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#include "qtriangulatingstroker_p.h"

#include <qmath.h>

#define CURVE_FLATNESS Q_PI / 8

void QTriangulatingStroker::endCapOrJoinClosed(const qreal *start, const qreal *cur,

                                               bool implicitClose, bool endsAtStart)

{

    if (endsAtStart) {

        join(start + 2);

    } else if (implicitClose) {

        join(start);

        lineTo(start);

        join(start+2);

    } else {

        endCap(cur);

    }

}

void QTriangulatingStroker::process(const QVectorPath &path, const QPen &pen)

{

    const qreal *pts = path.points();

    const QPainterPath::ElementType *types = path.elements();

    int count = path.elementCount();

    if (count < 2)

        return;

    float realWidth = qpen_widthf(pen);

    if (realWidth == 0)

        realWidth = 1;

    m_width = realWidth / 2;

    bool cosmetic = pen.isCosmetic();

    if (cosmetic) {

        m_width = m_width * m_inv_scale;

    }

    m_join_style = qpen_joinStyle(pen);

    m_cap_style = qpen_capStyle(pen);

    m_vertices.reset();

    m_miter_limit = pen.miterLimit() * qpen_widthf(pen);

    // The curvyness is based on the notion that I originally wanted

    // roughly one line segment pr 4 pixels. This may seem little, but

    // because we sample at constantly incrementing B(t) E [0<t<1], we

    // will get longer segments where the curvature is small and smaller

    // segments when the curvature is high.

    //

    // To get a rough idea of the length of each curve, I pretend that

    // the curve is a 90 degree arc, whose radius is

    // qMax(curveBounds.width, curveBounds.height). Based on this

    // logic we can estimate the length of the outline edges based on

    // the radius + a pen width and adjusting for scale factors

    // depending on if the pen is cosmetic or not.

    //

    // The curvyness value of PI/14 was based on,

    // arcLength=2*PI*r/4=PI/2 and splitting length into somewhere

    // between 3 and 8 where 5 seemed to be give pretty good results

    // hence: Q_PI/14. Lower divisors will give more detail at the

    // direct cost of performance.

    // simplfy pens that are thin in device size (2px wide or less)

    if (realWidth < 2.5 && (cosmetic || m_inv_scale == 1)) {

        if (m_cap_style == Qt::RoundCap)

            m_cap_style = Qt::SquareCap;

        if (m_join_style == Qt::RoundJoin)

            m_join_style = Qt::MiterJoin;

        m_curvyness_add = 0.5;

        m_curvyness_mul = CURVE_FLATNESS;

        m_roundness = 1;

    } else if (cosmetic) {

        m_curvyness_add = realWidth / 2;

        m_curvyness_mul = CURVE_FLATNESS;

        m_roundness = qMax<int>(4, realWidth * CURVE_FLATNESS);

    } else {

        m_curvyness_add = m_width;

        m_curvyness_mul = CURVE_FLATNESS / m_inv_scale;

        m_roundness = qMax<int>(4, realWidth * m_curvyness_mul);

    }

    // Over this level of segmentation, there doesn't seem to be any

    // benefit, even for huge penWidth

    if (m_roundness > 24)

        m_roundness = 24;

    m_sin_theta = qSin(Q_PI / m_roundness); // ### Use qFastSin

    m_cos_theta = qCos(Q_PI / m_roundness);

    const qreal *endPts = pts + (count<<1);

    const qreal *startPts;

    Qt::PenCapStyle cap = m_cap_style;

    if (!types) {

        startPts = pts;

        bool endsAtStart = startPts[0] == *(endPts-2) && startPts[1] == *(endPts-1);

        Qt::PenCapStyle cap = m_cap_style;

        if (endsAtStart || path.hasImplicitClose())

            m_cap_style = Qt::FlatCap;

        moveTo(pts);

        m_cap_style = cap;

        pts += 2;

        lineTo(pts);

        pts += 2;

        while (pts < endPts) {

            join(pts);

            lineTo(pts);

            pts += 2;

        }

        endCapOrJoinClosed(startPts, pts-2, path.hasImplicitClose(), endsAtStart);

    } else {

        bool endsAtStart;

        while (pts < endPts) {

            switch (*types) {

            case QPainterPath::MoveToElement: {

                if (pts != path.points())

                    endCapOrJoinClosed(startPts, pts, path.hasImplicitClose(), endsAtStart);

                startPts = pts;

                int end = (endPts - pts) / 2;

                int i = 2; // Start looking to ahead since we never have two moveto's in a row

                while (i<end && types[i] != QPainterPath::MoveToElement) {

                    ++i;

                }

                endsAtStart = startPts[0] == pts[i*2 - 2] && startPts[1] == pts[i*2 - 1];

                if (endsAtStart || path.hasImplicitClose())

                    m_cap_style = Qt::FlatCap;

                moveTo(pts);

                m_cap_style = cap;

                pts+=2;

