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Diffstat (limited to 'src/gui/painting/qstroker.cpp')
| -rw-r--r-- | src/gui/painting/qstroker.cpp | 1136 |
1 files changed, 1136 insertions, 0 deletions
diff --git a/src/gui/painting/qstroker.cpp b/src/gui/painting/qstroker.cpp new file mode 100644 index 0000000..b894c62 --- /dev/null +++ b/src/gui/painting/qstroker.cpp @@ -0,0 +1,1136 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (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 either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** 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 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "private/qstroker_p.h" +#include "private/qbezier_p.h" +#include "private/qmath_p.h" +#include "qline.h" +#include "qtransform.h" +#include <qmath.h> + +QT_BEGIN_NAMESPACE + +// #define QPP_STROKE_DEBUG + +class QSubpathForwardIterator +{ +public: + QSubpathForwardIterator(const QDataBuffer<QStrokerOps::Element> *path) + : m_path(path), m_pos(0) { } + inline int position() const { return m_pos; } + inline bool hasNext() const { return m_pos < m_path->size(); } + inline QStrokerOps::Element next() { Q_ASSERT(hasNext()); return m_path->at(m_pos++); } + +private: + const QDataBuffer<QStrokerOps::Element> *m_path; + int m_pos; +}; + +class QSubpathBackwardIterator +{ +public: + QSubpathBackwardIterator(const QDataBuffer<QStrokerOps::Element> *path) + : m_path(path), m_pos(path->size() - 1) { } + + inline int position() const { return m_pos; } + + inline bool hasNext() const { return m_pos >= 0; } + + inline QStrokerOps::Element next() + { + Q_ASSERT(hasNext()); + + QStrokerOps::Element ce = m_path->at(m_pos); // current element + + if (m_pos == m_path->size() - 1) { + --m_pos; + ce.type = QPainterPath::MoveToElement; + return ce; + } + + const QStrokerOps::Element &pe = m_path->at(m_pos + 1); // previous element + + switch (pe.type) { + case QPainterPath::LineToElement: + ce.type = QPainterPath::LineToElement; + break; + case QPainterPath::CurveToDataElement: + // First control point? + if (ce.type == QPainterPath::CurveToElement) { + ce.type = QPainterPath::CurveToDataElement; + } else { // Second control point then + ce.type = QPainterPath::CurveToElement; + } + break; + case QPainterPath::CurveToElement: + ce.type = QPainterPath::CurveToDataElement; + break; + default: + qWarning("QSubpathReverseIterator::next: Case %d unhandled", ce.type); + break; + } + --m_pos; + + return ce; + } + +private: + const QDataBuffer<QStrokerOps::Element> *m_path; + int m_pos; +}; + +class QSubpathFlatIterator +{ +public: + QSubpathFlatIterator(const QDataBuffer<QStrokerOps::Element> *path) + : m_path(path), m_pos(0), m_curve_index(-1) { } + + inline bool hasNext() const { return m_curve_index >= 0 || m_pos < m_path->size(); } + + QStrokerOps::Element next() + { + Q_ASSERT(hasNext()); + + if (m_curve_index >= 0) { + QStrokerOps::Element e = { QPainterPath::LineToElement, + qt_real_to_fixed(m_curve.at(m_curve_index).x()), + qt_real_to_fixed(m_curve.at(m_curve_index).y()) + }; + ++m_curve_index; + if (m_curve_index >= m_curve.size()) + m_curve_index = -1; + return e; + } + + QStrokerOps::Element e = m_path->at(m_pos); + if (e.isCurveTo()) { + Q_ASSERT(m_pos > 0); + Q_ASSERT(m_pos < m_path->size()); + + m_curve = QBezier::fromPoints(QPointF(qt_fixed_to_real(m_path->at(m_pos-1).x), + qt_fixed_to_real(m_path->at(m_pos-1).y)), + QPointF(qt_fixed_to_real(e.x), + qt_fixed_to_real(e.y)), + QPointF(qt_fixed_to_real(m_path->at(m_pos+1).x), + qt_fixed_to_real(m_path->at(m_pos+1).y)), + QPointF(qt_fixed_to_real(m_path->at(m_pos+2).x), + qt_fixed_to_real(m_path->at(m_pos+2).y))).toPolygon(); + m_curve_index = 1; + e.type = QPainterPath::LineToElement; + e.x = m_curve.at(0).x(); + e.y = m_curve.at(0).y(); + m_pos += 2; + } + Q_ASSERT(e.isLineTo() || e.isMoveTo()); + ++m_pos; + return e; + } + +private: + const QDataBuffer<QStrokerOps::Element> *m_path; + int m_pos; + QPolygonF m_curve; + int m_curve_index; +}; + +template <class Iterator> bool qt_stroke_side(Iterator *it, QStroker *stroker, + bool capFirst, QLineF *startTangent); + +/******************************************************************************* + * QLineF::angle gives us the smalles angle between two lines. Here we + * want to identify the line's angle direction on the unit circle. + */ +static inline qreal adapted_angle_on_x(const QLineF &line) +{ + qreal angle = line.angle(QLineF(0, 0, 1, 0)); + if (line.dy() > 0) + angle = 360 - angle; + return angle; +} + +QStrokerOps::QStrokerOps() + : m_customData(0), m_moveTo(0), m_lineTo(0), m_cubicTo(0) +{ +} + +QStrokerOps::~QStrokerOps() +{ +} + + +/*! + Prepares the stroker. Call this function once before starting a + stroke by calling moveTo, lineTo or cubicTo. + + The \a customData is passed back through that callback functions + and can be used by the user to for instance maintain state + information. +*/ +void QStrokerOps::begin(void *customData) +{ + m_customData = customData; + m_elements.reset(); +} + + +/*! + Finishes the stroke. Call this function once when an entire + primitive has been stroked. +*/ +void QStrokerOps::end() +{ + if (m_elements.size() > 1) + processCurrentSubpath(); + m_customData = 0; +} + +/*! + Convenience function that decomposes \a path into begin(), + moveTo(), lineTo(), curevTo() and end() calls. + + The \a customData parameter is used in the callback functions + + The \a matrix is used to transform the points before input to the + stroker. + + \sa begin() +*/ +void QStrokerOps::strokePath(const QPainterPath &path, void *customData, const QTransform &matrix) +{ + if (path.isEmpty()) + return; + + begin(customData); + int count = path.elementCount(); + if (matrix.isIdentity()) { + for (int i=0; i<count; ++i) { + const QPainterPath::Element &e = path.elementAt(i); + switch (e.type) { + case QPainterPath::MoveToElement: + moveTo(qt_real_to_fixed(e.x), qt_real_to_fixed(e.y)); + break; + case QPainterPath::LineToElement: + lineTo(qt_real_to_fixed(e.x), qt_real_to_fixed(e.y)); + break; + case QPainterPath::CurveToElement: + { + const QPainterPath::Element &cp2 = path.elementAt(++i); + const QPainterPath::Element &ep = path.elementAt(++i); + cubicTo(qt_real_to_fixed(e.x), qt_real_to_fixed(e.y), + qt_real_to_fixed(cp2.x), qt_real_to_fixed(cp2.y), + qt_real_to_fixed(ep.x), qt_real_to_fixed(ep.y)); + } + break; + default: + break; + } + } + } else { + for (int i=0; i<count; ++i) { + const QPainterPath::Element &e = path.elementAt(i); + QPointF pt = QPointF(e.x, e.y) * matrix; + switch (e.type) { + case QPainterPath::MoveToElement: + moveTo(qt_real_to_fixed(pt.x()), qt_real_to_fixed(pt.y())); + break; + case QPainterPath::LineToElement: + lineTo(qt_real_to_fixed(pt.x()), qt_real_to_fixed(pt.y())); + break; + case QPainterPath::CurveToElement: + { + QPointF cp2 = ((QPointF) path.elementAt(++i)) * matrix; + QPointF ep = ((QPointF) path.elementAt(++i)) * matrix; + cubicTo(qt_real_to_fixed(pt.x()), qt_real_to_fixed(pt.y()), + qt_real_to_fixed(cp2.x()), qt_real_to_fixed(cp2.y()), + qt_real_to_fixed(ep.x()), qt_real_to_fixed(ep.y())); + } + break; + default: + break; + } + } + } + end(); +} + +/*! + Convenience function for stroking a polygon of the \a pointCount + first points in \a points. If \a implicit_close is set to true a + line is implictly drawn between the first and last point in the + polygon. Typically true for polygons and false for polylines. + + The \a matrix is used to transform the points before they enter the + stroker. + + \sa begin() +*/ + +void QStrokerOps::strokePolygon(const QPointF *points, int pointCount, bool implicit_close, + void *data, const QTransform &matrix) +{ + if (!pointCount) + return; + begin(data); + if (matrix.isIdentity()) { + moveTo(qt_real_to_fixed(points[0].x()), qt_real_to_fixed(points[0].y())); + for (int i=1; i<pointCount; ++i) + lineTo(qt_real_to_fixed(points[i].x()), + qt_real_to_fixed(points[i].y())); + if (implicit_close) + lineTo(qt_real_to_fixed(points[0].x()), qt_real_to_fixed(points[0].y())); + } else { + QPointF start = points[0] * matrix; + moveTo(qt_real_to_fixed(start.x()), qt_real_to_fixed(start.y())); + for (int i=1; i<pointCount; ++i) { + QPointF pt = points[i] * matrix; + lineTo(qt_real_to_fixed(pt.x()), qt_real_to_fixed(pt.y())); + } + if (implicit_close) + lineTo(qt_real_to_fixed(start.x()), qt_real_to_fixed(start.y())); + } + end(); +} + +/*! + Convenience function for stroking an ellipse with bounding rect \a + rect. The \a matrix is used to transform the coordinates before + they enter the stroker. +*/ +void QStrokerOps::strokeEllipse(const QRectF &rect, void *data, const QTransform &matrix) +{ + int count = 0; + QPointF pts[12]; + QPointF start = qt_curves_for_arc(rect, 0, -360, pts, &count); + Q_ASSERT(count == 12); // a perfect circle.. + + if (!matrix.isIdentity()) { + start = start * matrix; + for (int i=0; i<12; ++i) { + pts[i] = pts[i] * matrix; + } + } + + begin(data); + moveTo(qt_real_to_fixed(start.x()), qt_real_to_fixed(start.y())); + for (int i=0; i<12; i+=3) { + cubicTo(qt_real_to_fixed(pts[i].x()), qt_real_to_fixed(pts[i].y()), + qt_real_to_fixed(pts[i+1].x()), qt_real_to_fixed(pts[i+1].y()), + qt_real_to_fixed(pts[i+2].x()), qt_real_to_fixed(pts[i+2].y())); + } + end(); +} + + +QStroker::QStroker() + : m_capStyle(SquareJoin), m_joinStyle(FlatJoin), + m_back1X(0), m_back1Y(0), + m_back2X(0), m_back2Y(0) +{ + m_strokeWidth = qt_real_to_fixed(1); + m_miterLimit = qt_real_to_fixed(2); + m_curveThreshold = qt_real_to_fixed(0.25); +} + +QStroker::~QStroker() +{ + +} + +Qt::PenCapStyle QStroker::capForJoinMode(LineJoinMode mode) +{ + if (mode == FlatJoin) return Qt::FlatCap; + else if (mode == SquareJoin) return Qt::SquareCap; + else return Qt::RoundCap; +} + +QStroker::LineJoinMode QStroker::joinModeForCap(Qt::PenCapStyle style) +{ + if (style == Qt::FlatCap) return FlatJoin; + else if (style == Qt::SquareCap) return SquareJoin; + else return RoundCap; +} + +Qt::PenJoinStyle QStroker::joinForJoinMode(LineJoinMode mode) +{ + if (mode == FlatJoin) return Qt::BevelJoin; + else if (mode == MiterJoin) return Qt::MiterJoin; + else if (mode == SvgMiterJoin) return Qt::SvgMiterJoin; + else return Qt::RoundJoin; +} + +QStroker::LineJoinMode QStroker::joinModeForJoin(Qt::PenJoinStyle joinStyle) +{ + if (joinStyle == Qt::BevelJoin) return FlatJoin; + else if (joinStyle == Qt::MiterJoin) return MiterJoin; + else if (joinStyle == Qt::SvgMiterJoin) return SvgMiterJoin; + else return RoundJoin; +} + + +/*! + This function is called to stroke the currently built up + subpath. The subpath is cleared when the function completes. +*/ +void QStroker::processCurrentSubpath() +{ + Q_ASSERT(!m_elements.isEmpty()); + Q_ASSERT(m_elements.first().type == QPainterPath::MoveToElement); + Q_ASSERT(m_elements.size() > 1); + + QSubpathForwardIterator fwit(&m_elements); + QSubpathBackwardIterator bwit(&m_elements); + + QLineF fwStartTangent, bwStartTangent; + + bool fwclosed = qt_stroke_side(&fwit, this, false, &fwStartTangent); + bool bwclosed = qt_stroke_side(&bwit, this, !fwclosed, &bwStartTangent); + + if (!bwclosed) + joinPoints(m_elements.at(0).x, m_elements.at(0).y, fwStartTangent, m_capStyle); +} + + +/*! + \internal +*/ +void QStroker::joinPoints(qfixed focal_x, qfixed focal_y, const QLineF &nextLine, LineJoinMode join) +{ +#ifdef QPP_STROKE_DEBUG + printf(" -----> joinPoints: around=(%.0f, %.0f), next_p1=(%.0f, %.f) next_p2=(%.0f, %.f)\n", + qt_fixed_to_real(focal_x), + qt_fixed_to_real(focal_y), + nextLine.x1(), nextLine.y1(), nextLine.x2(), nextLine.y2()); +#endif + // points connected already, don't join + +#if !defined (QFIXED_26_6) && !defined (Q_FIXED_32_32) + if (qFuzzyCompare(m_back1X, nextLine.x1()) && qFuzzyCompare(m_back1Y, nextLine.y1())) + return; +#else + if (m_back1X == qt_real_to_fixed(nextLine.x1()) + && m_back1Y == qt_real_to_fixed(nextLine.y1())) { + return; + } +#endif + + if (join == FlatJoin) { + emitLineTo(qt_real_to_fixed(nextLine.x1()), + qt_real_to_fixed(nextLine.y1())); + + } else { + QLineF prevLine(qt_fixed_to_real(m_back2X), qt_fixed_to_real(m_back2Y), + qt_fixed_to_real(m_back1X), qt_fixed_to_real(m_back1Y)); + + QPointF isect; + QLineF::IntersectType type = prevLine.intersect(nextLine, &isect); + + if (join == MiterJoin) { + qreal appliedMiterLimit = qt_fixed_to_real(m_strokeWidth * m_miterLimit); + + // If we are on the inside, do the short cut... + QLineF shortCut(prevLine.p2(), nextLine.p1()); + qreal angle = shortCut.angleTo(prevLine); + + if (type == QLineF::BoundedIntersection || (angle > 90 && !qFuzzyCompare(angle, (qreal)90))) { + emitLineTo(qt_real_to_fixed(nextLine.x1()), qt_real_to_fixed(nextLine.y1())); + return; + } + QLineF miterLine(QPointF(qt_fixed_to_real(m_back1X), + qt_fixed_to_real(m_back1Y)), isect); + if (type == QLineF::NoIntersection || miterLine.length() > appliedMiterLimit) { + QLineF l1(prevLine); + l1.setLength(appliedMiterLimit); + l1.translate(prevLine.dx(), prevLine.dy()); + + QLineF l2(nextLine); + l2.setLength(appliedMiterLimit); + l2.translate(-l2.dx(), -l2.dy()); + + emitLineTo(qt_real_to_fixed(l1.x2()), qt_real_to_fixed(l1.y2())); + emitLineTo(qt_real_to_fixed(l2.x1()), qt_real_to_fixed(l2.y1())); + emitLineTo(qt_real_to_fixed(nextLine.x1()), qt_real_to_fixed(nextLine.y1())); + } else { + emitLineTo(qt_real_to_fixed(isect.x()), qt_real_to_fixed(isect.y())); + emitLineTo(qt_real_to_fixed(nextLine.x1()), qt_real_to_fixed(nextLine.y1())); + } + + } else if (join == SquareJoin) { + qfixed offset = m_strokeWidth / 2; + + QLineF l1(prevLine); + l1.translate(l1.dx(), l1.dy()); + l1.setLength(qt_fixed_to_real(offset)); + QLineF l2(nextLine.p2(), nextLine.p1()); + l2.translate(l2.dx(), l2.dy()); + l2.setLength(qt_fixed_to_real(offset)); + emitLineTo(qt_real_to_fixed(l1.x2()), qt_real_to_fixed(l1.y2())); + emitLineTo(qt_real_to_fixed(l2.x2()), qt_real_to_fixed(l2.y2())); + emitLineTo(qt_real_to_fixed(l2.x1()), qt_real_to_fixed(l2.y1())); + + } else if (join == RoundJoin) { + qfixed offset = m_strokeWidth / 2; + + QLineF shortCut(prevLine.p2(), nextLine.p1()); + qreal angle = prevLine.angle(shortCut); + if (type == QLineF::BoundedIntersection || (angle > 90 && !qFuzzyCompare(angle, (qreal)90))) { + emitLineTo(qt_real_to_fixed(nextLine.x1()), qt_real_to_fixed(nextLine.y1())); + return; + } + qreal l1_on_x = adapted_angle_on_x(prevLine); + qreal l2_on_x = adapted_angle_on_x(nextLine); + + qreal sweepLength = qAbs(l2_on_x - l1_on_x); + + int point_count; + QPointF curves[15]; + + QPointF curve_start = + qt_curves_for_arc(QRectF(qt_fixed_to_real(focal_x - offset), + qt_fixed_to_real(focal_y - offset), + qt_fixed_to_real(offset * 2), + qt_fixed_to_real(offset * 2)), + l1_on_x + 90, -sweepLength, + curves, &point_count); + +// // line to the beginning of the arc segment, (should not be needed). +// emitLineTo(qt_real_to_fixed(curve_start.x()), qt_real_to_fixed(curve_start.y())); + + for (int i=0; i<point_count; i+=3) { + emitCubicTo(qt_real_to_fixed(curves[i].x()), + qt_real_to_fixed(curves[i].y()), + qt_real_to_fixed(curves[i+1].x()), + qt_real_to_fixed(curves[i+1].y()), + qt_real_to_fixed(curves[i+2].x()), + qt_real_to_fixed(curves[i+2].y())); + } + + // line to the end of the arc segment, (should also not be needed). + emitLineTo(qt_real_to_fixed(nextLine.x1()), qt_real_to_fixed(nextLine.y1())); + + // Same as round join except we know its 180 degrees. Can also optimize this + // later based on the addEllipse logic + } else if (join == RoundCap) { + qfixed offset = m_strokeWidth / 2; + + // first control line + QLineF l1 = prevLine; + l1.translate(l1.dx(), l1.dy()); + l1.setLength(QT_PATH_KAPPA * offset); + + // second control line, find through normal between prevLine and focal. + QLineF l2(qt_fixed_to_real(focal_x), qt_fixed_to_real(focal_y), + prevLine.x2(), prevLine.y2()); + l2.translate(-l2.dy(), l2.dx()); + l2.setLength(QT_PATH_KAPPA * offset); + + emitCubicTo(qt_real_to_fixed(l1.x2()), + qt_real_to_fixed(l1.y2()), + qt_real_to_fixed(l2.x2()), + qt_real_to_fixed(l2.y2()), + qt_real_to_fixed(l2.x1()), + qt_real_to_fixed(l2.y1())); + + // move