diff options
author | Andre de la Rocha <andre.rocha@qt.io> | 2019-09-02 16:46:07 +0200 |
---|---|---|
committer | Andre de la Rocha <andre.rocha@qt.io> | 2019-10-11 16:53:23 +0200 |
commit | 31012df705c37503be00f0ddc2c323e73fd28067 (patch) | |
tree | b75d19c181e1ba874cb0f421c729ba3d8f07d78b /src | |
parent | 014d7ac65417ed9b5ffb85cca24d16564ff5005a (diff) |
Fix QGraphicsScene::update() performance
A previous fix has caused a performance degradation while adding a
check for avoiding adding duplicated rectangles to the update list.
This patch fixes it by using a std::set instead of a QList, avoiding
duplication while using an O(log N) operation, instead of the O(N)
used before.
Fixes: QTBUG-77952
Change-Id: Ifa9fbf110e0bad60ee02a42d91281981fd98ceab
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Diffstat (limited to 'src')
-rw-r--r-- | src/widgets/graphicsview/qgraphicsscene.cpp | 13 | ||||
-rw-r--r-- | src/widgets/graphicsview/qgraphicsscene_p.h | 17 |
2 files changed, 26 insertions, 4 deletions
diff --git a/src/widgets/graphicsview/qgraphicsscene.cpp b/src/widgets/graphicsview/qgraphicsscene.cpp index 5238ea2f5c..03717d5d1a 100644 --- a/src/widgets/graphicsview/qgraphicsscene.cpp +++ b/src/widgets/graphicsview/qgraphicsscene.cpp @@ -386,7 +386,15 @@ void QGraphicsScenePrivate::_q_emitUpdated() // Notify the changes to anybody interested. QList<QRectF> oldUpdatedRects; - oldUpdatedRects = updateAll ? (QList<QRectF>() << q->sceneRect()) : updatedRects; + if (updateAll) { + oldUpdatedRects << q->sceneRect(); + } else { + // Switch to a ranged constructor in Qt 6... + oldUpdatedRects.reserve(int(updatedRects.size())); + std::copy(updatedRects.cbegin(), updatedRects.cend(), + std::back_inserter(oldUpdatedRects)); + } + updateAll = false; updatedRects.clear(); emit q->changed(oldUpdatedRects); @@ -3219,8 +3227,7 @@ void QGraphicsScene::update(const QRectF &rect) view->d_func()->updateRectF(rect); } } else { - if (!d->updatedRects.contains(rect)) - d->updatedRects << rect; + d->updatedRects.insert(rect); } } diff --git a/src/widgets/graphicsview/qgraphicsscene_p.h b/src/widgets/graphicsview/qgraphicsscene_p.h index a2d13436fc..14bafe6678 100644 --- a/src/widgets/graphicsview/qgraphicsscene_p.h +++ b/src/widgets/graphicsview/qgraphicsscene_p.h @@ -69,6 +69,9 @@ #include <QtWidgets/qstyle.h> #include <QtWidgets/qstyleoption.h> +#include <set> +#include <tuple> + QT_REQUIRE_CONFIG(graphicsview); QT_BEGIN_NAMESPACE @@ -122,7 +125,19 @@ public: QRectF growingItemsBoundingRect; void _q_emitUpdated(); - QList<QRectF> updatedRects; + + struct UpdatedRectsCmp + { + bool operator() (const QRectF &a, const QRectF &b) const noexcept + { + return std::make_tuple(a.y(), a.x(), a.height(), a.width()) + < std::make_tuple(b.y(), b.x(), b.height(), b.width()); + } + }; + + // std::set was used here instead of std::unordered_set due to requiring only a comparator and + // showing equivalent performance in empirical measurements within the ranges of interest... + std::set<QRectF, UpdatedRectsCmp> updatedRects; QPainterPath selectionArea; int selectionChanging; |