Revision control
++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include "graphwidget.h"
++ #include "edge.h"
++ #include "node.h"
++
++ #include <math.h>
++
++ #include <QKeyEvent>
++ #include <QRandomGenerator>
++
++ //! [0]
++ GraphWidget::GraphWidget(QWidget *parent)
++ : QGraphicsView(parent)
++ {
++ 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);
++ scale(qreal(0.8), qreal(0.8));
++ setMinimumSize(400, 400);
++ setWindowTitle(tr("Elastic Nodes"));
++ //! [0]
++
++ //! [1]
++ 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);
++ }
++ //! [1]
++
++ //! [2]
++ void GraphWidget::itemMoved()
++ {
++ using namespace std::chrono_literals;
++
++ if (!timer.isActive())
++ timer.start(1000ms / 25, this);
++ }
++ //! [2]
++
++ //! [3]
++ 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:
++ zoomIn();
++ break;
++ case Qt::Key_Minus:
++ zoomOut();
++ break;
++ case Qt::Key_Space:
++ case Qt::Key_Enter:
++ shuffle();
++ break;
++ default:
++ QGraphicsView::keyPressEvent(event);
++ }
++ }
++ //! [3]
++
++ //! [4]
++ void GraphWidget::timerEvent(QTimerEvent *event)
++ {
++ Q_UNUSED(event);
++
++ QList<Node *> nodes;
++ const QList<QGraphicsItem *> items = scene()->items();
++ for (QGraphicsItem *item : items) {
++ if (Node *node = qgraphicsitem_cast<Node *>(item))
++ nodes << node;
++ }
++
++ for (Node *node : std::as_const(nodes))
++ node->calculateForces();
++
++ bool itemsMoved = false;
++ for (Node *node : std::as_const(nodes)) {
++ if (node->advancePosition())
++ itemsMoved = true;
++ }
++
++ if (!itemsMoved)
++ timer.stop();
++ }
++ //! [4]
++
++ #if QT_CONFIG(wheelevent)
++ //! [5]
++ void GraphWidget::wheelEvent(QWheelEvent *event)
++ {
++ scaleView(pow(2., -event->angleDelta().y() / 240.0));
++ }
++ //! [5]
++ #endif
++
++ //! [6]
++ void GraphWidget::drawBackground(QPainter *painter, const QRectF &rect)
++ {
++ Q_UNUSED(rect);
++
++ // Shadow
++ 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);
++
++ // Fill
++ QLinearGradient gradient(sceneRect.topLeft(), sceneRect.bottomRight());
++ gradient.setColorAt(0, Qt::white);
++ gradient.setColorAt(1, Qt::lightGray);
++ painter->fillRect(rect.intersected(sceneRect), gradient);
++ painter->setBrush(Qt::NoBrush);
++ painter->drawRect(sceneRect);
++
++ // Text
++ 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);
++ }
++ //! [6]
++
++ //! [7]
++ void GraphWidget::scaleView(qreal scaleFactor)
++ {
++ qreal factor = transform().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width();
++ if (factor < 0.07 || factor > 100)
++ return;
++
++ scale(scaleFactor, scaleFactor);
++ }
++ //! [7]
++
++ void GraphWidget::shuffle()
++ {
++ const QList<QGraphicsItem *> items = scene()->items();
++ for (QGraphicsItem *item : items) {
++ if (qgraphicsitem_cast<Node *>(item))
++ item->setPos(-150 + QRandomGenerator::global()->bounded(300), -150 + QRandomGenerator::global()->bounded(300));
++ }
++ }
++
++ void GraphWidget::zoomIn()
++ {
++ scaleView(qreal(1.2));
++ }
++
++ void GraphWidget::zoomOut()
++ {
++ scaleView(1 / qreal(1.2));
++ }