--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/gui/painting/qtessellator.cpp Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,1498 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qtessellator_p.h"
+
+#include <QRect>
+#include <QList>
+#include <QDebug>
+
+#include <qmath.h>
+#include <limits.h>
+
+QT_BEGIN_NAMESPACE
+
+//#define DEBUG
+#ifdef DEBUG
+#define QDEBUG qDebug
+#else
+#define QDEBUG if (1){} else qDebug
+#endif
+
+static const bool emit_clever = true;
+static const bool mark_clever = false;
+
+enum VertexFlags {
+ LineBeforeStarts = 0x1,
+ LineBeforeEnds = 0x2,
+ LineBeforeHorizontal = 0x4,
+ LineAfterStarts = 0x8,
+ LineAfterEnds = 0x10,
+ LineAfterHorizontal = 0x20
+};
+
+
+
+class QTessellatorPrivate {
+public:
+ struct Vertices;
+
+ QTessellatorPrivate() {}
+
+ QRectF collectAndSortVertices(const QPointF *points, int *maxActiveEdges);
+ void cancelCoincidingEdges();
+
+ void emitEdges(QTessellator *tessellator);
+ void processIntersections();
+ void removeEdges();
+ void addEdges();
+ void addIntersections();
+
+ struct Vertex : public QTessellator::Vertex
+ {
+ int flags;
+ };
+
+ struct Intersection
+ {
+ Q27Dot5 y;
+ int edge;
+ bool operator <(const Intersection &other) const {
+ if (y != other.y)
+ return y < other.y;
+ return edge < other.edge;
+ }
+ };
+ struct IntersectionLink
+ {
+ int next;
+ int prev;
+ };
+ typedef QMap<Intersection, IntersectionLink> Intersections;
+
+ struct Edge {
+ Edge(const Vertices &v, int _edge);
+ int edge;
+ const Vertex *v0;
+ const Vertex *v1;
+ Q27Dot5 y_left;
+ Q27Dot5 y_right;
+ signed int winding : 8;
+ bool mark;
+ bool free;
+ bool intersect_left;
+ bool intersect_right;
+ bool isLeftOf(const Edge &other, Q27Dot5 y) const;
+ Q27Dot5 positionAt(Q27Dot5 y) const;
+ bool intersect(const Edge &other, Q27Dot5 *y, bool *det_positive) const;
+
+ };
+
+ class EdgeSorter
+ {
+ public:
+ EdgeSorter(int _y) : y(_y) {}
+ bool operator() (const Edge *e1, const Edge *e2);
+ int y;
+ };
+
+ class Scanline {
+ public:
+ Scanline();
+ ~Scanline();
+
+ void init(int maxActiveEdges);
+ void done();
+
+ int findEdgePosition(Q27Dot5 x, Q27Dot5 y) const;
+ int findEdgePosition(const Edge &e) const;
+ int findEdge(int edge) const;
+ void clearMarks();
+
+ void swap(int p1, int p2) {
+ Edge *tmp = edges[p1];
+ edges[p1] = edges[p2];
+ edges[p2] = tmp;
+ }
+ void insert(int pos, const Edge &e);
+ void removeAt(int pos);
+ void markEdges(int pos1, int pos2);
+
+ void prepareLine();
+ void lineDone();
+
+ Edge **old;
+ int old_size;
+
+ Edge **edges;
+ int size;
+
+ private:
+ Edge *edge_table;
+ int first_unused;
+ int max_edges;
+ enum { default_alloc = 32 };
+ };
+
+ struct Vertices {
+ enum { default_alloc = 128 };
+ Vertices();
+ ~Vertices();
+ void init(int maxVertices);
+ void done();
+ Vertex *storage;
+ Vertex **sorted;
+
+ Vertex *operator[] (int i) { return storage + i; }
+ const Vertex *operator[] (int i) const { return storage + i; }
+ int position(const Vertex *v) const {
+ return v - storage;
+ }
+ Vertex *next(Vertex *v) {
+ ++v;
+ if (v == storage + nPoints)
+ v = storage;
+ return v;
+ }
+ const Vertex *next(const Vertex *v) const {
+ ++v;
+ if (v == storage + nPoints)
+ v = storage;
+ return v;
+ }
+ int nextPos(const Vertex *v) const {
+ ++v;
+ if (v == storage + nPoints)
+ return 0;
+ return v - storage;
+ }
+ Vertex *prev(Vertex *v) {
+ if (v == storage)
+ v = storage + nPoints;
+ --v;
+ return v;
+ }
+ const Vertex *prev(const Vertex *v) const {
+ if (v == storage)
+ v = storage + nPoints;
+ --v;
+ return v;
+ }
+ int prevPos(const Vertex *v) const {
+ if (v == storage)
+ v = storage + nPoints;
+ --v;
+ return v - storage;
+ }
+ int nPoints;
+ int allocated;
+ };
+ Vertices vertices;
+ Intersections intersections;
+ Scanline scanline;
+ bool winding;
+ Q27Dot5 y;
+ int currentVertex;
+
+private:
+ void addIntersection(const Edge *e1, const Edge *e2);
+ bool edgeInChain(Intersection i, int edge);
+};
+
+
+QTessellatorPrivate::Edge::Edge(const QTessellatorPrivate::Vertices &vertices, int edge)
+{
+ this->edge = edge;
+ intersect_left = intersect_right = true;
+ mark = false;
+ free = false;
+
+ v0 = vertices[edge];
+ v1 = vertices.next(v0);
+
+ Q_ASSERT(v0->y != v1->y);
+
+ if (v0->y > v1->y) {
+ qSwap(v0, v1);
+ winding = -1;
+ } else {
+ winding = 1;
+ }
+ y_left = y_right = v0->y;
+}
+
+// This is basically the algorithm from graphics gems. The algorithm
+// is cubic in the coordinates at one place. Since we use 64bit
+// integers, this implies, that the allowed range for our coordinates
+// is limited to 21 bits. With 5 bits behind the decimal, this
+// implies that differences in coordaintes can range from 2*SHORT_MIN
+// to 2*SHORT_MAX, giving us efficiently a coordinate system from
+// SHORT_MIN to SHORT_MAX.
+//
+
+// WARNING: It's absolutely critical that the intersect() and isLeftOf() methods use
+// exactly the same algorithm to calulate yi. It's also important to be sure the algorithms
+// are transitive (ie. the conditions below are true for all input data):
+//
+// a.intersect(b) == b.intersect(a)
+// a.isLeftOf(b) != b.isLeftOf(a)
+//
+// This is tricky to get right, so be very careful when changing anything in here!
