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//-----------------------------------------------------------------------
// <copyright file="StrokeNodeOperations.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;
using MS.Utility;
using MS.Internal;
namespace MS.Internal.Ink
{
/// <summary>
/// The base operations class that implements polygonal node operations by default.
/// </summary>
internal partial class StrokeNodeOperations
{
#region Static API
/// <summary>
///
/// </summary>
/// <param name="nodeShape"></param>
/// <returns></returns>
internal static StrokeNodeOperations CreateInstance(StylusShape nodeShape)
{
if (nodeShape == null)
{
throw new ArgumentNullException("nodeShape");
}
if (nodeShape.IsEllipse)
{
return new EllipticalNodeOperations(nodeShape);
}
return new StrokeNodeOperations(nodeShape);
}
#endregion
#region API
/// <summary>
/// Constructor
/// </summary>
/// <param name="nodeShape">shape of the nodes</param>
internal StrokeNodeOperations(StylusShape nodeShape)
{
System.Diagnostics.Debug.Assert(nodeShape != null);
_vertices = nodeShape.GetVerticesAsVectors();
}
/// <summary>
/// This is probably not the best (design-wise) but the cheapest way to tell
/// EllipticalNodeOperations from all other implementations of node operations.
/// </summary>
internal virtual bool IsNodeShapeEllipse { get { return false; } }
/// <summary>
/// Computes the bounds of a node
/// </summary>
/// <param name="node">node to compute bounds of</param>
/// <returns>bounds of the node</returns>
internal Rect GetNodeBounds(StrokeNodeData node)
{
if (_shapeBounds.IsEmpty)
{
int i;
for (i = 0; (i + 1) < _vertices.Length; i += 2)
{
_shapeBounds.Union(new Rect((Point)_vertices[i], (Point)_vertices[i + 1]));
}
if (i < _vertices.Length)
{
_shapeBounds.Union((Point)_vertices[i]);
}
}
Rect boundingBox = _shapeBounds;
System.Diagnostics.Debug.Assert((boundingBox.X <= 0) && (boundingBox.Y <= 0));
double pressureFactor = node.PressureFactor;
if (!DoubleUtil.AreClose(pressureFactor,1d))
{
boundingBox = new Rect(
_shapeBounds.X * pressureFactor,
_shapeBounds.Y * pressureFactor,
_shapeBounds.Width * pressureFactor,
_shapeBounds.Height * pressureFactor);
}
boundingBox.Location += (Vector)node.Position;
return boundingBox;
}
internal void GetNodeContourPoints(StrokeNodeData node, List<Point> pointBuffer)
{
double pressureFactor = node.PressureFactor;
if (DoubleUtil.AreClose(pressureFactor, 1d))
{
for (int i = 0; i < _vertices.Length; i++)
{
pointBuffer.Add(node.Position + _vertices[i]);
}
}
else
{
for (int i = 0; i < _vertices.Length; i++)
{
pointBuffer.Add(node.Position + (_vertices[i] * pressureFactor));
}
}
}
/// <summary>
/// Returns an enumerator for edges of the contour comprised by a given node
/// and its connecting quadrangle.
/// Used for hit-testing a stroke against an other stroke (stroke and point erasing)
/// </summary>
/// <param name="node">node</param>
/// <param name="quad">quadrangle connecting the node to the preceeding node</param>
/// <returns>contour segments enumerator</returns>
internal virtual IEnumerable<ContourSegment> GetContourSegments(StrokeNodeData node, Quad quad)
{
System.Diagnostics.Debug.Assert(node.IsEmpty == false);
if (quad.IsEmpty)
{
Point vertex = node.Position + (_vertices[_vertices.Length - 1] * node.PressureFactor);
for (int i = 0; i < _vertices.Length; i++)
{
Point nextVertex = node.Position + (_vertices[i] * node.PressureFactor);
yield return new ContourSegment(vertex, nextVertex);
vertex = nextVertex;
}
}
else
{
yield return new ContourSegment(quad.A, quad.B);
for (int i = 0, count = _vertices.Length; i < count; i++)
{
Point vertex = node.Position + (_vertices[i] * node.PressureFactor);
if (vertex == quad.B)
{
for (int j = 0; (j < count) && (vertex != quad.C); j++)
{
i = (i + 1) % count;
Point nextVertex = node.Position + (_vertices[i] * node.PressureFactor);
yield return new ContourSegment(vertex, nextVertex);
vertex = nextVertex;
}
break;
}
}
yield return new ContourSegment(quad.C, quad.D);
yield return new ContourSegment(quad.D, quad.A);
}
}
/// <summary>
/// ISSUE-2004/06/15- temporary workaround to avoid hit-testing ellipses with ellipses
/// </summary>
/// <param name="beginNode"></param>
/// <param name="endNode"></param>
/// <returns></returns>
internal virtual IEnumerable<ContourSegment> GetNonBezierContourSegments(StrokeNodeData beginNode, StrokeNodeData endNode)
{
Quad quad = beginNode.IsEmpty ? Quad.Empty : GetConnectingQuad(beginNode, endNode);
return GetContourSegments(endNode, quad);
}
/// <summary>
/// Finds connecting points for a pair of stroke nodes (of a polygonal shape)
/// </summary>
/// <param name="beginNode">a node to connect</param>
/// <param name="endNode">another node, next to beginNode</param>
/// <returns>connecting quadrangle, that can be empty if one node is inside the other</returns>
internal virtual Quad GetConnectingQuad(StrokeNodeData beginNode, StrokeNodeData endNode)
{
// Return an empty quad if either of the nodes is empty (not a node)
// or if both nodes are at the same position.
if (beginNode.IsEmpty || endNode.IsEmpty || DoubleUtil.AreClose(beginNode.Position, endNode.Position))
{
return Quad.Empty;
}
// By definition, Quad's vertices (A,B,C,D) are ordered clockwise with points A and D located
// on the beginNode and B and C on the endNode. Basically, we're looking for segments AB and CD.