so that it matches + l2 = QLineF(l2.x1(), l2.y1(), l2.x1()-l2.dx(), l2.y1()-l2.dy()); + + // last line is parallel to l1 so just shift it down. + l1.translate(nextLine.x1() - l1.x1(), nextLine.y1() - l1.y1()); + + emitCubicTo(qt_real_to_fixed(l2.x2()), + qt_real_to_fixed(l2.y2()), + qt_real_to_fixed(l1.x2()), + qt_real_to_fixed(l1.y2()), + qt_real_to_fixed(l1.x1()), + qt_real_to_fixed(l1.y1())); + } else if (join == SvgMiterJoin) { + QLineF miterLine(QPointF(qt_fixed_to_real(focal_x), + qt_fixed_to_real(focal_y)), isect); + if (miterLine.length() > qt_fixed_to_real(m_strokeWidth * m_miterLimit) / 2) { + emitLineTo(qt_real_to_fixed(nextLine.x1()), + qt_real_to_fixed(nextLine.y1())); + } else { + emitLineTo(qt_real_to_fixed(isect.x()), qt_real_to_fixed(isect.y())); + emitLineTo(qt_real_to_fixed(nextLine.x1()), qt_real_to_fixed(nextLine.y1())); + } + } else { + Q_ASSERT(!"QStroker::joinPoints(), bad join style..."); + } + } +} + + +/* + Strokes a subpath side using the \a it as source. Results are put into + \a stroke. The function returns true if the subpath side was closed. + If \a capFirst is true, we will use capPoints instead of joinPoints to + connect the first segment, other segments will be joined using joinPoints. + This is to put capping in order... +*/ +template <class Iterator> bool qt_stroke_side(Iterator *it, + QStroker *stroker, + bool capFirst, + QLineF *startTangent) +{ + // Used in CurveToElement section below. + const int MAX_OFFSET = 16; + QBezier offsetCurves[MAX_OFFSET]; + + Q_ASSERT(it->hasNext()); // The initaial move to + QStrokerOps::Element first_element = it->next(); + Q_ASSERT(first_element.isMoveTo()); + + qfixed2d start = first_element; + +#ifdef QPP_STROKE_DEBUG + qDebug(" -> (side) [%.2f, %.2f], startPos=%d", + qt_fixed_to_real(start.x), + qt_fixed_to_real(start.y)); +#endif + + qfixed2d prev = start; + + bool first = true; + + qfixed offset = stroker->strokeWidth() / 2; + + while (it->hasNext()) { + QStrokerOps::Element e = it->next(); + + // LineToElement + if (e.isLineTo()) { +#ifdef QPP_STROKE_DEBUG + qDebug("\n ---> (side) lineto [%.2f, %.2f]", e.x, e.y); +#endif + QLineF line(qt_fixed_to_real(prev.x), qt_fixed_to_real(prev.y), + qt_fixed_to_real(e.x), qt_fixed_to_real(e.y)); + QLineF normal = line.normalVector(); + normal.setLength(offset); + line.translate(normal.dx(), normal.dy()); + + // If we are starting a new subpath, move to correct starting point. + if (first) { + if (capFirst) + stroker->joinPoints(prev.x, prev.y, line, stroker->capStyleMode()); + else + stroker->emitMoveTo(qt_real_to_fixed(line.x1()), qt_real_to_fixed(line.y1())); + *startTangent = line; + first = false; + } else { + stroker->joinPoints(prev.x, prev.y, line, stroker->joinStyleMode()); + } + + // Add the stroke for this line. + stroker->emitLineTo(qt_real_to_fixed(line.x2()), + qt_real_to_fixed(line.y2())); + prev = e; + + // CurveToElement + } else if (e.isCurveTo()) { + QStrokerOps::Element cp2 = it->next(); // control point 2 + QStrokerOps::Element ep = it->next(); // end point + +#ifdef QPP_STROKE_DEBUG + qDebug("\n ---> (side) cubicTo [%.2f, %.2f]", + qt_fixed_to_real(ep.x), + qt_fixed_to_real(ep.y)); +#endif + + QBezier bezier = + QBezier::fromPoints(QPointF(qt_fixed_to_real(prev.x), qt_fixed_to_real(prev.y)), + QPointF(qt_fixed_to_real(e.x), qt_fixed_to_real(e.y)), + QPointF(qt_fixed_to_real(cp2.x), qt_fixed_to_real(cp2.y)), + QPointF(qt_fixed_to_real(ep.x), qt_fixed_to_real(ep.y))); + + int count = bezier.shifted(offsetCurves, + MAX_OFFSET, + offset, + stroker->curveThreshold()); + + if (count) { + // If we are starting a new subpath, move to correct starting point + QLineF tangent = bezier.startTangent(); + tangent.translate(offsetCurves[0].pt1() - bezier.pt1()); + if (first) { + QPointF pt = offsetCurves[0].pt1(); + if (capFirst) { + stroker->joinPoints(prev.x, prev.y, + tangent, + stroker->capStyleMode()); + } else { + stroker->emitMoveTo(qt_real_to_fixed(pt.x()), + qt_real_to_fixed(pt.y())); + } + *startTangent = tangent; + first = false; + } else { + stroker->joinPoints(prev.x, prev.y, + tangent, + stroker->joinStyleMode()); + } + + // Add these beziers + for (int i=0; i<count; ++i) { + QPointF cp1 = offsetCurves[i].pt2(); + QPointF cp2 = offsetCurves[i].pt3(); + QPointF ep = offsetCurves[i].pt4(); + stroker->emitCubicTo(qt_real_to_fixed(cp1.x()), qt_real_to_fixed(cp1.y()), + qt_real_to_fixed(cp2.x()), qt_real_to_fixed(cp2.y()), + qt_real_to_fixed(ep.x()), qt_real_to_fixed(ep.y())); + } + } + + prev = ep; + } + } + + if (start == prev) { + // closed subpath, join first and last point +#ifdef QPP_STROKE_DEBUG + qDebug("\n ---> (side) closed subpath"); +#endif + stroker->joinPoints(prev.x, prev.y, *startTangent, stroker->joinStyleMode()); + return true; + } else { +#ifdef QPP_STROKE_DEBUG + qDebug("\n ---> (side) open subpath"); +#endif + return false; + } +} + +/*! + \internal + + For a given angle in the range [0 .. 90], finds the corresponding parameter t + of the prototype cubic bezier arc segment + b = fromPoints(QPointF(1, 0), QPointF(1, KAPPA), QPointF(KAPPA, 1), QPointF(0, 1)); + + From the bezier equation: + b.pointAt(t).x() = (1-t)^3 + t*(1-t)^2 + t^2*(1-t)*KAPPA + b.pointAt(t).y() = t*(1-t)^2 * KAPPA + t^2*(1-t) + t^3 + + Third degree coefficients: + b.pointAt(t).x() = at^3 + bt^2 + ct + d + where a = 2-3*KAPPA, b = 3*(KAPPA-1), c = 0, d = 1 + + b.pointAt(t).y() = at^3 + bt^2 + ct + d + where a = 3*KAPPA-2, b = 6*KAPPA+3, c = 3*KAPPA, d = 0 + + Newton's method to find the zero of a function: + given a function f(x) and initial guess x_0 + x_1 = f(x_0) / f'(x_0) + x_2 = f(x_1) / f'(x_1) + etc... +*/ + +qreal qt_t_for_arc_angle(qreal angle) +{ + if (qFuzzyCompare(angle + 1, qreal(1))) + return 0; + + if (qFuzzyCompare(angle, qreal(90))) + return 1; + + qreal radians = Q_PI * angle / 180; + qreal cosAngle = qCos(radians); + qreal sinAngle = qSin(radians); + + // initial guess + qreal tc = angle / 90; + // do some iterations of newton's method to approximate cosAngle + // finds the zero of the function b.pointAt(tc).x() - cosAngle + tc -= ((((2-3*QT_PATH_KAPPA) * tc + 3*(QT_PATH_KAPPA-1)) * tc) * tc + 1 - cosAngle) // value + / (((6-9*QT_PATH_KAPPA) * tc + 6*(QT_PATH_KAPPA-1)) * tc); // derivative + tc -= ((((2-3*QT_PATH_KAPPA) * tc + 3*(QT_PATH_KAPPA-1)) * tc) * tc + 1 - cosAngle) // value + / (((6-9*QT_PATH_KAPPA) * tc + 6*(QT_PATH_KAPPA-1)) * tc); // derivative + + // initial guess + qreal ts = tc; + // do some iterations of newton's method to approximate sinAngle + // finds the zero of the function b.pointAt(tc).y() - sinAngle + ts -= ((((3*QT_PATH_KAPPA-2) * ts - 6*QT_PATH_KAPPA + 3) * ts + 3*QT_PATH_KAPPA) * ts - sinAngle) + / (((9*QT_PATH_KAPPA-6) * ts + 12*QT_PATH_KAPPA - 6) * ts + 3*QT_PATH_KAPPA); + ts -= ((((3*QT_PATH_KAPPA-2) * ts - 6*QT_PATH_KAPPA + 3) * ts + 3*QT_PATH_KAPPA) * ts - sinAngle) + / (((9*QT_PATH_KAPPA-6) * ts + 12*QT_PATH_KAPPA - 6) * ts + 3*QT_PATH_KAPPA); + + // use the average of the t that best approximates cosAngle + // and the t that best approximates sinAngle + qreal t = 0.5 * (tc + ts); + +#if 0 + printf("angle: %f, t: %f\n", angle, t); + qreal a, b, c, d; + bezierCoefficients(t, a, b, c, d); + printf("cosAngle: %.10f, value: %.10f\n", cosAngle, a + b + c * QT_PATH_KAPPA); + printf("sinAngle: %.10f, value: %.10f\n", sinAngle, b * QT_PATH_KAPPA + c + d); +#endif + + return t; +} + +void qt_find_ellipse_coords(const QRectF &r, qreal angle, qreal length, + QPointF* startPoint, QPointF *endPoint); + +/*! + \internal + + Creates a number of curves for a given arc definition. The arc is + defined an arc along the ellipses that fits into \a rect starting + at \a startAngle and an arc length of \a sweepLength. + + The function has three out parameters. The return value is the + starting point of the arc. The \a curves array represents the list + of cubicTo elements up to a maximum of \a point_count. There are of