车的前后左右移动

cars.cpp

@@ -1,50 +1,81 @@
 #include "cars.h"
-#include <QPainter>
 
-Cars::Cars(QWidget *parent, int dir, Cars::Color color) : QWidget(parent)
+
+Cars::Cars(QGraphicsItem *parent, int dir, Cars::Color color) : QGraphicsPixmapItem(parent)
 {
+    m_pos = this->pos();
+    this->setRotation(dir);
     if(color==RANDOM)
         color = Cars::Color(rand()%3);  //车身颜色一定是确定的
     m_color = color;
-    m_dir = dir;
-    m_pos = this->pos();
-    resize(M_WID, M_LEN);
     switch (m_color) {
     case Pink:
-        m_pixmap = QPixmap(":/cars/pink");
+        m_pic = QPixmap(":/cars/pink");
         break;
     case Red:
-        m_pixmap = QPixmap(":/cars/red");
+        m_pic = QPixmap(":/cars/red");
         break;
     case Yellow:
-        m_pixmap = QPixmap(":/cars/yellow");
+        m_pic = QPixmap(":/cars/yellow");
         break;
     default:
-        m_pixmap = QPixmap(":/cars/red");
+        m_pic = QPixmap(":/cars/red");
         break;
     }
-}
-
-void Cars::paintEvent(QPaintEvent *event) {
-    QPainter painter(this);
-    m_pos = this->pos();
-    painter.translate(M_WID/2, M_LEN/2);    //转移远点，设置旋转中心
-    painter.rotate(m_dir);                  //旋转
-    painter.translate(-M_WID/2, -M_LEN/2);  //移回远点
-    painter.drawPixmap(0, 0, M_WID, M_LEN, m_pixmap);   //绘制小车
-    painter.setPen(QPen(Qt::red, 5));
-    painter.drawRect(0, 0, M_WID, M_LEN);
-    event->ignore();
+    m_pic = m_pic.scaled(M_WID, M_LEN);
+    this->setPixmap(m_pic);
 }
 
 void Cars::Forward(int vel)
 {
-    float ang = m_dir*PI/180;
-    this->move(m_pos.x()+vel*sin(ang), m_pos.y()-vel*cos(ang));
+    double ang = qDegreesToRadians(rotation());
+    this->moveBy(+vel*qSin(ang), -vel*qCos(ang));
 }
 
 void Cars::Backward(int vel)
 {
-    float ang = m_dir*PI/180;
-    this->move(m_pos.x()-vel*sin(ang), m_pos.y()+vel*cos(ang));
+    double ang = qDegreesToRadians(rotation());
+    this->moveBy(-vel*qSin(ang), +vel*qCos(ang));
+}
+
+void Cars::moveLeft(int vel)
+{
+    double ang = qDegreesToRadians(rotation());
+    moveBy(-vel*qCos(ang), -vel*qSin(ang));
+}
+
+void Cars::moveRight(int vel)
+{
+    double ang = qDegreesToRadians(rotation());
+    moveBy(vel*qCos(ang), vel*qSin(ang));
+}
+
+//ang为旋转角度（弧度），正数为顺时针，负数逆时针
+void Cars::Rotate(int ang)
+{
+    setRotation(rotation() + ang);
+}
+
+void Cars::turnLeft(int r, int ang)
+{
+    Forward(r*qSin(ang));
+    Rotate(-ang);
+    moveLeft(r*(1-qCos(ang)));
+}
+
+void Cars::turnRight(int r, int ang)
+{
+    Forward(r*qSin(ang));
+    Rotate(ang);
+    moveRight(r*(1-qCos(ang)));
+}
+
+Cars::Color Cars::getColor()
+{
+    return this->m_color;
+}
+
+qreal Cars::getDir()
+{
+    return this->rotation();
 }

cars.h

@@ -1,36 +1,38 @@
 #ifndef CARS_H
 #define CARS_H
 
-#include <QWidget>
+#include <QGraphicsPixmapItem>
 #include <QPixmap>
 #include <QString>
-#include <QPaintEvent>
 #include <QPoint>
+#include <QtMath>
 
 //车身长宽
 #define M_LEN   (200)
 #define M_WID   (130)
-#define PI      (3.1415926f)
 
-class Cars : public QWidget
+class Cars : public QGraphicsPixmapItem
 {
-    Q_OBJECT
 public:
     enum Color { Pink, Red, Yellow, RANDOM };
-    explicit Cars(QWidget *parent = nullptr, int dir = 0, Cars::Color color = RANDOM);
-    void paintEvent(QPaintEvent *event);
-    void Forward(int vel);
-    void Backward(int vel);
+    explicit Cars(QGraphicsItem *parent = Q_NULLPTR, int dir = 0, Cars::Color color = RANDOM);
+    void Forward(int vel = 3);
+    void Backward(int vel = 3);
+    void moveLeft(int vel = 3);
+    void moveRight(int vel = 3);
+    void Rotate(int ang = 30);
+    void turnLeft(int r, int ang);
+    void turnRight(int r, int ang);
+
+    Color getColor();
+    qreal getDir();
+
 private:
-    Color m_color;      //车身颜色
-    int m_dir;          //车头朝向 方向角 N为0， 顺时针递增
-    QPixmap m_pixmap;
+    Color m_color;      //车身颜色 N为0， 顺时针递增
+    QPixmap m_pic;
     QString m_number;
-    QPoint  m_pos;
+    QPointF  m_pos;
 
-signals:
-
-public slots:
 };
 
 #endif // CARS_H