QwtArrayPlotItem_boundingRect.cpp

QRectF QwtArrayPlotItem::boundingRect() const
{
	//if we have valid rect, return it
	if( m_boundingRect.isValid()) 
		return m_boundingRect;
	//need to calculate
	else if(m_data != 0 && m_size>1)
	{
		double min =0.0;
		double max =0.0;


		if(m_data[0]<m_data[1])
		{
			min = m_data[0];
			max = m_data[1];				
		}
		else
		{
			min = m_data[1];
			max = m_data[0];
		}

		//compare pairs
		for(int k=2;k<m_size-2;k+=2)
		{
			if(m_data[k]>m_data[k+1])
			{
				if(m_data[k]>max)
				{
					max = m_data[k];
				}

				if(m_data[k+1]<min)
				{
					min = m_data[k+1];			
				}
			}
			else
			{
				if(m_data[k+1]>max)
				{
					max = m_data[k+1];
				}
				if(m_data[k]<min)
				{
					min = m_data[k];
				}
			}			
		}
		
		m_boundingRect = QRectF(0.0,(double)min, m_size*m_dt, (double)(max-min));
		return m_boundingRect;
		
	}
	return  QRectF( 1.0, 1.0, -2.0, -2.0 );
}