/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*************************************************************************
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 * 
 * Copyright 2000, 2010 Oracle and/or its affiliates.
 *
 * OpenOffice.org - a multi-platform office productivity suite
 *
 * This file is part of OpenOffice.org.
 *
 * OpenOffice.org is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 3
 * only, as published by the Free Software Foundation.
 *
 * OpenOffice.org is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License version 3 for more details
 * (a copy is included in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU Lesser General Public License
 * version 3 along with OpenOffice.org.  If not, see
 * <http://www.openoffice.org/license.html>
 * for a copy of the LGPLv3 License.
 *
 ************************************************************************/
#ifndef _SW_PORTIONHANDLER_HXX
#define _SW_PORTIONHANDLER_HXX

#include <tools/solar.h>
class String;
namespace binfilter {


/** The SwPortionHandler interface implements a visitor for the layout
 * engine's text portions. This can be used to gather information of
 * the on-screen representation of a single paragraph.
 *
 * For each text portion, one of the methods text(...) or special(...)
 * is called, depending on whether it is a 'normal' run of text, or
 * any other portion. Additionally, the linebreak() method is called
 * once at the end of every on-screen line.
 *
 * All parameters relate to the 'model string', which is the text string
 * held by the corresponding SwTxtNode.
 *
 * The SwPortionHandler can be used with the
 * SwTextFrame::VisitPortions(...) method.  
 */
class SwPortionHandler
{
public:

    SwPortionHandler() {}           /// (emtpy) constructor

    virtual ~SwPortionHandler() {}  /// (empty) destructor

    /** text portion. A run of nLength characters from the model
     * string, that contains no special characters like embedded
     * fields, etc. Thus, the on-screen text of this portion
     * corresponds exactly to the corresponding characters in the
     * model string.
     */
    virtual void Text(
        USHORT nLength,      /// length of this portion in the model string
        USHORT nType         /// type of this portion
        ) = 0;

    /** special portion. This method is called for every non-text
     * portion. The parameters describe the length of the
     * corresponding characters in the model string (often 0 or 1),
     * the text which is displayed, and the type of the portion.
     */
    virtual void Special(
        USHORT nLength,      /// length of this portion in the model string
        const String& rText, /// text which is painted on-screen
        USHORT nType         /// type of this portion
        ) = 0;

    /** line break. This method is called whenever a line break in the
     * layout occurs.
     */
    virtual void LineBreak() = 0;

    /** skip characters. The SwTxtFrame may only display partially
     * display a certain paragraph (e.g. when the paragaph is split
     * across multiple pages). In this case, the Skip() method must be
     * called to inform the portion handler to ignore a certain run of
     * characters in the 'model string'. Skip(), if used at all, must
     * be called before any of the other methods is called. Calling
     * Skip() between portions is not allowed.
     */
    virtual void Skip(
        USHORT nLength   /// number of 'model string' characters to be skipped
        ) = 0;

    /** end of paragraph. This method is to be called when all the
     * paragraph's portions have been processed. 
     */
    virtual void Finish() = 0;
};

} //namespace binfilter
#endif

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