// We iterate through the vertices of the beginNode, at each vertex we analyze location of the
// connecting segment relative to the node's edges at the vertex, and enforce these rules:
// - if the vector of the connecting segment at a vertex V[i] is on the left from vector V[i]V[i+1]
// and not on the left from vector V[i-1]V[i], then it's the AB segment of the quad (V[i] == A).
// - if the vector of the connecting segment at a vertex V[i] is on the left from vector V[i-1]V[i]
// and not on the left from vector V[i]V[i+1], then it's the CD segment of the quad (V[i] == D).
//
Quad quad = Quad.Empty;
bool foundAB = false, foundCD = false;
// There's no need to build shapes of the two nodes in order to find their connecting quad.
// It's the spine vector between the nodes and their scaling diff (pressure delta) is all
// that matters here.
Vector spine = endNode.Position - beginNode.Position;
double pressureDelta = endNode.PressureFactor - beginNode.PressureFactor;
// Iterate through the vertices of the default shape
int count = _vertices.Length;
for (int i = 0, j = count - 1; i < count; i++, j = ((j + 1) % count))
{
// Compute vector of the connecting segment at the vertex [i]
Vector connection = spine + _vertices[i] * pressureDelta;
if ((pressureDelta != 0) && (connection.X == 0) && (connection.Y == 0))
{
// One of the nodes, |----|
// as well as the connecting quad, |__ |
// is entirely inside the other node. | | |
// [i] --> |__|_|
return Quad.Empty;
}
// Find out where this vector is about the node edge [i][i+1]
// (The vars names "goingTo" and "comingFrom" refer direction of the line defined
// by the connecting vector applied at vertex [i], relative to the contour of the node shape.
// Using these terms, (comingFrom != Right && goingTo == Left) corresponds to the segment AB,
// and (comingFrom == Right && goingTo != Left) describes the DC.
HitResult goingTo = WhereIsVectorAboutVector(connection, _vertices[(i + 1) % count] - _vertices[i]);
if (goingTo == HitResult.Left)
{
if (false == foundAB)
{
// Find out where the node edge [i-1][i] is about the connecting vector
HitResult comingFrom = WhereIsVectorAboutVector(_vertices[i] - _vertices[j], connection);
if (HitResult.Right != comingFrom)
{
foundAB = true;
quad.A = beginNode.Position + _vertices[i] * beginNode.PressureFactor;
quad.B = endNode.Position + _vertices[i] * endNode.PressureFactor;
if (true == foundCD)
{
// Found all 4 points. Break out from the 'for' loop.
break;
}
}
}
}
else
{
if (false == foundCD)
{
// Find out where the node edge [i-1][i] is about the connecting vector
HitResult comingFrom = WhereIsVectorAboutVector(_vertices[i] - _vertices[j], connection);
if (HitResult.Right == comingFrom)
{
foundCD = true;
quad.C = endNode.Position + _vertices[i] * endNode.PressureFactor;
quad.D = beginNode.Position + _vertices[i] * beginNode.PressureFactor;
if (true == foundAB)
{
// Found all 4 points. Break out from the 'for' loop.
break;
}
}
}
}
}
if (!foundAB || !foundCD || // (2)
((pressureDelta != 0) && Vector.Determinant(quad.B - quad.A, quad.D - quad.A) == 0)) // (1)
{
// _____ _______
// One of the nodes, (1) |__ | (2) | ___ |
// as well as the connecting quad, | | | | | | |
// is entirely inside the other node. |__| | | |__| |
// |____| |___ __|
return Quad.Empty;
}
return quad;
}
/// <summary>
/// Hit-tests ink segment defined by two nodes against a linear segment.
/// </summary>
/// <param name="beginNode">Begin node of the ink segment</param>
/// <param name="endNode">End node of the ink segment</param>
/// <param name="quad">Pre-computed quadrangle connecting the two ink nodes</param>
/// <param name="hitBeginPoint">Begin point of the hitting segment</param>
/// <param name="hitEndPoint">End point of the hitting segment</param>
/// <returns>true if there's intersection, false otherwise</returns>
internal virtual bool HitTest(
StrokeNodeData beginNode, StrokeNodeData endNode, Quad quad, Point hitBeginPoint, Point hitEndPoint)
{
// Check for special cases when the endNode is the very first one (beginNode.IsEmpty)
// or one node is completely inside the other. In either case the connecting quad
// would be Empty and we need to hit-test against the biggest node (the one with
// the greater PressureFactor)
if (quad.IsEmpty)
{
Point position;
double pressureFactor;
if (beginNode.IsEmpty || (endNode.PressureFactor > beginNode.PressureFactor))
{
position = endNode.Position;
pressureFactor = endNode.PressureFactor;
}
else
{
position = beginNode.Position;
pressureFactor = beginNode.PressureFactor;
}
// Find the coordinates of the hitting segment relative to the ink node
Vector hitBegin = hitBeginPoint - position, hitEnd = hitEndPoint - position;
if (pressureFactor != 1)
{
// Instead of applying pressure to the node, do reverse scaling on
// the hitting segment. This allows us use the original array of vertices
// in hit-testing.
System.Diagnostics.Debug.Assert(DoubleUtil.IsZero(pressureFactor) == false);
hitBegin /= pressureFactor;
hitEnd /= pressureFactor;
}
return HitTestPolygonSegment(_vertices, hitBegin, hitEnd);
}
else
{
// Iterate through the vertices of the contour of the ink segment
// check where the hitting segment is about them, return false if it's
// on the outer (left) side of the ink contour. This implementation might
// look more complex than straightforward separated hit-testing of three
// polygons (beginNode, quad, endNode), but it's supposed to be more optimal
// because the number of edges it hit-tests is approximately twice less
// than with the straightforward implementation.
