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//#define DEBUG_RENDERING_FEEDBACK
//-----------------------------------------------------------------------
// <copyright file="StrokeNode.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Ink;
using System.Windows.Media;
using System.Windows.Input;
using System.Diagnostics;
namespace MS.Internal.Ink
{
#region StrokeNode
/// <summary>
/// StrokeNode represents a single segment on a stroke spine.
/// It's used in enumerating through basic geometries making a stroke contour.
/// </summary>
internal struct StrokeNode
{
#region Constructors
/// <summary>
/// Constructor.
/// </summary>
/// <param name="operations">StrokeNodeOperations object created for particular rendering</param>
/// <param name="index">Index of the node on the stroke spine</param>
/// <param name="nodeData">StrokeNodeData for this node</param>
/// <param name="lastNodeData">StrokeNodeData for the precedeng node</param>
/// <param name="isLastNode">Whether the current node is the last node</param>
internal StrokeNode(
StrokeNodeOperations operations,
int index,
StrokeNodeData nodeData,
StrokeNodeData lastNodeData,
bool isLastNode)
{
System.Diagnostics.Debug.Assert(operations != null);
System.Diagnostics.Debug.Assert((nodeData.IsEmpty == false) && (index >= 0));
_operations = operations;
_index = index;
_thisNode = nodeData;
_lastNode = lastNodeData;
_isQuadCached = lastNodeData.IsEmpty;
_connectingQuad = Quad.Empty;
_isLastNode = isLastNode;
}
#endregion
#region Public API
/// <summary>
/// Position of the node on the stroke spine.
/// </summary>
/// <value></value>
internal Point Position { get { return _thisNode.Position; } }
/// <summary>
/// Position of the previous StrokeNode
/// </summary>
/// <value></value>
internal Point PreviousPosition { get { return _lastNode.Position; } }
/// <summary>
/// PressureFactor of the node on the stroke spine.
/// </summary>
/// <value></value>
internal float PressureFactor { get { return _thisNode.PressureFactor; } }
/// <summary>
/// PressureFactor of the previous StrokeNode
/// </summary>
/// <value></value>
internal float PreviousPressureFactor { get { return _lastNode.PressureFactor; } }
/// <summary>
/// Tells whether the node shape (the stylus shape used in the rendering)
/// is elliptical or polygonal. If the shape is an ellipse, GetContourPoints
/// returns the control points for the quadratic Bezier that defines the ellipse.
/// </summary>
/// <value>true if the shape is ellipse, false otherwise</value>
internal bool IsEllipse { get { return IsValid && _operations.IsNodeShapeEllipse; } }
/// <summary>
/// Returns true if this is the last node in the enumerator
/// </summary>
internal bool IsLastNode { get { return _isLastNode; } }
/// <summary>
/// Returns the bounds of the node shape w/o connecting quadrangle
/// </summary>
/// <returns></returns>
internal Rect GetBounds()
{
return IsValid ? _operations.GetNodeBounds(_thisNode) : Rect.Empty;
}
/// <summary>
/// Returns the bounds of the node shape and connecting quadrangle
/// </summary>
/// <returns></returns>
internal Rect GetBoundsConnected()
{
return IsValid ? Rect.Union(_operations.GetNodeBounds(_thisNode), ConnectingQuad.Bounds) : Rect.Empty;
}
/// <summary>
/// Returns the points that make up the stroke node shape (minus the connecting quad)
/// </summary>
internal void GetContourPoints(List<Point> pointBuffer)
{
if (IsValid)
{
_operations.GetNodeContourPoints(_thisNode, pointBuffer);
}
}
