LibrePilot/ground/src/plugins/config/mixercurvepoint.cpp

/**
 ******************************************************************************
 *
 * @file       mixercurvepoint.h
 * @author     Edouard Lafargue Copyright (C) 2010.
 *             Parts by Nokia Corporation (qt-info@nokia.com) Copyright (C) 2010.
 * @addtogroup GCSPlugins GCS Plugins
 * @{
 * @addtogroup ConfigPlugin Configuration Plugin
 * @{
 * @brief A point on the mixer curve
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <QGraphicsScene>
#include <QGraphicsSceneMouseEvent>
#include <QPainter>
#include <QStyleOption>

#include "mixercurveline.h"
#include "mixercurvepoint.h"
#include "mixercurvewidget.h"

Node::Node(MixerCurveWidget *graphWidget)
    : graph(graphWidget)
{
    setFlag(ItemIsMovable);
    setFlag(ItemSendsGeometryChanges);
    setCacheMode(DeviceCoordinateCache);
    setZValue(-1);
    vertical = false;
}

void Node::addEdge(Edge *edge)
{
    edgeList << edge;
    edge->adjust();
}

QList<Edge *> Node::edges() const
{
    return edgeList;
}

void Node::calculateForces()
{
    if (!scene() || scene()->mouseGrabberItem() == this) {
        newPos = pos();
        return;
    }
    
    // Sum up all forces pushing this item away
    qreal xvel = 0;
    qreal yvel = 0;
    foreach (QGraphicsItem *item, scene()->items()) {
        Node *node = qgraphicsitem_cast<Node *>(item);
        if (!node)
            continue;

        QLineF line(mapFromItem(node, 0, 0), QPointF(0, 0));
        qreal dx = line.dx();
        qreal dy = line.dy();
        double l = 2.0 * (dx * dx + dy * dy);
        if (l > 0) {
            xvel += (dx * 150.0) / l;
            yvel += (dy * 150.0) / l;
        }
    }

    // Now subtract all forces pulling items together
    double weight = (edgeList.size() + 1) * 10;
    foreach (Edge *edge, edgeList) {
        QPointF pos;
        if (edge->sourceNode() == this)
            pos = mapFromItem(edge->destNode(), 0, 0);
        else
            pos = mapFromItem(edge->sourceNode(), 0, 0);
        xvel += pos.x() / weight;
        yvel += pos.y() / weight;
    }
    
    if (qAbs(xvel) < 0.1 && qAbs(yvel) < 0.1)
        xvel = yvel = 0;

    QRectF sceneRect = scene()->sceneRect();
    newPos = pos() + QPointF(xvel, yvel);
    newPos.setX(qMin(qMax(newPos.x(), sceneRect.left() + 10), sceneRect.right() - 10));
    newPos.setY(qMin(qMax(newPos.y(), sceneRect.top() + 10), sceneRect.bottom() - 10));
}

bool Node::advance()
{
    if (newPos == pos())
        return false;

    setPos(newPos);
    return true;
}

QRectF Node::boundingRect() const
{
    qreal adjust = 2;
    return QRectF(-10 - adjust, -10 - adjust,
                  23 + adjust, 23 + adjust);
}

QPainterPath Node::shape() const
{
    QPainterPath path;
    path.addEllipse(-10, -10, 20, 20);
    return path;
}

void Node::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *)
{
    painter->setPen(Qt::NoPen);
    painter->setBrush(Qt::darkGray);
    painter->drawEllipse(-7, -7, 20, 20);

    QRadialGradient gradient(-3, -3, 10);
    if (option->state & QStyle::State_Sunken) {
        gradient.setCenter(3, 3);
        gradient.setFocalPoint(3, 3);
        gradient.setColorAt(1, QColor(Qt::yellow).light(120));
        gradient.setColorAt(0, QColor(Qt::darkYellow).light(120));
    } else {
        gradient.setColorAt(0, Qt::yellow);
        gradient.setColorAt(1, Qt::darkYellow);
    }
    painter->setBrush(gradient);
    painter->setPen(QPen(Qt::black, 0));
    painter->drawEllipse(-10, -10, 20, 20);
}

void Node::verticalMove(bool flag){
    vertical = flag;
}

QVariant Node::itemChange(GraphicsItemChange change, const QVariant &value)
{

    switch (change) {
    case ItemPositionChange: {
            if (!vertical)
                    break;
            // Foce node to move vertically
            QPointF newPos = value.toPointF();
            newPos.setX(pos().x());
            return newPos;
    }
    case ItemPositionHasChanged:
        foreach (Edge *edge, edgeList)
            edge->adjust();
        graph->itemMoved();
        break;
    default:
        break;
    };

    return QGraphicsItem::itemChange(change, value);
}

void Node::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    update();
    QGraphicsItem::mousePressEvent(event);
}

void Node::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    update();
    QGraphicsItem::mouseReleaseEvent(event);
}