utils.h

Rob Hess Linux下的SIFT提取源码

/**@file
   Miscellaneous utility functions.
   
   Copyright (C) 2006-2007  Rob Hess <[e-mail]>

   @version 1.1.1-20070913
*/

#ifndef UTILS_H
#define UTILS_H

#include "cxcore.h"

#include <stdio.h>
#include <dirent.h>


/* absolute value */
#ifndef ABS
#define ABS(x) ( ( x < 0 )? -x : x )
#endif

/***************************** Inline Functions ******************************/


/**
   A function to get a pixel value from an 8-bit unsigned image.
   
   @param img an image
   @param r row
   @param c column
   @return Returns the value of the pixel at (\a r, \a c) in \a img
*/
static inline int pixval8( IplImage* img, int r, int c )
{
  return (int)( ( (uchar*)(img->imageData + img->widthStep*r) )[c] );
}


/**
   A function to set a pixel value in an 8-bit unsigned image.
   
   @param img an image
   @param r row
   @param c column
   @param val pixel value
*/
static inline void setpix8( IplImage* img, int r, int c, uchar val)
{
  ( (uchar*)(img->imageData + img->widthStep*r) )[c] = val;
}


/**
   A function to get a pixel value from a 32-bit floating-point image.
   
   @param img an image
   @param r row
   @param c column
   @return Returns the value of the pixel at (\a r, \a c) in \a img
*/
static inline float pixval32f( IplImage* img, int r, int c )
{
  return ( (float*)(img->imageData + img->widthStep*r) )[c];
}


/**
   A function to set a pixel value in a 32-bit floating-point image.
   
   @param img an image
   @param r row
   @param c column
   @param val pixel value
*/
static inline void setpix32f( IplImage* img, int r, int c, float val )
{
  ( (float*)(img->imageData + img->widthStep*r) )[c] = val;
}


/**
   A function to get a pixel value from a 64-bit floating-point image.
   
   @param img an image
   @param r row
   @param c column
   @return Returns the value of the pixel at (\a r, \a c) in \a img
*/
static inline double pixval64f( IplImage* img, int r, int c )
{
  return (double)( ( (double*)(img->imageData + img->widthStep*r) )[c] );
}


/**
   A function to set a pixel value in a 64-bit floating-point image.
   
   @param img an image
   @param r row
   @param c column
   @param val pixel value
*/
static inline void setpix64f( IplImage* img, int r, int c, double val )
{
  ( (double*)(img->imageData + img->widthStep*r) )[c] = val;
}


/**************************** Function Prototypes ****************************/


/**
   Prints an error message and aborts the program.  The error message is
   of the form "Error: ...", where the ... is specified by the \a format
   argument
   
   @param format an error message format string (as with \c printf(3)).
*/
extern void fatal_error( char* format, ... );


/**
   Replaces a file's extension, which is assumed to be everything after the
   last dot ('.') character.

   @param file the name of a file

   @param extn a new extension for \a file; should not include a dot (i.e.
     \c "jpg", not \c ".jpg") unless the new file extension should contain
     two dots.

   @return Returns a new string formed as described above.  If \a file does
     not have an extension, this function simply adds one.
*/
extern char* replace_extension( const char* file, const char* extn );


/**
   Prepends a path to a filename.

   @param path a path
   @param file a file name

   @return Returns a new string containing a full path name consisting of
     \a path prepended to \a file.
*/
extern char* prepend_path( const char* path, const char* file );


/**
   A function that removes the path from a filename.  Similar to the Unix
   basename command.

   @param pathname a (full) path name

   @return Returns the basename of \a pathname.
*/
extern char* basename( const char* pathname );


/**
   Displays progress in the console with a spinning pinwheel.  Every time this
   function is called, the state of the pinwheel is incremented.  The pinwheel
   has four states that loop indefinitely: '|', '/', '-', '\'.
   
   @param done if 0, this function simply increments the state of the pinwheel;
     otherwise it prints "done"
*/
extern void progress( int done );


/**
   Erases a specified number of characters from a stream.
   
   @param stream the stream from which to erase characters
   @param n the number of characters to erase
*/
extern void erase_from_stream( FILE* stream, int n );


/**
   Doubles the size of an array with error checking

   @param array pointer to an array whose size is to be doubled
   @param n number of elements allocated for \a array
   @param size size in bytes of elements in \a array

   @return Returns the new number of elements allocated for \a array.  If no
     memory is available, returns 0 and frees \a array.
*/
extern int array_double( void** array, int n, int size );


/**
   Calculates the squared distance between two points.
   
   @param p1 a point
   @param p2 another point
*/
extern double dist_sq_2D( CvPoint2D64f p1, CvPoint2D64f p2 );


/**
   Draws an x on an image.

   @param img an image
   @param pt the center point of the x
   @param r the x's radius
   @param w the x's line weight
   @param color the color of the x
*/
extern void draw_x( IplImage* img, CvPoint pt, int r, int w, CvScalar color );


/**
   Combines two images by scacking one on top of the other
   
   @param img1 top image
   @param img2 bottom image

   @return Returns the image resulting from stacking \a img1 on top if \a img2
*/
extern IplImage* stack_imgs( IplImage* img1, IplImage* img2 );


/**
   Displays an image, making sure it fits on screen.  cvWaitKey() must be
   called after this function so the event loop is entered and the
   image is displayed.

   @param img an image, possibly too large to display on-screen
   @param title the title of the window in which \a img is displayed
*/
extern void display_big_img( IplImage* img, char* title );


/**
   Allows user to view an array of images as a video.  Keyboard controls
   are as follows:
   
   <ul>
   <li>Space - start and pause playback</li>
   <li>Page Up - skip forward 10 frames</li>
   <li>Page Down - jump back 10 frames</li>
   <li>Right Arrow - skip forward 1 frame</li>
   <li>Left Arrow - jump back 1 frame</li>
   <li>Backspace - jump back to beginning</li>
   <li>Esc - exit playback</li>
   <li>Closing the window also exits playback</li>
   </ul>

   @param imgs an array of images
   @param n number of images in \a imgs
   @param win_name name of window in which images are displayed
*/
extern void vid_view( IplImage** imgs, int n, char* win_name );


/**
   Checks if a HighGUI window is still open or not

   @param name the name of the window we're checking

   @return Returns 1 if the window named \a name has been closed or 0 otherwise
*/
extern int win_closed( char* name );

#endif