BoundingBoxSnapStrategy Class Reference

snaps to shape bounding boxes More...

#include <KoSnapStrategy.h>

Inheritance diagram for BoundingBoxSnapStrategy:

Public Member Functions
	BoundingBoxSnapStrategy ()
QPainterPath	decoration (const KoViewConverter &converter) const override
	returns the current snap strategy decoration
bool	snap (const QPointF &mousePosition, KoSnapProxy *proxy, qreal maxSnapDistance) override
Public Member Functions inherited from KoSnapStrategy
	KoSnapStrategy (KoSnapGuide::Strategy type)
QPointF	snappedPosition () const
	returns the snapped position form the last call to snapToPoints
SnapType	snappedType () const
KoSnapGuide::Strategy	type () const
	returns the strategies type
virtual	~KoSnapStrategy ()

Private Member Functions
qreal	squareDistanceToLine (const QPointF &lineA, const QPointF &lineB, const QPointF &point, QPointF &pointOnLine)

Private Attributes
QPointF	m_boxPoints [5]

Friends
class	TestSnapStrategy

Additional Inherited Members
Public Types inherited from KoSnapStrategy
enum	SnapType { ToPoint = 0 , ToLine }
Static Public Member Functions inherited from KoSnapStrategy
static qreal	scalarProduct (const QPointF &p1, const QPointF &p2)
static qreal	squareDistance (const QPointF &p1, const QPointF &p2)
Protected Member Functions inherited from KoSnapStrategy
void	setSnappedPosition (const QPointF &position, SnapType snapType)
	sets the current snapped position

Detailed Description

snaps to shape bounding boxes

Definition at line 119 of file KoSnapStrategy.h.

Constructor & Destructor Documentation

BoundingBoxSnapStrategy()

BoundingBoxSnapStrategy::BoundingBoxSnapStrategy

(

)

Definition at line 499 of file KoSnapStrategy.cpp.

    : KoSnapStrategy(KoSnapGuide::BoundingBoxSnapping)
{
}

Member Function Documentation

decoration()

QPainterPath BoundingBoxSnapStrategy::decoration ( const KoViewConverter & converter ) const

overridevirtual

returns the current snap strategy decoration

Implements KoSnapStrategy.

Definition at line 576 of file KoSnapStrategy.cpp.

{
    QSizeF unzoomedSize = converter.viewToDocument(QSizeF(5, 5));
 
    QPainterPath decoration;
    decoration.moveTo(snappedPosition() - QPointF(unzoomedSize.width(), unzoomedSize.height()));
    decoration.lineTo(snappedPosition() + QPointF(unzoomedSize.width(), unzoomedSize.height()));
    decoration.moveTo(snappedPosition() - QPointF(unzoomedSize.width(), -unzoomedSize.height()));
    decoration.lineTo(snappedPosition() + QPointF(unzoomedSize.width(), -unzoomedSize.height()));
 
    return decoration;
}

References decoration(), KoSnapStrategy::snappedPosition(), and KoViewConverter::viewToDocument().

snap()

bool BoundingBoxSnapStrategy::snap ( const QPointF & mousePosition, KoSnapProxy * proxy, qreal maxSnapDistance )

overridevirtual

Implements KoSnapStrategy.

Definition at line 504 of file KoSnapStrategy.cpp.

{
    Q_ASSERT(std::isfinite(maxSnapDistance));
    const qreal maxDistance = maxSnapDistance * maxSnapDistance;
    qreal minDistance = HUGE_VAL;
 
    QRectF rect(-maxSnapDistance, -maxSnapDistance, maxSnapDistance, maxSnapDistance);
 
    rect.moveCenter(mousePosition);
    QPointF snappedPoint = mousePosition;
    SnapType snapType = ToPoint;
 
    KoFlake::AnchorPosition pointId[5] = {
        KoFlake::TopLeft,
        KoFlake::TopRight,
        KoFlake::BottomRight,
        KoFlake::BottomLeft,
        KoFlake::Center
    };
 
    QList<KoShape*> shapes = proxy->shapesInRect(rect, true);
    Q_FOREACH (KoShape * shape, shapes) {
        qreal shapeMinDistance = HUGE_VAL;
        // first check the corner and center points
        for (int i = 0; i < 5; ++i) {
            m_boxPoints[i] = shape->absolutePosition(pointId[i]);
            qreal d = squareDistance(mousePosition, m_boxPoints[i]);
            if (d < minDistance && d < maxDistance) {
                shapeMinDistance = d;
                minDistance = d;
                snappedPoint = m_boxPoints[i];
                snapType = ToPoint;
            }
        }
        // prioritize points over edges
        if (shapeMinDistance < maxDistance)
            continue;
 
        // now check distances to edges of bounding box
        for (int i = 0; i < 4; ++i) {
            QPointF pointOnLine;
            qreal d = squareDistanceToLine(m_boxPoints[i], m_boxPoints[(i+1)%4], mousePosition, pointOnLine);
            if (d < minDistance && d < maxDistance) {
                minDistance = d;
                snappedPoint = pointOnLine;
                snapType = ToLine;
            }
        }
    }
    setSnappedPosition(snappedPoint, snapType);
 
    return (minDistance < maxDistance);
}

References KoShape::absolutePosition(), KoFlake::BottomLeft, KoFlake::BottomRight, KoFlake::Center, m_boxPoints, KoSnapStrategy::setSnappedPosition(), KoSnapProxy::shapesInRect(), KoSnapStrategy::squareDistance(), squareDistanceToLine(), KoSnapStrategy::ToLine, KoFlake::TopLeft, KoSnapStrategy::ToPoint, and KoFlake::TopRight.

squareDistanceToLine()

qreal BoundingBoxSnapStrategy::squareDistanceToLine ( const QPointF & lineA, const QPointF & lineB, const QPointF & point, QPointF & pointOnLine )

private

Definition at line 558 of file KoSnapStrategy.cpp.

{
    QPointF diff = lineB - lineA;
    if(lineA == lineB)
        return HUGE_VAL;
    const qreal diffLength = sqrt(diff.x() * diff.x() + diff.y() * diff.y());
 
    // project mouse position relative to start position on line
    const qreal scalar = KoSnapStrategy::scalarProduct(point - lineA, diff / diffLength);
 
    if (scalar < 0.0 || scalar > diffLength)
        return HUGE_VAL;
    // calculate vector between relative mouse position and projected mouse position
    pointOnLine = lineA + scalar / diffLength * diff;
    QPointF distVec = pointOnLine - point;
    return distVec.x()*distVec.x() + distVec.y()*distVec.y();
}

References KoSnapStrategy::scalarProduct().

Friends And Related Symbol Documentation

TestSnapStrategy

friend class TestSnapStrategy

friend

Definition at line 121 of file KoSnapStrategy.h.

Member Data Documentation

m_boxPoints

QPointF BoundingBoxSnapStrategy::m_boxPoints[5]

private

Definition at line 128 of file KoSnapStrategy.h.

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The documentation for this class was generated from the following files:

• libs/flake/KoSnapStrategy.h
• libs/flake/KoSnapStrategy.cpp