QPainterPath: Add option to cache calculations
Speeds up repeated calls to length and percentage functions. Change-Id: I357732e35de648e7da07ad492e58d5b94c2c0870 Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
This commit is contained in:
Eirik Aavitsland
parent
76b1424048
commit
90247966a7
@ -2821,6 +2821,44 @@ QPolygonF QPainterPath::toFillPolygon(const QTransform &matrix) const
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return polygon;
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}
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/*!
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Returns true if caching is enabled; otherwise returns false.
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\since 6.10
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\sa setCachingEnabled()
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*/
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bool QPainterPath::isCachingEnabled() const
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{
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Q_D(QPainterPath);
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return d && d->cacheEnabled;
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}
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/*!
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Enables or disables length caching according to the value of \a enabled.
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Enabling caching speeds up repeated calls to the member functions involving path length
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and percentage values, such as length(), percentAtLength(), pointAtPercent() etc., at the cost
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of some extra memory usage for storage of intermediate calculations. By default it is disabled.
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Disabling caching will release any allocated cache memory.
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\since 6.10
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\sa isCachingEnabled(), length(), percentAtLength(), pointAtPercent()
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*/
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void QPainterPath::setCachingEnabled(bool enabled)
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{
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ensureData();
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if (d_func()->cacheEnabled == enabled)
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return;
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detach();
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QPainterPathPrivate *d = d_func();
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d->cacheEnabled = enabled;
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if (!enabled) {
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d->m_runLengths.clear();
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d->m_runLengths.squeeze();
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}
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}
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//derivative of the equation
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static inline qreal slopeAt(qreal t, qreal a, qreal b, qreal c, qreal d)
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{
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@ -2835,6 +2873,11 @@ qreal QPainterPath::length() const
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Q_D(QPainterPath);
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if (isEmpty())
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return 0;
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if (d->cacheEnabled) {
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if (d->dirtyRunLengths)
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d->computeRunLengths();
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return d->m_runLengths.last();
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}
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qreal len = 0;
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for (int i=1; i<d->elements.size(); ++i) {
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@ -2883,6 +2926,32 @@ qreal QPainterPath::percentAtLength(qreal len) const
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if (len > totalLength)
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return 1;
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if (d->cacheEnabled) {
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const int ei = qMax(d->elementAtT(len / totalLength), 1); // Skip initial MoveTo
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qreal res = 0;
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const QPainterPath::Element &e = d->elements[ei];
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switch (e.type) {
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case QPainterPath::LineToElement:
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res = len / totalLength;
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break;
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case CurveToElement:
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{
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QBezier b = QBezier::fromPoints(d->elements.at(ei-1),
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e,
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d->elements.at(ei+1),
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d->elements.at(ei+2));
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qreal prevLen = d->m_runLengths[ei - 1];
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qreal blen = d->m_runLengths[ei] - prevLen;
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qreal elemRes = b.tAtLength(len - prevLen);
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res = (elemRes * blen + prevLen) / totalLength;
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break;
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}
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default:
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Q_UNREACHABLE();
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}
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return res;
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}
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qreal curLen = 0;
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for (int i=1; i<d->elements.size(); ++i) {
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const Element &e = d->elements.at(i);
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@ -2927,7 +2996,8 @@ qreal QPainterPath::percentAtLength(qreal len) const
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return 0;
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}
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static inline QBezier bezierAtT(const QPainterPath &path, qreal t, qreal *startingLength, qreal *bezierLength)
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static inline QBezier uncached_bezierAtT(const QPainterPath &path, qreal t, qreal *startingLength,
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qreal *bezierLength)
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{
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*startingLength = 0;
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if (t > 1)
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@ -2981,6 +3051,35 @@ static inline QBezier bezierAtT(const QPainterPath &path, qreal t, qreal *starti
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return QBezier();
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}
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QBezier QPainterPathPrivate::bezierAtT(const QPainterPath &path, qreal t, qreal *startingLength,
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qreal *bezierLength) const
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{
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Q_ASSERT(t >= 0 && t <= 1);
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QPainterPathPrivate *d = path.d_func();
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if (!path.isEmpty() && d->cacheEnabled) {
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const int ei = qMax(d->elementAtT(t), 1); // Avoid the initial MoveTo element
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const qreal prevRunLength = d->m_runLengths[ei - 1];
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*startingLength = prevRunLength;
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*bezierLength = d->m_runLengths[ei] - prevRunLength;
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const QPointF prev = d->elements[ei - 1];
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const QPainterPath::Element &e = d->elements[ei];
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switch (e.type) {
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case QPainterPath::LineToElement:
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{
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QPointF delta = (e - prev) / 3;
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return QBezier::fromPoints(prev, prev + delta, prev + 2 * delta, e);
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}
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case QPainterPath::CurveToElement:
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return QBezier::fromPoints(prev, e, elements[ei + 1], elements[ei + 2]);
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break;
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default:
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Q_UNREACHABLE();
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}
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}
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return uncached_bezierAtT(path, t, startingLength, bezierLength);
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}
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/*!
