public override bool PointInObject(Vector2D point, ICanvasScreenConvertable canvasProxy)
{
if (point == null)
{
throw new ArgumentNullException(nameof(point));
}
if (canvasProxy == null)
{
throw new ArgumentNullException(nameof(canvasProxy));
}
if (Rectangle2D == null)
{
return(false);
}
var screenPoint = canvasProxy.ToScreen(point);
//判断与中心的关系;
var centerScreenPoint = canvasProxy.ToScreen(Rectangle2D.Center);
var screenRect = Tida.Canvas.Infrastructure.Utils.NativeGeometryExtensions.GetNativeSuroundingScreenRect(
centerScreenPoint,
TolerantedScreenLength,
TolerantedScreenLength
);
if (screenRect.Contains(screenPoint))
{
return(true);
}
//判断与四边的关系;
var lines = Rectangle2D.GetLines();
var screenStartPoint = new Vector2D();
var screenEndPoint = new Vector2D();
foreach (var line in lines)
{
canvasProxy.ToScreen(line.Start, screenStartPoint);
canvasProxy.ToScreen(line.End, screenEndPoint);
var screenLine2D = new Line2D(
screenStartPoint, screenEndPoint
);
if (screenLine2D.Distance(screenPoint) < TolerantedScreenLength)
{
return(true);
}
}
return(false);
}
protected override ISnapShape MatchSnapShape(LineBase line, Vector2D position, ICanvasContext canvasContext)
{
if (!line.IsEditing)
{
return(null);
}
var screenPosition = canvasContext.CanvasProxy.ToScreen(position);
/*判断关注点是否"在线段的延长线上" */
var screenLine2D = new Line2D(
canvasContext.CanvasProxy.ToScreen(line.Line2D.Start),
canvasContext.CanvasProxy.ToScreen(line.Line2D.End)
);
//确定该点不"在"该线段上;
if (screenLine2D.Distance(screenPosition) <= TolerantedScreenLength)
{
return(null);
}
/*确定该点在该线段的延长线上;*/
var projectScreenPosition = screenPosition.ProjectOn(screenLine2D);
if (projectScreenPosition == null)
{
return(null);
}
if (projectScreenPosition.Distance(screenPosition) >= TolerantedScreenLength)
{
return(null);
}
//寻找距离投影点最近的一个端点作为延伸辅助线起始点;
var screenStart = canvasContext.CanvasProxy.ToScreen(line.Line2D.Start);
var screenEnd = canvasContext.CanvasProxy.ToScreen(line.Line2D.End);
var closestPosition = screenStart.Distance(projectScreenPosition) < screenEnd.Distance(projectScreenPosition) ? line.Line2D.Start :line.Line2D.End;
var projectPosition = canvasContext.CanvasProxy.ToUnit(projectScreenPosition);
return(new LineSnapShape(new Line2D(closestPosition, projectPosition), projectPosition));
}
/// <summary>
/// 判断画布中某个位置是否在某个线段附近;
/// </summary>
/// <param name="line2D"></param>
/// <param name="point"></param>
/// <param name="canvasProxy"></param>
/// <returns></returns>
public static bool PointInLine(Line2D line2D, Vector2D point, ICanvasScreenConvertable canvasProxy)
{
if (canvasProxy == null)
{
return(false);
}
if (line2D == null)
{
return(false);
}
//以视图单位为标准进行判断;
var screenPoint = canvasProxy.ToScreen(point);
var screenLine2D = new Line2D(
canvasProxy.ToScreen(line2D.Start),
canvasProxy.ToScreen(line2D.End)
);
return(screenLine2D.Distance(screenPoint) < TolerantedScreenLength);
}
public static float DistanceToLine(vec2 p, vec2 e0, vec2 e1, out float t)
{
return(Line2D.Distance(p, e0, e1, out t));
}
/// <summary>
/// 获取某个点是否在某个线段上的辅助;
/// </summary>
/// <param name="line2D"></param>
/// <param name="position"></param>
/// <param name="canvasContext"></param>
/// <returns></returns>
public static ISnapShape GetOnLineSnapShape(Line2D line2D, Vector2D position, ICanvasContext canvasContext)
{
if (line2D == null)
{
throw new ArgumentNullException(nameof(line2D));
}
if (position == null)
{
throw new ArgumentNullException(nameof(position));
}
if (canvasContext == null)
{
throw new ArgumentNullException(nameof(canvasContext));
}
var screenPosition = canvasContext.CanvasProxy.ToScreen(position);
/*判断关注点是否"在线段上" */
if (line2D.Length == 0)
{
return(null);
}
var screenLine2D = new Line2D(
canvasContext.CanvasProxy.ToScreen(line2D.Start),
canvasContext.CanvasProxy.ToScreen(line2D.End)
);
//若距离大于指定值,则无辅助点;
if (screenLine2D.Distance(screenPosition) > TolerantedScreenLength)
{
return(null);
}
//若上次编辑位置为空,则根据关注点与线段的垂直距离得到一个交点;
if (canvasContext.LastEditPosition == null)
{
return(GetVertextSnapShape(position, line2D));
}
///否则,以<see cref="canvasContext.LastEditPosition"/>
///上次编辑位置到关注点<see cref="position"/>的直线与线段的交点作为辅助点;
else
{
//计算上次编辑到
var lastToPositionLine2D = new Line2D(canvasContext.LastEditPosition, position);
var vertextPosition = lastToPositionLine2D.IntersectStraightLine(line2D);
//若无交点,则可能平行,无辅助点;
if (vertextPosition == null)
{
return(null);
}
//若关注点与两直线的相交点相距过远,则仍然根据关注点与线段的垂直距离得到一个交点;
if (canvasContext.CanvasProxy.ToScreen(position.Distance(vertextPosition)) > TolerantedScreenLength)
{
return(LineSnapExtensions.GetVertextSnapShape(position, line2D));
}
return(new SnapShapeForLine(vertextPosition, line2D)
{
Background = InLineSnapPointBackground
});
}
}