diff options
| author | Eirik Aavitsland <eirik.aavitsland@qt.io> | 2019-01-17 15:50:37 +0100 |
|---|---|---|
| committer | Eirik Aavitsland <eirik.aavitsland@qt.io> | 2019-02-05 22:47:16 +0000 |
| commit | 66c3a71e91edefdf5bc5c8efb009fb5f0f330cd1 (patch) | |
| tree | 7e5ce8966d8b2f1953cc6c7ce88c34184e6985cb /src/gui/painting | |
| parent | e96641d881f2106151995c812fabb9d6c58beccb (diff) | |
Painter path stroking: fix capping of beziers ending in tight turns
For some overly tight beziers where the start or end point and the
next control point are closer than the pen width, the stroker's
shifting algorithm will produce a start/end tangent pointing in the
opposite direction from what is expected, for one of the sides. This
would break the square and round capping logic. Fix by detecting the
situation in the capping function and reversing the tangent when
necessary.
Change-Id: I48f4f017403d7b289b0483dd2b3a7ff1bbd0cf2a
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Diffstat (limited to 'src/gui/painting')
| -rw-r--r-- | src/gui/painting/qstroker.cpp | 27 |
1 files changed, 14 insertions, 13 deletions
diff --git a/src/gui/painting/qstroker.cpp b/src/gui/painting/qstroker.cpp index 4776545be6..292952b7c0 100644 --- a/src/gui/painting/qstroker.cpp +++ b/src/gui/painting/qstroker.cpp @@ -455,12 +455,12 @@ void QStroker::joinPoints(qfixed focal_x, qfixed focal_y, const QLineF &nextLine return; } #endif + QLineF prevLine(qt_fixed_to_real(m_back2X), qt_fixed_to_real(m_back2Y), + qt_fixed_to_real(m_back1X), qt_fixed_to_real(m_back1Y)); + QPointF isect; + QLineF::IntersectType type = prevLine.intersect(nextLine, &isect); if (join == FlatJoin) { - QLineF prevLine(qt_fixed_to_real(m_back2X), qt_fixed_to_real(m_back2Y), - qt_fixed_to_real(m_back1X), qt_fixed_to_real(m_back1Y)); - QPointF isect; - QLineF::IntersectType type = prevLine.intersect(nextLine, &isect); QLineF shortCut(prevLine.p2(), nextLine.p1()); qreal angle = shortCut.angleTo(prevLine); if (type == QLineF::BoundedIntersection || (angle > 90 && !qFuzzyCompare(angle, (qreal)90))) { @@ -472,12 +472,6 @@ void QStroker::joinPoints(qfixed focal_x, qfixed focal_y, const QLineF &nextLine qt_real_to_fixed(nextLine.y1())); } else { - QLineF prevLine(qt_fixed_to_real(m_back2X), qt_fixed_to_real(m_back2Y), - qt_fixed_to_real(m_back1X), qt_fixed_to_real(m_back1Y)); - - QPointF isect; - QLineF::IntersectType type = prevLine.intersect(nextLine, &isect); - if (join == MiterJoin) { qreal appliedMiterLimit = qt_fixed_to_real(m_strokeWidth * m_miterLimit); @@ -512,7 +506,11 @@ void QStroker::joinPoints(qfixed focal_x, qfixed focal_y, const QLineF &nextLine qfixed offset = m_strokeWidth / 2; QLineF l1(prevLine); - l1.translate(l1.dx(), l1.dy()); + qreal dp = QPointF::dotProduct(QPointF(prevLine.dx(), prevLine.dy()), QPointF(nextLine.dx(), nextLine.dy())); + if (dp > 0) // same direction, means that prevLine is from a bezier that has been "reversed" by shifting + l1 = QLineF(prevLine.p2(), prevLine.p1()); + else + l1.translate(l1.dx(), l1.dy()); l1.setLength(qt_fixed_to_real(offset)); QLineF l2(nextLine.p2(), nextLine.p1()); l2.translate(l2.dx(), l2.dy()); @@ -570,7 +568,11 @@ void QStroker::joinPoints(qfixed focal_x, qfixed focal_y, const QLineF &nextLine // first control line QLineF l1 = prevLine; - l1.translate(l1.dx(), l1.dy()); + qreal dp = QPointF::dotProduct(QPointF(prevLine.dx(), prevLine.dy()), QPointF(nextLine.dx(), nextLine.dy())); + if (dp > 0) // same direction, means that prevLine is from a bezier that has been "reversed" by shifting + l1 = QLineF(prevLine.p2(), prevLine.p1()); + else + l1.translate(l1.dx(), l1.dy()); l1.setLength(QT_PATH_KAPPA * offset); // second control line, find through normal between prevLine and focal. @@ -705,7 +707,6 @@ template <class Iterator> bool qt_stroke_side(Iterator *it, QPointF(qt_fixed_to_real(e.x), qt_fixed_to_real(e.y)), QPointF(qt_fixed_to_real(cp2.x), qt_fixed_to_real(cp2.y)), QPointF(qt_fixed_to_real(ep.x), qt_fixed_to_real(ep.y))); - int count = bezier.shifted(offsetCurves, MAX_OFFSET, offset, |