QIntersectionFinder Class Reference

Public Functions
bool	hasIntersections (const QPathSegments &a, const QPathSegments &b) const
void	produceIntersections (QPathSegments &segments)

Private Functions
bool	linesIntersect (const QLineF &a, const QLineF &b) const

Detailed Description

Definition at line 104 of file qpathclipper.cpp.

Functions

hasIntersections()

bool QIntersectionFinder::hasIntersections	(	const QPathSegments &	a,
		const QPathSegments &	b
	)		const

Definition at line 181 of file qpathclipper.cpp.

Referenced by QPathClipper::contains(), and QPathClipper::intersect().

{
    if (a.segments() == 0 || b.segments() == 0)
        return false;

    const QRectF &rb0 = b.elementBounds(0);

    qreal minX = rb0.left();
    qreal minY = rb0.top();
    qreal maxX = rb0.right();
    qreal maxY = rb0.bottom();

    for (int i = 1; i < b.segments(); ++i) {
        const QRectF &r = b.elementBounds(i);
        minX = qMin(minX, r.left());
        minY = qMin(minY, r.top());
        maxX = qMax(maxX, r.right());
        maxY = qMax(maxY, r.bottom());
    }

    QRectF rb(minX, minY, maxX - minX, maxY - minY);

    for (int i = 0; i < a.segments(); ++i) {
        const QRectF &r1 = a.elementBounds(i);

        if (r1.left() > rb.right() || rb.left() > r1.right())
            continue;
        if (r1.top() > rb.bottom() || rb.top() > r1.bottom())
            continue;

        for (int j = 0; j < b.segments(); ++j) {
            const QRectF &r2 = b.elementBounds(j);

            if (r1.left() > r2.right() || r2.left() > r1.right())
                continue;
            if (r1.top() > r2.bottom() || r2.top() > r1.bottom())
                continue;

            if (linesIntersect(a.lineAt(i), b.lineAt(j)))
                return true;
        }
    }

    return false;
}

linesIntersect()

bool QIntersectionFinder::linesIntersect ( const QLineF &  a, const QLineF &  b  ) const

private

Definition at line 114 of file qpathclipper.cpp.

{
    const QPointF p1 = a.p1();
    const QPointF p2 = a.p2();

    const QPointF q1 = b.p1();
    const QPointF q2 = b.p2();

    if (comparePoints(p1, p2) || comparePoints(q1, q2))
        return false;

    const bool p1_equals_q1 = comparePoints(p1, q1);
    const bool p2_equals_q2 = comparePoints(p2, q2);

    if (p1_equals_q1 && p2_equals_q2)
        return true;

    const bool p1_equals_q2 = comparePoints(p1, q2);
    const bool p2_equals_q1 = comparePoints(p2, q1);

    if (p1_equals_q2 && p2_equals_q1)
        return true;

    const QPointF pDelta = p2 - p1;
    const QPointF qDelta = q2 - q1;

    const qreal par = pDelta.x() * qDelta.y() - pDelta.y() * qDelta.x();

    if (qFuzzyIsNull(par)) {
        const QPointF normal(-pDelta.y(), pDelta.x());

        // coinciding?
        if (qFuzzyIsNull(dot(normal, q1 - p1))) {
            const qreal dp = dot(pDelta, pDelta);

            const qreal tq1 = dot(pDelta, q1 - p1);
            const qreal tq2 = dot(pDelta, q2 - p1);

            if ((tq1 > 0 && tq1 < dp) || (tq2 > 0 && tq2 < dp))
                return true;

            const qreal dq = dot(qDelta, qDelta);

            const qreal tp1 = dot(qDelta, p1 - q1);
            const qreal tp2 = dot(qDelta, p2 - q1);

            if ((tp1 > 0 && tp1 < dq) || (tp2 > 0 && tp2 < dq))
                return true;
        }

        return false;
    }

    const qreal invPar = 1 / par;

    const qreal tp = (qDelta.y() * (q1.x() - p1.x()) -
                      qDelta.x() * (q1.y() - p1.y())) * invPar;

    if (tp < 0 || tp > 1)
        return false;

    const qreal tq = (pDelta.y() * (q1.x() - p1.x()) -
                      pDelta.x() * (q1.y() - p1.y())) * invPar;

    return tq >= 0 && tq <= 1;
}

produceIntersections()

void QIntersectionFinder::produceIntersections

(

QPathSegments &

segments

)

Definition at line 594 of file qpathclipper.cpp.

Referenced by QWingedEdge::intersectAndAdd().

{
    SegmentTree tree(segments);

    for (int i = 0; i < segments.segments(); ++i)
        tree.produceIntersections(i);
}

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The documentation for this class was generated from the following file:

• /src/gui/painting/qpathclipper.cpp