/// <summary>
/// Returns the points that make up the stroke node shape (minus the connecting quad)
/// </summary>
internal void GetPreviousContourPoints(List<Point> pointBuffer)
{
if (IsValid)
{
_operations.GetNodeContourPoints(_lastNode, pointBuffer);
}
}
/// <summary>
/// Returns the connecting quad
/// </summary>
internal Quad GetConnectingQuad()
{
if (IsValid)
{
return ConnectingQuad;
}
return Quad.Empty;
}
///// <summary>
///// IsPointWithinRectOrEllipse
///// </summary>
//internal bool IsPointWithinRectOrEllipse(Point point, double xRadiusOrHalfWidth, double yRadiusOrHalfHeight, Point center, bool isEllipse)
//{
// if (isEllipse)
// {
// //determine what delta is required to move the rect to be
// //centered at 0,0
// double xDelta = center.X + xRadiusOrHalfWidth;
// double yDelta = center.Y + yRadiusOrHalfHeight;
// //offset the point by that delta
// point.X -= xDelta;
// point.Y -= yDelta;
// //formula for ellipse is x^2/a^2 + y^2/b^2 = 1
// double a = xRadiusOrHalfWidth;
// double b = yRadiusOrHalfHeight;
// double res = (((point.X * point.X) / (a * a)) +
// ((point.Y * point.Y) / (b * b)));
// if (res <= 1)
// {
// return true;
// }
// return false;
// }
// else
// {
// if (point.X >= (center.X - xRadiusOrHalfWidth) &&
// point.X <= (center.X + xRadiusOrHalfWidth) &&
// point.Y >= (center.Y - yRadiusOrHalfHeight) &&
// point.Y <= (center.Y + yRadiusOrHalfHeight))
// {
// return true;
// }
// return false;
// }
//}
/// <summary>
/// GetPointsAtStartOfSegment
/// </summary>
internal void GetPointsAtStartOfSegment(List<Point> abPoints,
List<Point> dcPoints
#if DEBUG_RENDERING_FEEDBACK
, DrawingContext debugDC, double feedbackSize, bool showFeedback
#endif
)
{
if (IsValid)
{
Quad quad = ConnectingQuad;
if (IsEllipse)
{
Rect startNodeBounds = _operations.GetNodeBounds(_lastNode);
//add instructions to arc from D to A
abPoints.Add(quad.D);
abPoints.Add(StrokeRenderer.ArcToMarker);
abPoints.Add(new Point(startNodeBounds.Width, startNodeBounds.Height));
abPoints.Add(quad.A);
//simply start at D
dcPoints.Add(quad.D);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(null, new Pen(Brushes.Pink, feedbackSize / 2), _lastNode.Position, startNodeBounds.Width / 2, startNodeBounds.Height / 2);
debugDC.DrawEllipse(Brushes.Red, null, quad.A, feedbackSize, feedbackSize);
debugDC.DrawEllipse(Brushes.Blue, null, quad.D, feedbackSize, feedbackSize);
}
#endif
}
else
{
//we're interested in the A, D points as well as the
//nodecountour points between them
Rect endNodeRect = _operations.GetNodeBounds(_thisNode);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawRectangle(null, new Pen(Brushes.Pink, feedbackSize / 2), _operations.GetNodeBounds(_lastNode));
}
#endif
Vector[] vertices = _operations.GetVertices();
double pressureFactor = _lastNode.PressureFactor;
int maxCount = vertices.Length * 2;
int i = 0;
bool dIsInEndNode = true;
for (; i < maxCount; i++)
{
//look for the d point first
Point point = _lastNode.Position + (vertices[i % vertices.Length] * pressureFactor);
if (point == quad.D)
{
//ab always starts with the D position (only add if it's not in endNode's bounds)
if (!endNodeRect.Contains(quad.D))
{
dIsInEndNode = false;
abPoints.Add(quad.D);
dcPoints.Add(quad.D);
}
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Blue, null, quad.D, feedbackSize, feedbackSize);
}
#endif
break;
}
}
if (i == maxCount)
{
Debug.Assert(false, "StrokeNodeOperations.GetPointsAtStartOfSegment failed to find the D position");