+
+static inline bool sameSign(qint64 a, qint64 b) {
+ return (((qint64) ((quint64) a ^ (quint64) b)) >= 0 );
+}
+
+bool QTessellatorPrivate::Edge::intersect(const Edge &other, Q27Dot5 *y, bool *det_positive) const
+{
+ qint64 a1 = v1->y - v0->y;
+ qint64 b1 = v0->x - v1->x;
+
+ qint64 a2 = other.v1->y - other.v0->y;
+ qint64 b2 = other.v0->x - other.v1->x;
+
+ qint64 det = a1 * b2 - a2 * b1;
+ if (det == 0)
+ return false;
+
+ qint64 c1 = qint64(v1->x) * v0->y - qint64(v0->x) * v1->y;
+
+ qint64 r3 = a1 * other.v0->x + b1 * other.v0->y + c1;
+ qint64 r4 = a1 * other.v1->x + b1 * other.v1->y + c1;
+
+ // Check signs of r3 and r4. If both point 3 and point 4 lie on
+ // same side of line 1, the line segments do not intersect.
+ QDEBUG() << " " << r3 << r4;
+ if (r3 != 0 && r4 != 0 && sameSign( r3, r4 ))
+ return false;
+
+ qint64 c2 = qint64(other.v1->x) * other.v0->y - qint64(other.v0->x) * other.v1->y;
+
+ qint64 r1 = a2 * v0->x + b2 * v0->y + c2;
+ qint64 r2 = a2 * v1->x + b2 * v1->y + c2;
+
+ // Check signs of r1 and r2. If both point 1 and point 2 lie
+ // on same side of second line segment, the line segments do not intersect.
+ QDEBUG() << " " << r1 << r2;
+ if (r1 != 0 && r2 != 0 && sameSign( r1, r2 ))
+ return false;
+
+ // The det/2 is to get rounding instead of truncating. It
+ // is added or subtracted to the numerator, depending upon the
+ // sign of the numerator.
+ qint64 offset = det < 0 ? -det : det;
+ offset >>= 1;
+
+ qint64 num = a2 * c1 - a1 * c2;
+ *y = ( num < 0 ? num - offset : num + offset ) / det;
+
+ *det_positive = (det > 0);
+
+ return true;
+}
+
+#undef SAME_SIGNS
+
+bool QTessellatorPrivate::Edge::isLeftOf(const Edge &other, Q27Dot5 y) const
+{
+// QDEBUG() << "isLeftOf" << edge << other.edge << y;
+ qint64 a1 = v1->y - v0->y;
+ qint64 b1 = v0->x - v1->x;
+ qint64 a2 = other.v1->y - other.v0->y;
+ qint64 b2 = other.v0->x - other.v1->x;
+
+ qint64 c2 = qint64(other.v1->x) * other.v0->y - qint64(other.v0->x) * other.v1->y;
+
+ qint64 det = a1 * b2 - a2 * b1;
+ if (det == 0) {
+ // lines are parallel. Only need to check side of one point
+ // fixed ordering for coincident edges
+ qint64 r1 = a2 * v0->x + b2 * v0->y + c2;
+// QDEBUG() << "det = 0" << r1;
+ if (r1 == 0)
+ return edge < other.edge;
+ return (r1 < 0);
+ }
+
+ // not parallel, need to find the y coordinate of the intersection point
+ qint64 c1 = qint64(v1->x) * v0->y - qint64(v0->x) * v1->y;
+
+ qint64 offset = det < 0 ? -det : det;
+ offset >>= 1;
+
+ qint64 num = a2 * c1 - a1 * c2;
+ qint64 yi = ( num < 0 ? num - offset : num + offset ) / det;
+// QDEBUG() << " num=" << num << "offset=" << offset << "det=" << det;
+
+ return ((yi > y) ^ (det < 0));
+}
+
+static inline bool compareVertex(const QTessellatorPrivate::Vertex *p1,
+ const QTessellatorPrivate::Vertex *p2)
+{
+ if (p1->y == p2->y) {
+ if (p1->x == p2->x)
+ return p1 < p2;
+ return p1->x < p2->x;
+ }
+ return p1->y < p2->y;
+}
+
+Q27Dot5 QTessellatorPrivate::Edge::positionAt(Q27Dot5 y) const
+{
+ if (y == v0->y)
+ return v0->x;
+ else if (y == v1->y)
+ return v1->x;
+
+ qint64 d = v1->x - v0->x;
+ return (v0->x + d*(y - v0->y)/(v1->y-v0->y));
+}
+
+bool QTessellatorPrivate::EdgeSorter::operator() (const Edge *e1, const Edge *e2)
+{
+ return e1->isLeftOf(*e2, y);
+}
+
+
+QTessellatorPrivate::Scanline::Scanline()
+{
+ edges = 0;
+ edge_table = 0;
+ old = 0;
+}
+
+void QTessellatorPrivate::Scanline::init(int maxActiveEdges)
+{
+ maxActiveEdges *= 2;
+ if (!edges || maxActiveEdges > default_alloc) {
+ max_edges = maxActiveEdges;
+ int s = qMax(maxActiveEdges + 1, default_alloc + 1);
+ edges = q_check_ptr((Edge **)realloc(edges, s*sizeof(Edge *)));
+ edge_table = q_check_ptr((Edge *)realloc(edge_table, s*sizeof(Edge)));
+ old = q_check_ptr((Edge **)realloc(old, s*sizeof(Edge *)));
+ }
+ size = 0;
+ old_size = 0;
+ first_unused = 0;
+ for (int i = 0; i < maxActiveEdges; ++i)
+ edge_table[i].edge = i+1;
+ edge_table[maxActiveEdges].edge = -1;
+}
+
+void QTessellatorPrivate::Scanline::done()
+{
+ if (max_edges > default_alloc) {
+ free(edges);
+ free(old);
+ free(edge_table);
+ edges = 0;
+ old = 0;
+ edge_table = 0;
+ }
+}
+
+QTessellatorPrivate::Scanline::~Scanline()
+{
+ free(edges);
+ free(old);
+ free(edge_table);
+}
+
+int QTessellatorPrivate::Scanline::findEdgePosition(Q27Dot5 x, Q27Dot5 y) const
+{
+ int min = 0;
+ int max = size - 1;
+ while (min < max) {
+ int pos = min + ((max - min + 1) >> 1);
+ Q27Dot5 ax = edges[pos]->positionAt(y);
+ if (ax > x) {
