标签:math.h math 技术分享 obj src 正弦 enter 坐标系统 .cpp
circlewidget.h
#ifndef CIRCLAWIDGET_H #define CIRCLAWIDGET_H #include <QFrame> #include<QVector> #include<QMouseEvent> class CircleWidget:public QFrame { Q_OBJECT public: CircleWidget(QWidget *parent); ~CircleWidget(); private: void paintEvent(QPaintEvent *event); public: void Adjust(int period, int grain, int radius); QPoint origin(); // 坐标原点位置 QPoint toCoord(QPoint p); // 将GUI窗口的点(x,y)转换成坐标系统里的点 QPoint fromCoord(QPoint p); // 将坐标系内的(x,y)转成GUI的坐标 private: int m_period, m_grain, m_radius; }; #endif // CIRCLAWIDGET_H
circlewidget.cpp
# include"circlewidget.h" #include<QPainter> #include<QDebug> #include<math.h> CircleWidget::CircleWidget(QWidget *parent):QFrame(parent) { m_period = 20; //周期 m_grain = 1; //粒度 m_radius = 10; // 振幅 } CircleWidget::~CircleWidget() { } void CircleWidget::paintEvent(QPaintEvent *event) { QPainter painter(this); int width = this->width(); int height = this->height(); QRect rect(0,0, width, height); // 设置背景为黑色 painter.setBrush(QBrush(QColor(0x00,0x00, 0x00))); painter.drawRect(rect); painter.setPen(QPen(QColor(0, 255, 0))); // 设置线条为绿色 QPoint o = origin(); painter.drawLine(QPoint(0, o.y()), QPoint(width, o.y())); // x轴 painter.drawLine(QPoint(o.x(), 0), QPoint(o.x(), height));// y轴 // 正弦曲线: 从坐标原点,向左、向右伸展 QPoint p1(0,0); for(int x=0; x<width/2; x+=m_grain) { // y=sin(x) double angle = (double) x / m_period * 2 * 3.1415926; double y = m_radius * sin(angle); QPoint p2(x, y); // 右侧 painter.drawLine(fromCoord(p1), fromCoord(p2)); // 左侧 QPoint base(0,0); painter.drawLine(fromCoord(base-p1), fromCoord(base-p2)); p1 = p2; } } void CircleWidget::Adjust(int period, int grain, int radius) { m_period = period; m_grain = grain; m_radius = radius; update(); // 更新重绘 } QPoint CircleWidget::origin() { QRect r = this->rect(); return r.center(); } // 将GUI窗口的点(x,y)转换成数学坐标系统里的点 QPoint CircleWidget::toCoord(QPoint p) { // 圆心 QPoint o = this->origin(); QPoint result = p - o; result.setY(0 - result.y()); // y坐标反转 return result; } // 将数学坐标系内的(x,y)转成GUI的坐标 QPoint CircleWidget::fromCoord(QPoint p) { // 圆心 QPoint o = this->origin(); p.setY(0 - p.y()); // y坐标反转 return p + o; }
结果:
标签:math.h math 技术分享 obj src 正弦 enter 坐标系统 .cpp
原文地址:https://www.cnblogs.com/fuhang/p/9901091.html