graphwidget.cpp Example File
graphicsview/elasticnodes/graphwidget.cpp/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. 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IN NO EVENT SHALL THE COPYRIGHT ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "graphwidget.h" #include "edge.h" #include "node.h" #include <math.h> #include <QKeyEvent> GraphWidget::GraphWidget(QWidget *parent) : QGraphicsView(parent), 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); scale(qreal(0.8), qreal(0.8)); setMinimumSize(400, 400); setWindowTitle(tr("Elastic Nodes")); 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); } 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: zoomIn(); break; case Qt::Key_Minus: zoomOut(); break; case Qt::Key_Space: case Qt::Key_Enter: shuffle(); 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; } } #ifndef QT_NO_WHEELEVENT void GraphWidget::wheelEvent(QWheelEvent *event) { scaleView(pow((double)2, -event->delta() / 240.0)); } #endif 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); } 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); } void GraphWidget::shuffle() { foreach (QGraphicsItem *item, scene()->items()) { if (qgraphicsitem_cast<Node *>(item)) item->setPos(-150 + qrand() % 300, -150 + qrand() % 300); } } void GraphWidget::zoomIn() { scaleView(qreal(1.2)); } void GraphWidget::zoomOut() { scaleView(1 / qreal(1.2)); }