Qt使用cos、sin绘制圆

 

实例：

.pro

 1 QT       += core gui
 2 
 3 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 4 
 5 CONFIG += c++17
 6 
 7 # The following define makes your compiler emit warnings if you use
 8 # any Qt feature that has been marked deprecated (the exact warnings
 9 # depend on your compiler). Please consult the documentation of the
10 # deprecated API in order to know how to port your code away from it.
11 DEFINES += QT_DEPRECATED_WARNINGS
12 
13 # You can also make your code fail to compile if it uses deprecated APIs.
14 # In order to do so, uncomment the following line.
15 # You can also select to disable deprecated APIs only up to a certain version of Qt.
16 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
17 
18 SOURCES += \
19     main.cpp \
20     mainwindow.cpp
21 
22 HEADERS += \
23     mainwindow.h
24 
25 FORMS += \
26     mainwindow.ui
27 
28 # Default rules for deployment.
29 qnx: target.path = /tmp/$${TARGET}/bin
30 else: unix:!android: target.path = /opt/$${TARGET}/bin
31 !isEmpty(target.path): INSTALLS += target
32 
33 RESOURCES += \
34     resource.qrc
View Code

main.cpp

 1 #include "mainwindow.h"
 2 
 3 #include <QApplication>
 4 
 5 int main(int argc, char *argv[])
 6 {
 7     QApplication a(argc, argv);
 8     MainWindow w;
 9     w.show();
10     return a.exec();
11 }
View Code

mainwindow.h

 1 #ifndef MAINWINDOW_H
 2 #define MAINWINDOW_H
 3 
 4 #include <QMainWindow>
 5 #include <QPainter>
 6 #include <QDebug>
 7 #include <QtWidgets/QLabel>
 8 #include <QtWidgets/QLineEdit>
 9 #include <QtWidgets/QMainWindow>
10 #include <QtWidgets/QMenuBar>
11 #include <QtWidgets/QSlider>
12 #include <QtWidgets/QStatusBar>
13 #include <QtWidgets/QWidget>
14 #include <QtMath>
15 
16 QT_BEGIN_NAMESPACE
17 namespace Ui { class MainWindow; }
18 QT_END_NAMESPACE
19 
20 class MainWindow : public QMainWindow
21 {
22     Q_OBJECT
23 
24 public:
25     MainWindow(QWidget *parent = nullptr);
26     ~MainWindow();
27     void paintEvent(QPaintEvent *e);
28 private slots:
29     void on_horizontalSlider_valueChanged(int value);
30 
31     void on_horizontalSlider_2_valueChanged(int value);
32 
33     void on_pushButton_clicked();
34 
35     void on_pushButton_2_clicked();
36 
37 private:
38 
39     double getAngle(double lat_a, double lng_a, double lat_b, double lng_b); //lat_a表示上个点纬度， lat_b表示当前点的纬度
40 
41     Ui::MainWindow *ui;
42     int m_y = 0;//
43     int m_l = 100;//
44     int m_nSize = 200;
45     QPoint m_oCentre;
46     int m_nCentreWidth = 6;// 中心点宽度
47 };
48 #endif // MAINWINDOW_H
View Code

