualWidth, RelativeSource={RelativeSource AncestorType={x:Type Border}}}" Height="{Binding ActualHeight, RelativeSource={RelativeSource AncestorType={x:Type Border}}}"> <Canvas.RenderTransform> <TransformGroup/> </Canvas.RenderTransform> <Image x:Name="myImage" Source="{Binding IamgeSource}" Stretch="Uniform" RenderOptions.BitmapScalingMode="NearestNeighbor" > <Image.RenderTransform > <ScaleTransform x:Name="ImageScale"/> </Image.RenderTransform> </Image> </Canvas> </Border> <Button Click="BtnClickLoadPic" Grid.Row="2" HorizontalAlignment="Right" Content="載入圖片" /> <Button Click="BtnClickFullScreen" Grid.Row="2" HorizontalAlignment="Right" Content=" 全屏 " Margin="0,0,60,0" /> </Grid> </Window>
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using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Messaging;
using LiveCharts;
using LiveCharts.Wpf;
using MathNet.Numerics.LinearAlgebra.Double;
using Microsoft.Win32;
//using MathNet.Numerics.LinearAlgebra.Complex;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
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 WpfApp2
{
    /// <summary>
    /// MainWindow.xaml 的互動邏輯
    /// </summary>
    public partial class MainWindow : Window
    {
        Point previousPoint;
        bool isTranslateStart = false;
        public MainWindow()
        {
            InitializeComponent();
        }

        private void outsidewrapper_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            if (e.MiddleButton == MouseButtonState.Pressed && e.LeftButton == MouseButtonState.Released && e.RightButton == MouseButtonState.Released)
            {
                previousPoint = e.GetPosition(outside);
                isTranslateStart = true;
            }
            e.Handled = true;
        }

        private void outsidewrapper_PreviewMouseMove(object sender, MouseEventArgs e)
        {
            if (e.MiddleButton == MouseButtonState.Pressed && e.LeftButton == MouseButtonState.Released && e.RightButton == MouseButtonState.Released)
            {
                if (isTranslateStart)
                {
                    Point currentPoint = e.GetPosition(outside);  //不能用 inside,必須用outside
                    System.Windows.Vector v = currentPoint - previousPoint;
                    TransformGroup tg = inside.RenderTransform as TransformGroup;
                    tg.Children.Add(new TranslateTransform(v.X, v.Y));  //centerX和centerY用外部包裝元素的座標,不能用內部被變換的Canvas元素的座標
                    previousPoint = currentPoint;
                }
            }
            e.Handled = true;
        }

        private void outside_PreviewMouseUp(object sender, MouseButtonEventArgs e)
        {
            if (e.MiddleButton == MouseButtonState.Pressed && e.LeftButton == MouseButtonState.Released && e.RightButton == MouseButtonState.Released)
            {
                if (isTranslateStart)
                {
                    isTranslateStart = false;
                }
            }
            e.Handled = true;
        }
        private void outside_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
        {
            Point currentPoint = e.GetPosition(outside);  //不能用 inside,必須用outside
            TransformGroup tg = inside.RenderTransform as TransformGroup;
            double s = ((double)e.Delta) / 1000.0 + 1.0;
            if (myImage.Height * tg.Value.M22 < 200 || myImage.Width * tg.Value.M11 < 200)
            {
                if(s > 1.0)//當影象畫素寬度和高度小於200的時候只能放大,不再縮小
                    tg.Children.Add(new ScaleTransform(s, s, currentPoint.X, currentPoint.Y));
            }
            else
                tg.Children.Add(new ScaleTransform(s, s, currentPoint.X, currentPoint.Y));
            e.Handled = true;
        }

        private void BtnClickLoadPic(object sender, RoutedEventArgs e)
        {
            // Instantiate the dialog box
            var dlg = new Microsoft.Win32.OpenFileDialog
            {
                FileName = "",
                Filter = "All Files|*.*|PNG Files|*.png|JPG Files|*.jpg|TIF Files|*.tif"
            };
            var result = dlg.ShowDialog();
            // Process open file dialog box results
            if (result == true)
            {
                BitmapImage bitmapImage = new BitmapImage(new Uri(dlg.FileName));
                myImage.Source = bitmapImage;
                myImage.Height = bitmapImage.PixelHeight;//為了得到畫素對應的座標
                myImage.Width = bitmapImage.PixelWidth;//為了得到畫素對應的座標
            }
        }

        private void BtnClickFullScreen(object sender, RoutedEventArgs e)
        {
            TransformGroup tg = inside.RenderTransform as TransformGroup;
            System.Windows.Media.Matrix value = new System.Windows.Media.Matrix();
            value.M11 = outside.ActualWidth / myImage.Width / tg.Value.M11;//縮放倍數為Border的尺寸
            value.M22 =  outside.ActualHeight / myImage.Height / tg.Value.M22;
            value.OffsetX = (0 - tg.Value.OffsetX) * value.M11;//調整偏移XY到(0,0)
            value.OffsetY = (0 - tg.Value.OffsetY) * value.M22;
            MatrixTransform matrixTransform = new MatrixTransform(value);//新增矩陣變換
            tg.Children.Add(matrixTransform);
            e.Handled = true;
        }
    }
}
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