RetroShare/retroshare-gui/src/gui/elastic/arrow.cpp
2018-11-13 22:02:26 +01:00

128 lines
4.4 KiB
C++

/*******************************************************************************
* gui/elastic/arrow.cpp *
* *
* Copyright (c) 2012, RetroShare Team <retroshare.project@gmail.com> *
* *
* This program is free software: you can redistribute it and/or modify *
* it under the terms of the GNU Affero General Public License as *
* published by the Free Software Foundation, either version 3 of the *
* License, or (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU Affero General Public License for more details. *
* *
* You should have received a copy of the GNU Affero General Public License *
* along with this program. If not, see <https://www.gnu.org/licenses/>. *
* *
*******************************************************************************/
// This code is inspired from http://doc.qt.io/qt-5/qtwidgets-graphicsview-diagramscene-arrow-cpp.html
#include <QPainter>
#include "arrow.h"
#include "elnode.h"
#include <math.h>
static const double Pi = 3.14159265358979323846264338327950288419717;
static double TwoPi = 2.0 * Pi;
Arrow::Arrow(Node *sourceNode, Node *destNode)
: arrowSize(10)
{
setAcceptedMouseButtons(0);
source = sourceNode;
dest = destNode;
#ifdef SUSP
source->addArrow(this);
dest->addArrow(this);
#endif
adjust();
}
Arrow::~Arrow()
{
}
Node *Arrow::sourceNode() const
{
return source;
}
void Arrow::setSourceNode(Node *node)
{
source = node;
adjust();
}
Node *Arrow::destNode() const
{
return dest;
}
void Arrow::setDestNode(Node *node)
{
dest = node;
adjust();
}
void Arrow::adjust()
{
if (!source || !dest)
return;
QLineF line(mapFromItem(source, 0, 0), mapFromItem(dest, 0, 0));
qreal length = line.length();
QPointF edgeOffset((line.dx() * 10) / length, (line.dy() * 10) / length);
prepareGeometryChange();
sourcePoint = line.p1() + edgeOffset;
destPoint = line.p2() - edgeOffset;
}
QRectF Arrow::boundingRect() const
{
if (!source || !dest)
return QRectF();
qreal penWidth = 1;
qreal extra = (penWidth + arrowSize) / 2.0;
return QRectF(sourcePoint, QSizeF(destPoint.x() - sourcePoint.x(),
destPoint.y() - sourcePoint.y()))
.normalized()
.adjusted(-extra, -extra, extra, extra);
}
void Arrow::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
if (!source || !dest)
return;
// Draw the line itself
QLineF line(sourcePoint, destPoint);
//painter->setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
painter->setPen(QPen(Qt::red, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
painter->drawLine(line);
// Draw the arrows if there's enough room
double angle = ::acos(line.dx() / line.length());
if (line.dy() >= 0)
angle = TwoPi - angle;
QPointF sourceArrowP1 = sourcePoint + QPointF(sin(angle + Pi / 3) * arrowSize,
cos(angle + Pi / 3) * arrowSize);
QPointF sourceArrowP2 = sourcePoint + QPointF(sin(angle + Pi - Pi / 3) * arrowSize,
cos(angle + Pi - Pi / 3) * arrowSize);
QPointF destArrowP1 = destPoint + QPointF(sin(angle - Pi / 3) * arrowSize,
cos(angle - Pi / 3) * arrowSize);
QPointF destArrowP2 = destPoint + QPointF(sin(angle - Pi + Pi / 3) * arrowSize,
cos(angle - Pi + Pi / 3) * arrowSize);
painter->setBrush(Qt::black);
painter->drawPolygon(QPolygonF() << line.p1() << sourceArrowP1 << sourceArrowP2);
painter->drawPolygon(QPolygonF() << line.p2() << destArrowP1 << destArrowP2);
}