//we didn't find the d point, return
return;
}
//now look for the A position
//advance i
i++;
for (int j = 0; i < maxCount && j < vertices.Length; i++, j++)
{
//look for the A point now
Point point = _lastNode.Position + (vertices[i % vertices.Length] * pressureFactor);
//add everything in between to ab as long as it's not already in endNode's bounds
if (!endNodeRect.Contains(point))
{
abPoints.Add(point);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Wheat, null, point, feedbackSize, feedbackSize);
}
#endif
}
if (dIsInEndNode)
{
Debug.Assert(!endNodeRect.Contains(point));
//add the first point after d, clockwise
dIsInEndNode = false;
dcPoints.Add(point);
}
if (point == quad.A)
{
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Red, null, point, feedbackSize, feedbackSize);
}
#endif
break;
}
}
}
}
}
/// <summary>
/// GetPointsAtEndOfSegment
/// </summary>
internal void GetPointsAtEndOfSegment( List<Point> abPoints,
List<Point> dcPoints
#if DEBUG_RENDERING_FEEDBACK
, DrawingContext debugDC, double feedbackSize, bool showFeedback
#endif
)
{
if (IsValid)
{
Quad quad = ConnectingQuad;
if (IsEllipse)
{
Rect bounds = GetBounds();
//add instructions to arc from D to A
abPoints.Add(quad.B);
abPoints.Add(StrokeRenderer.ArcToMarker);
abPoints.Add(new Point(bounds.Width, bounds.Height));
abPoints.Add(quad.C);
//don't add to the dc points
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(null, new Pen(Brushes.Pink, feedbackSize / 2), _thisNode.Position, bounds.Width / 2, bounds.Height / 2);
debugDC.DrawEllipse(Brushes.Green, null, quad.B, feedbackSize, feedbackSize);
debugDC.DrawEllipse(Brushes.Yellow, null, quad.C, feedbackSize, feedbackSize);
}
#endif
}
else
{
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawRectangle(null, new Pen(Brushes.Pink, feedbackSize / 2), GetBounds());
}
#endif
//we're interested in the B, C points as well as the
//nodecountour points between them
double pressureFactor = _thisNode.PressureFactor;
Vector[] vertices = _operations.GetVertices();
int maxCount = vertices.Length * 2;
int i = 0;
for (; i < maxCount; i++)
{
//look for the d point first
Point point = _thisNode.Position + (vertices[i % vertices.Length] * pressureFactor);
if (point == quad.B)
{
abPoints.Add(quad.B);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Green, null, point, feedbackSize, feedbackSize);
}
#endif
break;
}
}
if (i == maxCount)
{
Debug.Assert(false, "StrokeNodeOperations.GetPointsAtEndOfSegment failed to find the B position");
//we didn't find the d point, return
return;
}
//now look for the C position
//advance i
i++;
for (int j = 0; i < maxCount && j < vertices.Length; i++, j++)
{
//look for the c point last
Point point = _thisNode.Position + (vertices[i % vertices.Length] * pressureFactor);
if (point == quad.C)
{
break;
}
//only add to ab if we didn't find C
abPoints.Add(point);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Wheat, null, quad.C, feedbackSize, feedbackSize);
}
#endif
}
//finally, add the D point
dcPoints.Add(quad.C);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Yellow, null, quad.C, feedbackSize, feedbackSize);
}
#endif
}
}
}
/// <summary>
/// GetPointsAtMiddleSegment
/// </summary>
internal void GetPointsAtMiddleSegment( StrokeNode previous,
double angleBetweenNodes,
List<Point> abPoints,
List<Point> dcPoints,
out bool missingIntersection
#if DEBUG_RENDERING_FEEDBACK
, DrawingContext debugDC, double feedbackSize, bool showFeedback
#endif
)
{
missingIntersection = false;
if (IsValid && previous.IsValid)
