Power Programmierung 2/Power-Programmierung CD 2 (Tewi)(1994).iso/gnu/gnulib/dkbtrace/pbmplus/source/pbm/pbmmask.c

C/C++ Source or Header | 1991-12-10 | 5.4 KB | 223 lines

/* pbmmask.c - create a mask bitmap from a portable bitmap
**
** Copyright (C) 1989, 1991 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation.  This software is provided "as is" without express or
** implied warranty.
*/

#include "pbm.h"

static void addflood ARGS(( int col, int row ));
static void flood ARGS(( void ));

static bit** bits;
static bit** mask;
static bit backcolor;
static int rows, cols;

void
main( argc, argv )
    int argc;
    char* argv[];
    {
    FILE* ifp;
    int argn, expand, wcount;
    register int row, col;
    char* usage = "[-expand] [pbmfile]";

    pbm_init( &argc, argv );

    argn = 1;
    expand = 0;

    if ( argn < argc && argv[argn][0] == '-' && argv[argn][1] != '\0' )
    {
    if ( pm_keymatch( argv[argn], "-expand", 2 ) )
        expand = 1;
    else if ( pm_keymatch( argv[argn], "-noexpand", 2 ) )
        expand = 0;
    else
        pm_usage( usage );
    ++argn;
    }

    if ( argn == argc )
    ifp = stdin;
    else
    {
    ifp = pm_openr( argv[argn] );
    ++argn;
    }

    if ( argn != argc )
    pm_usage( usage );

    bits = pbm_readpbm( ifp, &cols, &rows );
    pm_close( ifp );
    mask = pbm_allocarray( cols, rows );

    /* Clear out the mask. */
    for ( row = 0; row < rows; ++row )
        for ( col = 0; col < cols; ++col )
        mask[row][col] = PBM_BLACK;

    /* Figure out the background color, by counting along the edge. */
    wcount = 0;
    for ( row = 0; row < rows; ++row )
    {
    if ( bits[row][0] == PBM_WHITE )
        ++wcount;
    if ( bits[row][cols - 1] == PBM_WHITE )
        ++wcount;
    }
    for ( col = 1; col < cols - 1; ++col )
    {
    if ( bits[0][col] == PBM_WHITE )
        ++wcount;
    if ( bits[rows - 1][col] == PBM_WHITE )
        ++wcount;
    }
    if ( wcount >= rows + cols - 2 )
    backcolor = PBM_WHITE;
    else
    backcolor = PBM_BLACK;

    /* Flood the entire edge.  Probably the first call will be enough, but
    ** might as well be sure. */
    for ( col = cols - 3; col >= 2; col -= 2 )
    {
    addflood( col, rows - 1 );
    addflood( col, 0 );
    }
    for ( row = rows - 1; row >= 0; row -= 2 )
    {
    addflood( cols - 1, row );
    addflood( 0, row );
    }
    flood( );

    if ( ! expand )
    /* Done. */
    pbm_writepbm( stdout, mask, cols, rows, 0 );
    else
    { /* Expand by one pixel. */
    register int srow, scol;
    bit** emask;

    emask = pbm_allocarray( cols, rows );

    for ( row = 0; row < rows; ++row )
        for ( col = 0; col < cols; ++col )
        if ( mask[row][col] == PBM_BLACK )
            emask[row][col] = PBM_BLACK;
        else
            {
            emask[row][col] = PBM_WHITE;
            for ( srow = row - 1; srow <= row + 1; ++srow )
            for ( scol = col - 1; scol <= col + 1; ++scol )
                if ( srow >= 0 && srow < rows &&
                 scol >= 0 && scol < cols &&
                 mask[srow][scol] == PBM_BLACK )
                {
                emask[row][col] = PBM_BLACK;
                break;
                }
            }

    /* Done. */
    pbm_writepbm( stdout, emask, cols, rows, 0 );
    }

    pm_close( stdout );
    exit( 0 );
    }

static short* fcols;
static short* frows;
static int fstacksize = 0, fstackp = 0;

static void
addflood( col, row )
int col, row;
    {
    if ( bits[row][col] == backcolor && mask[row][col] == PBM_BLACK )
    {
    if ( fstackp >= fstacksize )
        {
        if ( fstacksize == 0 )
        {
        fstacksize = 1000;
        fcols = (short*) malloc( fstacksize * sizeof(short) );
        frows = (short*) malloc( fstacksize * sizeof(short) );
        if ( fcols == (short*) 0 || frows == (short*) 0 )
            pm_error( "out of memory" );
        }
        else
        {
        fstacksize *= 2;
        fcols = (short*) realloc(
            (char*) fcols, fstacksize * sizeof(short) );
        frows = (short*) realloc(
            (char*) frows, fstacksize * sizeof(short) );
        if ( fcols == (short*) 0 || frows == (short*) 0 )
            pm_error( "out of memory" );
        }
        }
    fcols[fstackp] = col;
    frows[fstackp] = row;
    ++fstackp;
    }
    }

static void
flood( )
    {
    register int col, row, c;

    while ( fstackp > 0 )
    {
    --fstackp;
    col = fcols[fstackp];
    row = frows[fstackp];
    if ( bits[row][col] == backcolor && mask[row][col] == PBM_BLACK )
        {
        mask[row][col] = PBM_WHITE;
        if ( row - 1 >= 0 )
        addflood( col, row - 1 );
        if ( row + 1 < rows )
        addflood( col, row + 1 );
        for ( c = col + 1; c < cols; ++c )
        {
        if ( bits[row][c] == backcolor && mask[row][c] == PBM_BLACK )
            {
            mask[row][c] = PBM_WHITE;
            if ( row - 1 >= 0 && ( bits[row - 1][c - 1] != backcolor || mask[row - 1][c - 1] != PBM_BLACK ) )
            addflood( c, row - 1 );
            if ( row + 1 < rows && ( bits[row + 1][c - 1] != backcolor || mask[row + 1][c - 1] != PBM_BLACK ) )
            addflood( c, row + 1 );
            }
        else
            break;
        }
        for ( c = col - 1; c >= 0; --c )
        {
        if ( bits[row][c] == backcolor && mask[row][c] == PBM_BLACK )
            {
            mask[row][c] = PBM_WHITE;
            if ( row - 1 >= 0 && ( bits[row - 1][c + 1] != backcolor || mask[row - 1][c + 1] != PBM_BLACK ) )
            addflood( c, row - 1 );
            if ( row + 1 < rows && ( bits[row + 1][c + 1] != backcolor || mask[row + 1][c + 1] != PBM_BLACK ) )
            addflood( c, row + 1 );
            }
        else
            break;
        }
        }
    }
    }