drawdemo.cpp

来自「一大堆的qt程序,在qte2.3.7下全部可以很好地运行」· C++ 代码 · 共 54 行

#define PI 3.1415926

#include <stdio.h>
#include "drawdemo.h"

DrawDemo::DrawDemo(QWidget *parent,const char *name)
		:QWidget(parent,name)
{
	setCaption("draw");

	frame = new QFrame(this,"frame");
	frame->setBackgroundColor(white);
	frame->setGeometry(QRect(40,40,402,252));
	
	for(int i=0;i<400;i++)
	{
		buffer[i] = (int)(sin((i*PI)/100)*100);
	}

	QTimer *timer = new QTimer(this,"timer");
	connect(timer,SIGNAL(timeout()),this,SLOT(flushBuff()));
	timer->start(30);
}

void DrawDemo::flushBuff()
{
	int tmp = buffer[0];
 	int i;
	for(i=0;i<400;i++)
	{
		buffer[i] = buffer[i+1];
	}
	buffer[399] = tmp;
	repaint(0,0,480,320,FALSE);
}

void DrawDemo::paintEvent(QPaintEvent *)
{
	frame->erase(0,0,400,320);
	QPainter painter(frame);
	QPoint beginPoint;
	QPoint endPoint;
	painter.setPen(blue);
	for(int i=0;i<399;i++)
	{	
		beginPoint.setX(i);
		beginPoint.setY(buffer[i]+126);
		endPoint.setX(i+1);
		endPoint.setY(buffer[i+1]+126);
		painter.drawLine(beginPoint,endPoint);
	}
}