Qt实时曲线绘制

screen.cpp:

#include "screen.h"
#include <qevent.h>
#include <qrect.h>
#include <qsize.h>
#include <qstring.h>
#include <QShowEvent>
#include <QFrame>
#include <QHideEvent>
#include <iostream>
#include <qmatrix.h>
#include <qfont.h>
#include <qpen.h>

Screen::Screen( QWidget *parent, const char *name, Qt::WFlags flags ): QFrame( parent, name, flags | Qt::WNoAutoErase ) 
{
        setLineWidth( FrameWidth );       
        setFrameStyle( Panel | Sunken );
        setBackgroundMode( Qt::PaletteBase );       
        setSizePolicy( QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding );
        firstShow = TRUE;
}
void Screen::showEvent( QShowEvent * )
{
        if ( firstShow )
                initNumber();
        initCordinate( drawPainter );
}
QSize Screen::minimumSize () const

{
         return QSize( 20 * SpaceMargin, 20 * SpaceMargin );
}
void Screen::hideEvent( QHideEvent * )
{
        firstShow = FALSE;
}
void Screen::setXTitle(QString str )
{
        stringXTitle = str;
}
void Screen::setYTitle( QString str )
{
        stringYTitle = str;
}
void Screen::initNumber( )
{
        saveBuffer.resize( size() ); //set the size and the backcolor of
        saveBuffer.fill( this, 0, 0 );//those three QPixmaps as same as the Screen
        newBuffer.resize( size() );
        newBuffer.fill( this, 0, 0 );
        midBuffer.resize( size() );
        midBuffer.fill( this, 0, 0 );
        drawPainter.begin(&newBuffer);
        QRect newWindow = drawPainter.window();
        newY = 0;
        oldY =0;
        sec = 0;
        min = 0;
        hour = 0;