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我正在嘗試製作一個簡單的圖像編輯器，用戶可以在其中加載圖像並在其上繪製箭頭，文本和矩形。如何讓用戶使用WPF中的畫布繪製線條
現在我有一個窗口，有一些按鈕和一個帶有畫布和裏面的圖像的視圖框。
基本上，用戶將單擊箭頭按鈕，單擊畫布上的某處，移動將顯示一條線的鼠標，然後單擊其他地方以實際繪製線條。
如何讓畫布在單擊繪圖按鈕後纔開始監聽鼠標點擊？這是我到目前爲止。
<Window x:Class="ImageEditor.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="600" Width="800">
<Window.CommandBindings>
<CommandBinding Command="local:CapturePointsCommand" Executed="CommandBinding_Executed" CanExecute="CommandBinding_CanExecute"/>
</Window.CommandBindings>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Button Grid.Row="0" Name="_drawArrow" Height="69" Width="69" Click="_drawArrow_Click" HorizontalAlignment="Left" Margin="5,5,0,5">
<Image Source="Media/arrow.png"/>
</Button>
<Button Grid.Row="0" Name="_drawBox" Height="69" Width="69" Click="_drawBox_Click" HorizontalAlignment="Left" Margin="79,5,0,5">
<Image Source="Media/rectangle.png"/>
</Button>
<Button Grid.Row="0" Name="_drawText" Height="69" Width="69" Click="_drawText_Click" HorizontalAlignment="Left" Margin="153,5,0,5">
<Image Source="Media/text.png"/>
</Button>
<Viewbox Grid.Row="1">
<Canvas Name="_canvas" Height="{Binding Height, ElementName=_picture}" Width="{Binding Width, ElementName=_picture}" MouseLeftButtonUp="_canvas_MouseLeftButtonUp">
<Image Name="_picture" Source="{Binding Image}" Height="488" Width="800"/>
</Canvas>
</Viewbox>
<Button Grid.Row="2" HorizontalAlignment="Right" Name="_Load_Button" Content="Load" Margin="0,5,5,5" Width="75" Height="23" Click="_Load_Button_Click" />
<Button Grid.Row="2" HorizontalAlignment="Right" Name="_Save_Button" Content="Save" Margin="0,5,85,5" Width="75" Height="23" Click="_Save_Button_Click" />
<Button Grid.Row="2" HorizontalAlignment="Right" Name="_Cancel_Button" Content="Cancel" Margin="0,5,165,5" Width="75" Height="23" Click="_Cancel_Button_Click" />
<Button Grid.Row="2" HorizontalAlignment="Right" Name="_Reset_Button" Content="Reset" Margin="0,5,245,5" Width="75" Height="23" Click="_Reset_Button_Click" />
</Grid>
</Window>
以此爲後面的代碼：
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.Windows.Forms;
using System.IO;
namespace ImageEditor
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public static readonly RoutedCommand CapturePointsCommand = new RoutedCommand();
private ImageSource _image;
public MainWindow()
{
InitializeComponent();
}
public ImageSource Image
{
get
{
return this._image;
}
set
{
this._image = value;
}
}
private List<Point> _points = new List<Point>();
public List<Point> Points
{
get
{
return this._points;
}
set
{
this._points = value;
}
}
private void _Save_Button_Click(object sender, RoutedEventArgs e)
{
if (Image == null)
System.Windows.Forms.MessageBox.Show("There is nothing to save");
else
{
Image = this._picture.Source;
this.Close();
}
}
private void _Reset_Button_Click(object sender, RoutedEventArgs e)
{
this._picture.Source = Image;
}
private void _Cancel_Button_Click(object sender, RoutedEventArgs e)
{
Image = null;
this._picture.Source = null;
this.Close();
}
private void _Load_Button_Click(object sender, RoutedEventArgs e)
{
OpenFileDialog ofd = new OpenFileDialog();
string path;
if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
path = ofd.FileName;
Uri pathUri = new Uri(path);
PngBitmapDecoder decoder = new PngBitmapDecoder(pathUri, BitmapCreateOptions.None, BitmapCacheOption.None);
BitmapSource pathSrc = decoder.Frames[0];
Image = pathSrc;
this._picture.Source = Image;
}
else
{
path = null;
}
}
private void _drawArrow_Click(object sender, RoutedEventArgs e)
{
Line line = new Line();
line.Stroke = Brushes.Black;
line.X1 = Points[0].X;
line.Y1 = Points[0].Y;
line.X2 = Points[1].X;
line.Y2 = Points[1].Y;
this._canvas.Children.Add(line);
}
private void _drawBox_Click(object sender, RoutedEventArgs e)
{
}
private void _drawText_Click(object sender, RoutedEventArgs e)
{
}
private void _canvas_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
Point p = Mouse.GetPosition(_canvas);
Points.Add(p);
}
private void _drawArrow_MouseDown(object sender, MouseButtonEventArgs e)
{
}
private void CommandBinding_Executed(object sender, ExecutedRoutedEventArgs e)
{
}
private void CommandBinding_CanExecute(object sender, CanExecuteRoutedEventArgs e)
{
}
}
}
謝謝你，我結束了這一修改。對於畫布 「IsHitTestVisible」設置爲false，直到您單擊按鈕並在添加形狀後設置爲false以防止提前捕獲點。 – Adam