Как использовать OpacityMask на последней точке сегмента?Это прекрасно работает, если не перемещать наш путь, но если мы перемещаем ваш путь, то непрозрачность не повлияет на последнюю точку;его позиция остается на том месте, где он был последним.
Пример кода
<UserControl x:Class="SLTest.Bezier"
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"
Width="500"
Height="500"
mc:Ignorable="d">
<Grid x:Name="LayoutRoot" Background="White">
<Canvas>
<Ellipse x:Name="PointStart"
Canvas.Left="26"
Canvas.Top="30"
Width="20"
Height="20"
Cursor="Hand"
Fill="DarkGreen" />
<Ellipse x:Name="PointMiddle"
Canvas.Left="200"
Canvas.Top="100"
Width="20"
Height="20"
Cursor="Hand"
Fill="Black" />
<Ellipse x:Name="PointEnd"
Canvas.Left="406"
Canvas.Top="42"
Width="20"
Height="20"
Cursor="Hand"
Fill="DarkRed" />
<Path Canvas.ZIndex="-1"
StrokeThickness="10" Canvas.Left="28" Canvas.Top="27" UseLayoutRounding="False">
<Path.Stroke>
<LinearGradientBrush SpreadMethod="Pad">
<GradientStop Offset="0" Color="DarkGreen" />
<GradientStop Offset="0.5" Color="Black" />
<GradientStop Offset="1" Color="DarkRed" />
</LinearGradientBrush>
</Path.Stroke>
<Path.Data>
<PathGeometry>
<PathFigure x:Name="Path" StartPoint="100,10">
<QuadraticBezierSegment x:Name="Segment"
Point1="200,100"
Point2="300,10" />
</PathFigure>
</PathGeometry>
</Path.Data>
</Path>
</Canvas>
</Grid>
CS Code
namespace SLTest
{
public partial class Bezier : UserControl
{
bool isDragging = false;
public Bezier()
{
InitializeComponent();
AttachEventHandlers(PointStart);
AttachEventHandlers(PointMiddle);
AttachEventHandlers(PointEnd);
// make sure the bezier reflects our gui control points
UpdateBezier();
}
private void AttachEventHandlers(Ellipse point)
{
point.MouseLeftButtonDown += new MouseButtonEventHandler(Point_MouseLeftButtonDown);
point.MouseLeftButtonUp += new MouseButtonEventHandler(Point_MouseLeftButtonUp);
point.MouseMove += new MouseEventHandler(Point_MouseMove);
}
private void UpdateBezier()
{
double radius = this.PointStart.Width / 2;
Path.StartPoint = Offset(GetPoint(PointStart), radius);
Segment.Point1 = Offset(GetPoint(PointMiddle), radius);
Segment.Point2 = Offset(GetPoint(PointEnd), radius);
}
private Point Offset(Point inpoint, double offset)
{
Point point = new Point(inpoint.X + offset, inpoint.Y + offset);
return point;
}
private static Point GetPoint(DependencyObject sobj)
{
Point point = new Point((double)sobj.GetValue(Canvas.LeftProperty), (double)sobj.GetValue(Canvas.TopProperty));
return point;
}
void Point_MouseMove(object sender, MouseEventArgs e)
{
if (!isDragging)
return;
Ellipse point = sender as Ellipse;
Point newLocation = e.GetPosition(this);
MoveShape(point, newLocation);
UpdateBezier();
}
private static void MoveShape(DependencyObject shape, Point newLocation)
{
shape.SetValue(Canvas.LeftProperty, newLocation.X);
shape.SetValue(Canvas.TopProperty, newLocation.Y);
}
void Point_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
if (!isDragging)
return;
isDragging = false;
Ellipse point = sender as Ellipse;
point.ReleaseMouseCapture();
}
void Point_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
Ellipse point = sender as Ellipse;
isDragging = true;
point.CaptureMouse();
}
}
}