Exemplo n.º 1
0
void QBezier::addToPolygon(QPolygonF *polygon, qreal bezier_flattening_threshold) const
{
    QBezier beziers[32];
    beziers[0] = *this;
    QBezier *b = beziers;

    while (b >= beziers) {
        // check if we can pop the top bezier curve from the stack
        qreal y4y1 = b->y4 - b->y1;
        qreal x4x1 = b->x4 - b->x1;
        qreal l = qAbs(x4x1) + qAbs(y4y1);
        qreal d;
        if (l > 1.) {
            d = qAbs( (x4x1)*(b->y1 - b->y2) - (y4y1)*(b->x1 - b->x2) )
                + qAbs( (x4x1)*(b->y1 - b->y3) - (y4y1)*(b->x1 - b->x3) );
        } else {
            d = qAbs(b->x1 - b->x2) + qAbs(b->y1 - b->y2) +
                qAbs(b->x1 - b->x3) + qAbs(b->y1 - b->y3);
            l = 1.;
        }
        if (d < bezier_flattening_threshold*l || b == beziers + 31) {
            // good enough, we pop it off and add the endpoint
            polygon->append(QPointF(b->x4, b->y4));
            --b;
        } else {
            // split, second half of the polygon goes lower into the stack
            b->split(b+1, b);
            ++b;
        }
    }
}
Exemplo n.º 2
0
int QBezier::shifted(QBezier *curveSegments, int maxSegments, qreal offset, float threshold) const
{
    Q_ASSERT(curveSegments);
    Q_ASSERT(maxSegments > 0);

    if (x1 == x2 && x1 == x3 && x1 == x4 &&
        y1 == y2 && y1 == y3 && y1 == y4)
        return 0;

    --maxSegments;
    QBezier beziers[10];
redo:
    beziers[0] = *this;
    QBezier *b = beziers;
    QBezier *o = curveSegments;

    while (b >= beziers) {
        int stack_segments = b - beziers + 1;
        if ((stack_segments == 10) || (o - curveSegments == maxSegments - stack_segments)) {
            threshold *= qreal(1.5);
            if (threshold > qreal(2.0))
                goto give_up;
            goto redo;
        }
        ShiftResult res = shift(b, o, offset, threshold);
        if (res == Discard) {
            --b;
        } else if (res == Ok) {
            ++o;
            --b;
            continue;
        } else if (res == Circle && maxSegments - (o - curveSegments) >= 2) {
            // add semi circle
            if (addCircle(b, offset, o))
                o += 2;
            --b;
        } else {
            b->split(b+1, b);
            ++b;
        }
    }

give_up:
    while (b >= beziers) {
        ShiftResult res = shift(b, o, offset, threshold);

        // if res isn't Ok or Split then *o is undefined
        if (res == Ok || res == Split)
            ++o;

        --b;
    }

    Q_ASSERT(o - curveSegments <= maxSegments);
    return o - curveSegments;
}
Exemplo n.º 3
0
void QBezier::addToPolygon(QDataBuffer<QPointF> &polygon, qreal bezier_flattening_threshold) const
{
    QBezier beziers[10];
    int levels[10];
    beziers[0] = *this;
    levels[0] = 9;
    QBezier *b = beziers;
    int *lvl = levels;

    while (b >= beziers) {
        // check if we can pop the top bezier curve from the stack
        qreal y4y1 = b->y4 - b->y1;
        qreal x4x1 = b->x4 - b->x1;
        qreal l = qAbs(x4x1) + qAbs(y4y1);
        qreal d;
        if (l > 1.) {
            d = qAbs( (x4x1)*(b->y1 - b->y2) - (y4y1)*(b->x1 - b->x2) )
                + qAbs( (x4x1)*(b->y1 - b->y3) - (y4y1)*(b->x1 - b->x3) );
        } else {
            d = qAbs(b->x1 - b->x2) + qAbs(b->y1 - b->y2) +
                qAbs(b->x1 - b->x3) + qAbs(b->y1 - b->y3);
            l = 1.;
        }
        if (d < bezier_flattening_threshold*l || *lvl == 0) {
            // good enough, we pop it off and add the endpoint
            polygon.add(QPointF(b->x4, b->y4));
            --b;
            --lvl;
        } else {
            // split, second half of the polygon goes lower into the stack
            b->split(b+1, b);
            lvl[1] = --lvl[0];
            ++b;
            ++lvl;
        }
    }
}