Gv::Capture Class Reference

A video capture abstract interface, exposing a file descriptor and a method to handle read events on it. More...

#include <gvcapture.h>

Inheritance diagram for Gv::Capture:

Public Member Functions
virtual	~Capture ()=0
	Destructor.
virtual void	start ()=0
	Restarts capturing after a stop(). Not normally needed.
virtual void	stop ()=0
	Stops capturing.
virtual bool	simple () const =0
	Returns true if a complete RGB24 image can be read out of the capture device and straight into a contiguous image buffer using the appropriate read() overload. More...
virtual bool	read (unsigned char *, size_t n)=0
	Does a read of an RGB24 image into the user-supplied buffer, on condition that the device is simple(). More...
virtual bool	read (CaptureCallback &)=0
	Delivers an image to the given callback fn. More...
virtual int	fd () const =0
	Returns the fd for select(). More...
virtual unsigned int	dx () const =0
	Returns the width.
virtual unsigned int	dy () const =0
	Returns the height.
virtual bool	active () const =0
	Returns true after construction or start(), and false after stop(). More...
virtual std::string	info () const =0
	Returns information for debugging and logging purposes.

Detailed Description

A video capture abstract interface, exposing a file descriptor and a method to handle read events on it.

The read method delivers images to a callback interface in a "capture buffer".

Definition at line 40 of file gvcapture.h.

Member Function Documentation

virtual bool Gv::Capture::active ( ) const

pure virtual

Returns true after construction or start(), and false after stop().

Implemented in Gv::CaptureV4l, and Gv::CaptureTest.

virtual int Gv::Capture::fd ( ) const

pure virtual

Returns the fd for select().

Note that when using streaming i/o there is no way to stop events being delivered to this file descriptor. Using stop() is not sufficient; also remove the file descriptor from the event loop.

Implemented in Gv::CaptureV4l, and Gv::CaptureTest.

virtual bool Gv::Capture::read ( unsigned char *  , size_t  n  )

pure virtual

Does a read of an RGB24 image into the user-supplied buffer, on condition that the device is simple().

Implemented in Gv::CaptureV4l, and Gv::CaptureTest.

virtual bool Gv::Capture::read ( CaptureCallback &  )

pure virtual

Delivers an image to the given callback fn.

Returns true if an image was delivered to the callback interface, or false if none was available.

Implemented in Gv::CaptureV4l, and Gv::CaptureTest.

virtual bool Gv::Capture::simple ( ) const

pure virtual

Returns true if a complete RGB24 image can be read out of the capture device and straight into a contiguous image buffer using the appropriate read() overload.

This is typically only true when using libv4l with the 'read' i/o method.

Implemented in Gv::CaptureV4l, and Gv::CaptureTest.

---

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

• /home/graeme/videotools/src/gvideo/gvcapture.h
• /home/graeme/videotools/src/gvideo/gvcapture.cpp