Qwt源码解读之QwtSystemClock类和QwtSamplingThread类

QwtSystemClock类提供了一个高分辨率的时钟功能（依赖于特定的系统）。

代码分析：

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;
};

QwtSystemClock类在QwtSamplingThread类里被用作了采样时钟。

--------------------------------------------------------------

QwtSamplingThread类：定期采集样品的线程，继承自QThread。

QwtSamplingThread自身也是一个抽象基类。

代码分析

class QWT_EXPORT QwtSamplingThread: public QThread
{
Q_OBJECT

public:
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; // 需重新实现

private:
class PrivateData;
PrivateData *d_data;