QtCreator，动态曲线实例

样式图：

.ui

在sloem1.ui文件中，拖入一个label控件，

头文件.h

#include "QtGui/QPainter.h"
#include "QtCore/QTimer.h"protected:bool eventFilter(QObject *obj,QEvent *event);void labelPaint();public slots:
//动态曲线void drawCoordinateSystem(QPainter *painter);void drawDynamicSpline(QPainter *painter);void drawDynamicPiont();//动态点

源文件.cpp

static int count = 60;//统一改变，动态曲线所有参数
static int i = 0;//动态曲线点数，所要调用的参数
static int num = 99;//动态曲线点数（不同要求可修改）
static double dynamicPoint[99];//存储动态曲线点数的数组，移动时需要存储以前的数据，（不同要求需修改）
static double interval = count * 12 * 1.0 /( num-1 );//每一个点之间的间隔sloem1::sloem1(QWidget* pParent, const QString& rszName): SlGfwDialogForm(pParent, rszName)
{setupUi(this);this->label->installEventFilter(this->label);QTimer * timer = new QTimer(this);QObject::connect(timer,SIGNAL(timeout()),this,SLOT(update()));timer->start(1000);//毫秒
} // <-- sloem1::sloem1 ()//事件过滤器
bool sloem1::eventFilter(QObject *watched, QEvent *event)
{if(watched == this->label && event->type() == QEvent::Paint){labelPaint();}//交由QWidget的事件过滤器处理return QWidget::eventFilter(watched,event);
}//==============================动态曲线图============================
void sloem1::labelPaint()
{int width  = this -> width ();//标准ui宽度559int height = this -> height();//标准ui高度394int side   = qMin( width, height ) / 2;QPainter painter( this->label );painter.setRenderHints ( QPainter::Antialiasing | QPainter::TextAntialiasing );//抗锯齿painter.translate ( 165, 60 );//图形中心点，默认中心点左上角painter.scale (side / 520.0, side / 520.0);//图形大小//动态曲线drawCoordinateSystem(&painter);drawDynamicPiont();drawDynamicSpline(&painter);
}void sloem1::drawCoordinateSystem(QPainter *painter)
{//int count = 60;//局部变量，统一改变所有参数painter->save();painter->setPen(Qt::black);painter->drawLine(QPointF(-count*6,count*3),QPointF( count*6, count*3  ));//x轴painter->drawLine(QPointF(-count*6,count*3),QPointF(-count*6,-count*2.5));//y轴painter->setPen(Qt::DashLine);//虚线painter->drawLine(QPointF(-count*6, count*2),QPointF(count*6, count*2));painter->drawLine(QPointF(-count*6, count*1),QPointF(count*6, count*1));painter->drawLine(QPointF(-count*6, count*0),QPointF(count*6, count*0));painter->drawLine(QPointF(-count*6,-count*1),QPointF(count*6,-count*1));painter->drawLine(QPointF(-count*6,-count*2),QPointF(count*6,-count*2));QFont font;//字体font.setPixelSize(40);painter->setFont(font);painter->drawText(-count*7.2, count*2.2,"1%" );painter->drawText(-count*7.2, count*1.2,"2%");painter->drawText(-count*7.2, count*0.2,"3%");painter->drawText(-count*7.2,-count*0.8,"4%");painter->drawText(-count*7.2,-count*1.8,"5%");painter->restore();
}void sloem1::drawDynamicPiont()
{if( i < num )//坐标轴上点没有满时，{dynamicPoint[i] = qrand()%180;}i = i + 1;if( i == num + 1 )//坐标轴上点已满，全体向左移动{i = i - 2;//坐标轴最后一个点for( int j = 0; j < num - 1; j++ ){dynamicPoint[j] = dynamicPoint[j+1];}dynamicPoint[i] = qrand()%180;i = i + 1;//不再进入坐标轴没满的循环}
}void sloem1::drawDynamicSpline(QPainter *painter)
{painter->save();QPen pen;pen.setColor(Qt::white);pen.setWidth(10);painter->setPen(pen);//painter->drawPoint(QPointF(-count*4,count*3));//坐标原点;//把横坐标按照点数分配；count*8/num，总长度/点数for( int j = 0; j < i; j++ ){painter->drawPoint(QPointF(interval*j-interval*((num-1)/2),dynamicPoint[j]));//}pen.setColor(QColor(255,192,203));pen.setWidth(4);painter->setPen(pen);//把点连成折线if( i != 0 ){for( int k = 0; k < i-1; k++ ){painter->drawLine(QPointF(interval*k-interval*((num-1)/2),dynamicPoint[k]),QPointF(QPointF(interval*(k+1)-interval*((num-1)/2),dynamicPoint[k+1])));}}painter->restore();
}