Qt 项目实战：幸运转盘

幸运电子转盘

• 基础绘图
• 通过paintEvent来绘图
• 鼠标事件：鼠标左键单击开始旋转
• Timer：定时器
• 信号与槽

 1 #ifndef WIDGET_H
 2 #define WIDGET_H
 3 
 4 #include <QWidget>
 5 #include <QEvent>
 6 #include <QDebug>
 7 #include <QTimer>
 8 #include <QTime>
 9 #include <QMouseEvent>
10 #include <QPainter>
11 
12 QT_BEGIN_NAMESPACE
13 namespace Ui { class Widget; }
14 QT_END_NAMESPACE
15 
16 class Widget : public QWidget
17 {
18     Q_OBJECT
19 
20 public:
21     Widget(QWidget *parent = nullptr);
22     ~Widget();
23 
24 protected:
25     // 绘图事件 ：显示隐藏 resize update
26     virtual void paintEvent(QPaintEvent *event);
27     virtual void mousePressEvent(QMouseEvent *event);
28 
29 
30 public slots:
31     void rtTimerOutSlot();
32     void luckStartSlot();
33 signals:
34     void luckStartSignal();
35 private:
36     Ui::Widget *ui;
37 
38 private:
39     // 堆区对象 画家
40     QPainter rotationPainter;
41     QPainter pointPainter;
42 
43     // 定时器
44     QTimer rtTimer;
45 
46     // 角度
47     qreal rtAngle;
48     int randNumber;
49 
50 };
51 #endif // WIDGET_H

 1 #include "widget.h"
 2 #include "ui_widget.h"
 3 
 4 Widget::Widget(QWidget *parent)
 5     : QWidget(parent)
 6     , ui(new Ui::Widget)
 7     ,rtAngle(0.0)
 8 {
 9     ui->setupUi(this);
10     
11     connect(this,SIGNAL(luckStartSignal()),this,
12             SLOT(luckStartSlot()));
13     
14     connect(&rtTimer,SIGNAL(timeout()),this,SLOT(rtTimerOutSlot()));
15 }
16 
17 Widget::~Widget()
18 {
19     delete ui;
20 }
21 
22 void Widget::paintEvent(QPaintEvent *event)
23 {
24     // 先准备一个画笔
25     rotationPainter.begin(this);
26     // 移动坐标
27     rotationPainter.translate(200,200);
28     // 旋转
29     rotationPainter.rotate(rtAngle);
30     // 设置反锯齿
31     rotationPainter.setRenderHints(QPainter::SmoothPixmapTransform);
32     // 0,0 为POS
33     rotationPainter.drawPixmap(-200,-200,400,400,QPixmap(":/img/1.jpg")); // pos
34     rotationPainter.end();
35     
36     // 绘制指针
37     pointPainter.begin(this);
38     pointPainter.translate(200,200);// 原点移动
39     static const QPoint point[4] = {QPoint(0,18),QPoint(20,0),
40                                     QPoint(0,-100),QPoint(-20,0)};
41     // 设置画笔
42     pointPainter.setBrush(QColor(Qt::darkBlue));
43     // 添加反锯齿（走样） 设置抗锯齿需要再绘图之前添加
44     pointPainter.setRenderHints(QPainter::Antialiasing);
45     // 描点画出多边形
46     pointPainter.drawPolygon(point, 4);
47     
48     // 多边形
49     QRect recatanle(-7,-7,14,18);
50     pointPainter.setBrush(QColor(Qt::yellow));
51     pointPainter.drawEllipse(recatanle);
52     pointPainter.end();
53 }
54 
55 void Widget::rtTimerOutSlot()
56 {
57     rtAngle++; //旋转因子
58     
59     if((rtAngle - randNumber) == 90)
60     {
61         rtTimer.setInterval(10);
62     }
63     else if((rtAngle - randNumber) == 180)
64         
65     {
66         rtTimer.setInterval(15);
67     }
68     else if((rtAngle - randNumber) == 270)
69     {
70         rtTimer.setInterval(20);
71     }
72     else if((rtAngle - randNumber) == 360)
73     {
74         rtAngle--; //停下来
75     }
76     update(); // 更新视图
77 }
78 
79 void Widget::luckStartSlot()
80 {
81     rtAngle = 1;
82     srand(QTime(0,0,0).secsTo(QTime::currentTime()));
83     randNumber = rand()%360 +180;// 180 -> 360之间
84     rtTimer.start(5);
85 }
86 
87 void Widget::mousePressEvent(QMouseEvent *event)
88 {
89     if(event->button() == Qt::LeftButton)
90     {
91         if(event->pos().x() >180 && event->pos().x()<220
92                 && event->pos().y()<216 && event->pos().y()>130)
93         {
94             emit luckStartSignal();
95         }
96     }
97     
98 }