RLE_GETROW(3)       UNIX Programmer's Manual        RLE_GETROW(3)



NAME
     rle_getrow - Read a scanline of pixels from an RLE file.

SYNOPSIS
     #include <rle.h>

     rle_getrow( the_hdr, rows );
     rle_hdr * the_hdr;
     rle_pixel ** rows;

DESCRIPTION
     _R_l_e__g_e_t_r_o_w reads information for a single scanline from the
     input file each time it is called. _T_h_e__h_d_r should point to
     the structure initialized by _r_l_e__g_e_t__s_e_t_u_p(3).  The array
     _r_o_w_s should contain pointers to arrays of characters, into
     which the scanline data will be written.  There should be as
     many elements in _r_o_w_s as there are primary colors in the
     input file (typically 1 or 3), and the scanline arrays must
     be indexable up to the maximum X coordinate, as specified by
     _t_h_e__h_d_r->_x_m_a_x.  _r_l_e__g_e_t_r_o_w returns the y value of the scan-
     line just read.  This will always be 1 greater than the y
     value from the scanline previously read, and starts at
     _t_h_e__h_d_r->_y_m_i_n.  Only those channels enabled by _t_h_e__h_d_r->_b_i_t_s
     will be returned.

NOTES
     If an alpha channel is present in the input and enabled (by
     _R_L_E__S_E_T__B_I_T, see _r_l_e__h_d_r(3)), then _r_o_w_s should include a -1
     entry.  (I.e., _r_o_w_s[-_1] should point to a valid scanline
     array.)  The easiest way to ensure this is to use
     _r_l_e__r_o_w__a_l_l_o_c(3) to allocate _r_o_w_s.

     _R_l_e__g_e_t_r_o_w will continue to return scanlines even after the
     end of the input file has been reached, incrementing the
     return scanline number each time it is called.  The calling
     program should use some other termination criterion (such as
     the scanline number reaching _t_h_e__h_d_r->_y_m_a_x, or explicitly
     testing testing for end of file on the input with
     _f_e_o_f(_i_n_f_i_l_e).  The second test may fail if _r_l_e__g_e_t_r_o_w has
     encountered a logical EOF in the file.  The first will
     always work eventually.)

EXAMPLE
     The code below reads the first two 3 color scanlines of 512
     pixels from an RLE file on the standard input.

               char scanline[2][3][512], *rows[3];
               int row, i;
               rle_dflt_hdr.rle_file = stdin;
               rle_get_setup( &rle_dflt_hdr );
               for ( row = 0; row < 2; row++ )
               {



Printed 5/12/93              2/2/87                             1






RLE_GETROW(3)       UNIX Programmer's Manual        RLE_GETROW(3)



                    for ( i = 0; i < 3; i++ )
                         rows[i] = scanline[row][i];
                    rle_getrow( &rle_dflt_hdr, rows );
               }

SEE ALSO
     _r_l_e__h_d_r(3), _r_l_e__r_o_w__a_l_l_o_c(3), _r_l_e__r_o_w__f_r_e_e(3),
     _r_l_e__g_e_t__s_e_t_u_p(3), _r_l_e__g_e_t_r_a_w(3), _r_l_e__g_e_t_s_k_i_p(3),
     _r_l_e__p_u_t_r_o_w(3), _l_i_b_r_l_e(3), _R_L_E(5).

AUTHOR
     Spencer W. Thomas, Todd Fuqua
     University of Utah










































Printed 5/12/93              2/2/87                             2