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-rw-r--r--src/gui/graphicsview/qgraphicsanchorlayout_p.cpp67
-rw-r--r--src/gui/graphicsview/qsimplex_p.h2
2 files changed, 57 insertions, 12 deletions
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
index d9f4e32..f3a1a69 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -49,9 +49,17 @@
#endif
#include "qgraphicsanchorlayout_p.h"
+
#ifndef QT_NO_GRAPHICSVIEW
QT_BEGIN_NAMESPACE
+// To ensure that all variables inside the simplex solver are non-negative,
+// we limit the size of anchors in the interval [-limit, limit]. Then before
+// sending them to the simplex solver we add "limit" as an offset, so that
+// they are actually calculated in the interval [0, 2 * limit]
+// To avoid numerical errors in platforms where we use single precision,
+// we use a tighter limit for the variables range.
+const qreal limit = (sizeof(qreal) == sizeof(double)) ? QWIDGETSIZE_MAX : QWIDGETSIZE_MAX / 32;
QGraphicsAnchorPrivate::QGraphicsAnchorPrivate(int version)
: QObjectPrivate(version), layoutPrivate(0), data(0),
@@ -2086,6 +2094,25 @@ void QGraphicsAnchorLayoutPrivate::calculateGraphs(
/*!
\internal
+ Shift all the constraints by a certain amount. This allows us to deal with negative values in
+ the linear program if they are bounded by a certain limit. Functions should be careful to
+ call it again with a negative amount, to shift the constraints back.
+*/
+static void shiftConstraints(const QList<QSimplexConstraint *> &constraints, qreal amount)
+{
+ for (int i = 0; i < constraints.count(); ++i) {
+ QSimplexConstraint *c = constraints.at(i);
+ qreal multiplier = 0;
+ foreach (qreal v, c->variables.values()) {
+ multiplier += v;
+ }
+ c->constant += multiplier * amount;
+ }
+}
+
+/*!
+ \internal
+
Calculate the sizes for all anchors which are part of the trunk. This works
on top of a (possibly) simplified graph.
*/
@@ -2106,6 +2133,8 @@ bool QGraphicsAnchorLayoutPrivate::calculateTrunk(Orientation orientation, const
QList<QSimplexConstraint *> sizeHintConstraints = constraintsFromSizeHints(variables);
QList<QSimplexConstraint *> allConstraints = constraints + sizeHintConstraints;
+ shiftConstraints(allConstraints, limit);
+
// Solve min and max size hints
qreal min, max;
feasible = solveMinMax(allConstraints, path, &min, &max);
@@ -2129,6 +2158,7 @@ bool QGraphicsAnchorLayoutPrivate::calculateTrunk(Orientation orientation, const
}
qDeleteAll(sizeHintConstraints);
+ shiftConstraints(constraints, -limit);
} else {
// No Simplex is necessary because the path was simplified all the way to a single
@@ -2160,6 +2190,10 @@ bool QGraphicsAnchorLayoutPrivate::calculateNonTrunk(const QList<QSimplexConstra
const QList<AnchorData *> &variables)
{
QList<QSimplexConstraint *> sizeHintConstraints = constraintsFromSizeHints(variables);
+
+ shiftConstraints(sizeHintConstraints, limit);
+ shiftConstraints(constraints, limit);
+
bool feasible = solvePreferred(constraints + sizeHintConstraints, variables);
if (feasible) {
@@ -2174,6 +2208,9 @@ bool QGraphicsAnchorLayoutPrivate::calculateNonTrunk(const QList<QSimplexConstra
}
qDeleteAll(sizeHintConstraints);
+
+ shiftConstraints(constraints, -limit);
+
return feasible;
}
@@ -2337,17 +2374,23 @@ QList<QSimplexConstraint *> QGraphicsAnchorLayoutPrivate::constraintsFromSizeHin
if (ad->dependency == AnchorData::Slave)
continue;
- if ((ad->minSize == ad->maxSize) || qFuzzyCompare(ad->minSize, ad->maxSize)) {
+ // To use negative variables inside simplex, we shift them so the minimum negative value is
+ // mapped to zero before solving. To make sure that it works, we need to guarantee that the
+ // variables are all inside a certain boundary.