+ max = pos - 1;
+ } else {
+ min = pos;
+ }
+ }
+ return min;
+}
+
+int QTessellatorPrivate::Scanline::findEdgePosition(const Edge &e) const
+{
+// qDebug() << ">> findEdgePosition";
+ int min = 0;
+ int max = size;
+ while (min < max) {
+ int pos = min + ((max - min) >> 1);
+// qDebug() << " " << min << max << pos << edges[pos]->isLeftOf(e, e.y0);
+ if (edges[pos]->isLeftOf(e, e.v0->y)) {
+ min = pos + 1;
+ } else {
+ max = pos;
+ }
+ }
+// qDebug() << "<< findEdgePosition got" << min;
+ return min;
+}
+
+int QTessellatorPrivate::Scanline::findEdge(int edge) const
+{
+ for (int i = 0; i < size; ++i) {
+ int item_edge = edges[i]->edge;
+ if (item_edge == edge)
+ return i;
+ }
+ //Q_ASSERT(false);
+ return -1;
+}
+
+void QTessellatorPrivate::Scanline::clearMarks()
+{
+ for (int i = 0; i < size; ++i) {
+ edges[i]->mark = false;
+ edges[i]->intersect_left = false;
+ edges[i]->intersect_right = false;
+ }
+}
+
+void QTessellatorPrivate::Scanline::prepareLine()
+{
+ Edge **end = edges + size;
+ Edge **e = edges;
+ Edge **o = old;
+ while (e < end) {
+ *o = *e;
+ ++o;
+ ++e;
+ }
+ old_size = size;
+}
+
+void QTessellatorPrivate::Scanline::lineDone()
+{
+ Edge **end = old + old_size;
+ Edge **e = old;
+ while (e < end) {
+ if ((*e)->free) {
+ (*e)->edge = first_unused;
+ first_unused = (*e - edge_table);
+ }
+ ++e;
+ }
+}
+
+void QTessellatorPrivate::Scanline::insert(int pos, const Edge &e)
+{
+ Edge *edge = edge_table + first_unused;
+ first_unused = edge->edge;
+ Q_ASSERT(first_unused != -1);
+ *edge = e;
+ memmove(edges + pos + 1, edges + pos, (size - pos)*sizeof(Edge *));
+ edges[pos] = edge;
+ ++size;
+}
+
+void QTessellatorPrivate::Scanline::removeAt(int pos)
+{
+ Edge *e = edges[pos];
+ e->free = true;
+ --size;
+ memmove(edges + pos, edges + pos + 1, (size - pos)*sizeof(Edge *));
+}
+
+void QTessellatorPrivate::Scanline::markEdges(int pos1, int pos2)
+{
+ if (pos2 < pos1)
+ return;
+
+ for (int i = pos1; i <= pos2; ++i)
+ edges[i]->mark = true;
+}
+
+
+QTessellatorPrivate::Vertices::Vertices()
+{
+ storage = 0;
+ sorted = 0;
+ allocated = 0;
+ nPoints = 0;
+}
+
+QTessellatorPrivate::Vertices::~Vertices()
+{
+ if (storage) {
+ free(storage);
+ free(sorted);
+ }
+}
+
+void QTessellatorPrivate::Vertices::init(int maxVertices)
+{
+ if (!storage || maxVertices > allocated) {
+ int size = qMax((int)default_alloc, maxVertices);
+ storage = q_check_ptr((Vertex *)realloc(storage, size*sizeof(Vertex)));
+ sorted = q_check_ptr((Vertex **)realloc(sorted, size*sizeof(Vertex *)));
+ allocated = maxVertices;
+ }
+}
+
+void QTessellatorPrivate::Vertices::done()
+{
+ if (allocated > default_alloc) {
+ free(storage);
+ free(sorted);
+ storage = 0;
+ sorted = 0;
+ allocated = 0;
+ }
+}
+
+
+
+static inline void fillTrapezoid(Q27Dot5 y1, Q27Dot5 y2, int left, int right,
+ const QTessellatorPrivate::Vertices &vertices,
+ QTessellator::Trapezoid *trap)
+{
+ trap->top = y1;
+ trap->bottom = y2;
+ const QTessellatorPrivate::Vertex *v = vertices[left];
+ trap->topLeft = v;
+ trap->bottomLeft = vertices.next(v);
+ if (trap->topLeft->y > trap->bottomLeft->y)
+ qSwap(trap->topLeft,trap->bottomLeft);
+ v = vertices[right];
+ trap->topRight = v;
+ trap->bottomRight = vertices.next(v);
+ if (trap->topRight->y > trap->bottomRight->y)
+ qSwap(trap->topRight, trap->bottomRight);
+}
+
+QRectF QTessellatorPrivate::collectAndSortVertices(const QPointF *points, int *maxActiveEdges)
+{
+ *maxActiveEdges = 0;
+ Vertex *v = vertices.storage;
+ Vertex **vv = vertices.sorted;
+
+ qreal xmin(points[0].x());
+ qreal xmax(points[0].x());
+ qreal ymin(points[0].y());
+ qreal ymax(points[0].y());
+
+ // collect vertex data
+ Q27Dot5 y_prev = FloatToQ27Dot5(points[vertices.nPoints-1].y());
+ Q27Dot5 x_next = FloatToQ27Dot5(points[0].x());
+ Q27Dot5 y_next = FloatToQ27Dot5(points[0].y());
+ int j = 0;
+ int i = 0;
+ while (i < vertices.nPoints) {
+ Q27Dot5 y_curr = y_next;
+
+ *vv = v;
+
+ v->x = x_next;
+ v->y = y_next;
+ v->flags = 0;
+
+ next_point:
+
+ xmin = qMin(xmin, points[i+1].x());
+ xmax = qMax(xmax, points[i+1].x());
+ ymin = qMin(ymin, points[i+1].y());
+ ymax = qMax(ymax, points[i+1].y());
+
+ y_next = FloatToQ27Dot5(points[i+1].y());
+ x_next = FloatToQ27Dot5(points[i+1].x());
+
+ // skip vertices on top of each other
+ if (v->x == x_next && v->y == y_next) {
+ ++i;
+ if (i < vertices.nPoints)
+ goto next_point;
+ Vertex *v0 = vertices.storage;
+ v0->flags &= ~(LineBeforeStarts|LineBeforeEnds|LineBeforeHorizontal);
+ if (y_prev < y_curr)