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Returns the point at at the percentage \a t of the current path.
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The argument \a t has to be between 0 and 1.
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@ -3006,7 +3105,7 @@ QPointF QPainterPath::pointAtPercent(qreal t) const
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qreal totalLength = length();
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qreal curLen = 0;
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qreal bezierLen = 0;
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QBezier b = bezierAtT(*this, t, &curLen, &bezierLen);
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QBezier b = d_ptr->bezierAtT(*this, t, &curLen, &bezierLen);
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qreal realT = (totalLength * t - curLen) / bezierLen;
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return b.pointAt(qBound(qreal(0), realT, qreal(1)));
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@ -3034,7 +3133,7 @@ qreal QPainterPath::angleAtPercent(qreal t) const
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qreal totalLength = length();
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qreal curLen = 0;
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qreal bezierLen = 0;
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QBezier bez = bezierAtT(*this, t, &curLen, &bezierLen);
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QBezier bez = d_ptr->bezierAtT(*this, t, &curLen, &bezierLen);
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qreal realT = (totalLength * t - curLen) / bezierLen;
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qreal m1 = slopeAt(realT, bez.x1, bez.x2, bez.x3, bez.x4);
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@ -3063,7 +3162,7 @@ qreal QPainterPath::slopeAtPercent(qreal t) const
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qreal totalLength = length();
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qreal curLen = 0;
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qreal bezierLen = 0;
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QBezier bez = bezierAtT(*this, t, &curLen, &bezierLen);
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QBezier bez = d_ptr->bezierAtT(*this, t, &curLen, &bezierLen);
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qreal realT = (totalLength * t - curLen) / bezierLen;
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qreal m1 = slopeAt(realT, bez.x1, bez.x2, bez.x3, bez.x4);
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@ -3283,9 +3382,10 @@ bool QPainterPath::contains(const QPainterPath &p) const
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void QPainterPath::setDirty(bool dirty)
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{
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d_func()->pathConverter.reset();
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d_func()->dirtyBounds = dirty;
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d_func()->dirtyControlBounds = dirty;
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d_func()->pathConverter.reset();
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d_func()->dirtyRunLengths = dirty;
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d_func()->convex = false;
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}
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@ -3358,6 +3458,43 @@ void QPainterPath::computeControlPointRect() const
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d->controlBounds = QRectF(minx, miny, maxx - minx, maxy - miny);
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}
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void QPainterPathPrivate::computeRunLengths()
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{
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Q_ASSERT(!elements.isEmpty());
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m_runLengths.clear();
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const int numElems = elements.size();
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m_runLengths.reserve(numElems);
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QPointF runPt = elements[0];
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qreal runLen = 0.0;
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for (int i = 0; i < numElems; i++) {
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QPainterPath::Element e = elements[i];
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switch (e.type) {
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case QPainterPath::LineToElement:
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runLen += QLineF(runPt, e).length();
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runPt = e;
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break;
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case QPainterPath::CurveToElement: {
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Q_ASSERT(i < numElems - 2);
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QPainterPath::Element ee = elements[i + 2];
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runLen += QBezier::fromPoints(runPt, e, elements[i + 1], ee).length();
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runPt = ee;
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break;
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}
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case QPainterPath::MoveToElement:
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runPt = e;
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break;
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case QPainterPath::CurveToDataElement:
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break;
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}
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m_runLengths.append(runLen);
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}
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Q_ASSERT(m_runLengths.size() == elements.size());
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dirtyRunLengths = false;
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}
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#ifndef QT_NO_DEBUG_STREAM
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QDebug operator<<(QDebug s, const QPainterPath &p)
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{
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@ -134,8 +134,10 @@ public:
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QPainterPath::Element elementAt(int i) const;
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void setElementPositionAt(int i, qreal x, qreal y);
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bool isCachingEnabled() const;
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void setCachingEnabled(bool enabled);
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qreal length() const;
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qreal percentAtLength(qreal t) const;
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qreal percentAtLength(qreal len) const;
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QPointF pointAtPercent(qreal t) const;
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qreal angleAtPercent(qreal t) const;
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qreal slopeAtPercent(qreal t) const;
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@ -174,6 +176,7 @@ private:
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friend class QPainterPathStroker;
