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50
51#include "car.h"
52#include <QtWidgets/QtWidgets>
53#include <qmath.h>
54
55QRectF Car::boundingRect() const
56{
57 return QRectF(-35, -81, 70, 115);
58}
59
60Car::Car() : color(Qt::green), wheelsAngle(0), speed(0)
61{
62 startTimer(interval: 1000 / 33);
63 setFlag(flag: QGraphicsItem::ItemIsMovable, enabled: true);
64 setFlag(flag: QGraphicsItem::ItemIsFocusable, enabled: true);
65}
66
67void Car::accelerate()
68{
69 if (speed < 10)
70 ++speed;
71}
72
73void Car::decelerate()
74{
75 if (speed > -10)
76 --speed;
77}
78
79void Car::turnLeft()
80{
81 if (wheelsAngle > -30)
82 wheelsAngle -= 5;
83}
84
85void Car::turnRight()
86{
87 if (wheelsAngle < 30)
88 wheelsAngle += 5;
89}
90
91void Car::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
92{
93 Q_UNUSED(option);
94 Q_UNUSED(widget);
95
96 painter->setBrush(Qt::gray);
97 painter->drawRect(x: -20, y: -58, w: 40, h: 2); // front axel
98 painter->drawRect(x: -20, y: 7, w: 40, h: 2); // rear axel
99
100 painter->setBrush(color);
101 painter->drawRect(x: -25, y: -79, w: 50, h: 10); // front wing
102
103 painter->drawEllipse(x: -25, y: -48, w: 50, h: 20); // side pods
104 painter->drawRect(x: -25, y: -38, w: 50, h: 35); // side pods
105 painter->drawRect(x: -5, y: 9, w: 10, h: 10); // back pod
106
107 painter->drawEllipse(x: -10, y: -81, w: 20, h: 100); // main body
108
109 painter->drawRect(x: -17, y: 19, w: 34, h: 15); // rear wing
110
111 painter->setBrush(Qt::black);
112 painter->drawPie(x: -5, y: -51, w: 10, h: 15, a: 0, alen: 180 * 16);
113 painter->drawRect(x: -5, y: -44, w: 10, h: 10); // cocpit
114
115 painter->save();
116 painter->translate(dx: -20, dy: -58);
117 painter->rotate(a: wheelsAngle);
118 painter->drawRect(x: -10, y: -7, w: 10, h: 15); // front left
119 painter->restore();
120
121 painter->save();
122 painter->translate(dx: 20, dy: -58);
123 painter->rotate(a: wheelsAngle);
124 painter->drawRect(x: 0, y: -7, w: 10, h: 15); // front left
125 painter->restore();
126
127 painter->drawRect(x: -30, y: 0, w: 12, h: 17); // rear left
128 painter->drawRect(x: 19, y: 0, w: 12, h: 17); // rear right
129}
130
131void Car::timerEvent(QTimerEvent *event)
132{
133 Q_UNUSED(event);
134
135 const qreal axelDistance = 54;
136 qreal wheelsAngleRads = qDegreesToRadians(degrees: wheelsAngle);
137 qreal turnDistance = ::cos(x: wheelsAngleRads) * axelDistance * 2;
138 qreal turnRateRads = wheelsAngleRads / turnDistance; // rough estimate
139 qreal turnRate = qRadiansToDegrees(radians: turnRateRads);
140 qreal rotation = speed * turnRate;
141
142 setTransform(matrix: QTransform().rotate(a: rotation), combine: true);
143 setTransform(matrix: QTransform::fromTranslate(dx: 0, dy: -speed), combine: true);
144 update();
145}
146

source code of qtbase/examples/dbus/remotecontrolledcar/car/car.cpp