Qt编写的速度仪表盘

#include "myspeed.h" #include <QPainter> #include <qmath.h> mySpeed::mySpeed(QWidget *parent) : QMainWindow(parent) { m_background = Qt::black; m_foreground = Qt::green; m_startAngle=60; m_endAngle=60; m_scaleMajor=10; m_minValue=0; m_maxValue=100; m_scaleMajor = 10;//分度 m_scaleMinor = 10; m_units = "km/h"; m_title = "Speed Meter"; m_precision = 0; m_value=0; m_updateTimer = new QTimer(this); m_updateTimer->setInterval(50);//间隔，微妙微单位，大家可以改一下这个值看看转动速度。 connect(m_updateTimer,SIGNAL(timeout()),this,SLOT(UpdateAngle())); m_updateTimer->start();//启动定时器 setWindowFlags(Qt::FramelessWindowHint);//无窗体 setAttribute(Qt::WA_TranslucentBackground);//背景透明 resize(400,400); } mySpeed::~mySpeed() { } void mySpeed::drawCrown(QPainter *painter) { painter->save(); int radius =100; QLinearGradient lg1(0,-radius,0,radius); lg1.setColorAt(0.2,Qt::white); lg1.setColorAt(1,Qt::black); painter->setBrush(lg1); painter->drawEllipse(-100, -100, 200 ,200); painter->restore(); } void mySpeed::drawBackground(QPainter *painter) { painter->save(); painter->setBrush(m_background); painter->drawEllipse(-90, -90, 180 ,180); painter->restore(); } void mySpeed::drawScaleNum(QPainter *painter) { painter->save(); painter->setPen(m_foreground); double startRad = (360 - m_startAngle - 90) * (3.14 / 180); double deltaRad = (360 - m_startAngle - m_endAngle) * (3.14 / 180) / m_scaleMajor; double sina,cosa; int x, y; QFontMetricsF fm(this->font()); double w, h, tmpVal; QString str; for (int i = 0; i <= m_scaleMajor; i++) { sina = sin(startRad - i * deltaRad); cosa = cos(startRad - i * deltaRad); tmpVal = 1.0 * i *((m_maxValue - m_minValue) / m_scaleMajor) + m_minValue; str = QString( "%1" ).arg(tmpVal); w = fm.size(Qt::TextSingleLine,str).width(); h = fm.size(Qt::TextSingleLine,str).height(); x = 82 * cosa - w / 2; y = -82 * sina + h / 4; painter->drawText(x, y, str); } painter->restore(); } void mySpeed::drawScale(QPainter *painter) { painter->save(); painter->rotate(m_startAngle); int steps = (m_scaleMajor * m_scaleMinor); //相乘后的值是分的份数 double angleStep = (360.0 - m_startAngle - m_endAngle) / steps; //每一个份数的角度 painter->setPen(m_foreground); // QPen pen = painter->pen(); for (int i = 0; i <= steps; i++) { if (i % m_scaleMinor == 0)//整数刻度显示加粗 { pen.setWidth(1); painter->setPen(pen); painter->drawLine(0, 62, 0, 72); //两个参数应该是两个坐标值 } else { pen.setWidth(0); painter->setPen(pen); painter->drawLine(0, 67, 0, 72); } painter->rotate(angleStep); } painter->restore(); } /* QFontMetricsF这个类用于获取字体的像素信息，例如字体的高度，一个给定字符串的像素宽度等等。 */ void mySpeed::drawTitle(QPainter *painter) { painter->save(); painter->setPen(m_foreground); //painter->setBrush(m_foreground); QString str(m_title); //显示仪表的功能 QFontMetricsF fm(this->font()); double w = fm.size(Qt::TextSingleLine,str).width(); painter->drawText(-w / 2, -30, str); painter->restore(); } void mySpeed::drawNumericValue(QPainter *painter) { QString str = QString("%1 %2").arg(m_value, 0, 'f', m_precision).arg(m_units); QFontMetricsF fm(font()); double w = fm.size(Qt::TextSingleLine,str).width(); painter->setPen(m_foreground); painter->drawText(-w / 2, 42, str); } void mySpeed::drawIndicator(QPainter *painter) { painter->save(); QPolygon pts; pts.setPoints(3, -2,0, 2,0, 0,60); /* (-2,0)/(2,0)/(0,60) *///第一个参数是 ，坐标的个数。后边的是坐标 painter->rotate(m_startAngle); double degRotate = (360.0 - m_startAngle - m_endAngle)/(m_maxValue - m_minValue)*(m_value - m_minValue); //画指针 painter->rotate(degRotate); //顺时针旋转坐标系统 QRadialGradient haloGradient(0, 0, 60, 0, 0); //辐射渐变 haloGradient.setColorAt(0, QColor(60,60,60)); haloGradient.setColorAt(1, QColor(160,160,160)); //灰 painter->setPen(Qt::white); //定义线条文本颜色 设置线条的颜色 painter->setBrush(haloGradient);//刷子定义形状如何填满 填充后的颜色 painter->drawConvexPolygon(pts); //这是个重载函数，绘制多边形。 painter->restore(); //画中心点 QColor niceBlue(150, 150, 200); QConicalGradient coneGradient(0, 0, -90.0); //角度渐变 coneGradient.setColorAt(0.0, Qt::darkGray); coneGradient.setColorAt(0.2, niceBlue); coneGradient.setColorAt(0.5, Qt::white); coneGradient.setColorAt(1.0, Qt::darkGray); painter->setPen(Qt::NoPen); //没有线，填满没有边界 painter->setBrush(coneGradient); painter->drawEllipse(-5, -5, 10, 10); } void mySpeed::paintEvent(QPaintEvent *) { QPainter painter (this); painter.setRenderHint(QPainter::Antialiasing); painter.translate(width()/2,height()/2); int side = qMin(width(),height()); painter.scale(side /200.0,side /200.0); drawCrown(&painter); drawBackground(&painter); drawScaleNum(&painter); drawScale(&painter); /* 画刻度线 */ drawTitle(&painter); /* 画单位 */ drawNumericValue(&painter); /* 画数字显示 */ drawIndicator(&painter); } void mySpeed::UpdateAngle() { m_value += 1; if(m_value > 100) { m_value = 0; } //m_angle = ((m_angle + 1) % 360);与上面几行功能一样 update();//刷新控件，会调用paintEvent函数 }