// Start with the segment quad.C->quad.D
Vector hitBegin = hitBeginPoint - beginNode.Position;
Vector hitEnd = hitEndPoint - beginNode.Position;
HitResult hitResult = WhereIsSegmentAboutSegment(
hitBegin, hitEnd, quad.C - beginNode.Position, quad.D - beginNode.Position);
if (HitResult.Left == hitResult)
{
return false;
}
// Continue clockwise from quad.D to quad.C
HitResult firstResult = hitResult, lastResult = hitResult;
double pressureFactor = beginNode.PressureFactor;
// Find the index of the vertex that is quad.D
// Use count var to avoid infinite loop, normally it shouldn't
// happen but it doesn't hurt to check it just in case.
int i = 0, count = _vertices.Length;
Vector vertex = new Vector();
for (i = 0; i < count; i++)
{
vertex = _vertices[i] * pressureFactor;
// Here and in a few more places down the code, when comparing
// a quad's vertex vs a scaled shape vertex, it's important to
// compute them the same way as in GetConnectingQuad, so that not
// hit that double's computation error. For instance, sometimes the
// expression (vertex == quad.D - beginNode.Position) gives 'false'
// while the expression below gives 'true'. (Another workaround is to
// use DoubleUtil.AreClose but that;d be less performant)
if ((beginNode.Position + vertex) == quad.D)
{
break;
}
}
System.Diagnostics.Debug.Assert(count > 0);
// This loop does the iteration thru the edges of the ink segment
// clockwise from quad.D to quad.C.
for (int node = 0; node < 2; node++)
{
Point nodePosition = (node == 0) ? beginNode.Position : endNode.Position;
Point end = (node == 0) ? quad.A : quad.C;
count = _vertices.Length;
while (((nodePosition + vertex) != end) && (count != 0))
{
i = (i + 1) % _vertices.Length;
Vector nextVertex = (pressureFactor == 1) ? _vertices[i] : (_vertices[i] * pressureFactor);
hitResult = WhereIsSegmentAboutSegment(hitBegin, hitEnd, vertex, nextVertex);
if (HitResult.Hit == hitResult)
{
return true;
}
if (true == IsOutside(hitResult, lastResult))
{
return false;
}
lastResult = hitResult;
vertex = nextVertex;
count--;
}
System.Diagnostics.Debug.Assert(count > 0);
if (node == 0)
{
// The first iteration is done thru the outer segments of beginNode
// and ends at quad.A, for the second one make some adjustments
// to continue iterating through quad.AB and the outer segments of
// endNode up to quad.C
pressureFactor = endNode.PressureFactor;
Vector spineVector = endNode.Position - beginNode.Position;
vertex -= spineVector;
hitBegin -= spineVector;
hitEnd -= spineVector;
// Find the index of the vertex that is quad.B
count = _vertices.Length;
while (((endNode.Position + _vertices[i] * pressureFactor) != quad.B) && (count != 0))
{
i = (i + 1) % _vertices.Length;
count--;
}
System.Diagnostics.Debug.Assert(count > 0);
i--;
}
}
return (false == IsOutside(firstResult, hitResult));
}
}
/// <summary>
/// Hit-tests a stroke segment defined by two nodes against another stroke segment.
/// </summary>
/// <param name="beginNode">Begin node of the stroke segment to hit-test. Can be empty (none)</param>
/// <param name="endNode">End node of the stroke segment</param>
/// <param name="quad">Pre-computed quadrangle connecting the two nodes.
/// Can be empty if the begion node is empty or when one node is entirely inside the other</param>
/// <param name="hitContour">a collection of basic segments outlining the hitting contour</param>
/// <returns>true if the contours intersect or overlap</returns>
internal virtual bool HitTest(
StrokeNodeData beginNode, StrokeNodeData endNode, Quad quad, IEnumerable<ContourSegment> hitContour)
{
// Check for special cases when the endNode is the very first one (beginNode.IsEmpty)
// or one node is completely inside the other. In either case the connecting quad
// would be Empty and we need to hittest against the biggest node (the one with
// the greater PressureFactor)
if (quad.IsEmpty)
{
// NTRAID#Window OS bug-1029694-2004/10/15-xiaotu, refactor the code to make it a method
// to increase the maintainability of the program. FxCop bug.
// Make a call to hit-test the biggest node the hitting contour.
return HitTestPolygonContourSegments(hitContour, beginNode, endNode);
}
else
{
// NTRAID#Window OS bug-1029694-2004/10/15-xiaotu, refactor the code to make it a method
// to increase the maintainability of the program. FxCop bug.
// HitTest the the hitting contour against the inking contour
return HitTestInkContour(hitContour, quad, beginNode, endNode);
}
}
/// <summary>
/// Hit-tests ink segment defined by two nodes against a linear segment.
/// </summary>
/// <param name="beginNode">Begin node of the ink segment</param>
/// <param name="endNode">End node of the ink segment</param>
/// <param name="quad">Pre-computed quadrangle connecting the two ink nodes</param>
/// <param name="hitBeginPoint">Begin point of the hitting segment</param>
/// <param name="hitEndPoint">End point of the hitting segment</param>
/// <returns>Exact location to cut at represented by StrokeFIndices</returns>
internal virtual StrokeFIndices CutTest(
StrokeNodeData beginNode, StrokeNodeData endNode, Quad quad, Point hitBeginPoint, Point hitEndPoint)
{
StrokeFIndices result = StrokeFIndices.Empty;
// First, find out if the hitting segment intersects with either of the ink nodes
for (int node = (beginNode.IsEmpty ? 1 : 0); node < 2; node++)
{
Point position = (node == 0) ? beginNode.Position : endNode.Position;
double pressureFactor = (node == 0) ? beginNode.PressureFactor : endNode.PressureFactor;
// Adjust the segment for the node's pressure factor
Vector hitBegin = hitBeginPoint - position;
Vector hitEnd = hitEndPoint - position;
if (pressureFactor != 1)
{
System.Diagnostics.Debug.Assert(DoubleUtil.IsZero(pressureFactor) == false);
hitBegin /= pressureFactor;
hitEnd /= pressureFactor;
}
// Hit-test the node against the segment
if (true == HitTestPolygonSegment(_vertices, hitBegin, hitEnd))
{
if (node == 0)
{
result.BeginFIndex = StrokeFIndices.BeforeFirst;
result.EndFIndex = 0;
}
else
{
result.EndFIndex = StrokeFIndices.AfterLast;
if (beginNode.IsEmpty)
{
result.BeginFIndex = StrokeFIndices.BeforeFirst;
}
else if (result.BeginFIndex != StrokeFIndices.BeforeFirst)
{
result.BeginFIndex = 1;
}
}
}
}
// If both nodes are hit, return.