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friend class QPainterPathStrokerPrivate;
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friend class QPainterPathPrivate;
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friend class QTransform;
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friend class QVectorPath;
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friend Q_GUI_EXPORT const QVectorPath &qtVectorPathForPath(const QPainterPath &);
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@ -24,6 +24,7 @@
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#include <private/qvectorpath_p.h>
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#include <private/qstroker_p.h>
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#include <private/qbezier_p.h>
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#include <memory>
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@ -111,7 +112,8 @@ public:
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dirtyBounds(false),
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dirtyControlBounds(false),
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convex(false),
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hasWindingFill(false)
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hasWindingFill(false),
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cacheEnabled(false)
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{
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}
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@ -124,21 +126,25 @@ public:
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dirtyBounds(false),
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dirtyControlBounds(false),
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convex(false),
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hasWindingFill(false)
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hasWindingFill(false),
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cacheEnabled(false)
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{
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}
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QPainterPathPrivate(const QPainterPathPrivate &other) noexcept
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: QSharedData(other),
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elements(other.elements),
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m_runLengths(other.m_runLengths),
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bounds(other.bounds),
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controlBounds(other.controlBounds),
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cStart(other.cStart),
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require_moveTo(false),
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dirtyBounds(other.dirtyBounds),
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dirtyControlBounds(other.dirtyControlBounds),
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dirtyRunLengths(other.dirtyRunLengths),
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convex(other.convex),
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hasWindingFill(other.hasWindingFill)
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hasWindingFill(other.hasWindingFill),
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cacheEnabled(other.cacheEnabled)
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{
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}
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@ -149,6 +155,10 @@ public:
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inline void close();
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inline void maybeMoveTo();
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inline void clear();
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void computeRunLengths();
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int elementAtT(qreal t);
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QBezier bezierAtT(const QPainterPath &path, qreal t, qreal *startingLength,
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qreal *bezierLength) const;
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const QVectorPath &vectorPath() {
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if (!pathConverter)
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@ -159,6 +169,7 @@ public:
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private:
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QList<QPainterPath::Element> elements;
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std::unique_ptr<QVectorPathConverter> pathConverter;
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QList<qreal> m_runLengths;
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QRectF bounds;
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QRectF controlBounds;
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@ -167,8 +178,10 @@ private:
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bool require_moveTo : 1;
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bool dirtyBounds : 1;
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bool dirtyControlBounds : 1;
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bool dirtyRunLengths : 1;
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bool convex : 1;
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bool hasWindingFill : 1;
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bool cacheEnabled : 1;
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};
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class QPainterPathStrokerPrivate
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@ -257,6 +270,7 @@ inline void QPainterPathPrivate::clear()
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Q_ASSERT(ref.loadRelaxed() == 1);
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elements.clear();
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m_runLengths.clear();
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cStart = 0;
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bounds = {};
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@ -265,12 +279,23 @@ inline void QPainterPathPrivate::clear()
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require_moveTo = false;
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dirtyBounds = false;
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dirtyControlBounds = false;
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dirtyRunLengths = false;
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convex = false;
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pathConverter.reset();
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}
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#define KAPPA qreal(0.5522847498)
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inline int QPainterPathPrivate::elementAtT(qreal t)
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{
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Q_ASSERT(cacheEnabled);
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if (dirtyRunLengths)
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computeRunLengths();
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qreal len = t * m_runLengths.constLast();
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const auto it = std::lower_bound(m_runLengths.constBegin(), m_runLengths.constEnd(), len);
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return (it == m_runLengths.constEnd()) ? m_runLengths.size() - 1 : int(it - m_runLengths.constBegin());