+ v0->flags |= LineBeforeEnds;
+ else if (y_prev > y_curr)
+ v0->flags |= LineBeforeStarts;
+ else
+ v0->flags |= LineBeforeHorizontal;
+ if ((v0->flags & (LineBeforeStarts|LineAfterStarts))
+ && !(v0->flags & (LineAfterEnds|LineBeforeEnds)))
+ *maxActiveEdges += 2;
+ break;
+ }
+
+ if (y_prev < y_curr)
+ v->flags |= LineBeforeEnds;
+ else if (y_prev > y_curr)
+ v->flags |= LineBeforeStarts;
+ else
+ v->flags |= LineBeforeHorizontal;
+
+
+ if (y_curr < y_next)
+ v->flags |= LineAfterStarts;
+ else if (y_curr > y_next)
+ v->flags |= LineAfterEnds;
+ else
+ v->flags |= LineAfterHorizontal;
+ // ### could probably get better limit by looping over sorted list and counting down on ending edges
+ if ((v->flags & (LineBeforeStarts|LineAfterStarts))
+ && !(v->flags & (LineAfterEnds|LineBeforeEnds)))
+ *maxActiveEdges += 2;
+ y_prev = y_curr;
+ ++v;
+ ++vv;
+ ++j;
+ ++i;
+ }
+ vertices.nPoints = j;
+
+ QDEBUG() << "maxActiveEdges=" << *maxActiveEdges;
+ vv = vertices.sorted;
+ qSort(vv, vv + vertices.nPoints, compareVertex);
+
+ return QRectF(xmin, ymin, xmax-xmin, ymax-ymin);
+}
+
+struct QCoincidingEdge {
+ QTessellatorPrivate::Vertex *start;
+ QTessellatorPrivate::Vertex *end;
+ bool used;
+ bool before;
+
+ inline bool operator<(const QCoincidingEdge &e2) const
+ {
+ return end->y == e2.end->y ? end->x < e2.end->x : end->y < e2.end->y;
+ }
+};
+
+static void cancelEdges(QCoincidingEdge &e1, QCoincidingEdge &e2)
+{
+ if (e1.before) {
+ e1.start->flags &= ~(LineBeforeStarts|LineBeforeHorizontal);
+ e1.end->flags &= ~(LineAfterEnds|LineAfterHorizontal);
+ } else {
+ e1.start->flags &= ~(LineAfterStarts|LineAfterHorizontal);
+ e1.end->flags &= ~(LineBeforeEnds|LineBeforeHorizontal);
+ }
+ if (e2.before) {
+ e2.start->flags &= ~(LineBeforeStarts|LineBeforeHorizontal);
+ e2.end->flags &= ~(LineAfterEnds|LineAfterHorizontal);
+ } else {
+ e2.start->flags &= ~(LineAfterStarts|LineAfterHorizontal);
+ e2.end->flags &= ~(LineBeforeEnds|LineBeforeHorizontal);
+ }
+ e1.used = e2.used = true;
+}
+
+void QTessellatorPrivate::cancelCoincidingEdges()
+{
+ Vertex **vv = vertices.sorted;
+
+ QCoincidingEdge *tl = 0;
+ int tlSize = 0;
+
+ for (int i = 0; i < vertices.nPoints - 1; ++i) {
+ Vertex *v = vv[i];
+ int testListSize = 0;
+ while (i < vertices.nPoints - 1) {
+ Vertex *n = vv[i];
+ if (v->x != n->x || v->y != n->y)
+ break;
+
+ if (testListSize > tlSize - 2) {
+ tlSize = qMax(tlSize*2, 16);
+ tl = q_check_ptr((QCoincidingEdge *)realloc(tl, tlSize*sizeof(QCoincidingEdge)));
+ }
+ if (n->flags & (LineBeforeStarts|LineBeforeHorizontal)) {
+ tl[testListSize].start = n;
+ tl[testListSize].end = vertices.prev(n);
+ tl[testListSize].used = false;
+ tl[testListSize].before = true;
+ ++testListSize;
+ }
+ if (n->flags & (LineAfterStarts|LineAfterHorizontal)) {
+ tl[testListSize].start = n;
+ tl[testListSize].end = vertices.next(n);
+ tl[testListSize].used = false;
+ tl[testListSize].before = false;
+ ++testListSize;
+ }
+ ++i;
+ }
+ if (!testListSize)
+ continue;
+
+ qSort(tl, tl + testListSize);
+
+ for (int j = 0; j < testListSize; ++j) {
+ if (tl[j].used)
+ continue;
+
+ for (int k = j + 1; k < testListSize; ++k) {
+ if (tl[j].end->x != tl[k].end->x
+ || tl[j].end->y != tl[k].end->y
+ || tl[k].used)
+ break;
+
+ if (!winding || tl[j].before != tl[k].before) {
+ cancelEdges(tl[j], tl[k]);
+ break;
+ }
+ ++k;
+ }
+ ++j;
+ }
+ }
+ free(tl);
+}
+
+
+void QTessellatorPrivate::emitEdges(QTessellator *tessellator)
+{
+ //QDEBUG() << "TRAPS:";
+ if (!scanline.old_size)
+ return;
+
+ // emit edges
+ if (winding) {
+ // winding fill rule
+ int w = 0;
+
+ scanline.old[0]->y_left = y;
+
+ for (int i = 0; i < scanline.old_size - 1; ++i) {
+ Edge *left = scanline.old[i];
+ Edge *right = scanline.old[i+1];
+ w += left->winding;
+// qDebug() << "i=" << i << "edge->winding=" << left->winding << "winding=" << winding;
+ if (w == 0) {
+ left->y_right = y;
+ right->y_left = y;
+ } else if (!emit_clever || left->mark || right->mark) {
+ Q27Dot5 top = qMax(left->y_right, right->y_left);
+ if (top != y) {
+ QTessellator::Trapezoid trap;
+ fillTrapezoid(top, y, left->edge, right->edge, vertices, &trap);
+ tessellator->addTrap(trap);
+// QDEBUG() << " top=" << Q27Dot5ToDouble(top) << "left=" << left->edge << "right=" << right->edge;
+ }
+ right->y_left = y;
+ left->y_right = y;
+ }
+ left->mark = false;
+ }
+ if (scanline.old[scanline.old_size - 1]->mark) {
+ scanline.old[scanline.old_size - 1]->y_right = y;
+ scanline.old[scanline.old_size - 1]->mark = false;
+ }