if (result.IsFull)
{
return result;
}
// If there's no hit at all, return.
if (result.IsEmpty && (quad.IsEmpty || !HitTestQuadSegment(quad, hitBeginPoint, hitEndPoint)))
{
return result;
}
// The segments do intersect. Find findices on the ink segment to cut it at.
if (result.BeginFIndex != StrokeFIndices.BeforeFirst)
{
// The begin node is not hit, i.e. the begin findex is on this spine segment, find it.
result.BeginFIndex = ClipTest(
(endNode.Position - beginNode.Position) / beginNode.PressureFactor,
(endNode.PressureFactor / beginNode.PressureFactor) - 1,
(hitBeginPoint - beginNode.Position) / beginNode.PressureFactor,
(hitEndPoint - beginNode.Position) / beginNode.PressureFactor);
}
if (result.EndFIndex != StrokeFIndices.AfterLast)
{
// The end node is not hit, i.e. the end findex is on this spine segment, find it.
result.EndFIndex = 1 - ClipTest(
(beginNode.Position - endNode.Position) / endNode.PressureFactor,
(beginNode.PressureFactor / endNode.PressureFactor) - 1,
(hitBeginPoint - endNode.Position) / endNode.PressureFactor,
(hitEndPoint - endNode.Position) / endNode.PressureFactor);
}
if (IsInvalidCutTestResult(result))
{
return StrokeFIndices.Empty;
}
return result;
}
/// <summary>
/// CutTest
/// </summary>
/// <param name="beginNode">Begin node of the stroke segment to hit-test. Can be empty (none)</param>
/// <param name="endNode">End node of the stroke segment</param>
/// <param name="quad">Pre-computed quadrangle connecting the two nodes.
/// Can be empty if the begion node is empty or when one node is entirely inside the other</param>
/// <param name="hitContour">a collection of basic segments outlining the hitting contour</param>
/// <returns></returns>
internal virtual StrokeFIndices CutTest(
StrokeNodeData beginNode, StrokeNodeData endNode, Quad quad, IEnumerable<ContourSegment> hitContour)
{
if (beginNode.IsEmpty)
{
if (HitTest(beginNode, endNode, quad, hitContour) == true)
{
return StrokeFIndices.Full;
}
return StrokeFIndices.Empty;
}
StrokeFIndices result = StrokeFIndices.Empty;
bool isInside = true;
Vector spineVector = (endNode.Position - beginNode.Position) / beginNode.PressureFactor;
Vector spineVectorReversed = (beginNode.Position - endNode.Position) / endNode.PressureFactor;
double pressureDelta = (endNode.PressureFactor / beginNode.PressureFactor) - 1;
double pressureDeltaReversed = (beginNode.PressureFactor / endNode.PressureFactor) - 1;
foreach (ContourSegment hitSegment in hitContour)
{
// NTRAID#Window OS bug-1029694-2004/10/19-xiaotu, refactor the code to make it a method
// to increase the maintainability of the program. FxCop bug.
// First, find out if hitSegment intersects with either of the ink nodes
bool isHit = HitTestStrokeNodes(hitSegment,beginNode,endNode, ref result);
// If both nodes are hit, return.
if (result.IsFull)
{
return result;
}
// If neither of the nodes is hit, hit-test the connecting quad
if (isHit == false)
{
// If neither of the nodes is hit and the contour of one node is entirely
// inside the contour of the other node, then done with this hitting segment
if (!quad.IsEmpty)
{
isHit = hitSegment.IsArc
? HitTestQuadCircle(quad, hitSegment.Begin + hitSegment.Radius, hitSegment.Radius)
: HitTestQuadSegment(quad, hitSegment.Begin, hitSegment.End);
}
if (isHit == false)
{
if (isInside == true)
{
isInside = hitSegment.IsArc
? (WhereIsVectorAboutArc(endNode.Position - hitSegment.Begin - hitSegment.Radius,
-hitSegment.Radius, hitSegment.Vector - hitSegment.Radius) != HitResult.Hit)
: (WhereIsVectorAboutVector(
endNode.Position - hitSegment.Begin, hitSegment.Vector) == HitResult.Right);
}
continue;
}
}
isInside = false;
// NTRAID#Window OS bug-1029694-2004/10/15-xiaotu, refactor the code to make it a new method
// CalculateClipLocation to increase the maintainability of the program. FxCop bug.
// If the begin node is not hit, find the begin findex on the ink segment to cut it at
if (!DoubleUtil.AreClose(result.BeginFIndex, StrokeFIndices.BeforeFirst))
{
double findex = CalculateClipLocation(hitSegment, beginNode, spineVector, pressureDelta);
if (findex != StrokeFIndices.BeforeFirst)
{
System.Diagnostics.Debug.Assert(findex >= 0 && findex <= 1);
if (result.BeginFIndex > findex)
{
result.BeginFIndex = findex;
}
}
}
// If the end node is not hit, find the end findex on the ink segment to cut it at
if (!DoubleUtil.AreClose(result.EndFIndex, StrokeFIndices.AfterLast))
{
double findex = CalculateClipLocation(hitSegment, endNode, spineVectorReversed, pressureDeltaReversed);
if (findex != StrokeFIndices.BeforeFirst)
{
System.Diagnostics.Debug.Assert(findex >= 0 && findex <= 1);
findex = 1 - findex;
if (result.EndFIndex < findex)
{
result.EndFIndex = findex;
}
}
}
}
if (DoubleUtil.AreClose(result.BeginFIndex, StrokeFIndices.AfterLast))
{
if (!DoubleUtil.AreClose(result.EndFIndex, StrokeFIndices.BeforeFirst))
{
result.BeginFIndex = StrokeFIndices.BeforeFirst;
}
}
else if (DoubleUtil.AreClose(result.EndFIndex, StrokeFIndices.BeforeFirst))
{
result.EndFIndex = StrokeFIndices.AfterLast;
}
if (IsInvalidCutTestResult(result))
{
return StrokeFIndices.Empty;
}
return (result.IsEmpty && isInside) ? StrokeFIndices.Full : result;
}
/// <summary>
/// Cutting ink with polygonal tip shapes with a linear segment
/// </summary>
/// <param name="spineVector">Vector representing the starting and ending point for the inking
/// segment</param>
/// <param name="pressureDelta">Represents the difference in the node size for startNode and endNode.