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}
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#define KAPPA qreal(0.5522847498)
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QT_END_NAMESPACE
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@ -1145,10 +1145,16 @@ void tst_QPainterPath::pointAtPercent()
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QFETCH(qreal, percent);
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QFETCH(QPointF, point);
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QVERIFY(!path.isCachingEnabled());
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QPointF result = path.pointAtPercent(percent);
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QVERIFY(pathFuzzyCompare(point.x() , result.x()));
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QVERIFY(pathFuzzyCompare(point.y() , result.y()));
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path.setCachingEnabled(true);
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QVERIFY(path.isCachingEnabled());
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result = path.pointAtPercent(percent);
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QVERIFY2(pathFuzzyCompare(point.x() , result.x()), "caching");
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QVERIFY2(pathFuzzyCompare(point.y() , result.y()), "caching");
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}
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void tst_QPainterPath::lengths_data()
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@ -1190,11 +1196,20 @@ void tst_QPainterPath::lengths()
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QFETCH(qreal, lenAt50);
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QFETCH(qreal, lenAt75);
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QVERIFY(!path.isCachingEnabled());
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QVERIFY(pathFuzzyCompare(path.length() / 1000, length / 1000));
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QVERIFY(pathFuzzyCompare(path.percentAtLength(lenAt25), qreal(0.25)));
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QVERIFY(pathFuzzyCompare(path.percentAtLength(lenAt50), qreal(0.50)));
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QVERIFY(pathFuzzyCompare(path.percentAtLength(lenAt75), qreal(0.75)));
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QVERIFY(pathFuzzyCompare(path.percentAtLength(length), qreal(1)));
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path.setCachingEnabled(true);
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QVERIFY(path.isCachingEnabled());
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QVERIFY2(pathFuzzyCompare(path.length() / 1000, length / 1000), "caching");
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QVERIFY2(pathFuzzyCompare(path.percentAtLength(lenAt25), qreal(0.25)), "caching");
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QVERIFY2(pathFuzzyCompare(path.percentAtLength(lenAt50), qreal(0.50)), "caching");
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QVERIFY2(pathFuzzyCompare(path.percentAtLength(lenAt75), qreal(0.75)), "caching");
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QVERIFY2(pathFuzzyCompare(path.percentAtLength(length), qreal(1)), "caching");
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}
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void tst_QPainterPath::setElementPositionAt()
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@ -1226,6 +1241,11 @@ void tst_QPainterPath::angleAtPercent()
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path.moveTo(line.p1());
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path.lineTo(line.p2());
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QVERIFY(!path.isCachingEnabled());
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QCOMPARE(path.angleAtPercent(0.5), line.angle());
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path.setCachingEnabled(true);
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QVERIFY(path.isCachingEnabled());
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QCOMPARE(path.angleAtPercent(0.5), line.angle());
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}
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}
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@ -15,8 +15,12 @@ public:
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private slots:
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void initTestCase_data();
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void general_data();
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void length_data() { general_data(); }
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void length();
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void percentAtLength_data() { general_data(); }
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void percentAtLength();
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void pointAtPercent_data() { general_data(); }
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void pointAtPercent();
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};
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@ -62,11 +66,19 @@ void tst_QPainterPath::initTestCase_data()
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QTest::newRow("2k_text") << p;
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}
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void tst_QPainterPath::general_data()
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{
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QTest::addColumn<bool>("caching");
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QTest::newRow("Uncached") << false;
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QTest::newRow("Cached") << true;
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}
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void tst_QPainterPath::length()
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{
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QFETCH_GLOBAL(QPainterPath, path);
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//const qreal len = path.length() * 0.72;
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QFETCH(bool, caching);
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path.setCachingEnabled(caching);
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QBENCHMARK {
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path.length();
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@ -76,6 +88,8 @@ void tst_QPainterPath::length()
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void tst_QPainterPath::percentAtLength()
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{
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QFETCH_GLOBAL(QPainterPath, path);
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QFETCH(bool, caching);
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path.setCachingEnabled(caching);
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const qreal len = path.length() * 0.72;
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@ -87,6 +101,8 @@ void tst_QPainterPath::percentAtLength()
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void tst_QPainterPath::pointAtPercent()
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{
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QFETCH_GLOBAL(QPainterPath, path);
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||||
QFETCH(bool, caching);
|
||||
path.setCachingEnabled(caching);
|
||||
|
||||
const qreal t = 0.72;
|
||||
|
||||
|
||||
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Reference in New Issue
Block a user