{
Quad quad1 = previous.ConnectingQuad;
if (!quad1.IsEmpty)
{
Quad quad2 = ConnectingQuad;
if (!quad2.IsEmpty)
{
if (IsEllipse)
{
Rect node1Bounds = _operations.GetNodeBounds(previous._lastNode);
Rect node2Bounds = _operations.GetNodeBounds(_lastNode);
Rect node3Bounds = _operations.GetNodeBounds(_thisNode);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(null, new Pen(Brushes.Pink, feedbackSize / 2), _lastNode.Position, node2Bounds.Width / 2, node2Bounds.Height / 2);
}
#endif
if (angleBetweenNodes == 0.0d || ((quad1.B == quad2.A) && (quad1.C == quad2.D)))
{
//quads connections are the same, just add them
abPoints.Add(quad1.B);
dcPoints.Add(quad1.C);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Green, null, quad1.B, feedbackSize, feedbackSize);
debugDC.DrawEllipse(Brushes.Yellow, null, quad1.C, feedbackSize, feedbackSize);
}
#endif
}
else if (angleBetweenNodes > 0.0)
{
//the stroke angled towards the AB side
//this part is easy
if (quad1.B == quad2.A)
{
abPoints.Add(quad1.B);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Green, null, quad1.B, feedbackSize, feedbackSize);
}
#endif
}
else
{
Point intersection = GetIntersection(quad1.A, quad1.B, quad2.A, quad2.B);
Rect union = Rect.Union(node1Bounds, node2Bounds);
union.Inflate(1.0, 1.0);
//make sure we're not off in space
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Green, null, quad1.B, feedbackSize * 1.5, feedbackSize * 1.5);
debugDC.DrawEllipse(Brushes.Red, null, quad2.A, feedbackSize, feedbackSize);
}
#endif
if (union.Contains(intersection))
{
abPoints.Add(intersection);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Orange, null, intersection, feedbackSize, feedbackSize);
}
#endif
}
else
{
//if we missed the intersection we'll need to close the stroke segment
//this work is done in StrokeRenderer
missingIntersection = true;
return; //we're done.
}
}
if (quad1.C == quad2.D)
{
dcPoints.Add(quad1.C);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Yellow, null, quad1.C, feedbackSize, feedbackSize);
}
#endif
}
else
{
//add instructions to arc from quad1.C to quad2.D in reverse order (since we walk this array backwards to render)
dcPoints.Add(quad1.C);
dcPoints.Add(new Point(node2Bounds.Width, node2Bounds.Height));
dcPoints.Add(StrokeRenderer.ArcToMarker);
dcPoints.Add(quad2.D);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Yellow, null, quad1.C, feedbackSize, feedbackSize);
debugDC.DrawEllipse(Brushes.Blue, null, quad2.D, feedbackSize, feedbackSize);
}
#endif
}
}
else
{
//the stroke angled towards the CD side
//this part is easy
if (quad1.C == quad2.D)
{
dcPoints.Add(quad1.C);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Yellow, null, quad1.C, feedbackSize, feedbackSize);
}
#endif
}
else
{
Point intersection = GetIntersection(quad1.D, quad1.C, quad2.D, quad2.C);
Rect union = Rect.Union(node1Bounds, node2Bounds);
union.Inflate(1.0, 1.0);
//make sure we're not off in space
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Yellow, null, quad1.C, feedbackSize * 1.5, feedbackSize * 1.5);
debugDC.DrawEllipse(Brushes.Blue, null, quad2.D, feedbackSize, feedbackSize);
}
#endif
if (union.Contains(intersection))
{
dcPoints.Add(intersection);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Orange, null, intersection, feedbackSize, feedbackSize);
}
#endif
}
else
{
//if we missed the intersection we'll need to close the stroke segment
//this work is done in StrokeRenderer
missingIntersection = true;
return; //we're done.
