Is it possible to use a deque as plot data?

[P@u1]

there was a dangerous bug in PlotDataBuffer.cpp (initializing min and max with 0.0 instead of numerical limits).
Also I wrote minY_ instead of maxY_ in one getter.

Unfortuantely I cannot edit it anymore, so here is the new version, just in case that some1 wants to use it:

PlotDataBuffer.cpp

#include "PlotDataBuffer.h"
#include <cmath>
#include <algorithm>
#include <limits>
 
using namespace std;
 
class MinMax
{
public:
	MinMax():
	minX_(numeric_limits<double>::max()),
	maxX_(numeric_limits<double>::min()),
	minY_(numeric_limits<double>::max()),
	maxY_(numeric_limits<double>::min()),
	empty_(true)
	{
 
	}
 
	void operator()(const QPointF& p)
	{
		empty_ = false;
		minX_ = min(minX_, p.x());
		maxX_ = max(maxX_, p.x());
 
		minY_ = min(minY_, p.y());
		maxY_ = max(maxY_, p.y());
	}
 
	double getMinX() const
	{
		if(empty_)
		{
			return 0.0;
		}
		return minX_;
	}
 
	double getMaxX() const
	{
		if(empty_)
		{
			return 0.0;
		}
		return maxX_;
	}
 
	double getMinY() const
	{
		if(empty_)
		{
			return 0.0;
		}
		return minY_;
	}
 
	double getMaxY() const
	{
		if(empty_)
		{
			return 0.0;
		}
		return maxY_;
	}
 
private:
	double minX_;
	double maxX_;
 
	double minY_;
	double maxY_;
 
	bool empty_;
};
 
PlotDataBuffer::PlotDataBuffer(int windowSize):
minX_(0.0),
maxX_(0.0),
minY_(0.0),
maxY_(0.0),
windowSize_(windowSize),
minMaxValid_(true)
{
 
}
 
void PlotDataBuffer::setWindowSize(int windowSize)
{
	if(windowSize == windowSize_)
	{
		return;
	}
	windowSize_ = windowSize;
	while(deque_.size() > windowSize_)
	{
		deque_.pop_front();
	}
	minMaxValid_ = false;
}
 
void PlotDataBuffer::clear()
{
	deque_.clear();
}
 
QRectF PlotDataBuffer::boundingRect() const
{
	makeMinMaxValid();
	return QRectF(minX_, minY_, maxX_ - minX_, maxY_ - minY_); 
}
 
void PlotDataBuffer::addData(const QPointF& p)
{
	deque_.push_back(p);
	while(deque_.size() > windowSize_)
	{
		deque_.pop_front();
	}
	minMaxValid_ = false;
}
 
void PlotDataBuffer::makeMinMaxValid() const
{
	if(!minMaxValid_)
	{
		MinMax m = for_each(deque_.begin(), deque_.end(), MinMax());
		minX_ = m.getMinX();
		maxX_ = m.getMaxX();
		minY_ = m.getMinY();
		maxY_ = m.getMaxY();
		minMaxValid_ = true;
	}
}
 
double PlotDataBuffer::getMinX() const
{
	makeMinMaxValid();
	return minX_;
}
 
double PlotDataBuffer::getMaxX() const
{
	makeMinMaxValid();
	return maxX_;
}
 
double PlotDataBuffer::getMinY() const
{
	makeMinMaxValid();
	return minY_;
}
 
double PlotDataBuffer::getMaxY() const
{
	makeMinMaxValid();
	return maxY_;
}

#include "PlotDataBuffer.h"
#include <cmath>
#include <algorithm>
#include <limits>

using namespace std;

class MinMax
{
public:
	MinMax():
	minX_(numeric_limits<double>::max()),
	maxX_(numeric_limits<double>::min()),
	minY_(numeric_limits<double>::max()),
	maxY_(numeric_limits<double>::min()),
	empty_(true)
	{

	}

	void operator()(const QPointF& p)
	{
		empty_ = false;
		minX_ = min(minX_, p.x());
		maxX_ = max(maxX_, p.x());

		minY_ = min(minY_, p.y());
		maxY_ = max(maxY_, p.y());
	}

	double getMinX() const
	{
		if(empty_)
		{
			return 0.0;
		}
		return minX_;
	}

	double getMaxX() const
	{
		if(empty_)
		{
			return 0.0;
		}
		return maxX_;
	}

	double getMinY() const
	{
		if(empty_)
		{
			return 0.0;
		}
		return minY_;
	}

	double getMaxY() const
	{
		if(empty_)
		{
			return 0.0;
		}
		return maxY_;
	}

private:
	double minX_;
	double maxX_;
	
	double minY_;
	double maxY_;

	bool empty_;
};

PlotDataBuffer::PlotDataBuffer(int windowSize):
minX_(0.0),
maxX_(0.0),
minY_(0.0),
maxY_(0.0),
windowSize_(windowSize),
minMaxValid_(true)
{

}

void PlotDataBuffer::setWindowSize(int windowSize)
{
	if(windowSize == windowSize_)
	{
		return;
	}
	windowSize_ = windowSize;
	while(deque_.size() > windowSize_)
	{
		deque_.pop_front();
	}
	minMaxValid_ = false;
}

void PlotDataBuffer::clear()
{
	deque_.clear();
}

QRectF PlotDataBuffer::boundingRect() const
{
	makeMinMaxValid();
	return QRectF(minX_, minY_, maxX_ - minX_, maxY_ - minY_); 
}

void PlotDataBuffer::addData(const QPointF& p)
{
	deque_.push_back(p);
	while(deque_.size() > windowSize_)
	{
		deque_.pop_front();
	}
	minMaxValid_ = false;
}

void PlotDataBuffer::makeMinMaxValid() const
{
	if(!minMaxValid_)
	{
		MinMax m = for_each(deque_.begin(), deque_.end(), MinMax());
		minX_ = m.getMinX();
		maxX_ = m.getMaxX();
		minY_ = m.getMinY();
		maxY_ = m.getMaxY();
		minMaxValid_ = true;
	}
}

double PlotDataBuffer::getMinX() const
{
	makeMinMaxValid();
	return minX_;
}

double PlotDataBuffer::getMaxX() const
{
	makeMinMaxValid();
	return maxX_;
}

double PlotDataBuffer::getMinY() const
{
	makeMinMaxValid();
	return minY_;
}

double PlotDataBuffer::getMaxY() const
{
	makeMinMaxValid();
	return maxY_;
}

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Edit: I discovered a serious problem with the QwtSeriesData API. It takes ownership of the data...
I want to use one of my buffers for more than one plotcurve, which does not work with this ownership problem.
I'm thinking of employing some kind of smart pointer and share the data of the PlotDataBuffer to work around this problem.

Edit2: What does happen if first call setData and later call setRawSamples?