diff options
| -rw-r--r-- | src/gui/graphicsview/qgraphicsanchorlayout_p.cpp | 46 | ||||
| -rw-r--r-- | src/gui/graphicsview/qgraphicsanchorlayout_p.h | 9 |
2 files changed, 45 insertions, 10 deletions
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp index 7ad994c..95922ca 100644 --- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp +++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp @@ -218,9 +218,20 @@ bool AnchorData::refreshSizeHints(const QLayoutStyleInfo *styleInfo) void ParallelAnchorData::updateChildrenSizes() { - firstEdge->sizeAtMinimum = secondEdge->sizeAtMinimum = sizeAtMinimum; - firstEdge->sizeAtPreferred = secondEdge->sizeAtPreferred = sizeAtPreferred; - firstEdge->sizeAtMaximum = secondEdge->sizeAtMaximum = sizeAtMaximum; + firstEdge->sizeAtMinimum = sizeAtMinimum; + firstEdge->sizeAtPreferred = sizeAtPreferred; + firstEdge->sizeAtMaximum = sizeAtMaximum; + + const bool secondFwd = (secondEdge->from == from); + if (secondFwd) { + secondEdge->sizeAtMinimum = sizeAtMinimum; + secondEdge->sizeAtPreferred = sizeAtPreferred; + secondEdge->sizeAtMaximum = sizeAtMaximum; + } else { + secondEdge->sizeAtMinimum = -sizeAtMinimum; + secondEdge->sizeAtPreferred = -sizeAtPreferred; + secondEdge->sizeAtMaximum = -sizeAtMaximum; + } firstEdge->updateChildrenSizes(); secondEdge->updateChildrenSizes(); @@ -239,8 +250,16 @@ bool ParallelAnchorData::refreshSizeHints_helper(const QLayoutStyleInfo *styleIn return false; } - minSize = qMax(firstEdge->minSize, secondEdge->minSize); - maxSize = qMin(firstEdge->maxSize, secondEdge->maxSize); + // Account for parallel anchors where the second edge is backwards. + // We rely on the fact that a forward anchor of sizes min, pref, max is equivalent + // to a backwards anchor of size (-max, -pref, -min) + const bool secondFwd = (secondEdge->from == from); + const qreal secondMin = secondFwd ? secondEdge->minSize : -secondEdge->maxSize; + const qreal secondPref = secondFwd ? secondEdge->prefSize : -secondEdge->prefSize; + const qreal secondMax = secondFwd ? secondEdge->maxSize : -secondEdge->minSize; + + minSize = qMax(firstEdge->minSize, secondMin); + maxSize = qMin(firstEdge->maxSize, secondMax); // This condition means that the maximum size of one anchor being simplified is smaller than // the minimum size of the other anchor. The consequence is that there won't be a valid size @@ -249,7 +268,22 @@ bool ParallelAnchorData::refreshSizeHints_helper(const QLayoutStyleInfo *styleIn return false; } - prefSize = qMax(firstEdge->prefSize, secondEdge->prefSize); + // The equivalent preferred Size of a parallel anchor is calculated as to + // reduce the deviation from the original preferred sizes _and_ to avoid shrinking + // items below their preferred sizes, unless strictly needed. + + // ### This logic only holds if all anchors in the layout are "well-behaved" in the + // following terms: + // + // - There are no negative-sized anchors + // - All sequential anchors are composed of children in the same direction as the + // sequential anchor itself + // + // With these assumptions we can grow a child knowing that no hidden items will + // have to shrink as the result of that. + // If any of these does not hold, we have a situation where the ParallelAnchor + // does not have enough information to calculate its equivalent prefSize. + prefSize = qMax(firstEdge->prefSize, secondPref); prefSize = qMin(prefSize, maxSize); // See comment in AnchorData::refreshSizeHints() about sizeAt* values diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.h b/src/gui/graphicsview/qgraphicsanchorlayout_p.h index 1e11ee2..8d77b1a 100644 --- a/src/gui/graphicsview/qgraphicsanchorlayout_p.h +++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.h @@ -256,10 +256,11 @@ struct ParallelAnchorData : public AnchorData type = AnchorData::Parallel; orientation = first->orientation; - // ### Those asserts force that both child anchors have the same direction, - // but can't we simplify a pair of anchors in opposite directions? - Q_ASSERT(first->from == second->from); - Q_ASSERT(first->to == second->to); + // This assert whether the child anchors share their vertices + Q_ASSERT(((first->from == second->from) && (first->to == second->to)) || + ((first->from == second->to) && (first->to == second->from))); + + // We arbitrarily choose the direction of the first child as "our" direction from = first->from; to = first->to; #ifdef QT_DEBUG |