QPointF RoundCornersCommand::tangentAtEnd( const KoPathSegment &s )
{
QList<QPointF> cp = s.controlPoints();
QPointF tn = cp[cp.count()-2] - cp.last();
qreal length = sqrt( tn.x()*tn.x() + tn.y()*tn.y() );
return tn / length;
}
QPointF RoundCornersCommand::tangentAtStart(const KoPathSegment &s)
{
QVector<QPointF> cp = s.controlPoints();
QPointF tn = cp[1] - cp.first();
qreal length = sqrt(tn.x() * tn.x() + tn.y() * tn.y());
return tn / length;
}
void KoPathSegmentChangeStrategy::handleMouseMove(const QPointF &mouseLocation, Qt::KeyboardModifiers modifiers)
{
m_tool->canvas()->updateCanvas(m_tool->canvas()->snapGuide()->boundingRect());
QPointF snappedPosition = m_tool->canvas()->snapGuide()->snap(mouseLocation, modifiers);
m_tool->canvas()->updateCanvas(m_tool->canvas()->snapGuide()->boundingRect());
QPointF localPos = m_path->documentToShape(snappedPosition);
if (m_segment.degree() == 1) {
// line segment is converted to a curve
KoPathSegmentTypeCommand cmd(m_pointData1, KoPathSegmentTypeCommand::Curve);
cmd.redo();
}
QPointF move1, move2;
if (m_segment.degree() == 2) {
// interpolate quadratic segment between segment start, mouse position and segment end
KoPathSegment ipol = KoPathSegment::interpolate(m_segment.first()->point(),
localPos,
m_segment.second()->point(),
m_segmentParam);
if (ipol.isValid()) {
move1 = move2 = ipol.controlPoints()[1] - m_segment.controlPoints()[1];
}
}
else if (m_segment.degree() == 3) {
/*
* method from inkscape, original method and idea borrowed from Simon Budig
* <*****@*****.**> and the GIMP
* cf. app/vectors/gimpbezierstroke.c, gimp_bezier_stroke_point_move_relative()
*
* feel good is an arbitrary parameter that distributes the delta between handles
* if t of the drag point is less than 1/6 distance form the endpoint only
* the corresponding handle is adjusted. This matches the behavior in GIMP
*/
const qreal t = m_segmentParam;
qreal feel_good;
if (t <= 1.0 / 6.0)
feel_good = 0;
else if (t <= 0.5)
feel_good = (pow((6 * t - 1) / 2.0, 3)) / 2;
else if (t <= 5.0 / 6.0)
feel_good = (1 - pow((6 * (1-t) - 1) / 2.0, 3)) / 2 + 0.5;
else
feel_good = 1;
QPointF lastLocalPos = m_path->documentToShape(m_lastPosition);
QPointF delta = localPos - lastLocalPos;
move2 = ((1-feel_good)/(3*t*(1-t)*(1-t))) * delta;
move1 = (feel_good/(3*t*t*(1-t))) * delta;
}
m_path->update();
if(m_segment.first()->activeControlPoint2()) {
KoPathControlPointMoveCommand cmd(m_pointData1, move2, KoPathPoint::ControlPoint2);
cmd.redo();
}
if(m_segment.second()->activeControlPoint1()) {
KoPathControlPointMoveCommand cmd(m_pointData2, move1, KoPathPoint::ControlPoint1);
cmd.redo();
}
m_path->normalize();
m_path->update();
m_ctrlPoint1Move += move1;
m_ctrlPoint2Move += move2;
// save last mouse position
m_lastPosition = mouseLocation;
}