/// pressureDelta = (endNode.PressureFactor / beginNode.PressureFactor) - 1</param>
/// <param name="hitBegin">Start point of the hitting segment</param>
/// <param name="hitEnd">End point of the hitting segment</param>
/// <returns>a double representing the point of clipping</returns>
private double ClipTest(Vector spineVector, double pressureDelta, Vector hitBegin, Vector hitEnd)
{
// Let's represent the vertices for the startNode are N1, N2, ..., Ni and for the endNode, M1, M2,
// ..., Mi.
// When ink tip shape is a convex polygon, one may iterate in a constant direction
// (for instance, clockwise) through the edges of the polygon P1 and hit test the cutting segment
// against quadrangles NIMIMI+1NI+1 with MI on the left side off the vector NINI+1.
// If the cutting segment intersects the quadrangle, on the intersected part of the segment,
// one may then find point Q (the nearest to the line NINI+1) and point QP
// (the point of the intersection of the segment NIMI and vector NI+1NI started at Q).
// Next,
// QP = NI + s * LengthOf(MI - NI) (1)
// s = LengthOf(QP - NI ) / LengthOf(MI - NI). (2)
// If the cutting segment intersects more than one quadrant, one may then use the smallest s
// to find the split point:
// S = P1 + s * LengthOf(P2 - P1) (3)
double findex = StrokeFIndices.AfterLast;
Vector hitVector = hitEnd - hitBegin;
Vector lastVertex = _vertices[_vertices.Length - 1];
// Note the definition of pressureDelta = (endNode.PressureFactor / beginNode.PressureFactor) - 1
// So the equation below gives
// nextNode = spineVector + (endNode.PressureFactor / beginNode.PressureFactor)*lastVertex - lastVertex
// As a result, nextNode is a Vector pointing from lastVertex of the beginNode to the correspoinding "lastVertex"
// of the endNode.
Vector nextNode = spineVector + lastVertex * pressureDelta;
bool testNextEdge = false;
for (int k = 0, count = _vertices.Length; k < count || (k == count && testNextEdge); k++)
{
Vector vertex = _vertices[k % count];
Vector nextVertex = vertex - lastVertex;
// Point from vertex in beginNode to the corresponding "vertex" in endNode
Vector nextVertexNextNode = spineVector + (vertex * pressureDelta);
// Find out a "nextNode" on the endNode (nextNode) that is on the left side off the vector
// (lastVertex, vertex).
if ((DoubleUtil.IsZero(nextNode.X) && DoubleUtil.IsZero(nextNode.Y)) ||
(!testNextEdge && (HitResult.Left != WhereIsVectorAboutVector(nextNode, nextVertex))))
{
lastVertex = vertex;
nextNode = nextVertexNextNode;
continue;
}
// Now we need to do hit testing of the hitting segment against quarangle (NI, MI, MI+1, NI+1),
// that is, (lastVertex, nextNode, nextVertexNextNode, vertex)
testNextEdge = false;
HitResult hit = HitResult.Left;
int side = 0;
for (int i = 0; i < 2; i++)
{
Vector hitPoint = ((0 == i) ? hitBegin : hitEnd) - lastVertex;
hit = WhereIsVectorAboutVector(hitPoint, nextNode);
if (hit == HitResult.Hit)
{
double r = (Math.Abs(nextNode.X) < Math.Abs(nextNode.Y)) //DoubleUtil.IsZero(nextNode.X)
? (hitPoint.Y / nextNode.Y)
: (hitPoint.X / nextNode.X);
if ((findex > r) && DoubleUtil.IsBetweenZeroAndOne(r))
{
findex = r;
}
}
else if (hit == HitResult.Right)
{
side++;
if (HitResult.Left == WhereIsVectorAboutVector(
hitPoint - nextVertex, nextVertexNextNode))
{
double r = GetPositionBetweenLines(nextVertex, nextNode, hitPoint);
if ((findex > r) && DoubleUtil.IsBetweenZeroAndOne(r))
{
findex = r;
}
}
else
{
testNextEdge = true;
}
}
else
{
side--;
}
}
//
if (0 == side)
{
if (hit == HitResult.Hit)
{
// This segment is collinear with the edge connecting the nodes,
// no need to hit-test the other edges.
System.Diagnostics.Debug.Assert(true == DoubleUtil.IsBetweenZeroAndOne(findex));
break;
}
// The hitting segment intersects the line of the edge connecting
// the nodes. Find the findex of the intersection point.
double det = -Vector.Determinant(nextNode, hitVector);
if (DoubleUtil.IsZero(det) == false)
{
double s = Vector.Determinant(hitVector, hitBegin - lastVertex) / det;
if ((findex > s) && DoubleUtil.IsBetweenZeroAndOne(s))
{
findex = s;
}
}
}
//
lastVertex = vertex;
nextNode = nextVertexNextNode;
}
return AdjustFIndex(findex);
}
/// <summary>
/// Clip-Testing a polygonal inking segment against an arc (circle)
/// </summary>
/// <param name="spineVector">Vector representing the starting and ending point for the inking
/// segment</param>
/// <param name="pressureDelta">Represents the difference in the node size for startNode and endNode.
