【发布时间】:2020-09-26 01:59:57
【问题描述】:
我在从 Path 绘制的画布中有弧线,其中包含以下详细信息。我想得到点(115,225)。请查看屏幕截图以获取更多详细信息。请帮我把公式算到点 (115,225)。
startX=250
startY=250
ArcSegment Size (70,70)
ArcSegment Point (250,200)
Computation
var meanX=(startX+startX)/2-rX;//(250+250)/2-70=180
var meanY=(startY+ArcSegment.Point.Y)/2-rY;//(250+200)/2-70=225
//center Point (180,225)
//What is the formula if I want to get Point(115,225)
XAML
<Canvas Name="canvas" Background="White" Opacity="99">
<Path Stroke="Blue" MouseLeftButtonDown="Path_MouseLeftButtonDown" >
<Path.Data>
<PathGeometry>
<PathFigureCollection>
<PathFigure StartPoint="250,250" IsClosed="True">
<ArcSegment Size="70,70" IsLargeArc="True" SweepDirection="Clockwise" Point="250,200"/>
</PathFigure>
</PathFigureCollection>
</PathGeometry>
</Path.Data>
</Path>
</Canvas>
C#
private void Path_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
var curve = sender as Path;
var geometry = curve.Data as PathGeometry;
var figure = geometry.Figures.FirstOrDefault();
var arcSegment = figure.Segments.FirstOrDefault() as ArcSegment;
var startX = figure.StartPoint.X;
var yStart = figure.StartPoint.Y;
var startAngle = arcSegment.Point.X;
var sweepAngle = arcSegment.Point.Y;
var rX = arcSegment.Size.Width;
var rY = arcSegment.Size.Height;
var endAngle = startAngle + sweepAngle;
var meanX = (startX + startAngle) / 2 - rX;
var meanY = (yStart + sweepAngle) / 2 - rY;
}
【问题讨论】:
-
我完全不确定我是否遵循您想要实现的目标。但这看起来像是一个圆圈的一部分,而不是任何旧的弧线。在我看来,某种平均角度然后使用矢量或方位角从中心平移将是要走的路。如果近似整数值可行并且您需要进行大量此类计算,那么还有 bresenham 圆。
-
既然已经知道值,为什么还要计算点115225?
标签: c# wpf wpf-controls