Qwtsystemclock and qwtsamplingthread

The qwtsystemclock class provides a high-resolution clock function (dependent on a specific system ).

Code Analysis:

class QWT_EXPORT QwtSystemClock{public:    QwtSystemClock();    virtual ~QwtSystemClock();    bool isNull() const;    void start();    double restart();    double elapsed() const;    static double precision();private:    class PrivateData;    PrivateData *d_data;};

The qwtsystemclock class is used as a sampling clock in the qwtsamplingthread class.

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Qwtsamplingthread class: the thread that periodically collects samples, inherited from qthread.

Qwtsamplingthread itself is also an abstract base class.

Code Analysis

Class qwt_export qwtsamplingthread: Public qthread {q_objectpublic: Virtual ~ Qwtsamplingthread (); double interval () const; double elapsed () const; Public q_slots: void setinterval (double interval); void stop (); protected: explicit qwtsamplingthread (qobject * parent = NULL); Virtual void run ();/*! Collect a sample \ Param elapsed time since the thread was started in miliseconds */virtual void sample (double elapsed) = 0; // Private: Class privatedata needs to be implemented again; privatedata * d_data ;};

The example of D: \ qwt-6.0.1 \ examples \ oscilloscope. Pro contains examples for the above two classes.