前面说到了InkCanvas的基本操作,这里用一个实例来说明具体应用:绘制矩形和椭圆。
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效果图
xaml代码
后台代码
using Microsoft.Win32; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Ink; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Shapes; namespace WPF_InkCanvas { ////// ROI_InkCanvas.xaml 的交互逻辑 /// public partial class ROI_InkCanvas : Window { private ViewModel viewModel; private System.Windows.Point iniP; public ROI_InkCanvas() { InitializeComponent(); DrawingAttributes drawingAttributes = new DrawingAttributes { Color = Colors.Red, Width = 2, Height = 2, StylusTip = StylusTip.Rectangle, //FitToCurve = true, IsHighlighter = false, IgnorePressure = true, }; inkCanvasMeasure.DefaultDrawingAttributes = drawingAttributes; viewModel = new ViewModel { MeaInfo = "测试······", InkStrokes = new StrokeCollection(), }; DataContext = viewModel; } private void OpenFile_Click(object sender, RoutedEventArgs e) { OpenFileDialog openDialog = new OpenFileDialog { Filter = "Image Files (*.jpg)|*.jpg|Image Files (*.png)|*.png|Image Files (*.bmp)|*.bmp", Title = "Open Image File" }; if (openDialog.ShowDialog() == true) { BitmapImage image = new BitmapImage(); image.BeginInit(); image.UriSource = new Uri(openDialog.FileName, UriKind.RelativeOrAbsolute); image.EndInit(); imgMeasure.Source = image; } } private void DrawSquare_Click(object sender, RoutedEventArgs e) { if (btnSquare.IsChecked == true) { btnEllipse.IsChecked = false; } } private void DrawEllipse_Click(object sender, RoutedEventArgs e) { if (btnEllipse.IsChecked == true) { btnSquare.IsChecked = false; } } private ListGenerateEclipseGeometry(System.Windows.Point st, System.Windows.Point ed) { double a = 0.5 * (ed.X - st.X); double b = 0.5 * (ed.Y - st.Y); List pointList = new List (); for (double r = 0; r <= 2 * Math.PI; r = r + 0.01) { pointList.Add(new System.Windows.Point(0.5 * (st.X + ed.X) + a * Math.Cos(r), 0.5 * (st.Y + ed.Y) + b * Math.Sin(r))); } return pointList; } private void InkCanvasMeasure_MouseDown(object sender, MouseButtonEventArgs e) { if (e.LeftButton == MouseButtonState.Pressed) { iniP = e.GetPosition(inkCanvasMeasure); } } private void InkCanvasMeasure_MouseMove(object sender, MouseEventArgs e) { if (e.LeftButton == MouseButtonState.Pressed) { // Draw square if (btnSquare.IsChecked == true) { System.Windows.Point endP = e.GetPosition(inkCanvasMeasure); List pointList = new List { new System.Windows.Point(iniP.X, iniP.Y), new System.Windows.Point(iniP.X, endP.Y), new System.Windows.Point(endP.X, endP.Y), new System.Windows.Point(endP.X, iniP.Y), new System.Windows.Point(iniP.X, iniP.Y), }; StylusPointCollection point = new StylusPointCollection(pointList); Stroke stroke = new Stroke(point) { DrawingAttributes = inkCanvasMeasure.DefaultDrawingAttributes.Clone() }; viewModel.InkStrokes.Clear(); viewModel.InkStrokes.Add(stroke); } // Draw Eclipse else if (btnEllipse.IsChecked == true) { System.Windows.Point endP = e.GetPosition(inkCanvasMeasure); List pointList = GenerateEclipseGeometry(iniP, endP); StylusPointCollection point = new StylusPointCollection(pointList); Stroke stroke = new Stroke(point) { DrawingAttributes = inkCanvasMeasure.DefaultDrawingAttributes.Clone() }; viewModel.InkStrokes.Clear(); viewModel.InkStrokes.Add(stroke); } } } } }
ViewModel.cs代码
using System; using System.Collections.Generic; using System.ComponentModel; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Ink; namespace WPF_InkCanvas { class ViewModel : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; protected virtual void OnPropertyChanged(string propertyName = null) { if (PropertyChanged != null) PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName)); } private string meaInfo; public string MeaInfo { get => meaInfo; set { meaInfo = value; OnPropertyChanged("MeaInfo"); } } private StrokeCollection inkStrokes; public StrokeCollection InkStrokes { get { return inkStrokes; } set { inkStrokes = value; OnPropertyChanged("InkStrokes"); } } } }
补充说明:为什么要注释掉画笔属性//FitToCurve = true,可以自行体会下不注释会是个什么效果;将InkCanvas的Strokes绑定到变量有好处,在别的窗口也能获取到这个对象的哦,因为它是在viewModel里的,传viewModel参数就可以了;椭圆绘制完成后设置InkCanvas的EdittingMode为Select就可以修改大小和形状。
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