course + 3 points pr curve. +*/ +QPointF qt_curves_for_arc(const QRectF &rect, qreal startAngle, qreal sweepLength, + QPointF *curves, int *point_count) +{ + Q_ASSERT(point_count); + Q_ASSERT(curves); + + *point_count = 0; + if (qt_is_nan(rect.x()) || qt_is_nan(rect.y()) || qt_is_nan(rect.width()) || qt_is_nan(rect.height()) + || qt_is_nan(startAngle) || qt_is_nan(sweepLength)) { + qWarning("QPainterPath::arcTo: Adding arc where a parameter is NaN, results are undefined"); + return QPointF(); + } + + if (rect.isNull()) { + return QPointF(); + } + + qreal x = rect.x(); + qreal y = rect.y(); + + qreal w = rect.width(); + qreal w2 = rect.width() / 2; + qreal w2k = w2 * QT_PATH_KAPPA; + + qreal h = rect.height(); + qreal h2 = rect.height() / 2; + qreal h2k = h2 * QT_PATH_KAPPA; + + QPointF points[16] = + { + // start point + QPointF(x + w, y + h2), + + // 0 -> 270 degrees + QPointF(x + w, y + h2 + h2k), + QPointF(x + w2 + w2k, y + h), + QPointF(x + w2, y + h), + + // 270 -> 180 degrees + QPointF(x + w2 - w2k, y + h), + QPointF(x, y + h2 + h2k), + QPointF(x, y + h2), + + // 180 -> 90 degrees + QPointF(x, y + h2 - h2k), + QPointF(x + w2 - w2k, y), + QPointF(x + w2, y), + + // 90 -> 0 degrees + QPointF(x + w2 + w2k, y), + QPointF(x + w, y + h2 - h2k), + QPointF(x + w, y + h2) + }; + + if (sweepLength > 360) sweepLength = 360; + else if (sweepLength < -360) sweepLength = -360; + + // Special case fast paths + if (startAngle == 0.0) { + if (sweepLength == 360.0) { + for (int i = 11; i >= 0; --i) + curves[(*point_count)++] = points[i]; + return points[12]; + } else if (sweepLength == -360.0) { + for (int i = 1; i <= 12; ++i) + curves[(*point_count)++] = points[i]; + return points[0]; + } + } + + int startSegment = int(floor(startAngle / 90)); + int endSegment = int(floor((startAngle + sweepLength) / 90)); + + qreal startT = (startAngle - startSegment * 90) / 90; + qreal endT = (startAngle + sweepLength - endSegment * 90) / 90; + + int delta = sweepLength > 0 ? 1 : -1; + if (delta < 0) { + startT = 1 - startT; + endT = 1 - endT; + } + + // avoid empty start segment + if (qFuzzyCompare(startT, qreal(1))) { + startT = 0; + startSegment += delta; + } + + // avoid empty end segment + if (qFuzzyCompare(endT + 1, qreal(1))) { + endT = 1; + endSegment -= delta; + } + + startT = qt_t_for_arc_angle(startT * 90); + endT = qt_t_for_arc_angle(endT * 90); + + const bool splitAtStart = !qFuzzyCompare(startT + 1, qreal(1)); + const bool splitAtEnd = !qFuzzyCompare(endT, qreal(1)); + + const int end = endSegment + delta; + + // empty arc? + if (startSegment == end) { + const int quadrant = 3 - ((startSegment % 4) + 4) % 4; + const int j = 3 * quadrant; + return delta > 0 ? points[j + 3] : points[j]; + } + + QPointF startPoint, endPoint; + qt_find_ellipse_coords(rect, startAngle, sweepLength, &startPoint, &endPoint); + + for (int i = startSegment; i != end; i += delta) { + const int quadrant = 3 - ((i % 4) + 4) % 4; + const int j = 3 * quadrant; + + QBezier b; + if (delta > 0) + b = QBezier::fromPoints(points[j + 3], points[j + 2], points[j + 1], points[j]); + else + b = QBezier::fromPoints(points[j], points[j + 1], points[j + 2], points[j + 3]); + + // empty arc? + if (startSegment == endSegment && qFuzzyCompare(startT, endT)) + return startPoint; + + if (i == startSegment) { + if (i == endSegment && splitAtEnd) + b = b.bezierOnInterval(startT, endT); + else if (splitAtStart) + b = b.bezierOnInterval(startT, 1); + } else if (i == endSegment && splitAtEnd) { + b = b.bezierOnInterval(0, endT); + } + + // push control points + curves[(*point_count)++] = b.pt2(); + curves[(*point_count)++] = b.pt3(); + curves[(*point_count)++] = b.pt4(); + } + + Q_ASSERT(*point_count > 0); + curves[*(point_count)-1] = endPoint; + + return startPoint; +} + + +/******************************************************************************* + * QDashStroker members + */ +QDashStroker::QDashStroker(QStroker *stroker) + : m_stroker(stroker), m_dashOffset(0) +{ + +} + +QVector<qfixed> QDashStroker::patternForStyle(Qt::PenStyle style) +{ + const qfixed space = 2; + const qfixed dot = 1; + const qfixed dash = 4; + + QVector<qfixed> pattern; + + switch (style) { + case Qt::DashLine: + pattern << dash << space; + break; + case Qt::DotLine: + pattern << dot << space; + break; + case Qt::DashDotLine: + pattern << dash << space << dot << space; + break; + case Qt::DashDotDotLine: + pattern << dash << space << dot << space << dot << space; + break; + default: + break; + } + + return pattern; +} + + +void QDashStroker::processCurrentSubpath() +{ + int dashCount = qMin(m_dashPattern.size(), 32); + qfixed dashes[32]; + + qreal sumLength = 0; + for (int i=0; i<dashCount; ++i) { + dashes[i] = qMax(m_dashPattern.at(i), qreal(0)) * m_stroker->strokeWidth(); + sumLength += dashes[i]; + } + + if (qFuzzyCompare(sumLength + 1, qreal(1))) + return; + + Q_ASSERT(dashCount > 0); + + dashCount = (dashCount / 2) * 2; // Round down to even number + + int idash = 0; // Index to current dash + qreal pos = 0; // The position on the curve, 0 <= pos <= path.length + qreal elen = 0; // element length + qreal doffset = m_dashOffset * m_stroker->strokeWidth(); + + // make sure doffset is in range [0..sumLength) + doffset -= qFloor(doffset / sumLength) * sumLength; + + while (doffset >= dashes[idash]) { + doffset -= dashes[idash]; + idash = (idash + 1) % dashCount; + } + + qreal estart = 0; // The elements starting position + qreal estop = 0; // The element stop position + + QLineF cline; + + QPainterPath dashPath; + + QSubpathFlatIterator it(&m_elements); + qfixed2d prev = it.next(); + + bool clipping = !m_clip_rect.isEmpty(); + qfixed2d move_to_pos = prev; + qfixed2d line_to_pos; + + // Pad to avoid clipping the borders of thick pens. + qfixed padding = qMax(m_stroker->strokeWidth(), m_stroker->miterLimit()); + qfixed2d clip_tl = { qt_real_to_fixed(m_clip_rect.left()) - padding, + qt_real_to_fixed(m_clip_rect.top()) - padding }; + qfixed2d clip_br = { qt_real_to_fixed(m_clip_rect.right()) + padding , + qt_real_to_fixed(m_clip_rect.bottom()) + padding }; + + bool hasMoveTo = false; + while (it.hasNext()) { + QStrokerOps::Element e = it.next(); + + Q_ASSERT(e.isLineTo()); + cline = QLineF(qt_fixed_to_real(prev.x), + qt_fixed_to_real(prev.y), + qt_fixed_to_real(e.x), + qt_fixed_to_real(e.y)); + elen = cline.length(); + + estop = estart + elen; + + bool done = pos >= estop; + // Dash away... + while (!done) { + QPointF p2; + + int idash_incr = 0; + bool has_offset = doffset > 0; + qreal dpos = pos + dashes[idash] - doffset - estart; + + Q_ASSERT(dpos >= 0); + + if (dpos > elen) { // dash extends this line + doffset = dashes[idash] - (dpos - elen); // subtract the part already used + pos = estop; // move pos to next path element + done = true; + p2 = cline.p2(); + } else { // Dash is on this line + p2 = cline.pointAt(dpos/elen); + pos = dpos + estart; + done = pos >= estop; + idash_incr = 1; + doffset = 0; // full segment so no offset on next. + } + + if (idash % 2 == 0) { + line_to_pos.x = qt_real_to_fixed(p2.x()); + line_to_pos.y = qt_real_to_fixed(p2.y()); + + // If we have an offset, we're continuing a dash + // from a previous element and should only + // continue the current dash, without starting a + // new subpath. + if (!has_offset || !hasMoveTo) { + m_stroker->moveTo(move_to_pos.x, move_to_pos.y); + hasMoveTo = true; + } + + if (!clipping + // if move_to is inside... + || (move_to_pos.x > clip_tl.x && move_to_pos.x < clip_br.x + && move_to_pos.y > clip_tl.y && move_to_pos.y < clip_br.y) + // Or if line_to is inside... + || (line_to_pos.x > clip_tl.x && line_to_pos.x < clip_br.x + && line_to_pos.y > clip_tl.y && line_to_pos.y < clip_br.y)) + { + m_stroker->lineTo(line_to_pos.x, line_to_pos.y); + } + } else { + move_to_pos.x = qt_real_to_fixed(p2.x()); + move_to_pos.y = qt_real_to_fixed(p2.y()); + } + + idash = (idash + idash_incr) % dashCount; + } + + // Shuffle to the next cycle... + estart = estop; + prev = e; + } +} + +QT_END_NAMESPACE |