/// pressureDelta = (endNode.PressureFactor / beginNode.PressureFactor) - 1</param>
/// <param name="hitCenter">The center of the hitting circle</param>
/// <param name="hitRadius">The radius of the hitting circle</param>
/// <returns>a double representing the point of clipping</returns>
private double ClipTestArc(Vector spineVector, double pressureDelta, Vector hitCenter, Vector hitRadius)
{
// NTRAID#WINDOWS-1448096-2006/1/9-SAMGEO, this code is not called, but will be in VNext
throw new NotImplementedException();
/*
double findex = StrokeFIndices.AfterLast;
double radiusSquared = hitRadius.LengthSquared;
Vector vertex, lastVertex = _vertices[_vertices.Length - 1];
Vector nextVertexNextNode, nextNode = spineVector + lastVertex * pressureDelta;
bool testNextEdge = false;
for (int k = 0, count = _vertices.Length;
k < count || (k == count && testNextEdge);
k++, lastVertex = vertex, nextNode = nextVertexNextNode)
{
vertex = _vertices[k % count];
Vector nextVertex = vertex - lastVertex;
nextVertexNextNode = spineVector + (vertex * pressureDelta);
if (DoubleUtil.IsZero(nextNode.X) && DoubleUtil.IsZero(nextNode.Y))
{
continue;
}
bool testConnectingEdge = false;
if (HitResult.Left == WhereIsVectorAboutVector(nextNode, nextVertex))
{
testNextEdge = false;
Vector normal = GetProjection(lastVertex - hitCenter, vertex - hitCenter);
if (radiusSquared <= normal.LengthSquared)
{
if (WhereIsVectorAboutVector(hitCenter - lastVertex, nextVertex) == HitResult.Left)
{
Vector hitPoint = hitCenter + (normal * Math.Sqrt(radiusSquared / normal.LengthSquared));
if (HitResult.Right == WhereIsVectorAboutVector(hitPoint - vertex, nextVertexNextNode))
{
testNextEdge = true;
}
else if (HitResult.Left == WhereIsVectorAboutVector(hitPoint - lastVertex, nextNode))
{
testConnectingEdge = true;
}
else
{
// this is it
findex = GetPositionBetweenLines(nextVertex, nextNode, hitPoint - lastVertex);
System.Diagnostics.Debug.Assert(DoubleUtil.IsBetweenZeroAndOne(findex));
break;
}
}
}
else if (HitResult.Right == WhereIsVectorAboutVector(hitCenter + normal - lastVertex, nextNode))
{
testNextEdge = true;
}
else
{
testConnectingEdge = true;
}
}
else if (testNextEdge == true)
{
testNextEdge = false;
testConnectingEdge = true;
}
if (testConnectingEdge)
{
// Find out the projection of hitCenter on nextNode
Vector v = lastVertex - hitCenter;
double findexNearest = GetProjectionFIndex(v, v + nextNode);
if (findexNearest > 0)
{
Vector nearest = nextNode * findexNearest;
double squaredDistanceFromNearestToHitPoint = radiusSquared - (nearest + v).LengthSquared;
if (DoubleUtil.IsZero(squaredDistanceFromNearestToHitPoint) && (findexNearest <= 1))
{
if (findexNearest < findex)
{
findex = findexNearest;
}
}
else if ((squaredDistanceFromNearestToHitPoint > 0)
&& (nearest.LengthSquared >= squaredDistanceFromNearestToHitPoint))
{
double hitPointFIndex = findexNearest - Math.Sqrt(
squaredDistanceFromNearestToHitPoint / nextNode.LengthSquared);
System.Diagnostics.Debug.Assert(DoubleUtil.GreaterThanOrClose(hitPointFIndex, 0));
if (hitPointFIndex < findex)
{
findex = hitPointFIndex;
}
}
}
}
}
return AdjustFIndex(findex);
*/
}
/// <summary>
/// Internal access to __vertices
/// </summary>
/// <returns></returns>
internal Vector[] GetVertices()
{
return _vertices;
}
/// <summary>
/// Helper function to hit-test the biggest node against hitting contour segments
/// </summary>
/// <param name="hitContour">a collection of basic segments outlining the hitting contour</param>
/// <param name="beginNode">Begin node of the stroke segment to hit-test. Can be empty (none)</param>
/// <param name="endNode">End node of the stroke segment</param>
/// <returns>true if hit; false otherwise</returns>
private bool HitTestPolygonContourSegments(
IEnumerable<ContourSegment> hitContour, StrokeNodeData beginNode, StrokeNodeData endNode)
{
bool isHit = false;
// The bool variable isInside is used here to track that case. It answers to
// 'Is ink contour inside if the hitting contour?'. It's initialized to 'true"
// and then verified for each edge of the hitting contour until there's a hit or
// until it's false.
bool isInside = true;
Point position;
double pressureFactor;
if (beginNode.IsEmpty || endNode.PressureFactor > beginNode.PressureFactor)
{
position = endNode.Position;
pressureFactor = endNode.PressureFactor;
}
else
{
position = beginNode.Position;
pressureFactor = beginNode.PressureFactor;
}
// Enumerate through the segments of the hitting contour and test them
// one by one against the contour of the ink node.
foreach (ContourSegment hitSegment in hitContour)
{
if (hitSegment.IsArc)
{
// Adjust the arc for the node' pressure factor.
