libppm(3)	  Image	Format Library C++ Reference Manual	     libppm(3)

NAME    [Toc]    [Back]

     libppm - functions	to support portable pixmap programs

SYNOPSIS    [Toc]    [Back]

     #include <ppm.h>
     cc	... libppm.a libpgm.a libpbm.a

DESCRIPTION    [Toc]    [Back]

   TYPES AND CONSTANTS
     typedef ... pixel;
     typedef ... pixval;
     #define PPM_MAXMAXVAL ...
     extern pixval ppm_pbmmaxval;

     Each pixel	contains three pixvals,	each of	which should contain only the
     values between 0 and PPM_MAXMAXVAL.  ppm_pbmmaxval	is the maxval used
     when a PPM	program	reads a	PBM file.  Normally it is 1; however, for some
     programs, a larger	value gives better results.

     #define PPM_FORMAT	...
     #define RPPM_FORMAT ...
     #define PPM_TYPE PPM_FORMAT
     int PPM_FORMAT_TYPE( int format )

     For distinguishing	different file formats and types.

     pixval PPM_GETR( pixel p )
     pixval PPM_GETG( pixel p )
     pixval PPM_GETB( pixel p )

     These three macros	retrieve the red, green	or blue	value from the given
     pixel.

     void PPM_ASSIGN( pixel p, pixval red, pixval grn, pixval blu )

     This macro	assigns	the given red, green and blue values to	the pixel.

     int PPM_EQUAL( pixel p, pixel q )

     This macro	checks two pixels for equality.

     void PPM_DEPTH( pixel newp, pixel p, pixval oldmaxval, pixval newmaxval )

     This macro	scales the colors of pixel p according the old and new maximum
     values and	assigns	the new	values to newp.	 It is intended	to make
     writing ppmtowhatever easier.

     float PPM_LUMIN( pixel p )

     This macro	determines the luminance of the	pixel p.




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libppm(3)	  Image	Format Library C++ Reference Manual	     libppm(3)



   MEMORY MANAGEMENT    [Toc]    [Back]
     pixel** ppm_allocarray( int cols, int rows	)

     Allocate an array of pixels.

     pixel* ppm_allocrow( int cols )

     Allocate a	row of the given number	of pixels.

     void ppm_freearray( pixel** pixels, int rows )

     Free the array allocated with ppm_allocarray() containing the given
     number of rows.

     void pbm_freerow( pixel* pixelrow )

     Free a row	of pixels.

   READING PBM FILES    [Toc]    [Back]
     void ppm_readppminit( FILE* fp, int* colsP, int* rowsP, pixval* maxvalP, int* formatP )

     Read the header from a PPM	file, filling in the rows, cols, maxval	and
     format variables.

     void ppm_readppmrow( FILE*	fp, pixel* pixelrow, int cols, pixval maxval, int format )

     Read a row	of pixels into the pixelrow array.  Format, cols, and maxval
     were filled in by ppm_readppminit().

     pixel** ppm_readppm( FILE*	fp, int* colsP,	int* rowsP, pixval* maxvalP )

     Read an entire pixmap file	into memory, returning the allocated array and
     filling in	the rows, cols and maxval variables.  This function combines
     ppm_readppminit(),	ppm_allocarray() and ppm_readppmrow().

   WRITING FILES    [Toc]    [Back]
     void ppm_writeppminit( FILE* fp, int cols,	int rows, pixval maxval, int forceplain	)

     Write the header for a portable pixmap file.  The forceplain flag forces
     a plain-format file to be written,	as opposed to a	raw-format one.

     void ppm_writeppmrow( FILE* fp, pixel* pixelrow, int cols,	pixval maxval, int forceplain )

     Write a row from a	portable pixmap.

     void ppm_writeppm(	FILE* fp, pixel** pixels, int cols, int	rows, pixval maxval, int forceplain )

     Write the header and all data for a portable pixmap.  This	function
     combines ppm_writeppminit() and ppm_writeppmrow().






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libppm(3)	  Image	Format Library C++ Reference Manual	     libppm(3)



   COLOR NAMES    [Toc]    [Back]
     pixel ppm_parsecolor( char* colorname, pixval maxval )

     Parses an ASCII color name	into a pixel.  The color can be	specified in
     three ways.  One, as a name, assuming that	a pointer to an	X11-style
     color names file was compiled in.	Two, as	an X11-style hexadecimal
     number: #rgb, #rrggbb, #rrrgggbbb,	or #rrrrggggbbbb.  Three, as a triplet
     of	decimal	floating point numbers separated by commas: r.r,g.g,b.b.

     char* ppm_colorname( pixel* colorP, pixval	maxval,	int hexok )

     Returns a pointer to a string describing the given	color.	If the X11
     color names file is available and the color appears in it,	that name is
     returned.	Otherwise, if the hexok	flag is	true then a hexadecimal
     colorspec is returned; if hexok is	false and the X11 color	names file is
     available,	then the closest matching color	is returned; otherwise,	it's
     an	error.

SEE ALSO    [Toc]    [Back]

     pbm(3), pgm(3)

AUTHOR    [Toc]    [Back]

     Copyright (C) 1989, 1991 by Tony Hansen and Jef Poskanzer.


									PPPPaaaaggggeeee 3333