+ } else {
+ // odd-even fill rule
+ for (int i = 0; i < scanline.old_size; i += 2) {
+ Edge *left = scanline.old[i];
+ Edge *right = scanline.old[i+1];
+ if (!emit_clever || left->mark || right->mark) {
+ Q27Dot5 top = qMax(left->y_right, right->y_left);
+ if (top != y) {
+ QTessellator::Trapezoid trap;
+ fillTrapezoid(top, y, left->edge, right->edge, vertices, &trap);
+ tessellator->addTrap(trap);
+ }
+// QDEBUG() << " top=" << Q27Dot5ToDouble(top) << "left=" << left->edge << "right=" << right->edge;
+ left->y_left = y;
+ left->y_right = y;
+ right->y_left = y;
+ right->y_right = y;
+ left->mark = right->mark = false;
+ }
+ }
+ }
+}
+
+
+void QTessellatorPrivate::processIntersections()
+{
+ QDEBUG() << "PROCESS INTERSECTIONS";
+ // process intersections
+ while (!intersections.isEmpty()) {
+ Intersections::iterator it = intersections.begin();
+ if (it.key().y != y)
+ break;
+
+ // swap edges
+ QDEBUG() << " swapping intersecting edges ";
+ int min = scanline.size;
+ int max = 0;
+ Q27Dot5 xmin = INT_MAX;
+ Q27Dot5 xmax = INT_MIN;
+ int num = 0;
+ while (1) {
+ const Intersection &i = it.key();
+ int next = it->next;
+
+ int edgePos = scanline.findEdge(i.edge);
+ if (edgePos >= 0) {
+ ++num;
+ min = qMin(edgePos, min);
+ max = qMax(edgePos, max);
+ Edge *edge = scanline.edges[edgePos];
+ xmin = qMin(xmin, edge->positionAt(y));
+ xmax = qMax(xmax, edge->positionAt(y));
+ }
+ Intersection key;
+ key.y = y;
+ key.edge = next;
+ it = intersections.find(key);
+ intersections.remove(i);
+ if (it == intersections.end())
+ break;
+ }
+ if (num < 2)
+ continue;
+
+ Q_ASSERT(min != max);
+ QDEBUG() << "sorting between" << min << "and" << max << "xpos=" << xmin << xmax;
+ while (min > 0 && scanline.edges[min - 1]->positionAt(y) >= xmin) {
+ QDEBUG() << " adding edge on left";
+ --min;
+ }
+ while (max < scanline.size - 1 && scanline.edges[max + 1]->positionAt(y) <= xmax) {
+ QDEBUG() << " adding edge on right";
+ ++max;
+ }
+
+ qSort(scanline.edges + min, scanline.edges + max + 1, EdgeSorter(y));
+#ifdef DEBUG
+ for (int i = min; i <= max; ++i)
+ QDEBUG() << " " << scanline.edges[i]->edge << "at pos" << i;
+#endif
+ for (int i = min; i <= max; ++i) {
+ Edge *edge = scanline.edges[i];
+ edge->intersect_left = true;
+ edge->intersect_right = true;
+ edge->mark = true;
+ }
+ }
+}
+
+void QTessellatorPrivate::removeEdges()
+{
+ int cv = currentVertex;
+ while (cv < vertices.nPoints) {
+ const Vertex *v = vertices.sorted[cv];
+ if (v->y > y)
+ break;
+ if (v->flags & LineBeforeEnds) {
+ QDEBUG() << " removing edge" << vertices.prevPos(v);
+ int pos = scanline.findEdge(vertices.prevPos(v));
+ if (pos == -1)
+ continue;
+ scanline.edges[pos]->mark = true;
+ if (pos > 0)
+ scanline.edges[pos - 1]->intersect_right = true;
+ if (pos < scanline.size - 1)
+ scanline.edges[pos + 1]->intersect_left = true;
+ scanline.removeAt(pos);
+ }
+ if (v->flags & LineAfterEnds) {
+ QDEBUG() << " removing edge" << vertices.position(v);
+ int pos = scanline.findEdge(vertices.position(v));
+ if (pos == -1)
+ continue;
+ scanline.edges[pos]->mark = true;
+ if (pos > 0)
+ scanline.edges[pos - 1]->intersect_right = true;
+ if (pos < scanline.size - 1)
+ scanline.edges[pos + 1]->intersect_left = true;
+ scanline.removeAt(pos);
+ }
+ ++cv;
+ }
+}
+
+void QTessellatorPrivate::addEdges()
+{
+ while (currentVertex < vertices.nPoints) {
+ const Vertex *v = vertices.sorted[currentVertex];
+ if (v->y > y)
+ break;
+ if (v->flags & LineBeforeStarts) {
+ // add new edge
+ int start = vertices.prevPos(v);
+ Edge e(vertices, start);
+ int pos = scanline.findEdgePosition(e);
+ QDEBUG() << " adding edge" << start << "at position" << pos;
+ scanline.insert(pos, e);
+ if (!mark_clever || !(v->flags & LineAfterEnds)) {
+ if (pos > 0)
+ scanline.edges[pos - 1]->mark = true;
+ if (pos < scanline.size - 1)
+ scanline.edges[pos + 1]->mark = true;
+ }
+ }
+ if (v->flags & LineAfterStarts) {
+ Edge e(vertices, vertices.position(v));
+ int pos = scanline.findEdgePosition(e);
+ QDEBUG() << " adding edge" << vertices.position(v) << "at position" << pos;
+ scanline.insert(pos, e);
+ if (!mark_clever || !(v->flags & LineBeforeEnds)) {
+ if (pos > 0)
+ scanline.edges[pos - 1]->mark = true;
+ if (pos < scanline.size - 1)
+ scanline.edges[pos + 1]->mark = true;
+ }
+ }
+ if (v->flags & LineAfterHorizontal) {
+ int pos1 = scanline.findEdgePosition(v->x, v->y);
+ const Vertex *next = vertices.next(v);
+ Q_ASSERT(v->y == next->y);
+ int pos2 = scanline.findEdgePosition(next->x, next->y);