Vector hitCenter = hitSegment.Begin + hitSegment.Radius - position;
Vector hitRadius = hitSegment.Radius;
if (!DoubleUtil.AreClose(pressureFactor, 1d))
{
System.Diagnostics.Debug.Assert(DoubleUtil.IsZero(pressureFactor) == false);
hitCenter /= pressureFactor;
hitRadius /= pressureFactor;
}
// If the segment is an arc, hit-test against the entire circle the arc is part of.
if (true == HitTestPolygonCircle(_vertices, hitCenter, hitRadius))
{
isHit = true;
break;
}
//
if (isInside && (WhereIsVectorAboutArc(
position - hitSegment.Begin - hitSegment.Radius,
-hitSegment.Radius, hitSegment.Vector - hitSegment.Radius) == HitResult.Hit))
{
isInside = false;
}
}
else
{
// Adjust the segment for the node's pressure factor
Vector hitBegin = hitSegment.Begin - position;
Vector hitEnd = hitBegin + hitSegment.Vector;
if (!DoubleUtil.AreClose(pressureFactor, 1d))
{
System.Diagnostics.Debug.Assert(DoubleUtil.IsZero(pressureFactor) == false);
hitBegin /= pressureFactor;
hitEnd /= pressureFactor;
}
// Hit-test the node against the segment
if (true == HitTestPolygonSegment(_vertices, hitBegin, hitEnd))
{
isHit = true;
break;
}
//
if (isInside && WhereIsVectorAboutVector(
position - hitSegment.Begin, hitSegment.Vector) != HitResult.Right)
{
isInside = false;
}
}
}
return (isInside || isHit);
}
/// <summary>
/// Helper function to HitTest the the hitting contour against the inking contour
/// </summary>
/// <param name="hitContour">a collection of basic segments outlining the hitting contour</param>
/// <param name="quad">A connecting quad</param>
/// <param name="beginNode">Begin node of the stroke segment to hit-test. Can be empty (none)</param>
/// <param name="endNode">End node of the stroke segment</param>
/// <returns>true if hit; false otherwise</returns>
private bool HitTestInkContour(
IEnumerable<ContourSegment> hitContour, Quad quad, StrokeNodeData beginNode, StrokeNodeData endNode)
{
System.Diagnostics.Debug.Assert(!quad.IsEmpty);
bool isHit = false;
// When hit-testing a contour against another contour, like in this case,
// the default implementation checks whether any edge (segment) of the hitting
// contour intersects with the contour of the ink segment. But this doesn't cover
// the case when the ink segment is entirely inside of the hitting segment.
// The bool variable isInside is used here to track that case. It answers to
// 'Is ink contour inside if the hitting contour?'. It's initialized to 'true"
// and then verified for each edge of the hitting contour until there's a hit or
// until it's false.
bool isInside = true;
// The ink connecting quad is not empty, enumerate through the segments of the
// hitting contour and hit-test them one by one against the ink contour.
foreach (ContourSegment hitSegment in hitContour)
{
// Iterate through the vertices of the contour of the ink segment
// check where the hit segment is about them, return false if it's
// on the left side off either of the ink contour segments.
Vector hitBegin, hitEnd;
HitResult hitResult;
// Start with the segment quad.C->quad.D
if (hitSegment.IsArc)
{
hitBegin = hitSegment.Begin + hitSegment.Radius - beginNode.Position;
hitEnd = hitSegment.Radius;
hitResult = WhereIsCircleAboutSegment(
hitBegin, hitEnd, quad.C - beginNode.Position, quad.D - beginNode.Position);
}
else
{
hitBegin = hitSegment.Begin - beginNode.Position;
hitEnd = hitBegin + hitSegment.Vector;
hitResult = WhereIsSegmentAboutSegment(
hitBegin, hitEnd, quad.C - beginNode.Position, quad.D - beginNode.Position);
}
if (HitResult.Left == hitResult)
{
if (isInside)
{
isInside = hitSegment.IsArc
? (WhereIsVectorAboutArc(-hitBegin, -hitSegment.Radius, hitSegment.Vector - hitSegment.Radius) != HitResult.Hit)
: (WhereIsVectorAboutVector(-hitBegin, hitSegment.Vector) == HitResult.Right);
}
// This hitSegment is completely outside of the ink contour,
// continue with the next one.
continue;
}
// Continue clockwise from quad.D to quad.A, then to quad.B, ..., quad.C
HitResult firstResult = hitResult, lastResult = hitResult;
double pressureFactor = beginNode.PressureFactor;
// Find the index of the vertex that is quad.D
// Use count var to avoid infinite loop, normally this shouldn't
// happen but it doesn't hurt to check it just in case.
int i = 0, count = _vertices.Length;
Vector vertex = new Vector();
for (i = 0; i < count; i++)
{
vertex = _vertices[i] * pressureFactor;
if (DoubleUtil.AreClose((beginNode.Position + vertex), quad.D))
{
break;
}
}
System.Diagnostics.Debug.Assert(i < count);
int k;
for (k = 0; k < 2; k++)
{
count = _vertices.Length;
Point nodePosition = (k == 0) ? beginNode.Position : endNode.Position;
Point end = (k == 0) ? quad.A : quad.C;
// Iterate over the vertices on
// beginNode(k=0)from quad.D to quad.A
// or
// endNode(k=1)from quad.A to quad.B ... to quad.C
while (((nodePosition + vertex) != end) && (count != 0))
{
// Find out the next vertex
i = (i + 1) % _vertices.Length;
Vector nextVertex = _vertices[i] * pressureFactor;
// Hit-test the hitting segment against the current edge
hitResult = hitSegment.IsArc
? WhereIsCircleAboutSegment(hitBegin, hitEnd, vertex, nextVertex)
: WhereIsSegmentAboutSegment(hitBegin, hitEnd, vertex, nextVertex);
if (HitResult.Hit == hitResult)
{
return true; //Got a hit
}
if (true == IsOutside(hitResult, lastResult))
{
// This hitSegment is definitely outside the ink contour, drop it.
// Change k to something > 2 to leave the for loop and skip
// IsOutside at the bottom
k = 3;
break;
}
lastResult = hitResult;
vertex = nextVertex;
count--;
}
System.Diagnostics.Debug.Assert(count > 0);
if (k == 0)
{
// Make some adjustments for the second one to continue iterating through
// quad.AB and the outer segments of endNode up to quad.C
pressureFactor = endNode.PressureFactor;
Vector spineVector = endNode.Position - beginNode.Position;
vertex -= spineVector; // now vertex = quad.A - spineVector
hitBegin -= spineVector; // adjust hitBegin to the space of endNode
if (hitSegment.IsArc == false)
{
hitEnd -= spineVector;
}
// Find the index of the vertex that is quad.B
count = _vertices.Length;
while (!DoubleUtil.AreClose((endNode.Position + _vertices[i] * pressureFactor), quad.B) && (count != 0))
{
i = (i + 1) % _vertices.Length;
count--;
}
System.Diagnostics.Debug.Assert(count > 0);
i--;
}
}
if ((k == 2) && (false == IsOutside(firstResult, hitResult)))
{
isHit = true;
break;
}
//
if (isInside)
{
isInside = hitSegment.IsArc
? (WhereIsVectorAboutArc(-hitBegin, -hitSegment.Radius, hitSegment.Vector - hitSegment.Radius) != HitResult.Hit)
: (WhereIsVectorAboutVector(-hitBegin, hitSegment.Vector) == HitResult.Right);
}
}
return (isHit||isInside);
}
/// <summary>
/// Helper function to Hit-test against the two stroke nodes only (excluding the connecting quad).