mainwindow.cpp

  1 #include "mainwindow.h"
  2 #include "ui_mainwindow.h"
  3 
  4 MainWindow::MainWindow(QWidget *parent)
  5     : QMainWindow(parent)
  6     , ui(new Ui::MainWindow)
  7 {
  8     ui->setupUi(this);
  9     setWindowTitle(QStringLiteral("Qt使用cos、sin绘制圆"));
 10 }
 11 
 12 MainWindow::~MainWindow()
 13 {
 14     delete ui;
 15 }
 16 
 17 void MainWindow::paintEvent(QPaintEvent *e)
 18 {
 19     m_oCentre.setX((m_nSize/2));
 20     m_oCentre.setY((m_nSize/2));
 21 
 22     int nDeviation = 0;
 23     // 生成绘制
 24     QPainter oLinePainter(this);
 25     oLinePainter.setWindow(nDeviation, nDeviation, this->width(), this->height());
 26     // 背景
 27     QBrush objBrush(Qt::yellow, Qt::SolidPattern);
 28     oLinePainter.fillRect(0, 0, m_nSize, m_nSize, objBrush);
 29     // ---------------------画中心点--------------------------
 30     QPainter oCentrePainter(this);
 31     oCentrePainter.setWindow(nDeviation, nDeviation, this->width(), this->height());
 32     QPen oCentrePen;
 33     oCentrePen.setColor(Qt::red);
 34     oCentrePen.setWidth(1);
 35     oCentrePen.setStyle(Qt::SolidLine);
 36     oCentrePainter.setPen(oCentrePen);
 37 
 38     QBrush oCentreBrush(QColor(255,0,0), Qt::SolidPattern);
 39     oCentrePainter.setBrush(oCentreBrush);
 40 
 41     QPainterPath oCentreDrawPath;
 42 
 43     oCentreDrawPath.addRect(m_oCentre.x(),
 44                             m_oCentre.y(),
 45                             m_nCentreWidth,
 46                             m_nCentreWidth);
 47     //
 48     oCentrePainter.drawPath(oCentreDrawPath);
 49     // ---------------------画中心点--------------------------
 50     float x = 0;
 51     float y = 0;
 52     float fPI = 3.14159265358979323;
 53     x = sin(m_y*fPI/180)*m_l + m_oCentre.x();
 54     y = -cos(m_y*fPI/180)*m_l + m_oCentre.x();
 55 
 56 
 57     QPainter oPainter(this);
 58     oCentrePainter.setWindow(nDeviation, nDeviation, this->width(), this->height());
 59     QPen oPen;
 60     oPen.setColor(Qt::blue);
 61     oPen.setWidth(1);
 62     oPen.setStyle(Qt::SolidLine);
 63     oPainter.setPen(oPen);
 64 
 65     QBrush oBrush(QColor(255,0,0), Qt::SolidPattern);
 66     oPainter.setBrush(oBrush);
 67 
 68     QPainterPath oDrawPath;
 69 
 70     oDrawPath.addRect(x,
 71                       y,
 72                       m_nCentreWidth,
 73                       m_nCentreWidth);
 74     //
 75     oPainter.drawPath(oDrawPath);
 76 }
 77 
 78 void MainWindow::on_horizontalSlider_valueChanged(int value)
 79 {
 80     ui->label->setText(QString::number(value));
 81     m_y = value;
 82     this->repaint();
 83 }
 84 
 85 void MainWindow::on_horizontalSlider_2_valueChanged(int value)
 86 {
 87     ui->label_2->setText(QString::number(value));