}
}
if (quad1.B == quad2.A)
{
abPoints.Add(quad1.B);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Green, null, quad1.B, feedbackSize, feedbackSize);
}
#endif
}
else
{
//we need to arc between quad1.B and quad2.A along node2
abPoints.Add(quad1.B);
abPoints.Add(StrokeRenderer.ArcToMarker);
abPoints.Add(new Point(node2Bounds.Width, node2Bounds.Height));
abPoints.Add(quad2.A);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Green, null, quad1.B, feedbackSize, feedbackSize);
debugDC.DrawEllipse(Brushes.Red, null, quad2.A, feedbackSize, feedbackSize);
}
#endif
}
}
}
else
{
//rectangle
int indexA = -1;
int indexB = -1;
int indexC = -1;
int indexD = -1;
Vector[] vertices = _operations.GetVertices();
double pressureFactor = _lastNode.PressureFactor;
for (int i = 0; i < vertices.Length; i++)
{
Point point = _lastNode.Position + (vertices[i % vertices.Length] * pressureFactor);
if (point == quad2.A)
{
indexA = i;
}
if (point == quad1.B)
{
indexB = i;
}
if (point == quad1.C)
{
indexC = i;
}
if (point == quad2.D)
{
indexD = i;
}
}
if (indexA == -1 || indexB == -1 || indexC == -1 || indexD == -1)
{
Debug.Assert(false, "Couldn't find all 4 indexes in StrokeNodeOperations.GetPointsAtMiddleSegment");
return;
}
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawRectangle(null, new Pen(Brushes.Pink, feedbackSize / 2), _operations.GetNodeBounds(_lastNode));
debugDC.DrawEllipse(Brushes.Red, null, quad2.A, feedbackSize, feedbackSize);
debugDC.DrawEllipse(Brushes.Green, null, quad1.B, feedbackSize, feedbackSize);
debugDC.DrawEllipse(Brushes.Yellow, null, quad1.C, feedbackSize, feedbackSize);
debugDC.DrawEllipse(Brushes.Blue, null, quad2.D, feedbackSize, feedbackSize);
}
#endif
Rect node3Rect = _operations.GetNodeBounds(_thisNode);
//take care of a-b first
if (indexA == indexB)
{
//quad connection is the same, just add it
if (!node3Rect.Contains(quad1.B))
{
abPoints.Add(quad1.B);
}
}
else if ((indexA == 0 && indexB == 3) || ((indexA != 3 || indexB != 0) && (indexA > indexB)))
{
if (!node3Rect.Contains(quad1.B))
{
abPoints.Add(quad1.B);
}
if (!node3Rect.Contains(quad2.A))
{
abPoints.Add(quad2.A);
}
}
else
{
Point intersection = GetIntersection(quad1.A, quad1.B, quad2.A, quad2.B);
Rect node12 = Rect.Union(_operations.GetNodeBounds(previous._lastNode), _operations.GetNodeBounds(_lastNode));
node12.Inflate(1.0, 1.0);
//make sure we're not off in space
if (node12.Contains(intersection))
{
abPoints.Add(intersection);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Orange, null, intersection, feedbackSize, feedbackSize * 1.5);
}
#endif
}
else
{
//if we missed the intersection we'll need to close the stroke segment
//this work is done in StrokeRenderer.
missingIntersection = true;
return; //we're done.
}
}
// now take care of c-d.
if (indexC == indexD)
{
//quad connection is the same, just add it
if (!node3Rect.Contains(quad1.C))
{
dcPoints.Add(quad1.C);
}
}
else if ((indexC == 0 && indexD == 3) || ((indexC != 3 || indexD != 0) && (indexC > indexD)))
{
if (!node3Rect.Contains(quad1.C))
{
dcPoints.Add(quad1.C);
}
if (!node3Rect.Contains(quad2.D))
{
dcPoints.Add(quad2.D);
}
}
else
{
Point intersection = GetIntersection(quad1.D, quad1.C, quad2.D, quad2.C);
Rect node12 = Rect.Union(_operations.GetNodeBounds(previous._lastNode), _operations.GetNodeBounds(_lastNode));
node12.Inflate(1.0, 1.0);
//make sure we're not off in space
if (node12.Contains(intersection))
{
dcPoints.Add(intersection);
#if DEBUG_RENDERING_FEEDBACK
if (showFeedback)
{
debugDC.DrawEllipse(Brushes.Orange, null, intersection, feedbackSize, feedbackSize * 1.5);
}
#endif
}
else
{
//if we missed the intersection we'll need to close the stroke segment
//this work is done in StrokeRenderer.
missingIntersection = true;
return; //we're done.
