我在 wpf 中绘制了一些到屏幕的路径。所使用的坐标非常小，因此它们被制作为用视图框填充屏幕。我现在正在尝试实现平移和缩放功能。我希望能够缩放到鼠标相对于 ui 的任何位置（即缩放的屏幕中心等于鼠标坐标）。当前结果是缩放时屏幕的中心不反映 ui 上的确切鼠标位置。
如果你想看看发生了什么......这是我当前的解决方案文件。
或者
继承人一些代码：
查看 Xaml
<Grid Name="MasterGrid" DataContext="{StaticResource mainWindowViewModel}">
<ScrollViewer HorizontalScrollBarVisibility="Visible" VerticalScrollBarVisibility="Visible" Name="VisualisationScroller">
<Viewbox Name="VisualisationBox" Stretch="Fill" Loaded="VisualisationBox_Loaded">
<ItemsControl Name="CustomDrawingElement" ItemsSource="{Binding Trajectories}" Width="{Binding VisualisationWidth}" Height="{Binding VisualisationHeight}">
<ItemsControl.ItemTemplate>
<DataTemplate DataType="data:VisualisedTrajectory">
<Path Data = "{Binding PathData}" Stroke="Red" StrokeThickness="0.001" Fill="Transparent" />
</DataTemplate>
</ItemsControl.ItemTemplate>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas
Background="DarkGray"
IsItemsHost="True">
</Canvas>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.RenderTransform>
<TransformGroup>
<ScaleTransform ScaleX="1" ScaleY="1" />
<TranslateTransform />
</TransformGroup>
</ItemsControl.RenderTransform>
</ItemsControl>
</Viewbox>
</ScrollViewer>
</Grid>
查看模型
public class MainWindowViewModel : BaseViewModel
{
public MainWindowViewModel()
{
VisualiseRawTrajectories();
}
private ObservableCollection<VisualisedTrajectory> _trajectories = new ObservableCollection<VisualisedTrajectory>();
public ObservableCollection<VisualisedTrajectory> Trajectories
{
get { return _trajectories; }
}
#region VisualisationDimensions
private double _visualisationWidth = 100;
public double VisualisationWidth
{
get { return _visualisationWidth; }
private set { _visualisationWidth = value; }
}
private double _visualisationHeight = 100;
public double VisualisationHeight
{
get { return _visualisationHeight; }
private set { _visualisationHeight = value; }
}
#endregion
public void VisualiseRawTrajectories()
{
var rand = new Random();
for (int i = 0; i < 5; i++)
{
var currentTrajectorySet = new List<Point>(); //each time through reinitialise
for (int j = 0; j < 5; j++)
{
currentTrajectorySet.Add(new Point(rand.NextDouble() * 0.5, rand.NextDouble() * 0.5)); //add a new point with max 0.5
if(j == 4)
{
currentTrajectorySet.Add(new Point(0.5, 0.5)); //for good measure :)
_trajectories.Add(new VisualisedTrajectory(CreatePathData(currentTrajectorySet)));
}
}
}
VisualisationHeight = 0.5;
VisualisationWidth = 0.5; //just for demonstration purposes
OnPropertyChanged("VisualisationHeight");
OnPropertyChanged("VisualisationWidth");
}
private Geometry CreatePathData(IList<Point> points)
{
var geometry = new StreamGeometry {FillRule = FillRule.EvenOdd};
using (StreamGeometryContext ctx = geometry.Open())
{
ctx.BeginFigure(points[0], false, false); //use the first index
ctx.PolyLineTo(points, true, true);
}
return (Geometry)geometry.GetAsFrozen();
}
}
查看后面的代码
public MainWindow()
{
InitializeComponent();
VisualisationScroller.PreviewMouseWheel += OnPreviewMouseWheel;
}
private Point originalDimensions;
private void VisualisationBox_Loaded(object sender, RoutedEventArgs e)
{
Viewbox viewBox = sender as Viewbox;
viewBox.Width = viewBox.ActualWidth;
viewBox.Height = viewBox.ActualHeight;
originalDimensions = new Point(viewBox.ActualWidth, viewBox.ActualHeight);
}
#region Zoom
private int _numberDrawnItems = 0;
private void OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
var zoomScale = new Point(CustomDrawingElement.RenderTransform.Value.M11,
CustomDrawingElement.RenderTransform.Value.M22); //gets the scale x and scale y
if (CustomDrawingElement != null && _numberDrawnItems != CustomDrawingElement.Items.Count) //if there was something draw to screen
{
_numberDrawnItems = CustomDrawingElement.Items.Count;
CustomDrawingElement.RenderTransformOrigin = new Point(0.5, 0.5); //if not set zoom from center
}
if (e.Delta > 0)
{
if (CustomDrawingElement != null)
{
VisualisationBox.Width = originalDimensions.X * (zoomScale.X + 1);
VisualisationBox.Height = originalDimensions.Y * (zoomScale.Y + 1);
var mousePosition = e.GetPosition(MasterGrid);
CustomDrawingElement.RenderTransformOrigin = new Point(mousePosition.X / MasterGrid.ActualWidth, mousePosition.Y / MasterGrid.ActualHeight);
CustomDrawingElement.RenderTransform = new MatrixTransform(zoomScale.X + 1, 0, 0, zoomScale.Y + 1, 0, 0);
}
}
if (e.Delta < 0)
{
if (zoomScale.X > 1 && zoomScale.Y > 1) //stops you from zooming out too much
{
if (CustomDrawingElement != null)
{
VisualisationBox.Width = VisualisationBox.Width - originalDimensions.X;
VisualisationBox.Height = VisualisationBox.Height - originalDimensions.Y;
CustomDrawingElement.RenderTransform = new MatrixTransform(zoomScale.X - 1, 0, 0, zoomScale.Y - 1, 0, 0);
}
}
}
e.Handled = true;
}
#endregion //Zooming code
}