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+/****************************************************************************
+**
+** 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 QtOpenGL 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QTRIANGULATINGSTROKER_P_H
+#define QTRIANGULATINGSTROKER_P_H
+
+#include <private/qdatabuffer_p.h>
+#include <private/qvectorpath_p.h>
+#include <private/qbezier_p.h>
+#include <private/qnumeric_p.h>
+#include <private/qmath_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QTriangulatingStroker
+{
+public:
+ void process(const QVectorPath &path, const QPen &pen);
+
+ inline int vertexCount() const { return m_vertices.size(); }
+ inline const float *vertices() const { return m_vertices.data(); }
+
+ inline void setInvScale(qreal invScale) { m_inv_scale = invScale; }
+
+private:
+ inline void emitLineSegment(float x, float y, float nx, float ny);
+ inline void moveTo(const qreal *pts);
+ inline void lineTo(const qreal *pts);
+ void cubicTo(const qreal *pts);
+ inline void join(const qreal *pts);
+ inline void normalVector(float x1, float y1, float x2, float y2, float *nx, float *ny);
+ inline void endCap(const qreal *pts);
+ inline void arc(float x, float y);
+ void endCapOrJoinClosed(const qreal *start, const qreal *cur, bool implicitClose, bool endsAtStart);
+
+
+ QDataBuffer<float> m_vertices;
+
+ float m_cx, m_cy; // current points
+ float m_nvx, m_nvy; // normal vector...
+ float m_width;
+ qreal m_miter_limit;
+
+ int m_roundness; // Number of line segments in a round join
+ qreal m_sin_theta; // sin(m_roundness / 360);
+ qreal m_cos_theta; // cos(m_roundness / 360);
+ qreal m_inv_scale;
+ float m_curvyness_mul;
+ float m_curvyness_add;
+
+ Qt::PenJoinStyle m_join_style;
+ Qt::PenCapStyle m_cap_style;
+};
+
+class QDashedStrokeProcessor
+{
+public:
+ QDashedStrokeProcessor();
+
+ void process(const QVectorPath &path, const QPen &pen);
+
+ inline void addElement(QPainterPath::ElementType type, qreal x, qreal y) {
+ m_points.add(x);
+ m_points.add(y);
+ m_types.add(type);
+ }
+
+ inline int elementCount() const { return m_types.size(); }
+ inline qreal *points() const { return m_points.data(); }
+ inline QPainterPath::ElementType *elementTypes() const { return m_types.data(); }
+
+ inline void setInvScale(qreal invScale) { m_inv_scale = invScale; }
+
+private:
+ QDataBuffer<qreal> m_points;
+ QDataBuffer<QPainterPath::ElementType> m_types;
+ QDashStroker m_dash_stroker;
+ qreal m_inv_scale;
+};
+
+
+
+
+
+inline void QTriangulatingStroker::normalVector(float x1, float y1, float x2, float y2,
+ float *nx, float *ny)
+{
+ float dx = x2 - x1;
+ float dy = y2 - y1;
+
+ float pw;
+
+ if (dx == 0)
+ pw = m_width / dy;
+ else if (dy == 0)
+ pw = m_width / dx;
+ else
+ pw = m_width / sqrt(dx*dx + dy*dy);
+
+ *nx = -dy * pw;
+ *ny = dx * pw;
+}
+
+
+
+inline void QTriangulatingStroker::emitLineSegment(float x, float y, float vx, float vy)
+{
+ m_vertices.add(x + vx);
+ m_vertices.add(y + vy);
+ m_vertices.add(x - vx);
+ m_vertices.add(y - vy);
+}
+
+
+
+// We draw a full circle for any round join or round cap which is a
+// bit of overkill...
+inline void QTriangulatingStroker::arc(float x, float y)
+{
+ float dx = m_width;
+ float dy = 0;
+ for (int i=0; i<=m_roundness; ++i) {
+ float tmpx = dx * m_cos_theta - dy * m_sin_theta;
+ float tmpy = dx * m_sin_theta + dy * m_cos_theta;
+ dx = tmpx;
+ dy = tmpy;
+ emitLineSegment(x, y, dx, dy);
+ }
+}
+
+
+
+inline void QTriangulatingStroker::endCap(const qreal *pts)
+{
+ switch (m_cap_style) {
+ case Qt::FlatCap:
+ break;
+ case Qt::SquareCap: {
+ float dx = m_cx - *(pts - 2);
+ float dy = m_cy - *(pts - 1);
+
+ float len = m_width / sqrt(dx * dx + dy * dy);
+ dx = dx * len;
+ dy = dy * len;
+
+ emitLineSegment(m_cx + dx, m_cy + dy, m_nvx, m_nvy);
+ break; }
+ case Qt::RoundCap:
+ arc(m_cx, m_cy);
+ break;
+ default: break; // to shut gcc up...