/// </summary>
/// <param name="hitSegment"></param>
/// <param name="beginNode"></param>
/// <param name="endNode"></param>
/// <param name="result"></param>
/// <returns></returns>
private bool HitTestStrokeNodes(
ContourSegment hitSegment, StrokeNodeData beginNode, StrokeNodeData endNode, ref StrokeFIndices result)
{
// First, find out if hitSegment intersects with either of the ink nodes
bool isHit = false;
for (int node = 0; node < 2; node++)
{
Point position;
double pressureFactor;
if (node == 0)
{
if (isHit && DoubleUtil.AreClose(result.BeginFIndex, StrokeFIndices.BeforeFirst))
{
continue;
}
position = beginNode.Position;
pressureFactor = beginNode.PressureFactor;
}
else
{
if (isHit && DoubleUtil.AreClose(result.EndFIndex, StrokeFIndices.AfterLast))
{
continue;
}
position = endNode.Position;
pressureFactor = endNode.PressureFactor;
}
Vector hitBegin, hitEnd;
// Adjust the segment for the node's pressure factor
if (hitSegment.IsArc)
{
hitBegin = hitSegment.Begin - position + hitSegment.Radius;
hitEnd = hitSegment.Radius;
}
else
{
hitBegin = hitSegment.Begin - position;
hitEnd = hitBegin + hitSegment.Vector;
}
if (pressureFactor != 1)
{
System.Diagnostics.Debug.Assert(DoubleUtil.IsZero(pressureFactor) == false);
hitBegin /= pressureFactor;
hitEnd /= pressureFactor;
}
// Hit-test the node against the segment
if (hitSegment.IsArc
? HitTestPolygonCircle(_vertices, hitBegin, hitEnd)
: HitTestPolygonSegment(_vertices, hitBegin, hitEnd))
{
isHit = true;
if (node == 0)
{
result.BeginFIndex = StrokeFIndices.BeforeFirst;
if (DoubleUtil.AreClose(result.EndFIndex, StrokeFIndices.AfterLast))
{
break;
}
}
else
{
result.EndFIndex = StrokeFIndices.AfterLast;
if (beginNode.IsEmpty)
{
result.BeginFIndex = StrokeFIndices.BeforeFirst;
break;
}
if (DoubleUtil.AreClose(result.BeginFIndex, StrokeFIndices.BeforeFirst))
{
break;
}
}
}
}
return isHit;
}
/// <summary>
/// Calculate the clip location
/// </summary>
/// <param name="hitSegment">the hitting segment</param>
/// <param name="beginNode">begin node</param>
/// <param name="spineVector"></param>
/// <param name="pressureDelta"></param>
/// <returns>the clip location. not-clip if return StrokeFIndices.BeforeFirst</returns>
private double CalculateClipLocation(
ContourSegment hitSegment, StrokeNodeData beginNode, Vector spineVector, double pressureDelta)
{
double findex = StrokeFIndices.BeforeFirst;
bool clipIt = hitSegment.IsArc ? true
//? (WhereIsVectorAboutArc(beginNode.Position - hitSegment.Begin - hitSegment.Radius,
// -hitSegment.Radius, hitSegment.Vector - hitSegment.Radius) == HitResult.Hit)
: (WhereIsVectorAboutVector(
beginNode.Position - hitSegment.Begin, hitSegment.Vector) == HitResult.Left);
if (clipIt)
{
findex = hitSegment.IsArc
? ClipTestArc(spineVector, pressureDelta,
(hitSegment.Begin + hitSegment.Radius - beginNode.Position) / beginNode.PressureFactor,
hitSegment.Radius / beginNode.PressureFactor)
: ClipTest(spineVector, pressureDelta,
(hitSegment.Begin - beginNode.Position) / beginNode.PressureFactor,
(hitSegment.End - beginNode.Position) / beginNode.PressureFactor);
// NTRAID#WINDOWS-1384646-2005/11/17-WAYNEZEN,
// ClipTest returns StrokeFIndices.AfterLast to indicate a false hit test.
// But the caller CutTest expects StrokeFIndices.BeforeFirst when there is no hit.
if ( findex == StrokeFIndices.AfterLast )
{
findex = StrokeFIndices.BeforeFirst;
}
else
{
System.Diagnostics.Debug.Assert(findex >= 0 && findex <= 1);
}
}
return findex;
}
/// <summary>
/// Helper method used to determine if we came up with a bogus result during hit testing
/// </summary>
protected bool IsInvalidCutTestResult(StrokeFIndices result)
{
//
// check for three invalid states
// 1) BeforeFirst == AfterLast
// 2) BeforeFirst, < 0
// 3) > 1, AfterLast
//
if (DoubleUtil.AreClose(result.BeginFIndex, result.EndFIndex) ||
DoubleUtil.AreClose(result.BeginFIndex, StrokeFIndices.BeforeFirst) && result.EndFIndex < 0.0f ||
result.BeginFIndex > 1.0f && DoubleUtil.AreClose(result.EndFIndex, StrokeFIndices.AfterLast))
{
return true;
}
return false;
}
#endregion
#region Instance data
// Shape parameters
private Rect _shapeBounds = Rect.Empty;
protected Vector[] _vertices;
#endregion
}
}
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