使用mainwindow，做的Graphicsview编程框架

#include "myitem.h" #include <QPainter> #include <QGraphicsScene> #include <math.h> static const double Pi = 3.1415926535897932384626; static double TwoPi = 2.0 * Pi; //int MouseCount; static qreal normalizeAngle(qreal angle) { while (angle < 0) angle += TwoPi; while (angle > TwoPi) angle -= TwoPi; return angle; } MyItem::MyItem() :angle(0),speed(0),mouseEyeDirection(0), color(qrand() % 256, qrand() % 256, qrand() % 256) { setFlag(QGraphicsItem::ItemIsMovable, true); setFlag(QGraphicsItem::ItemIsSelectable, true); setRotation(qrand() % (360 * 16)); } //! [2] QPainterPath MyItem::shape() const { QPainterPath path; path.addRect(-10, -20, 20, 40); return path; } //! [2] QRectF MyItem::boundingRect() const //返回项的外框，场景类必须利用这个外框来确定项的位置 { qreal adjust = 0.5; return QRectF(-18 - adjust, -22 - adjust, 36 + adjust, 60 + adjust); } void MyItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) //绘制项 { // painter->drawRect(0,0,20,20); //Body painter->setBrush(color); painter->drawEllipse(-10, -20, 20, 40); //Eyes painter->setBrush(Qt::white); painter->drawEllipse(-10, -17, 8, 8); painter->drawEllipse(2, -17, 8, 8); // Nose painter->setBrush(Qt::black); painter->drawEllipse(QRectF(-2, -22, 4, 4)); // Pupils painter->drawEllipse(QRectF(-8.0 + mouseEyeDirection, -17, 4, 4)); painter->drawEllipse(QRectF(4.0 + mouseEyeDirection, -17, 4, 4)); // Ears painter->setBrush(scene()->collidingItems(this).isEmpty() ? Qt::darkYellow : Qt::red); painter->drawEllipse(-17, -12, 16, 16); painter->drawEllipse(1, -12, 16, 16); // Tail QPainterPath path(QPointF(0, 20)); path.cubicTo(-5, 22, -5, 22, 0, 25); path.cubicTo(5, 27, 5, 32, 0, 30); path.cubicTo(-5, 32, -5, 42, 0, 35); painter->setBrush(Qt::NoBrush); painter->drawPath(path); } /* void MyItem::mousePressEvent(QGraphicsSceneMouseEvent *event) { update(); QGraphicsItem::mousePressEvent(event); } */ void MyItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event) { // MouseCount++; update(); QGraphicsItem::mouseReleaseEvent(event); } //! [4] void MyItem::advance(int step) { if (!step) return; //! [4] // Don't move too far away //! [5] QLineF lineToCenter(QPointF(0, 0), mapFromScene(0, 0)); if (lineToCenter.length() > 150) { qreal angleToCenter = ::acos(lineToCenter.dx() / lineToCenter.length()); if (lineToCenter.dy() < 0) angleToCenter = TwoPi - angleToCenter; angleToCenter = normalizeAngle((Pi - angleToCenter) + Pi / 2); if (angleToCenter < Pi && angleToCenter > Pi / 4) { // Rotate left angle += (angle < -Pi / 2) ? 0.25 : -0.25; } else if (angleToCenter >= Pi && angleToCenter < (Pi + Pi / 2 + Pi / 4)) { // Rotate right angle += (angle < Pi / 2) ? 0.25 : -0.25; } } else if (::sin(angle) < 0) { angle += 0.25; } else if (::sin(angle) > 0) { angle -= 0.25; //! [5] //! [6] } //! [6] // Try not to crash with any other mice //! [7] QList<QGraphicsItem *> dangerMice = scene()->items(QPolygonF() << mapToScene(0, 0) << mapToScene(-30, -50) << mapToScene(30, -50)); foreach (QGraphicsItem *item, dangerMice) { if (item == this) continue; QLineF lineToMouse(QPointF(0, 0), mapFromItem(item, 0, 0)); qreal angleToMouse = ::acos(lineToMouse.dx() / lineToMouse.length()); if (lineToMouse.dy() < 0) angleToMouse = TwoPi - angleToMouse; angleToMouse = normalizeAngle((Pi - angleToMouse) + Pi / 2); if (angleToMouse >= 0 && angleToMouse < Pi / 2) { // Rotate right angle += 0.5; } else if (angleToMouse <= TwoPi && angleToMouse > (TwoPi - Pi / 2)) { // Rotate left angle -= 0.5; //! [7] //! [8] } //! [8] //! [9] } //! [9] // Add some random movement //! [10] if (dangerMice.size() > 1 && (qrand() % 10) == 0) { if (qrand() % 1) angle += (qrand() % 100) / 500.0; else angle -= (qrand() % 100) / 500.0; } //! [10] //! [11] speed += (-50 + qrand() % 100) / 100.0; qreal dx = ::sin(angle) * 10; mouseEyeDirection = (qAbs(dx / 5) < 1) ? 0 : dx / 5; setRotation(rotation() + dx); setPos(mapToParent(0, -(3 + sin(speed) * 3))); } //! [11]