QBezier QBezier::bezierOnInterval(qreal t0, qreal t1) const
{
if (t0 == 0 && t1 == 1)
return *this;
QBezier bezier = *this;
QBezier result;
bezier.parameterSplitLeft(t0, &result);
qreal trueT = (t1-t0)/(1-t0);
bezier.parameterSplitLeft(trueT, &result);
return result;
}
qreal QBezier::tAtLength(qreal l) const
{
qreal len = length();
qreal t = qreal(1.0);
const qreal error = qreal(0.01);
if (l > len || qFuzzyCompare(l, len))
return t;
t *= qreal(0.5);
//int iters = 0;
//qDebug()<<"LEN is "<<l<<len;
qreal lastBigger = qreal(1.0);
while (1) {
//qDebug()<<"\tt is "<<t;
QBezier right = *this;
QBezier left;
right.parameterSplitLeft(t, &left);
qreal lLen = left.length();
if (qAbs(lLen - l) < error)
break;
if (lLen < l) {
t += (lastBigger - t) * qreal(0.5);
} else {
lastBigger = t;
t -= t * qreal(0.5);
}
//++iters;
}
//qDebug()<<"number of iters is "<<iters;
return t;
}
QBezier QBezier::getSubRange(qreal t0, qreal t1) const
{
QBezier result;
QBezier temp;
// cut at t1
if (qFuzzyIsNull(t1 - qreal(1.))) {
result = *this;
} else {
temp = *this;
temp.parameterSplitLeft(t1, &result);
}
// cut at t0
if (!qFuzzyIsNull(t0))
result.parameterSplitLeft(t0 / t1, &temp);
return result;
}