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authorAndreas Aardal Hanssen <andreas.aardal.hanssen@nokia.com>2009-04-23 15:46:54 (GMT)
committerAndreas Aardal Hanssen <andreas.aardal.hanssen@nokia.com>2009-04-23 15:49:36 (GMT)
commit5423ba187c62ea861ccfcc013fb15fcc4a5ae28d (patch)
tree81135e3cf5ec81aff1c533c1a1157ae519d2d352 /src
parent4ec0d20bda2d7c4dfd1da41d52404481f5ecd42c (diff)
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Fix bugs in QGraphicsItem::childrenBoundingRect()
While working on layering in Graphics View I stumbled over this bug. The QGraphicsItem::childrenBoundingRect() function had an accumulating error caused by recursive adding of rectangles that individually were mapped to the local parent using QGraphicsItem::mapRectToParent() / QTransform::mapRect. This caused the brect to be way too large for items with children that are rotated (fex, alternating 45 and -45 degrees). The new version should be just as fast, but with no loss of precision. Reviewed-by: bnilsen
Diffstat (limited to 'src')
-rw-r--r--src/gui/graphicsview/qgraphicsitem.cpp41
-rw-r--r--src/gui/graphicsview/qgraphicsitem_p.h1
2 files changed, 35 insertions, 7 deletions
diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 8a7a080..65d1e0a 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -885,6 +885,38 @@ void QGraphicsItemPrivate::setParentItemHelper(QGraphicsItem *newParent, bool de
/*!
\internal
+ Returns the bounding rect of this item's children (excluding itself).
+*/
+void QGraphicsItemPrivate::childrenBoundingRectHelper(QTransform *x, QRectF *rect)
+{
+ for (int i = 0; i < children.size(); ++i) {
+ QGraphicsItem *child = children.at(i);
+ QGraphicsItemPrivate *childd = child->d_ptr;
+ bool hasX = childd->hasTransform;
+ bool hasPos = !childd->pos.isNull();
+ if (hasPos || hasX) {
+ QTransform matrix;
+ if (hasX)
+ matrix = child->transform();
+ if (hasPos) {
+ const QPointF &p = childd->pos;
+ matrix *= QTransform::fromTranslate(p.x(), p.y());
+ }
+ matrix *= *x;
+ *rect |= matrix.mapRect(child->boundingRect());
+ if (!childd->children.isEmpty())
+ childd->childrenBoundingRectHelper(&matrix, rect);
+ } else {
+ *rect |= x->mapRect(child->boundingRect());
+ if (!childd->children.isEmpty())
+ childd->childrenBoundingRectHelper(x, rect);
+ }
+ }
+}
+
+/*!
+ \internal
+
Empty all cached pixmaps from the pixmap cache.
*/
void QGraphicsItemCache::purge()
@@ -3019,13 +3051,8 @@ void QGraphicsItem::setZValue(qreal z)
QRectF QGraphicsItem::childrenBoundingRect() const
{
QRectF childRect;
- foreach (QGraphicsItem *child, children()) {
- QPointF childPos = child->pos();
- QTransform matrix = child->transform();
- if (!childPos.isNull())
- matrix *= QTransform::fromTranslate(childPos.x(), childPos.y());
- childRect |= matrix.mapRect(child->boundingRect() | child->childrenBoundingRect());
- }
+ QTransform x;
+ d_ptr->childrenBoundingRectHelper(&x, &childRect);
return childRect;
}
diff --git a/src/gui/graphicsview/qgraphicsitem_p.h b/src/gui/graphicsview/qgraphicsitem_p.h
index 078c543..940e566 100644
--- a/src/gui/graphicsview/qgraphicsitem_p.h
+++ b/src/gui/graphicsview/qgraphicsitem_p.h
@@ -178,6 +178,7 @@ public:
void addChild(QGraphicsItem *child);
void removeChild(QGraphicsItem *child);
void setParentItemHelper(QGraphicsItem *parent, bool deleting);
+ void childrenBoundingRectHelper(QTransform *x, QRectF *rect);
virtual void resolveFont(uint inheritedMask)
{