cavapa_gui::HTTPCapture Class Reference

The Capture device for HTTP images. More...

#include <httpcapture.h>

Inheritance diagram for cavapa_gui::HTTPCapture:

Public Member Functions
	DISALLOW_COPY_AND_ASSIGN (HTTPCapture)
	Copy and assign of the class is not allowed.
double	getBarrelCorrection () override
	Retrieves the barrel correction applied to the source. More...
FrameCapture	getBuffered () override
	Retrieves the currently buffered frame. More...
std::string	getDescription () const override
	Retrieves the description of the device. More...
int	getDeviceID () const override
	Returns the ID number the device was initialized with. More...
double	getFramerate () const override
	Retrieves the capture device framerate. More...
int	getMissedFrames () const override
	Retrieves the logged frame misses. More...
FrameCapture	getNext (bool skip, bool *error) override
	Retrieves the next frame. More...
std::string	getPath () const override
	Retrieves the path given during the initialization. More...
cv::Size	getResolution () const override
	Retrieves the capture device resolution. More...
int	getRetrievedFrames () const override
	Retrieves the total logged frames. More...
INTERFACE_TYPE	getType () const override
	Retrieves the type of the device. More...
bool	hasNew () override
	Checks whether the device has a new image to retrieve or not. More...
bool	isOpen () const override
	Checks whether the capturing device is open or not. More...
bool	open (const std::string &path) override
	Opens the video file or the stream. More...
void	resetStats () override
	Resets the statistical counters. More...
void	setBarrelCorrection (double amount) override
	Sets the amount of the barrel correction to be applied. More...
bool	setResolution (const cv::Size &new_size) override
	Sets the capturing device resolution. More...
Public Member Functions inherited from cavapa_gui::CaptureInterface
	DISALLOW_COPY_AND_ASSIGN (CaptureInterface)
	Copy and assign of the class is not allowed.

Additional Inherited Members
Public Types inherited from cavapa_gui::CaptureInterface
enum	INTERFACE_TYPE { HTTP, OPENCV }
	Used to define the type of source interface.

Detailed Description

The Capture device for HTTP images.

The class can be used as the interface device for capturing the HTTP images from websites (like webcam). It uses CURL library for it's image retrieval.

Remarks

The class was design to be a backup interface for network cameras. As it turned out, there was no real need for the class so it was excluded from the build. It is still here in case it is needed.

Author

Petri Partanen

Member Function Documentation

double cavapa_gui::HTTPCapture::getBarrelCorrection ( )

inlineoverridevirtual

Retrieves the barrel correction applied to the source.

Returns

The amount of the barrel correction.

Implements cavapa_gui::CaptureInterface.

FrameCapture cavapa_gui::HTTPCapture::getBuffered ( )

overridevirtual

Retrieves the currently buffered frame.

Returns

The buffered frame.

Remarks

This does not signal for a new image fetch from the device.

Implements cavapa_gui::CaptureInterface.

std::string cavapa_gui::HTTPCapture::getDescription ( ) const

inlineoverridevirtual

Retrieves the description of the device.

Returns

For the devices initialized with HW index, this will be the name of the HW device. For other devices this is the path given during initialization.

Implements cavapa_gui::CaptureInterface.

int cavapa_gui::HTTPCapture::getDeviceID ( ) const

inlineoverridevirtual

Returns the ID number the device was initialized with.

Returns

The device ID used in the initialization or UNKNOWN_DEVICE if not specified.

UNKNOWN_DEVICE. The HTTP devices are not real devices.

Implements cavapa_gui::CaptureInterface.

double cavapa_gui::HTTPCapture::getFramerate ( ) const

inlineoverridevirtual

Retrieves the capture device framerate.

Returns

The current framerate.

0. The HTTP devices do not have framerate.

Implements cavapa_gui::CaptureInterface.

int cavapa_gui::HTTPCapture::getMissedFrames ( ) const

inlineoverridevirtual

Retrieves the logged frame misses.

A frame miss occurs everytime when getNext() is called and the previous retrieval was still ongoing.

Returns

The count of the missed frames.

Implements cavapa_gui::CaptureInterface.

FrameCapture cavapa_gui::HTTPCapture::getNext ( bool  skip, bool *  error  )

overridevirtual

Retrieves the next frame.

Basically it returns the currently buffered frame and signals the device to grab a new image for next call to the function. If the device has not returned from previous image grab the call is recorded as a missed frame.

Parameters

skip	Specifies if the frame can be skipped. When set to true, this will force the main thread to wait for a new image from the device. This can result in a huge lag if the device is not capable of retrieving images fast enough.
error	Will receive an error message if something went wrong.

Returns

The next frame with the reference to the image! You must make a clone if you wish to alter it!

Implements cavapa_gui::CaptureInterface.

std::string cavapa_gui::HTTPCapture::getPath ( ) const

inlineoverridevirtual

Retrieves the path given during the initialization.

Returns

The path of the device or an empty string if not found.

Implements cavapa_gui::CaptureInterface.

cv::Size cavapa_gui::HTTPCapture::getResolution ( ) const

overridevirtual

Retrieves the capture device resolution.

Returns

The resolution of the device.

Remarks

On HTTP sources this can only be known after the first successful image retrieval.

Implements cavapa_gui::CaptureInterface.

int cavapa_gui::HTTPCapture::getRetrievedFrames ( ) const

inlineoverridevirtual

Retrieves the total logged frames.

Basically, this is a counter on how many times getNext() has been called.

Returns

The count of the total frames returned.

Implements cavapa_gui::CaptureInterface.

INTERFACE_TYPE cavapa_gui::HTTPCapture::getType ( ) const

inlineoverridevirtual

Retrieves the type of the device.

Returns

The interface type.

Implements cavapa_gui::CaptureInterface.

bool cavapa_gui::HTTPCapture::hasNew ( )

inlineoverridevirtual

Checks whether the device has a new image to retrieve or not.

This checks if the FrameTime on the buffered image differs from what was retrieved on the last getNext().

Returns

True if new image or false otherwise.

true. HTTP devices always have new images.

Implements cavapa_gui::CaptureInterface.

bool cavapa_gui::HTTPCapture::isOpen ( ) const

inlineoverridevirtual

Checks whether the capturing device is open or not.

Returns

True if the device is open or false otherwise.

Implements cavapa_gui::CaptureInterface.

bool cavapa_gui::HTTPCapture::open ( const std::string &  path )

overridevirtual

Opens the video file or the stream.

Parameters

path	The path of the video file or the network stream.

Returns

True if it was opened successfully or false otherwise.

Implements cavapa_gui::CaptureInterface.

void cavapa_gui::HTTPCapture::resetStats ( )

overridevirtual

Resets the statistical counters.

This affects the missed and total frame counters.

Implements cavapa_gui::CaptureInterface.

void cavapa_gui::HTTPCapture::setBarrelCorrection ( double  amount )

inlineoverridevirtual

Sets the amount of the barrel correction to be applied.

Parameters

amount

The barrel effect. 0.0 means none.

Implements cavapa_gui::CaptureInterface.

bool cavapa_gui::HTTPCapture::setResolution ( const cv::Size &  new_size )

inlineoverridevirtual

Sets the capturing device resolution.

Parameters

new_size

The size to be set.

Returns

True if at least one of the dimension was set or false otherwise.

false. You cannot change resolution of HTTP sources.

Implements cavapa_gui::CaptureInterface.

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

• source/httpcapture.h
• source/httpcapture.cpp