+ if (pos2 < pos1)
+ qSwap(pos1, pos2);
+ if (pos1 > 0)
+ --pos1;
+ if (pos2 == scanline.size)
+ --pos2;
+ //QDEBUG() << "marking horizontal edge from " << pos1 << "to" << pos2;
+ scanline.markEdges(pos1, pos2);
+ }
+ ++currentVertex;
+ }
+}
+
+#ifdef DEBUG
+static void checkLinkChain(const QTessellatorPrivate::Intersections &intersections,
+ QTessellatorPrivate::Intersection i)
+{
+// qDebug() << " Link chain: ";
+ int end = i.edge;
+ while (1) {
+ QTessellatorPrivate::IntersectionLink l = intersections.value(i);
+// qDebug() << " " << i.edge << "next=" << l.next << "prev=" << l.prev;
+ if (l.next == end)
+ break;
+ Q_ASSERT(l.next != -1);
+ Q_ASSERT(l.prev != -1);
+
+ QTessellatorPrivate::Intersection i2 = i;
+ i2.edge = l.next;
+ QTessellatorPrivate::IntersectionLink l2 = intersections.value(i2);
+
+ Q_ASSERT(l2.next != -1);
+ Q_ASSERT(l2.prev != -1);
+ Q_ASSERT(l.next == i2.edge);
+ Q_ASSERT(l2.prev == i.edge);
+ i = i2;
+ }
+}
+#endif
+
+bool QTessellatorPrivate::edgeInChain(Intersection i, int edge)
+{
+ int end = i.edge;
+ while (1) {
+ if (i.edge == edge)
+ return true;
+ IntersectionLink l = intersections.value(i);
+ if (l.next == end)
+ break;
+ Q_ASSERT(l.next != -1);
+ Q_ASSERT(l.prev != -1);
+
+ Intersection i2 = i;
+ i2.edge = l.next;
+
+#ifndef QT_NO_DEBUG
+ IntersectionLink l2 = intersections.value(i2);
+ Q_ASSERT(l2.next != -1);
+ Q_ASSERT(l2.prev != -1);
+ Q_ASSERT(l.next == i2.edge);
+ Q_ASSERT(l2.prev == i.edge);
+#endif
+ i = i2;
+ }
+ return false;
+}
+
+
+void QTessellatorPrivate::addIntersection(const Edge *e1, const Edge *e2)
+{
+ const IntersectionLink emptyLink = {-1, -1};
+
+ int next = vertices.nextPos(vertices[e1->edge]);
+ if (e2->edge == next)
+ return;
+ int prev = vertices.prevPos(vertices[e1->edge]);
+ if (e2->edge == prev)
+ return;
+
+ Q27Dot5 yi;
+ bool det_positive;
+ bool isect = e1->intersect(*e2, &yi, &det_positive);
+ QDEBUG("checking edges %d and %d", e1->edge, e2->edge);
+ if (!isect) {
+ QDEBUG() << " no intersection";
+ return;
+ }
+
+ // don't emit an intersection if it's at the start of a line segment or above us
+ if (yi <= y) {
+ if (!det_positive)
+ return;
+ QDEBUG() << " ----->>>>>> WRONG ORDER!";
+ yi = y;
+ }
+ QDEBUG() << " between edges " << e1->edge << "and" << e2->edge << "at point ("
+ << Q27Dot5ToDouble(yi) << ')';
+
+ Intersection i1;
+ i1.y = yi;
+ i1.edge = e1->edge;
+ IntersectionLink link1 = intersections.value(i1, emptyLink);
+ Intersection i2;
+ i2.y = yi;
+ i2.edge = e2->edge;
+ IntersectionLink link2 = intersections.value(i2, emptyLink);
+
+ // new pair of edges
+ if (link1.next == -1 && link2.next == -1) {
+ link1.next = link1.prev = i2.edge;
+ link2.next = link2.prev = i1.edge;
+ } else if (link1.next == i2.edge || link1.prev == i2.edge
+ || link2.next == i1.edge || link2.prev == i1.edge) {
+#ifdef DEBUG
+ checkLinkChain(intersections, i1);
+ checkLinkChain(intersections, i2);
+ Q_ASSERT(edgeInChain(i1, i2.edge));
+#endif
+ return;
+ } else if (link1.next == -1 || link2.next == -1) {
+ if (link2.next == -1) {
+ qSwap(i1, i2);
+ qSwap(link1, link2);
+ }
+ Q_ASSERT(link1.next == -1);
+#ifdef DEBUG
+ checkLinkChain(intersections, i2);
+#endif
+ // only i2 in list
+ link1.next = i2.edge;
+ link1.prev = link2.prev;
+ link2.prev = i1.edge;
+ Intersection other;
+ other.y = yi;
+ other.edge = link1.prev;
+ IntersectionLink link = intersections.value(other, emptyLink);
+ Q_ASSERT(link.next == i2.edge);
+ Q_ASSERT(link.prev != -1);
+ link.next = i1.edge;
+ intersections.insert(other, link);
+ } else {
+ bool connected = edgeInChain(i1, i2.edge);
+ if (connected)
+ return;
+#ifdef DEBUG
+ checkLinkChain(intersections, i1);
+ checkLinkChain(intersections, i2);
+#endif
+ // both already in some list. Have to make sure they are connected
+ // this can be done by cutting open the ring(s) after the two eges and
+ // connecting them again
+ Intersection other1;
+ other1.y = yi;
+ other1.edge = link1.next;
+ IntersectionLink linko1 = intersections.value(other1, emptyLink);
+ Intersection other2;
+ other2.y = yi;
+ other2.edge = link2.next;
+ IntersectionLink linko2 = intersections.value(other2, emptyLink);
+
+ linko1.prev = i2.edge;
+ link2.next = other1.edge;
+
+ linko2.prev = i1.edge;
+ link1.next = other2.edge;
+ intersections.insert(other1, linko1);
+ intersections.insert(other2, linko2);
+ }
+ intersections.insert(i1, link1);
+ intersections.insert(i2, link2);
+#ifdef DEBUG
+ checkLinkChain(intersections, i1);
+ checkLinkChain(intersections, i2);