}
}
}
}
}
}
}
/// <summary>
/// Returns the intersection between two lines. This code assumes there is an intersection
/// and should only be called if that assumption is valid
/// </summary>
/// <returns></returns>
internal static Point GetIntersection(Point line1Start, Point line1End, Point line2Start, Point line2End)
{
double a1 = line1End.Y - line1Start.Y;
double b1 = line1Start.X - line1End.X;
double c1 = (line1End.X * line1Start.Y) - (line1Start.X * line1End.Y);
double a2 = line2End.Y - line2Start.Y;
double b2 = line2Start.X - line2End.X;
double c2 = (line2End.X * line2Start.Y) - (line2Start.X * line2End.Y);
double d = (a1 * b2) - (a2 * b1);
if (d != 0.0)
{
double x = ((b1 * c2) - (b2 * c1)) / d;
double y = ((a2 * c1) - (a1 * c2)) / d;
//capture the min and max points
double line1XMin, line1XMax, line1YMin, line1YMax, line2XMin, line2XMax, line2YMin, line2YMax;
if (line1Start.X < line1End.X)
{
line1XMin = Math.Floor(line1Start.X);
line1XMax = Math.Ceiling(line1End.X);
}
else
{
line1XMin = Math.Floor(line1End.X);
line1XMax = Math.Ceiling(line1Start.X);
}
if (line2Start.X < line2End.X)
{
line2XMin = Math.Floor(line2Start.X);
line2XMax = Math.Ceiling(line2End.X);
}
else
{
line2XMin = Math.Floor(line2End.X);
line2XMax = Math.Ceiling(line2Start.X);
}
if (line1Start.Y < line1End.Y)
{
line1YMin = Math.Floor(line1Start.Y);
line1YMax = Math.Ceiling(line1End.Y);
}
else
{
line1YMin = Math.Floor(line1End.Y);
line1YMax = Math.Ceiling(line1Start.Y);
}
if (line2Start.Y < line2End.Y)
{
line2YMin = Math.Floor(line2Start.Y);
line2YMax = Math.Ceiling(line2End.Y);
}
else
{
line2YMin = Math.Floor(line2End.Y);
line2YMax = Math.Ceiling(line2Start.Y);
}
// now see if we have an intersection between the lines
// and not just the projection of the lines
if ((line1XMin <= x && x <= line1XMax) &&
(line1YMin <= y && y <= line1YMax) &&
(line2XMin <= x && x <= line2XMax) &&
(line2YMin <= y && y <= line2YMax))
{
return new Point(x, y);
}
}
if ((long)line1End.X == (long)line2Start.X &&
(long)line1End.Y == (long)line2Start.Y)
{
return new Point(line1End.X, line1End.Y);
}
return new Point(Double.NaN, Double.NaN);
}
/// <summary>
/// This method tells whether the contour of a given stroke node
/// intersects with the contour of this node. The contours of both nodes
/// include their connecting quadrangles.
/// </summary>
/// <param name="hitNode"></param>
/// <returns></returns>
internal bool HitTest(StrokeNode hitNode)
{
if (!IsValid || !hitNode.IsValid)
{
return false;
}
IEnumerable<ContourSegment> hittingContour = hitNode.GetContourSegments();
return _operations.HitTest(_lastNode, _thisNode, ConnectingQuad, hittingContour);
}
/// <summary>
/// Finds out if a given node intersects with this one,
/// and returns findices of the intersection.
