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<pre><span class="comment"> /****************************************************************************
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**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
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#include "graphwidget.h"
#include "edge.h"
#include "node.h"
#include <QDebug>
#include <QGraphicsScene>
#include <QWheelEvent>
#include <math.h>
GraphWidget::GraphWidget()
: timerId(0)
{
QGraphicsScene *scene = new QGraphicsScene(this);
scene->setItemIndexMethod(QGraphicsScene::NoIndex);
scene->setSceneRect(-200, -200, 400, 400);
setScene(scene);
setCacheMode(CacheBackground);
setViewportUpdateMode(BoundingRectViewportUpdate);
setRenderHint(QPainter::Antialiasing);
setTransformationAnchor(AnchorUnderMouse);
setResizeAnchor(AnchorViewCenter);
Node *node1 = new Node(this);
Node *node2 = new Node(this);
Node *node3 = new Node(this);
Node *node4 = new Node(this);
centerNode = new Node(this);
Node *node6 = new Node(this);
Node *node7 = new Node(this);
Node *node8 = new Node(this);
Node *node9 = new Node(this);
scene->addItem(node1);
scene->addItem(node2);
scene->addItem(node3);
scene->addItem(node4);
scene->addItem(centerNode);
scene->addItem(node6);
scene->addItem(node7);
scene->addItem(node8);
scene->addItem(node9);
scene->addItem(new Edge(node1, node2));
scene->addItem(new Edge(node2, node3));
scene->addItem(new Edge(node2, centerNode));
scene->addItem(new Edge(node3, node6));
scene->addItem(new Edge(node4, node1));
scene->addItem(new Edge(node4, centerNode));
scene->addItem(new Edge(centerNode, node6));
scene->addItem(new Edge(centerNode, node8));
scene->addItem(new Edge(node6, node9));
scene->addItem(new Edge(node7, node4));
scene->addItem(new Edge(node8, node7));
scene->addItem(new Edge(node9, node8));
node1->setPos(-50, -50);
node2->setPos(0, -50);
node3->setPos(50, -50);
node4->setPos(-50, 0);
centerNode->setPos(0, 0);
node6->setPos(50, 0);
node7->setPos(-50, 50);
node8->setPos(0, 50);
node9->setPos(50, 50);
scale(qreal(0.8), qreal(0.8));
setMinimumSize(400, 400);
setWindowTitle(tr("Elastic Nodes"));
}
void GraphWidget::itemMoved()
{
if (!timerId)
timerId = startTimer(1000 / 25);
}
void GraphWidget::keyPressEvent(QKeyEvent *event)
{
switch (event->key()) {
case Qt::Key_Up:
centerNode->moveBy(0, -20);
break;
case Qt::Key_Down:
centerNode->moveBy(0, 20);
break;
case Qt::Key_Left:
centerNode->moveBy(-20, 0);
break;
case Qt::Key_Right:
centerNode->moveBy(20, 0);
break;
case Qt::Key_Plus:
scaleView(qreal(1.2));
break;
case Qt::Key_Minus:
scaleView(1 / qreal(1.2));
break;
case Qt::Key_Space:
case Qt::Key_Enter:
foreach (QGraphicsItem *item, scene()->items()) {
if (qgraphicsitem_cast<Node *>(item))
item->setPos(-150 + qrand() % 300, -150 + qrand() % 300);
}
break;
default:
QGraphicsView::keyPressEvent(event);
}
}
void GraphWidget::timerEvent(QTimerEvent *event)
{
Q_UNUSED(event);
QList<Node *> nodes;
foreach (QGraphicsItem *item, scene()->items()) {
if (Node *node = qgraphicsitem_cast<Node *>(item))
nodes << node;
}
foreach (Node *node, nodes)
node->calculateForces();
bool itemsMoved = false;
foreach (Node *node, nodes) {
if (node->advance())
itemsMoved = true;
}
if (!itemsMoved) {
killTimer(timerId);
timerId = 0;
}
}
void GraphWidget::wheelEvent(QWheelEvent *event)
{
scaleView(pow((double)2, -event->delta() / 240.0));
}
void GraphWidget::drawBackground(QPainter *painter, const QRectF &rect)
{
Q_UNUSED(rect);
<span class="comment">// Shadow</span>
QRectF sceneRect = this->sceneRect();
QRectF rightShadow(sceneRect.right(), sceneRect.top() + 5, 5, sceneRect.height());
QRectF bottomShadow(sceneRect.left() + 5, sceneRect.bottom(), sceneRect.width(), 5);
if (rightShadow.intersects(rect) || rightShadow.contains(rect))
painter->fillRect(rightShadow, Qt::darkGray);
if (bottomShadow.intersects(rect) || bottomShadow.contains(rect))
painter->fillRect(bottomShadow, Qt::darkGray);
<span class="comment">// Fill</span>
QLinearGradient gradient(sceneRect.topLeft(), sceneRect.bottomRight());
gradient.setColorAt(0, Qt::white);
gradient.setColorAt(1, Qt::lightGray);
painter->fillRect(rect.intersect(sceneRect), gradient);
painter->setBrush(Qt::NoBrush);
painter->drawRect(sceneRect);
<span class="comment">// Text</span>
QRectF textRect(sceneRect.left() + 4, sceneRect.top() + 4,
sceneRect.width() - 4, sceneRect.height() - 4);
QString message(tr("Click and drag the nodes around, and zoom with the mouse "
"wheel or the '+' and '-' keys"));
QFont font = painter->font();
font.setBold(true);
font.setPointSize(14);
painter->setFont(font);
painter->setPen(Qt::lightGray);
painter->drawText(textRect.translated(2, 2), message);
painter->setPen(Qt::black);
painter->drawText(textRect, message);
}
void GraphWidget::scaleView(qreal scaleFactor)
{
qreal factor = matrix().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width();
if (factor < 0.07 || factor > 100)
return;
scale(scaleFactor, scaleFactor);
}</pre>
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