+ Q_ASSERT(edgeInChain(i1, i2.edge));
+#endif
+ return;
+
+}
+
+
+void QTessellatorPrivate::addIntersections()
+{
+ if (scanline.size) {
+ QDEBUG() << "INTERSECTIONS";
+ // check marked edges for intersections
+#ifdef DEBUG
+ for (int i = 0; i < scanline.size; ++i) {
+ Edge *e = scanline.edges[i];
+ QDEBUG() << " " << i << e->edge << "isect=(" << e->intersect_left << e->intersect_right
+ << ')';
+ }
+#endif
+
+ for (int i = 0; i < scanline.size - 1; ++i) {
+ Edge *e1 = scanline.edges[i];
+ Edge *e2 = scanline.edges[i + 1];
+ // check for intersection
+ if (e1->intersect_right || e2->intersect_left)
+ addIntersection(e1, e2);
+ }
+ }
+#if 0
+ if (intersections.constBegin().key().y == y) {
+ QDEBUG() << "----------------> intersection on same line";
+ scanline.clearMarks();
+ scanline.processIntersections(y, &intersections);
+ goto redo;
+ }
+#endif
+}
+
+
+QTessellator::QTessellator()
+{
+ d = new QTessellatorPrivate;
+}
+
+QTessellator::~QTessellator()
+{
+ delete d;
+}
+
+void QTessellator::setWinding(bool w)
+{
+ d->winding = w;
+}
+
+
+QRectF QTessellator::tessellate(const QPointF *points, int nPoints)
+{
+ Q_ASSERT(points[0] == points[nPoints-1]);
+ --nPoints;
+
+#ifdef DEBUG
+ QDEBUG()<< "POINTS:";
+ for (int i = 0; i < nPoints; ++i) {
+ QDEBUG() << points[i];
+ }
+#endif
+
+ // collect edges and calculate bounds
+ d->vertices.nPoints = nPoints;
+ d->vertices.init(nPoints);
+
+ int maxActiveEdges = 0;
+ QRectF br = d->collectAndSortVertices(points, &maxActiveEdges);
+ d->cancelCoincidingEdges();
+
+#ifdef DEBUG
+ QDEBUG() << "nPoints = " << nPoints << "using " << d->vertices.nPoints;
+ QDEBUG()<< "VERTICES:";
+ for (int i = 0; i < d->vertices.nPoints; ++i) {
+ QDEBUG() << " " << i << ": "
+ << "point=" << d->vertices.position(d->vertices.sorted[i])
+ << "flags=" << d->vertices.sorted[i]->flags
+ << "pos=(" << Q27Dot5ToDouble(d->vertices.sorted[i]->x) << '/'
+ << Q27Dot5ToDouble(d->vertices.sorted[i]->y) << ')';
+ }
+#endif
+
+ d->scanline.init(maxActiveEdges);
+ d->y = INT_MIN/256;
+ d->currentVertex = 0;
+
+ while (d->currentVertex < d->vertices.nPoints) {
+ d->scanline.clearMarks();
+
+ d->y = d->vertices.sorted[d->currentVertex]->y;
+ if (!d->intersections.isEmpty())
+ d->y = qMin(d->y, d->intersections.constBegin().key().y);
+
+ QDEBUG()<< "===== SCANLINE: y =" << Q27Dot5ToDouble(d->y) << " =====";
+
+ d->scanline.prepareLine();
+ d->processIntersections();
+ d->removeEdges();
+ d->addEdges();
+ d->addIntersections();
+ d->emitEdges(this);
+ d->scanline.lineDone();
+
+#ifdef DEBUG
+ QDEBUG()<< "===== edges:";
+ for (int i = 0; i < d->scanline.size; ++i) {
+ QDEBUG() << " " << d->scanline.edges[i]->edge
+ << "p0= (" << Q27Dot5ToDouble(d->scanline.edges[i]->v0->x)
+ << '/' << Q27Dot5ToDouble(d->scanline.edges[i]->v0->y)
+ << ") p1= (" << Q27Dot5ToDouble(d->scanline.edges[i]->v1->x)
+ << '/' << Q27Dot5ToDouble(d->scanline.edges[i]->v1->y) << ')'
+ << "x=" << Q27Dot5ToDouble(d->scanline.edges[i]->positionAt(d->y))
+ << "isLeftOfNext="
+ << ((i < d->scanline.size - 1)
+ ? d->scanline.edges[i]->isLeftOf(*d->scanline.edges[i+1], d->y)
+ : true);
+ }
+#endif
+}
+
+ d->scanline.done();
+ d->intersections.clear();
+ return br;
+}
+
+// tessellates the given convex polygon
+void QTessellator::tessellateConvex(const QPointF *points, int nPoints)
+{
+ Q_ASSERT(points[0] == points[nPoints-1]);
+ --nPoints;
+
+ d->vertices.nPoints = nPoints;
+ d->vertices.init(nPoints);
+
+ for (int i = 0; i < nPoints; ++i) {
+ d->vertices[i]->x = FloatToQ27Dot5(points[i].x());
+ d->vertices[i]->y = FloatToQ27Dot5(points[i].y());
+ }
+
+ int left = 0, right = 0;
+
+ int top = 0;
+ for (int i = 1; i < nPoints; ++i) {
+ if (d->vertices[i]->y < d->vertices[top]->y)
+ top = i;
+ }
+
+ left = (top + nPoints - 1) % nPoints;
+ right = (top + 1) % nPoints;
+
+ while (d->vertices[left]->x == d->vertices[top]->x && d->vertices[left]->y == d->vertices[top]->y && left != right)
+ left = (left + nPoints - 1) % nPoints;
+
+ while (d->vertices[right]->x == d->vertices[top]->x && d->vertices[right]->y == d->vertices[top]->y && left != right)
+ right = (right + 1) % nPoints;
+
+ if (left == right)
+ return;
+
+ int dir = 1;
+
+ Vertex dLeft = { d->vertices[top]->x - d->vertices[left]->x,
+ d->vertices[top]->y - d->vertices[left]->y };
+
+ Vertex dRight = { d->vertices[right]->x - d->vertices[top]->x,
+ d->vertices[right]->y - d->vertices[top]->y };
+
+ Q27Dot5 cross = dLeft.x * dRight.y - dLeft.y * dRight.x;
+
+ // flip direction if polygon is clockwise
