AnimTimer Class Reference

#include <AnimTimer.h>

Public Types
enum	State { kStopped_State , kPaused_State , kRunning_State }

Public Member Functions
	AnimTimer ()
State	state () const
double	nanos () const
float	getSpeed () const
void	setSpeed (float speed)
void	run ()
void	pause ()
void	togglePauseResume ()
void	updateTime ()

Detailed Description

Class to track a "timer". It supports 3 states: stopped, paused, and running. Playback speed is variable.

The caller must call updateTime() to resync with the clock (typically just before using the timer). Forcing the caller to do this ensures that the timer's return values are consistent if called repeatedly, as they only reflect the time since the last calle to updateTimer().

Definition at line 23 of file AnimTimer.h.

Member Enumeration Documentation

State

enum AnimTimer::State

Enumerator
kStopped_State
kPaused_State
kRunning_State

Definition at line 30 of file AnimTimer.h.

{ kStopped_State, kPaused_State, kRunning_State };

Constructor & Destructor Documentation

AnimTimer()

AnimTimer::AnimTimer ( )

inline

Class begins in the "stopped" state.

Definition at line 28 of file AnimTimer.h.

{}

Member Function Documentation

getSpeed()

float AnimTimer::getSpeed ( ) const

inline

Control the rate at which time advances.

Definition at line 39 of file AnimTimer.h.

{ return fSpeed; }

nanos()

double AnimTimer::nanos ( ) const

inline

Definition at line 34 of file AnimTimer.h.

{ return fElapsedNanos; }

pause()

void AnimTimer::pause ( )

inline

Definition at line 59 of file AnimTimer.h.

                 {
        if (kRunning_State == this->state()) {
            fState = kPaused_State;
        }  // else stay stopped or paused
    }

run()

void AnimTimer::run ( )

inline

If the timer is paused or stopped, it will resume (or start if it was stopped).

Definition at line 45 of file AnimTimer.h.

               {
        switch (this->state()) {
            case kStopped_State:
                fPreviousNanos = SkTime::GetNSecs();
                fElapsedNanos  = 0;
                break;
            case kPaused_State:  // they want "resume"
                fPreviousNanos = SkTime::GetNSecs();
                break;
            case kRunning_State: break;
        }
        fState = kRunning_State;
    }

setSpeed()

void AnimTimer::setSpeed ( float  speed )

inline

Definition at line 40 of file AnimTimer.h.

{ fSpeed = speed; }

state()

State AnimTimer::state ( ) const

inline

Definition at line 32 of file AnimTimer.h.

{ return fState; }

togglePauseResume()

void AnimTimer::togglePauseResume ( )

inline

If the timer is stopped, start running, else it toggles between paused and running.

Definition at line 68 of file AnimTimer.h.

                             {
        if (kRunning_State == this->state()) {
            this->pause();
        } else {
            this->run();
        }
    }

updateTime()

void AnimTimer::updateTime ( )

inline

Call this each time you want to sample the clock for the timer. This is NOT done automatically, so that repeated calls to msec() or secs() will always return the same value.

This may safely be called with the timer in any state.

Definition at line 83 of file AnimTimer.h.

                      {
        if (kRunning_State == this->state()) {
            double now = SkTime::GetNSecs();
            fElapsedNanos += (now - fPreviousNanos) * fSpeed;
            fPreviousNanos = now;
        }
    }

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The documentation for this class was generated from the following file:

• third_party/skia/tools/viewer/AnimTimer.h