wpf图片查看器,支持鼠标滚动缩放拖拽

最近项目需要,要用到一个图片查看器,类似于windows自带的图片查看器那样,鼠标滚动可以缩放,可以拖拽图片,于是就写了这个简单的图片查看器。

前台代码:

<Window x:Class="PictureViewer.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
AllowDrop="True"
Title="图片查看器" Height="" Width="" Loaded="Window_Loaded"
SizeChanged="Window_SizeChanged" DragEnter="Window_DragEnter" Drop="Window_Drop">
<Grid x:Name="mainGrid">
<Grid.Resources>
<TransformGroup x:Key="TfGroup">
<ScaleTransform ScaleX="" ScaleY=""/>
<TranslateTransform X="" Y=""/>
</TransformGroup>
</Grid.Resources>
<Grid.RowDefinitions>
<RowDefinition Height=""></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
</Grid.RowDefinitions> <Button Grid.Row="" Width="" Height="" Cursor="Hand" Background="Transparent" BorderThickness="" Content="打开图片" Click="OpenImg_Click" x:Name="OpenImg" HorizontalAlignment="Left" VerticalAlignment="Center" Margin="20,0,0,0"/>
<Label Content="缩放倍数:" HorizontalAlignment="Left" VerticalAlignment="Center" Margin="130,0,0,0"/>
<TextBox x:Name="txtMinSize" Width="" Height="" VerticalContentAlignment="Center" HorizontalAlignment="Left" VerticalAlignment="Center" Margin="200,0,0,0" TextChanged="txtMinSize_TextChanged" Text="0.1"/>
<Label Content="--" HorizontalAlignment="Left" VerticalAlignment="Center" Margin="240,0,0,0"/>
<TextBox x:Name="txtMaxSize" Width="" Height="" VerticalContentAlignment="Center" HorizontalAlignment="Left" VerticalAlignment="Center" Margin="260,0,0,0" TextChanged="txtMaxSize_TextChanged" Text=""/>
<ScrollViewer x:Name="mainScrollv" HorizontalAlignment="Center" VerticalAlignment="Center" HorizontalScrollBarVisibility="Disabled"
VerticalScrollBarVisibility="Disabled" Cursor="SizeAll" Margin="" Focusable="False" Grid.Row="">
<ContentControl MouseLeftButtonDown="ContentControl_MouseLeftButtonDown"
MouseLeftButtonUp="ContentControl_MouseLeftButtonUp"
MouseMove="ContentControl_MouseMove"
MouseWheel="ContentControl_MouseWheel"
HorizontalAlignment="Center" VerticalAlignment="Center">
<Image x:Name="IMG" Margin="" RenderTransform="{StaticResource TfGroup}" RenderOptions.BitmapScalingMode="NearestNeighbor"/> </ContentControl> </ScrollViewer>
</Grid>
</Window>

代码解析:

  通过一个定义一个TransformGroup,通过Key绑定到图片控件中,并且里面使用ScaleTransform实现缩放(scaleX是水平方向的缩放倍数,现默认为1倍,即无缩放,scaleY同理),TranslateTransform实现平移(鼠标拖动,X为水平方向的偏移量,Y为垂直方向的偏移量)。

  另通过一个ContentControl控件摆放图片控件,并为控件绑定各种事件(鼠标点下、抬起、拖动、滚动),图片控件的RenderOptions.BitmapscalingMode="NearestNeighbor"属性用于优化图片变换过程,防止出现图片移动或缩放模糊。

后台代码:

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 PictureViewer
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
} private bool mouseDown;
private Point mouseXY;
private double min = 0.1, max = 3.0;//最小/最大放大倍数 private void Domousemove(ContentControl img, MouseEventArgs e)
{
if (e.LeftButton != MouseButtonState.Pressed)
{
return;
}
var group = IMG.FindResource("TfGroup") as TransformGroup;
var transform = group.Children[] as TranslateTransform;
var position = e.GetPosition(img);
transform.X -= mouseXY.X - position.X;
transform.Y -= mouseXY.Y - position.Y;
mouseXY = position;
} private void DowheelZoom(TransformGroup group, Point point, double delta)
{
var pointToContent = group.Inverse.Transform(point);
var transform = group.Children[] as ScaleTransform;
if (transform.ScaleX + delta < min) return;
if (transform.ScaleX + delta > max) return;
transform.ScaleX += delta;
transform.ScaleY += delta;
var transform1 = group.Children[] as TranslateTransform;
transform1.X = - * ((pointToContent.X * transform.ScaleX) - point.X);
transform1.Y = - * ((pointToContent.Y * transform.ScaleY) - point.Y);
} private void ContentControl_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
var img = sender as ContentControl;
if (img == null)
{
return;
}
img.CaptureMouse();
mouseDown = true;
mouseXY = e.GetPosition(img);
} private void ContentControl_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
var img = sender as ContentControl;
if (img == null)
{
return;
}
img.ReleaseMouseCapture();
mouseDown = false;
} private void ContentControl_MouseMove(object sender, MouseEventArgs e)
{
var img = sender as ContentControl;
if (img == null)
{
return;
}
if (mouseDown)
{
Domousemove(img, e);
}
} private void ContentControl_MouseWheel(object sender, MouseWheelEventArgs e)
{
var img = sender as ContentControl;
if (img == null)
{
return;
}
var point = e.GetPosition(img);
var group = IMG.FindResource("TfGroup") as TransformGroup;
var delta = e.Delta * 0.001;
DowheelZoom(group, point, delta);
} private void OpenImg_Click(object sender, RoutedEventArgs e)
{
// 在WPF中, OpenFileDialog位于Microsoft.Win32名称空间
Microsoft.Win32.OpenFileDialog dialog = new Microsoft.Win32.OpenFileDialog();
dialog.Filter = "Files (*.png)|*.png|Files(*.jpg)|*.jpg";
if (dialog.ShowDialog() == true)
{
//MessageBox.Show(dialog.FileName);
this.IMG.Source = new BitmapImage(new Uri(dialog.FileName));
}
} private void Window_Loaded(object sender, RoutedEventArgs e)
{
setViewSize();
}
private void setViewSize()
{
mainScrollv.Width = this.ActualWidth;
mainScrollv.Height = this.ActualHeight - ;
} private void Window_SizeChanged(object sender, SizeChangedEventArgs e)
{
setViewSize();
} private void txtMinSize_TextChanged(object sender, TextChangedEventArgs e)
{
this.min = double.Parse(txtMinSize.Text);
} private void txtMaxSize_TextChanged(object sender, TextChangedEventArgs e)
{
this.max = double.Parse(txtMaxSize.Text);
} private void Window_DragEnter(object sender, DragEventArgs e)
{
if (e.Data.GetDataPresent(DataFormats.FileDrop))
e.Effects = DragDropEffects.Link;//WinForm中为e.Effect = DragDropEffects.Link
else e.Effects = DragDropEffects.None;//WinFrom中为e.Effect = DragDropEffects.None } private void Window_Drop(object sender, DragEventArgs e)
{
string filename = ((System.Array)e.Data.GetData(DataFormats.FileDrop)).GetValue().ToString();
this.IMG.Source = new BitmapImage(new Uri(filename));
} }
}

可将图片拖拽到窗口打开,Window_DragEnter里验证拖拽进来的文件是否可用,Window_Drop处理拖拽进来之后的事情

源码:http://files.cnblogs.com/files/huangli321456/PictureViewer.zip

代码参照:http://www.cnblogs.com/snake-hand/archive/2012/08/13/2636227.html

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