 88     m_l = value;
 89     this->repaint();
 90 }
 91 
 92 void MainWindow::on_pushButton_clicked()
 93 {
 94     qreal long1 = ui->lineEdit->text().toDouble();//得到第一个点的经度
 95     qreal lat1 = ui->lineEdit_2->text().toDouble();//得到第一个点的纬度
 96 
 97     qreal long2 = ui->lineEdit_3->text().toDouble();//得到第二个点的经度
 98     qreal lat2 = ui->lineEdit_4->text().toDouble();//得到第二个点的纬度
 99 
100     qreal a, b, R;
101     R = 6378137; // 地球半径
102     lat1 = lat1 * M_PI / 180.0;
103     lat2 = lat2 * M_PI / 180.0;
104     a = lat1 - lat2;
105     b = (long1 - long2) * M_PI / 180.0;
106     qreal sa2, sb2;
107     sa2 = sin(a / 2.0);
108     sb2 = sin(b / 2.0);
109     qreal distance //计算出距离
110     = 2 * R * asin(sqrt(sa2 * sa2 + cos(lat1) * cos(lat2) * sb2 * sb2));
111     ui->lineEdit_5->setText(QString::number(distance,'f',3)); //同步到控件上并保留三位小数
112 }
113 
114 void MainWindow::on_pushButton_2_clicked()
115 {
116     ui->lineEdit_6->setText(QString::number(
117                                 getAngle(
118                                     ui->lineEdit_2->text().toDouble(),
119                                     ui->lineEdit->text().toDouble(),
120                                     ui->lineEdit_4->text().toDouble(),
121                                     ui->lineEdit_3->text().toDouble()
122                                     )
123                                 ));
124 
125 }
126 
127 double MainWindow::getAngle(double lat_a, double lng_a, double lat_b, double lng_b)
128 {
129 #define PI 3.14
130 
131         double lat1 = lat_a* PI / 180.0;
132         double lat2 = lat_b* PI / 180.0;
133         double lon1 = lng_a* PI / 180.0;
134         double lon2 = lng_b* PI / 180.0;
135         double azimuth = sin(lat1) * sin(lat2) + cos(lat1)
136                 * cos(lat2) * cos(lon2 - lon1);
137         azimuth = sqrt(1 - azimuth * azimuth);
138         azimuth = cos(lat2) * sin(lon2 - lon1) / azimuth;
139         azimuth = asin(azimuth) * 180 / PI;
140         if (azimuth == NAN) {
141             if (lon1 < lon2) {
142                 azimuth = 90.0;
143                 return azimuth;
144             } else {
145                 azimuth = 270.0;
146                 return azimuth;
147             }
148         }
149 
150         double x = lat_b - lat_a;
151         double y = lng_b - lng_a;
152         if(x > 0 && y > 0){
153             return azimuth;
154         }
155         else if(x < 0 && y > 0){
156             return 180 - azimuth;
157         }
158         else if(x < 0 && y < 0){
159             return 180 - azimuth;
160         }
161         else if(x > 0 && y < 0){
162             return 360 + azimuth;
163         }
164         else{
165             return NAN;
166         }
167 }
View Code