+ }
+
+ int count = m_vertices.size();
+ m_vertices.add(m_vertices.at(count-2));
+ m_vertices.add(m_vertices.at(count-1));
+}
+
+
+void QTriangulatingStroker::moveTo(const qreal *pts)
+{
+ m_cx = pts[0];
+ m_cy = pts[1];
+
+ float x2 = pts[2];
+ float y2 = pts[3];
+ normalVector(m_cx, m_cy, x2, y2, &m_nvx, &m_nvy);
+
+
+ // To acheive jumps we insert zero-area tringles. This is done by
+ // adding two identical points in both the end of previous strip
+ // and beginning of next strip
+ bool invisibleJump = m_vertices.size();
+
+ switch (m_cap_style) {
+ case Qt::FlatCap:
+ if (invisibleJump) {
+ m_vertices.add(m_cx + m_nvx);
+ m_vertices.add(m_cy + m_nvy);
+ }
+ break;
+ case Qt::SquareCap: {
+ float dx = x2 - m_cx;
+ float dy = y2 - m_cy;
+ float len = m_width / sqrt(dx * dx + dy * dy);
+ dx = dx * len;
+ dy = dy * len;
+ float sx = m_cx - dx;
+ float sy = m_cy - dy;
+ if (invisibleJump) {
+ m_vertices.add(sx + m_nvx);
+ m_vertices.add(sy + m_nvy);
+ }
+ emitLineSegment(sx, sy, m_nvx, m_nvy);
+ break; }
+ case Qt::RoundCap:
+ if (invisibleJump) {
+ m_vertices.add(m_cx + m_nvx);
+ m_vertices.add(m_cy + m_nvy);
+ }
+
+ // This emitLineSegment is not needed for the arc, but we need
+ // to start where we put the invisibleJump vertex, otherwise
+ // we'll have visible triangles between subpaths.
+ emitLineSegment(m_cx, m_cy, m_nvx, m_nvy);
+ arc(m_cx, m_cy);
+ break;
+ default: break; // ssssh gcc...
+ }
+ emitLineSegment(m_cx, m_cy, m_nvx, m_nvy);
+}
+
+
+
+void QTriangulatingStroker::lineTo(const qreal *pts)
+{
+ emitLineSegment(pts[0], pts[1], m_nvx, m_nvy);
+ m_cx = pts[0];
+ m_cy = pts[1];
+}
+
+
+
+
+
+void QTriangulatingStroker::join(const qreal *pts)
+{
+ // Creates a join to the next segment (m_cx, m_cy) -> (pts[0], pts[1])
+ normalVector(m_cx, m_cy, pts[0], pts[1], &m_nvx, &m_nvy);
+
+ switch (m_join_style) {
+ case Qt::BevelJoin:
+ break;
+ case Qt::MiterJoin: {
+ int p1 = m_vertices.size() - 6;
+ int p2 = m_vertices.size() - 2;
+ QLineF line(m_vertices.at(p1), m_vertices.at(p1+1),
+ m_vertices.at(p2), m_vertices.at(p2+1));
+ QLineF nextLine(m_cx - m_nvx, m_cy - m_nvy,
+ pts[0] - m_nvx, pts[1] - m_nvy);
+
+ QPointF isect;
+ if (line.intersect(nextLine, &isect) != QLineF::NoIntersection
+ && QLineF(line.p2(), isect).length() <= m_miter_limit) {
+ // The intersection point mirrored over the m_cx, m_cy point
+ m_vertices.add(m_cx - (isect.x() - m_cx));
+ m_vertices.add(m_cy - (isect.y() - m_cy));
+
+ // The intersection point
+ m_vertices.add(isect.x());
+ m_vertices.add(isect.y());
+ }
+ // else
+ // Do a plain bevel join if the miter limit is exceeded or if
+ // the lines are parallel. This is not what the raster
+ // engine's stroker does, but it is both faster and similar to
+ // what some other graphics API's do.
+
+ break; }
+ case Qt::RoundJoin:
+ arc(m_cx, m_cy);
+ break;
+
+ default: break; // gcc warn--
+ }
+
+ emitLineSegment(m_cx, m_cy, m_nvx, m_nvy);
+}
+
+QT_END_NAMESPACE
+
+#endif
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