/// </summary>
/// <param name="hitNode"></param>
/// <returns></returns>
internal StrokeFIndices CutTest(StrokeNode hitNode)
{
if ((IsValid == false) || (hitNode.IsValid == false))
{
return StrokeFIndices.Empty;
}
IEnumerable<ContourSegment> hittingContour = hitNode.GetContourSegments();
// If the node contours intersect, the result is a pair of findices
// this segment should be cut at to let the hitNode's contour through it.
StrokeFIndices cutAt = _operations.CutTest(_lastNode, _thisNode, ConnectingQuad, hittingContour);
return (_index == 0) ? cutAt : BindFIndices(cutAt);
}
/// <summary>
/// Finds out if a given linear segment intersects with the contour of this node
/// (including connecting quadrangle), and returns findices of the intersection.
/// </summary>
/// <param name="begin"></param>
/// <param name="end"></param>
/// <returns></returns>
internal StrokeFIndices CutTest(Point begin, Point end)
{
if (IsValid == false)
{
return StrokeFIndices.Empty;
}
// If the node contours intersect, the result is a pair of findices
// this segment should be cut at to let the hitNode's contour through it.
StrokeFIndices cutAt = _operations.CutTest(_lastNode, _thisNode, ConnectingQuad, begin, end);
System.Diagnostics.Debug.Assert(!double.IsNaN(cutAt.BeginFIndex) && !double.IsNaN(cutAt.EndFIndex));
// Bind the found findices to the node and return the result
return BindFIndicesForLassoHitTest(cutAt);
}
#endregion
#region Private helpers
/// <summary>
/// Binds a local fragment to this node by setting the integer part of the
/// fragment findices equal to the index of the previous node
/// </summary>
/// <param name="fragment"></param>
/// <returns></returns>
private StrokeFIndices BindFIndices(StrokeFIndices fragment)
{
System.Diagnostics.Debug.Assert(IsValid && (_index >= 0));
if (fragment.IsEmpty == false)
{
// Adjust only findices which are on this segment of thew spine (i.e. between 0 and 1)
if (!DoubleUtil.AreClose(fragment.BeginFIndex, StrokeFIndices.BeforeFirst))
{
System.Diagnostics.Debug.Assert(fragment.BeginFIndex >= 0 && fragment.BeginFIndex <= 1);
fragment.BeginFIndex += _index - 1;
}
if (!DoubleUtil.AreClose(fragment.EndFIndex, StrokeFIndices.AfterLast))
{
System.Diagnostics.Debug.Assert(fragment.EndFIndex >= 0 && fragment.EndFIndex <= 1);
fragment.EndFIndex += _index - 1;
}
}
return fragment;
}
internal int Index
{
get { return _index; }
}
/// <summary>
/// Bind the StrokeFIndices for lasso hit test results.
/// </summary>
/// <param name="fragment"></param>
/// <returns></returns>
private StrokeFIndices BindFIndicesForLassoHitTest(StrokeFIndices fragment)
{
System.Diagnostics.Debug.Assert(IsValid);
if (!fragment.IsEmpty)
{
// Adjust BeginFIndex
if (DoubleUtil.AreClose(fragment.BeginFIndex, StrokeFIndices.BeforeFirst))
{
// set it to be the index of the previous node, indicating intersection start from previous node
fragment.BeginFIndex = (_index == 0 ? StrokeFIndices.BeforeFirst:_index - 1);
}
else
{
// Adjust findices which are on this segment of the spine (i.e. between 0 and 1)
System.Diagnostics.Debug.Assert(DoubleUtil.GreaterThanOrClose(fragment.BeginFIndex, 0f));
System.Diagnostics.Debug.Assert(DoubleUtil.LessThanOrClose(fragment.BeginFIndex, 1f));
// Adjust the value to consider index, say from 0.75 to 3.75 (for _index = 4)
fragment.BeginFIndex += _index - 1;
}
//Adjust EndFIndex
if (DoubleUtil.AreClose(fragment.EndFIndex, StrokeFIndices.AfterLast))
{
// set it to be the index of the current node, indicating the intersection cover the end of the node
fragment.EndFIndex = (_isLastNode ? StrokeFIndices.AfterLast:_index);
}
else
{
System.Diagnostics.Debug.Assert(DoubleUtil.GreaterThanOrClose(fragment.EndFIndex, 0f));
System.Diagnostics.Debug.Assert(DoubleUtil.LessThanOrClose(fragment.EndFIndex, 1f));
// Ajust the value to consider the index
fragment.EndFIndex += _index - 1;
}
}
return fragment;
}
/// <summary>
/// Tells whether the StrokeNode instance is valid or not (created via the default ctor)
/// </summary>
internal bool IsValid { get { return _operations != null; } }
/// <summary>
/// The quadrangle that connects this and the previous node.
