rle_box.c

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/* 
 * rle_box.c - Common code between rlebox and crop.
 * 
 * Author:  Spencer W. Thomas
 *      EECS Dept.
 *      University of Michigan
 * Date:    Tue Jun  5 1990
 * Copyright (c) 1990, University of Michigan
 */

#include <stdio.h>
#include "rle.h"
#include "rle_raw.h"

void
rle_box( the_hdr, xminp, xmaxp, yminp, ymaxp )
rle_hdr *the_hdr;
int *xminp, *xmaxp, *yminp, *ymaxp;
{
    rle_op ** raw;
    register rle_op ** rawp;
    register int i;
    int y, * nrawp;
    int xmin, xmax, ymin, ymax;

    if ( rle_raw_alloc( the_hdr, &raw, &nrawp ) < 0 )
    RLE_CHECK_ALLOC( the_hdr->cmd, 0, 0 );
    rawp = raw;

    ymax = -1;          /* smaller than it can ever be */
    ymin = 32768;       /* larger than it can ever be */
    xmax = -1;
    xmin = 32768;

    while ( ( y = rle_getraw( the_hdr, rawp, nrawp ) ) != 32768 )
    {
    if ( y < ymin )     /* found ymin yet? */
    {
        /* Only count it if there is really some data */
        for ( i = -the_hdr->alpha; i < the_hdr->ncolors; i++ )
        if ( nrawp[i] > 0 )
            ymin = y;
    }
    if ( y > ymax )     /* update ymax? */
    {
        /* Only count it if there is really some data */
        for ( i = -the_hdr->alpha; i < the_hdr->ncolors; i++ )
        if ( nrawp[i] > 0 )
            ymax = y;
    }

    /* Now do xmin and xmax */
        for ( i = -the_hdr->alpha; i < the_hdr->ncolors; i++ )
        if ( nrawp[i] > 0 )
        {
            if ( rawp[i][0].xloc < xmin )
            xmin = rawp[i][0].xloc;
            if ( xmax < rawp[i][nrawp[i]-1].xloc +
             rawp[i][nrawp[i]-1].length - 1 )
            xmax =  rawp[i][nrawp[i]-1].xloc +
                rawp[i][nrawp[i]-1].length - 1;
        }
    }

    /* If no data, arbitrarily use (0,0)x(0,0) */
    if ( xmax < xmin )
    {
    xmax = xmin = ymax = ymin = 0;
    }

    *xminp = xmin;
    *xmaxp = xmax;
    *yminp = ymin;
    *ymaxp = ymax;

    rle_raw_free( the_hdr, raw, nrawp );
}