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Filter Class Reference

#include <frame.h>

Inheritance diagram for Filter:

List of all members.

Public Methods
virtual	~Filter ()
virtual bool	filter_frame (FrameClass &frame)=0
virtual void	reset ()
virtual void	property_changed ()
virtual int	get_nb_inputs ()
virtual int	get_nb_outputs ()
Public Attributes
vector< Property * >	properties
string	name
GdkPixmap *	icon_pixmap
bool	is_input_filter

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Detailed Description

this is an abstract base class for a biometric filter it basicly just supplies a single function that should be overloaded in all subclasses. This function preformes the filtering operation, and some methods to be used to inform the filter of changes to it's properties

Note also that mearly subclassing filter is not enough to have it interface with the GUI. the GUI is dynamicly linked to all of the filters and so each filter must impliment a "C" function that will be called by the GUI to get a copy of the filter. also each filter needs an icon associated with it, so a function to return this icon must also be implimented these functions should be of the following form

in the .h file ifdef DYNAMIC_LINK extern "C"{ Filter * create_instance(); ifndef NO_GUI GdkPixmap *create_icon(GtkWidget *drawing_area); endif } endif

in the .cpp file ifdef DYNAMIC_LINK

Filter * create_instance(){ return new locator_filter; }

ifndef NO_GUI GdkPixmap *create_icon(GtkWidget *drawing_area){ return gdk_pixmap_create_from_xpm( drawing_area->window, NULL, NULL, "images/locator.xpm" ); } endif

endif

the extern "C" is so the names of the functions are not garbled by the C++ complier. the ifdef DYNAMIC_LINK is so that if the filters are staticly linked together the linker does not see many implimentations of a single function, the NO_GUI is used in the case that the user does not wish to compile the filters with GTK2.0 linked in

Author:

Robert Evans

Version:

0.1

Date:

Jan 24 2003

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Constructor & Destructor Documentation

Filter::~Filter (    )  [virtual]

we really need this to make everythign work properly

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Member Function Documentation

virtual bool Filter::filter_frame (  FrameClass &    frame )  [pure virtual]

this simply takes a frame and runs the current filter over it Parameters: frame  the current frame to be processed Implemented in eye_locator_filter.

int Filter::get_nb_inputs (    )  [virtual]

currently unused do not touch

int Filter::get_nb_outputs (    )  [virtual]

currently unused do not touch

void Filter::property_changed (    )  [virtual]

this method is called after the member properties has been updated, it informs the filter that properties has changed and those changes should take effect Reimplemented in eye_locator_filter.

void Filter::reset (    )  [virtual]

some filters are ment to be used on a movie and can increase performance by storing information about previous frames, this function is called after an entire movie has finnished playing so that the filter may reset it's data, NOTE that this is only virtual and not purly virtual it need not be imlemented unless the filter wishes to be reset after a complete, movie has been run through it Reimplemented in input_filter.

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Member Data Documentation

GdkPixmap* Filter::icon_pixmap

this is the icon that the filter will be identified with in the

bool Filter::is_input_filter

mearly states if this is an input filter or not, an input filter is one that updates the frame with a new image when it is called, it will always be the first filter in a sequence

string Filter::name

this is the name that the filter will be identified with in the GUI

vector<Property *> Filter::properties

a vector of properties for this particular filter this should be initilised in the filters constructor

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

• frame.h
• frame.cpp

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