1  /* Abstract output stream for CSS styled text.
       2     Copyright (C) 2006, 2019-2020 Free Software Foundation, Inc.
       3     Written by Bruno Haible <bruno@clisp.org>, 2006.
       4  
       5     This program is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU General Public License as published by
       7     the Free Software Foundation; either version 3 of the License, or
       8     (at your option) any later version.
       9  
      10     This program is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU General Public License for more details.
      14  
      15     You should have received a copy of the GNU General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  #ifndef _STYLED_OSTREAM_H
      19  #define _STYLED_OSTREAM_H
      20  
      21  #include <stdbool.h>
      22  
      23  #include "ostream.h"
      24  
      25  
      26  /* A styled output stream is an object to which one can feed a sequence of
      27     bytes, marking some runs of text as belonging to specific CSS classes,
      28     where the rendering of the CSS classes is defined through a CSS (cascading
      29     style sheet).  */
      30  
      31  struct styled_ostream : struct ostream
      32  {
      33  methods:
      34  
      35    /* Start a run of text belonging to CLASSNAME.  The CLASSNAME is the name
      36       of a CSS class.  It can be chosen arbitrarily and customized through
      37       an inline or external CSS.  */
      38    void begin_use_class (styled_ostream_t stream, const char *classname);
      39  
      40    /* End a run of text belonging to CLASSNAME.
      41       The begin_use_class / end_use_class calls must match properly.  */
      42    void end_use_class (styled_ostream_t stream, const char *classname);
      43  
      44    /* Get/set the hyperlink attribute and its id.  */
      45    const char * get_hyperlink_ref (styled_ostream_t stream);
      46    const char * get_hyperlink_id (styled_ostream_t stream);
      47    void         set_hyperlink (styled_ostream_t stream,
      48                                const char *ref, const char *id);
      49  
      50    /* Like styled_ostream_flush (first_arg, FLUSH_THIS_STREAM), except that it
      51       leaves the destination with the current text style enabled, instead
      52       of with the default text style.
      53       After calling this function, you can output strings without newlines(!)
      54       to the underlying stream, and they will be rendered like strings passed
      55       to 'ostream_write_mem', 'ostream_write_str', or 'ostream_write_printf'.  */
      56    void flush_to_current_style (styled_ostream_t stream);
      57  };
      58  
      59  #ifdef __cplusplus
      60  extern "C" {
      61  #endif
      62  
      63  
      64  /* Test whether a given output stream is a styled_ostream.  */
      65  extern bool is_instance_of_styled_ostream (ostream_t stream);
      66  
      67  
      68  #ifdef __cplusplus
      69  }
      70  #endif
      71  
      72  #endif /* _STYLED_OSTREAM_H */