diff options
| -rw-r--r-- | src/gui/graphicsview/qgraphicsanchorlayout_p.cpp | 90 |
1 files changed, 61 insertions, 29 deletions
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp index a92a63e..8b7ff08 100644 --- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp +++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp @@ -519,18 +519,51 @@ inline static qreal checkAdd(qreal a, qreal b) } /*! - * \internal - * - * Takes the sequence of vertices described by (\a before, \a vertices, \a after) and replaces - * all anchors connected to the vertices in \a vertices with one simplified anchor between - * \a before and \a after. The simplified anchor will be a placeholder for all the previous - * anchors between \a before and \a after, and can be restored back to the anchors it is a - * placeholder for. - */ -static bool simplifySequentialChunk(Graph<AnchorVertex, AnchorData> *graph, - AnchorVertex *before, - const QVector<AnchorVertex*> &vertices, - AnchorVertex *after) + \internal + + Adds \a newAnchor to the graph \a g. + + Returns the newAnchor itself if it could be added without further changes to the graph. If a + new parallel anchor had to be created, then returns the new parallel anchor. In case the + addition is unfeasible -- because a parallel setup is not possible, returns 0. +*/ +static AnchorData *addAnchorMaybeParallel(Graph<AnchorVertex, AnchorData> *g, + AnchorData *newAnchor) +{ + bool feasible = true; + + // If already exists one anchor where newAnchor is supposed to be, we create a parallel + // anchor. + if (AnchorData *oldAnchor = g->takeEdge(newAnchor->from, newAnchor->to)) { + ParallelAnchorData *parallel = new ParallelAnchorData(oldAnchor, newAnchor); + parallel->isLayoutAnchor = (oldAnchor->isLayoutAnchor + || newAnchor->isLayoutAnchor); + + // At this point we can identify that the parallel anchor is not feasible, e.g. one + // anchor minimum size is bigger than the other anchor maximum size. + feasible = parallel->refreshSizeHints_helper(0, false); + newAnchor = parallel; + } + + g->createEdge(newAnchor->from, newAnchor->to, newAnchor); + return feasible ? newAnchor : 0; +} + + +/*! + \internal + + Takes the sequence of vertices described by (\a before, \a vertices, \a after) and removes + all anchors connected to the vertices in \a vertices, returning one simplified anchor between + \a before and \a after. + + Note that this function doesn't add the created anchor to the graph. This should be done by + the caller. +*/ +static AnchorData *createSequence(Graph<AnchorVertex, AnchorData> *graph, + AnchorVertex *before, + const QVector<AnchorVertex*> &vertices, + AnchorVertex *after) { AnchorData *data = graph->edgeData(before, vertices.first()); Q_ASSERT(data); @@ -578,18 +611,7 @@ static bool simplifySequentialChunk(Graph<AnchorVertex, AnchorData> *graph, sequence->isLayoutAnchor = (sequence->m_edges.first()->isLayoutAnchor || sequence->m_edges.last()->isLayoutAnchor); - AnchorData *newAnchor = sequence; - if (AnchorData *oldAnchor = graph->takeEdge(before, after)) { - ParallelAnchorData *parallel = new ParallelAnchorData(oldAnchor, sequence); - parallel->isLayoutAnchor = (oldAnchor->isLayoutAnchor - || sequence->isLayoutAnchor); - parallel->refreshSizeHints_helper(0, false); - newAnchor = parallel; - } - graph->createEdge(before, after, newAnchor); - - // True if we created a parallel anchor - return newAnchor != sequence; + return sequence; } /*! @@ -803,11 +825,21 @@ bool QGraphicsAnchorLayoutPrivate::simplifyGraphIteration(QGraphicsAnchorLayoutP continue; } - // This function will remove the candidates from the graph and create one edge between - // beforeSequence and afterSequence. This function returns true if the sequential - // simplification also caused a parallel simplification to be created. In this case we end - // the iteration and start again (since all the visited state we have may be outdated). - if (simplifySequentialChunk(&g, beforeSequence, candidates, afterSequence)) + // + // Add the sequence to the graph. + // + + AnchorData *sequence = createSequence(&g, beforeSequence, candidates, afterSequence); + + // If 'beforeSequence' and 'afterSequence' already had an anchor between them, we'll + // create a parallel anchor between the new sequence and the old anchor. + AnchorData *newAnchor = addAnchorMaybeParallel(&g, sequence); + + // When a new parallel anchor is create in the graph, we finish the iteration and return + // true to indicate a new iteration is needed. This happens because a parallel anchor + // changes the number of adjacents one vertex has, possibly opening up oportunities for + // building candidate lists (when adjacents == 2). + if (newAnchor != sequence) return true; // If there was no parallel simplification, we'll keep walking the graph. So we clear the |