mainwindow.ui

  1 <?xml version="1.0" encoding="UTF-8"?>
  2 <ui version="4.0">
  3  <class>MainWindow</class>
  4  <widget class="QMainWindow" name="MainWindow">
  5   <property name="geometry">
  6    <rect>
  7     <x>0</x>
  8     <y>0</y>
  9     <width>678</width>
 10     <height>343</height>
 11    </rect>
 12   </property>
 13   <property name="windowTitle">
 14    <string>MainWindow</string>
 15   </property>
 16   <widget class="QWidget" name="centralwidget">
 17    <widget class="QSlider" name="horizontalSlider">
 18     <property name="geometry">
 19      <rect>
 20       <x>260</x>
 21       <y>20</y>
 22       <width>341</width>
 23       <height>22</height>
 24      </rect>
 25     </property>
 26     <property name="maximum">
 27      <number>360</number>
 28     </property>
 29     <property name="orientation">
 30      <enum>Qt::Horizontal</enum>
 31     </property>
 32    </widget>
 33    <widget class="QLabel" name="label">
 34     <property name="geometry">
 35      <rect>
 36       <x>620</x>
 37       <y>20</y>
 38       <width>54</width>
 39       <height>12</height>
 40      </rect>
 41     </property>
 42     <property name="text">
 43      <string>TextLabel</string>
 44     </property>
 45    </widget>
 46    <widget class="QLabel" name="label_2">
 47     <property name="geometry">
 48      <rect>
 49       <x>620</x>
 50       <y>60</y>
 51       <width>54</width>
 52       <height>12</height>
 53      </rect>
 54     </property>
 55     <property name="text">
 56      <string>TextLabel</string>
 57     </property>
 58    </widget>
 59    <widget class="QSlider" name="horizontalSlider_2">
 60     <property name="geometry">
 61      <rect>
 62       <x>260</x>
 63       <y>60</y>
 64       <width>341</width>
 65       <height>22</height>
 66      </rect>
 67     </property>
 68     <property name="maximum">
 69      <number>150</number>
 70     </property>
 71     <property name="value">
 72      <number>100</number>
 73     </property>
 74     <property name="orientation">
 75      <enum>Qt::Horizontal</enum>
 76     </property>
 77    </widget>
 78    <widget class="QPushButton" name="pushButton">
 79     <property name="geometry">
 80      <rect>
 81       <x>390</x>
 82       <y>230</y>
 83       <width>89</width>
 84       <height>24</height>
 85      </rect>
 86     </property>
 87     <property name="text">
 88      <string>两点距离</string>
 89     </property>
 90    </widget>
 91    <widget class="QLineEdit" name="lineEdit">
 92     <property name="geometry">
 93      <rect>
 94       <x>70</x>
 95       <y>230</y>
 96       <width>113</width>
 97       <height>23</height>
 98      </rect>
 99     </property>
100     <property name="text">
101      <string>116.313468</string>
102     </property>
103    </widget>
104    <widget class="QLineEdit" name="lineEdit_2">
105     <property name="geometry">
106      <rect>
107       <x>200</x>
108       <y>230</y>
109       <width>113</width>
110       <height>23</height>
111      </rect>
112     </property>
113     <property name="text">
114      <string>40.074599</string>
115     </property>
116    </widget>
117    <widget class="QLineEdit" name="lineEdit_3">
118     <property name="geometry">
119      <rect>
120       <x>70</x>
121       <y>280</y>
122       <width>113</width>
123       <height>23</height>
124      </rect>
125     </property>
126     <property name="text">
127      <string>116.224182</string>
128     </property>
129    </widget>
130    <widget class="QLineEdit" name="lineEdit_4">
131     <property name="geometry">
132      <rect>
133       <x>200</x>
134       <y>280</y>
135       <width>113</width>
136       <height>23</height>
137      </rect>
138     </property>
139     <property name="text">
140      <string>37.475040</string>
141     </property>
142    </widget>
143    <widget class="QLineEdit" name="lineEdit_5">
144     <property name="geometry">
145      <rect>
146       <x>500</x>
147       <y>230</y>
148       <width>113</width>
149       <height>23</height>
150      </rect>
151     </property>
152    </widget>
153    <widget class="QPushButton" name="pushButton_2">
154     <property name="geometry">
155      <rect>
156       <x>390</x>
157       <y>280</y>
158       <width>89</width>
159       <height>24</height>
160      </rect>
161     </property>
162     <property name="text">
163      <string>两点角度</string>
164     </property>
165    </widget>
166    <widget class="QLineEdit" name="lineEdit_6">
167     <property name="geometry">
168      <rect>
169       <x>500</x>
170       <y>280</y>
171       <width>113</width>
172       <height>23</height>
173      </rect>
174     </property>
175    </widget>
176    <widget class="QLabel" name="label_3">
177     <property name="geometry">
178      <rect>
179       <x>620</x>
180       <y>233</y>
181       <width>72</width>
182       <height>15</height>
183      </rect>
184     </property>
185     <property name="text">
186      <string>米</string>
187     </property>
188    </widget>
189   </widget>
190  </widget>
191  <resources/>
192  <connections/>
193 </ui>
View Code

 ps:代码中计算方位的代码可能有问题，以下是另一个算法（弧度 返回弧度 正北为零，这点和osgEarth不同，osgEarth是正东为0）。

来源：https://blog.csdn.net/yangdaocheng/article/details/43195037

double MainWindow::getAngle(double lat_a, double lng_a, double lat_b, double lng_b)
{
    #define PI 3.14

    double lat1 = lat_a* PI / 180.0;
    double lat2 = lat_b* PI / 180.0;
    double lon1 = lng_a* PI / 180.0;
    double lon2 = lng_b* PI / 180.0;


    double dLon = (lon2-lon1);
    double y = sin(dLon) * cos(lat2);
    double x = cos(lat1)*sin(lat2) - sin(lat1)*cos(lat2)*cos(dLon);
    double brng = atan2(y, x);
    return brng * 180 / PI;
}

　　

 

 

posted on 2021-08-11 08:57  疯狂delphi  阅读(1000)  评论(0)  编辑  收藏  举报

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