+ if (cross < 0 || (cross == 0 && dLeft.x > 0)) {
+ qSwap(left, right);
+ dir = -1;
+ }
+
+ Vertex *lastLeft = d->vertices[top];
+ Vertex *lastRight = d->vertices[top];
+
+ QTessellator::Trapezoid trap;
+
+ while (lastLeft->y == d->vertices[left]->y && left != right) {
+ lastLeft = d->vertices[left];
+ left = (left + nPoints - dir) % nPoints;
+ }
+
+ while (lastRight->y == d->vertices[right]->y && left != right) {
+ lastRight = d->vertices[right];
+ right = (right + nPoints + dir) % nPoints;
+ }
+
+ while (true) {
+ trap.top = qMax(lastRight->y, lastLeft->y);
+ trap.bottom = qMin(d->vertices[left]->y, d->vertices[right]->y);
+ trap.topLeft = lastLeft;
+ trap.topRight = lastRight;
+ trap.bottomLeft = d->vertices[left];
+ trap.bottomRight = d->vertices[right];
+
+ if (trap.bottom > trap.top)
+ addTrap(trap);
+
+ if (left == right)
+ break;
+
+ if (d->vertices[right]->y < d->vertices[left]->y) {
+ do {
+ lastRight = d->vertices[right];
+ right = (right + nPoints + dir) % nPoints;
+ }
+ while (lastRight->y == d->vertices[right]->y && left != right);
+ } else {
+ do {
+ lastLeft = d->vertices[left];
+ left = (left + nPoints - dir) % nPoints;
+ }
+ while (lastLeft->y == d->vertices[left]->y && left != right);
+ }
+ }
+}
+
+// tessellates the stroke of the line from a_ to b_ with the given width and a flat cap
+void QTessellator::tessellateRect(const QPointF &a_, const QPointF &b_, qreal width)
+{
+ Vertex a = { FloatToQ27Dot5(a_.x()), FloatToQ27Dot5(a_.y()) };
+ Vertex b = { FloatToQ27Dot5(b_.x()), FloatToQ27Dot5(b_.y()) };
+
+ QPointF pa = a_, pb = b_;
+
+ if (a.y > b.y) {
+ qSwap(a, b);
+ qSwap(pa, pb);
+ }
+
+ Vertex delta = { b.x - a.x, b.y - a.y };
+
+ if (delta.x == 0 && delta.y == 0)
+ return;
+
+ qreal hw = 0.5 * width;
+
+ if (delta.x == 0) {
+ Q27Dot5 halfWidth = FloatToQ27Dot5(hw);
+
+ if (halfWidth == 0)
+ return;
+
+ Vertex topLeft = { a.x - halfWidth, a.y };
+ Vertex topRight = { a.x + halfWidth, a.y };
+ Vertex bottomLeft = { a.x - halfWidth, b.y };
+ Vertex bottomRight = { a.x + halfWidth, b.y };
+
+ QTessellator::Trapezoid trap = { topLeft.y, bottomLeft.y, &topLeft, &bottomLeft, &topRight, &bottomRight };
+ addTrap(trap);
+ } else if (delta.y == 0) {
+ Q27Dot5 halfWidth = FloatToQ27Dot5(hw);
+
+ if (halfWidth == 0)
+ return;
+
+ if (a.x > b.x)
+ qSwap(a.x, b.x);
+
+ Vertex topLeft = { a.x, a.y - halfWidth };
+ Vertex topRight = { b.x, a.y - halfWidth };
+ Vertex bottomLeft = { a.x, a.y + halfWidth };
+ Vertex bottomRight = { b.x, a.y + halfWidth };
+
+ QTessellator::Trapezoid trap = { topLeft.y, bottomLeft.y, &topLeft, &bottomLeft, &topRight, &bottomRight };
+ addTrap(trap);
+ } else {
+ QPointF perp(pb.y() - pa.y(), pa.x() - pb.x());
+ qreal length = qSqrt(perp.x() * perp.x() + perp.y() * perp.y());
+
+ if (qFuzzyIsNull(length))
+ return;
+
+ // need the half of the width
+ perp *= hw / length;
+
+ QPointF pta = pa + perp;
+ QPointF ptb = pa - perp;
+ QPointF ptc = pb - perp;
+ QPointF ptd = pb + perp;
+
+ Vertex ta = { FloatToQ27Dot5(pta.x()), FloatToQ27Dot5(pta.y()) };
+ Vertex tb = { FloatToQ27Dot5(ptb.x()), FloatToQ27Dot5(ptb.y()) };
+ Vertex tc = { FloatToQ27Dot5(ptc.x()), FloatToQ27Dot5(ptc.y()) };
+ Vertex td = { FloatToQ27Dot5(ptd.x()), FloatToQ27Dot5(ptd.y()) };
+
+ if (ta.y < tb.y) {
+ if (tb.y < td.y) {
+ QTessellator::Trapezoid top = { ta.y, tb.y, &ta, &tb, &ta, &td };
+ QTessellator::Trapezoid bottom = { td.y, tc.y, &tb, &tc, &td, &tc };
+ addTrap(top);
+ addTrap(bottom);
+
+ QTessellator::Trapezoid middle = { tb.y, td.y, &tb, &tc, &ta, &td };
+ addTrap(middle);
+ } else {
+ QTessellator::Trapezoid top = { ta.y, td.y, &ta, &tb, &ta, &td };
+ QTessellator::Trapezoid bottom = { tb.y, tc.y, &tb, &tc, &td, &tc };
+ addTrap(top);
+ addTrap(bottom);
+
+ if (tb.y != td.y) {
+ QTessellator::Trapezoid middle = { td.y, tb.y, &ta, &tb, &td, &tc };
+ addTrap(middle);
+ }
+ }
+ } else {
+ if (ta.y < tc.y) {
+ QTessellator::Trapezoid top = { tb.y, ta.y, &tb, &tc, &tb, &ta };
+ QTessellator::Trapezoid bottom = { tc.y, td.y, &tc, &td, &ta, &td };
+ addTrap(top);
+ addTrap(bottom);
+
+ QTessellator::Trapezoid middle = { ta.y, tc.y, &tb, &tc, &ta, &td };
+ addTrap(middle);
+ } else {
+ QTessellator::Trapezoid top = { tb.y, tc.y, &tb, &tc, &tb, &ta };
+ QTessellator::Trapezoid bottom = { ta.y, td.y, &tc, &td, &ta, &td };
+ addTrap(top);
+ addTrap(bottom);
+
+ if (ta.y != tc.y) {
+ QTessellator::Trapezoid middle = { tc.y, ta.y, &tc, &td, &tb, &ta };
+ addTrap(middle);
+ }
+ }
+ }
+ }
+}
+
+QT_END_NAMESPACE