/// Can be empty if this node is the first one or if one of the nodes is
/// completely inside the other.
/// The type Quad is supposed to be internal even if we surface StrokeNode.
/// External users of StrokeNode should use GetConnectionPoints instead.
/// </summary>
private Quad ConnectingQuad
{
get
{
System.Diagnostics.Debug.Assert(IsValid);
if (_isQuadCached == false)
{
_connectingQuad = _operations.GetConnectingQuad(_lastNode, _thisNode);
_isQuadCached = true;
}
return _connectingQuad;
}
}
/// <summary>
/// Returns an enumerator for edges of the contour comprised by the node
/// and connecting quadrangle (_lastNode is excluded)
/// Used for hit-testing a stroke against an other stroke (stroke and point erasing)
/// </summary>
private IEnumerable<ContourSegment> GetContourSegments()
{
System.Diagnostics.Debug.Assert(IsValid);
// Calls thru to the StrokeNodeOperations object
if (IsEllipse)
{
// ISSUE-2004/06/15- temporary workaround to avoid hit-testing with ellipses
return _operations.GetNonBezierContourSegments(_lastNode, _thisNode);
}
return _operations.GetContourSegments(_thisNode, ConnectingQuad);
}
/// <summary>
/// Returns the spine point that corresponds to the given findex.
/// </summary>
/// <param name="findex">A local findex between the previous index and this one (ex: between 2.0 and 3.0)</param>
/// <returns>Point on the spine</returns>
internal Point GetPointAt(double findex)
{
System.Diagnostics.Debug.Assert(IsValid);
if (_lastNode.IsEmpty)
{
System.Diagnostics.Debug.Assert(findex == 0);
return _thisNode.Position;
}
System.Diagnostics.Debug.Assert((findex >= _index - 1) && (findex <= _index));
if (DoubleUtil.AreClose(findex, (double)_index))
{
//
// we're being asked for this exact point
// if we don't return it here, our algorithm
// below doesn't work
//
return _thisNode.Position;
}
//
// get the spare change to the left of the decimal point
// eg turn 2.75 into .75
//
double floor = Math.Floor(findex);
findex = findex - floor;
double xDiff = (_thisNode.Position.X - _lastNode.Position.X) * findex;
double yDiff = (_thisNode.Position.Y - _lastNode.Position.Y) * findex;
//
// return the previous point plus the delta's
//
return new Point( _lastNode.Position.X + xDiff,
_lastNode.Position.Y + yDiff);
}
#endregion
#region Fields
// Internal objects created for particular rendering
private StrokeNodeOperations _operations;
// Node's index on the stroke spine
private int _index;
// This and the previous node data that used by the StrokeNodeOperations object to build
// and/or hit-test the contour of the node/segment
private StrokeNodeData _thisNode;
private StrokeNodeData _lastNode;
// Calculating of the connecting quadrangle is not a cheap operations, therefore,
// first, it's computed only by request, and second, once computed it's cached in the StrokeNode
private bool _isQuadCached;
private Quad _connectingQuad;
// Is the current stroke node the last node?
private bool _isLastNode;
#endregion
}
#endregion
}
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