+ qreal boundedMin = qBound(-limit, ad->minSize, limit);
+ qreal boundedMax = qBound(-limit, ad->maxSize, limit);
+
+ if ((boundedMin == boundedMax) || qFuzzyCompare(boundedMin, boundedMax)) {
QSimplexConstraint *c = new QSimplexConstraint;
c->variables.insert(ad, 1.0);
- c->constant = ad->minSize;
+ c->constant = boundedMin;
c->ratio = QSimplexConstraint::Equal;
anchorConstraints += c;
unboundedProblem = false;
} else {
QSimplexConstraint *c = new QSimplexConstraint;
c->variables.insert(ad, 1.0);
- c->constant = ad->minSize;
+ c->constant = boundedMin;
c->ratio = QSimplexConstraint::MoreOrEqual;
anchorConstraints += c;
@@ -2359,7 +2402,7 @@ QList<QSimplexConstraint *> QGraphicsAnchorLayoutPrivate::constraintsFromSizeHin
c = new QSimplexConstraint;
c->variables.insert(ad, 1.0);
- c->constant = ad->maxSize;
+ c->constant = boundedMax;
c->ratio = QSimplexConstraint::LessOrEqual;
anchorConstraints += c;
unboundedProblem = false;
@@ -2370,7 +2413,8 @@ QList<QSimplexConstraint *> QGraphicsAnchorLayoutPrivate::constraintsFromSizeHin
if (unboundedProblem) {
QSimplexConstraint *c = new QSimplexConstraint;
c->variables.insert(layoutEdge, 1.0);
- c->constant = QWIDGETSIZE_MAX;
+ // The maximum size that the layout can take
+ c->constant = limit;
c->ratio = QSimplexConstraint::LessOrEqual;
anchorConstraints += c;
}
@@ -2691,27 +2735,28 @@ bool QGraphicsAnchorLayoutPrivate::solveMinMax(const QList<QSimplexConstraint *>
for (iter = path.negatives.constBegin(); iter != path.negatives.constEnd(); ++iter)
objective.variables.insert(*iter, -1.0);
+ const qreal objectiveOffset = (path.positives.count() - path.negatives.count()) * limit;
simplex.setObjective(&objective);
// Calculate minimum values
- *min = simplex.solveMin();
+ *min = simplex.solveMin() - objectiveOffset;
// Save sizeAtMinimum results
QList<AnchorData *> variables = getVariables(constraints);
for (int i = 0; i < variables.size(); ++i) {
AnchorData *ad = static_cast<AnchorData *>(variables.at(i));
- ad->sizeAtMinimum = ad->result;
+ ad->sizeAtMinimum = ad->result - limit;
Q_ASSERT(ad->sizeAtMinimum >= ad->minSize ||
qAbs(ad->sizeAtMinimum - ad->minSize) < 0.00000001);
}
// Calculate maximum values
- *max = simplex.solveMax();
+ *max = simplex.solveMax() - objectiveOffset;
// Save sizeAtMaximum results
for (int i = 0; i < variables.size(); ++i) {
AnchorData *ad = static_cast<AnchorData *>(variables.at(i));
- ad->sizeAtMaximum = ad->result;
+ ad->sizeAtMaximum = ad->result - limit;
// Q_ASSERT(ad->sizeAtMaximum <= ad->maxSize ||
// qAbs(ad->sizeAtMaximum - ad->maxSize) < 0.00000001);
}
@@ -2756,7 +2801,7 @@ bool QGraphicsAnchorLayoutPrivate::solvePreferred(const QList<QSimplexConstraint
c->variables.insert(ad, 1.0);
c->variables.insert(shrinker, 1.0);
c->variables.insert(grower, -1.0);
- c->constant = ad->prefSize;
+ c->constant = ad->prefSize + limit;
preferredConstraints += c;
preferredVariables += grower;
@@ -2778,7 +2823,7 @@ bool QGraphicsAnchorLayoutPrivate::solvePreferred(const QList<QSimplexConstraint
// Save sizeAtPreferred results
for (int i = 0; i < variables.size(); ++i) {
AnchorData *ad = variables.at(i);
- ad->sizeAtPreferred = ad->result;
+ ad->sizeAtPreferred = ad->result - limit;
}
// Make sure we delete the simplex solver -before- we delete the
diff --git a/src/gui/graphicsview/qsimplex_p.h b/src/gui/graphicsview/qsimplex_p.h
index a5816d1..2004471 100644
--- a/src/gui/graphicsview/qsimplex_p.h
+++ b/src/gui/graphicsview/qsimplex_p.h
@@ -107,7 +107,7 @@ struct QSimplexConstraint
Q_ASSERT(constant > 0 || qFuzzyCompare(1, 1 + constant));
- if ((leftHandSide == constant) || qAbs(leftHandSide - constant) < 0.00000001)
+ if ((leftHandSide == constant) || qAbs(leftHandSide - constant) < 0.0000001)
return true;
switch (ratio) {
generated by cgit v0.12 at 2025-08-13 05:11:50 (GMT)