实现刻度循环移动，环形循环显示

#include "graphitem.h" #include<QPainter> GraphItem::GraphItem(QGraphicsItem *parent) : QGraphicsObject(parent) { m_image=new QImage(m_width*3,m_height,QImage::Format_ARGB32); m_image->fill(Qt::black); rectF=QRectF(0,0,m_width+1,m_height); QPainter p(m_image); QPen pen(Qt::white); pen.setWidthF(0.5); p.setPen(pen); QPointF startPos(5,15); for(int i=0;i<120;i++) { QPointF pos=startPos+QPointF(12*i,10); if(i%5==0) { p.drawLine(pos,pos+QPointF(0,10)); QRectF rect(0,0,40,15); rect.moveCenter(startPos+QPointF(12*i,0)); p.drawText(rect,Qt::AlignCenter,QString("%1").arg(3*i,1,'f',0)); } else { p.drawLine(pos+QPointF(0,5),pos+QPointF(0,10)); } } p.drawLine(0,35,m_width*3-1,35); moveRight(5); moveLeft(m_width/2); m_num=0; img=m_image->copy(); } void GraphItem::setValue(double value) { const uchar* bits_img=img.bits(); uchar* bits_image=m_image->bits(); memcpy(bits_image,bits_img,img.byteCount()); // int num=(value)*4-m_num; // if(num>0) // { // moveRight(qAbs(num)); // } // else { // moveLeft(qAbs(num)); // } // m_num+=num; moveRight(value*4); update(); } void GraphItem::moveRight(int num) { int image_width=m_image->width(); int image_height=m_image->height(); for(int i=0;i<image_height;i++) { QRgb* buff=(QRgb*)m_image->scanLine(i); QRgb temp[num]; memmove(temp,buff,num*sizeof(QRgb));// memmove(buff,buff+num,(image_width-num)*sizeof(QRgb)); memmove(buff+image_width-num-1,temp,(num)*sizeof(QRgb)); } } void GraphItem::moveLeft(int num) { int image_width=m_image->width(); int image_height=m_image->height(); for(int i=0;i<image_height;i++) { QRgb* buff=(QRgb*)m_image->scanLine(i); QRgb temp[num]; memmove(temp,buff+image_width-num-1,num*sizeof(QRgb));// memmove(buff+num,buff,(image_width-num)*sizeof(QRgb)); memmove(buff,temp,(num)*sizeof(QRgb)); } } void GraphItem::slt_update() { } QRectF GraphItem::boundingRect() const { QRectF rectF=QRectF(0,0,m_width+1,m_height); rectF.moveCenter(QPointF(0,0)); return rectF; } void GraphItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) { QPixmap pixmap=QPixmap::fromImage(*m_image); painter->drawPixmap(boundingRect(),pixmap,rectF); // QRectF rect(0,0,60,25); // rect.moveCenter(QPointF(0,-10)); // painter->setBrush(QColor(255,0,0,255)); // painter->drawRect(rect); // painter->drawText(rect,Qt::AlignCenter,QString::number(m_value,'f',2)); QPolygonF polygon; polygon<<QPointF(0.5,10)<<QPointF(-4.5,23)<<QPointF(5.5,23); painter->setBrush(QColor(0,0,255,255)); painter->setPen(Qt::NoPen); painter->drawPolygon(polygon); }