                ++types;

                break; }

            case QPainterPath::LineToElement:

                if (*(types - 1) != QPainterPath::MoveToElement)

                    join(pts);

                lineTo(pts);

                pts+=2;

                ++types;

                break;

            case QPainterPath::CurveToElement:

                if (*(types - 1) != QPainterPath::MoveToElement)

                    join(pts);

                cubicTo(pts);

                pts+=6;

                types+=3;

                break;

            default:

                Q_ASSERT(false);

                break;

            }

        }

        endCapOrJoinClosed(startPts, pts-2, path.hasImplicitClose(), endsAtStart);

    }

}

void QTriangulatingStroker::cubicTo(const qreal *pts)

{

    const QPointF *p = (const QPointF *) pts;

    QBezier bezier = QBezier::fromPoints(*(p - 1), p[0], p[1], p[2]);

    QRectF bounds = bezier.bounds();

    float rad = qMax(bounds.width(), bounds.height());

    int threshold = qMin<float>(64, (rad + m_curvyness_add) * m_curvyness_mul);

    if (threshold < 4)

        threshold = 4;

    qreal threshold_minus_1 = threshold - 1;

    float vx, vy;

    float cx = m_cx, cy = m_cy;

    float x, y;

    for (int i=1; i<threshold; ++i) {

        qreal t = qreal(i) / threshold_minus_1;

        QPointF p = bezier.pointAt(t);

        x = p.x();

        y = p.y();

        normalVector(cx, cy, x, y, &vx, &vy);

        emitLineSegment(x, y, vx, vy);

        cx = x;

        cy = y;

    }

    m_cx = cx;

    m_cy = cy;

    m_nvx = vx;

    m_nvy = vy;

}

static void qdashprocessor_moveTo(qreal x, qreal y, void *data)

{

    ((QDashedStrokeProcessor *) data)->addElement(QPainterPath::MoveToElement, x, y);

}

static void qdashprocessor_lineTo(qreal x, qreal y, void *data)

{

    ((QDashedStrokeProcessor *) data)->addElement(QPainterPath::LineToElement, x, y);

}

static void qdashprocessor_cubicTo(qreal, qreal, qreal, qreal, qreal, qreal, void *)

{

    Q_ASSERT(0); // The dasher should not produce curves...

}

QDashedStrokeProcessor::QDashedStrokeProcessor()

    : m_dash_stroker(0), m_inv_scale(1)

{

    m_dash_stroker.setMoveToHook(qdashprocessor_moveTo);

    m_dash_stroker.setLineToHook(qdashprocessor_lineTo);

    m_dash_stroker.setCubicToHook(qdashprocessor_cubicTo);

}

void QDashedStrokeProcessor::process(const QVectorPath &path, const QPen &pen)

{

    const qreal *pts = path.points();

    const QPainterPath::ElementType *types = path.elements();

    int count = path.elementCount();

    m_points.reset();

    m_types.reset();

    qreal width = pen.width();

    if (width == 0)

        width = 1;

    m_dash_stroker.setDashPattern(pen.dashPattern());

    m_dash_stroker.setStrokeWidth(width);

    m_dash_stroker.setMiterLimit(pen.miterLimit());

    qreal curvyness = sqrt(width) * m_inv_scale / 8;

    if (count < 2)

        return;

    const qreal *endPts = pts + (count<<1);

    m_dash_stroker.begin(this);

    if (!types) {

        m_dash_stroker.moveTo(pts[0], pts[1]);

        pts += 2;

        while (pts < endPts) {

            m_dash_stroker.lineTo(pts[0], pts[1]);

            pts += 2;

        }

    } else {

        while (pts < endPts) {

            switch (*types) {

            case QPainterPath::MoveToElement:

                m_dash_stroker.moveTo(pts[0], pts[1]);

                pts += 2;

                ++types;

                break;

            case QPainterPath::LineToElement:

                m_dash_stroker.lineTo(pts[0], pts[1]);

                pts += 2;

                ++types;

                break;

            case QPainterPath::CurveToElement: {

                QBezier b = QBezier::fromPoints(*(((const QPointF *) pts) - 1),

                                                *(((const QPointF *) pts)),

                                                *(((const QPointF *) pts) + 1),

                                                *(((const QPointF *) pts) + 2));

                QRectF bounds = b.bounds();

                int threshold = qMin<float>(64, qMax(bounds.width(), bounds.height()) * curvyness);

                if (threshold < 4)

                    threshold = 4;

                qreal threshold_minus_1 = threshold - 1;

                for (int i=0; i<threshold; ++i) {

                    QPointF pt = b.pointAt(i / threshold_minus_1);

                    m_dash_stroker.lineTo(pt.x(), pt.y());

                }

                pts += 6;

                types += 3;

                break; }

            default: break;

            }

        }

    }

    m_dash_stroker.end();

}