sw/source/core/inc/SwPortionHandler.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_SW_SOURCE_CORE_INC_SWPORTIONHANDLER_HXX
  21 #define INCLUDED_SW_SOURCE_CORE_INC_SWPORTIONHANDLER_HXX
  22
  23 #include <swdllapi.h>
  24 #include <rtl/ustring.hxx>
  25 #include "TextFrameIndex.hxx"
  26
  27 class SwFont;
  28 enum class PortionType;
  29
  30 /** The SwPortionHandler interface implements a visitor for the layout
  31  * engine's text portions. This can be used to gather information of
  32  * the on-screen representation of a single paragraph.
  33  *
  34  * For each text portion, one of the methods text(...) or special(...)
  35  * is called, depending on whether it is a 'normal' run of text, or
  36  * any other portion. Additionally, the linebreak() method is called
  37  * once at the end of every on-screen line.
  38  *
  39  * All parameters relate to the 'view string', which is the text string
  40  * held by the sequence of all corresponding SwTextFrames.
  41  *
  42  * The SwPortionHandler can be used with the
  43  * SwTextFrame::VisitPortions(...) method.
  44  */
  45 class SW_DLLPUBLIC SwPortionHandler
  46 {
  47 public:
  48
  49     SwPortionHandler() {}           /// (empty) constructor
  50
  51     virtual ~SwPortionHandler() {}  /// (empty) destructor
  52
  53     /** text portion. A run of nLength characters from the view
  54      * string, that contains no special characters like embedded
  55      * fields, etc. Thus, the on-screen text of this portion
  56      * corresponds exactly to the corresponding characters in the
  57      * view string.
  58      */
  59     virtual void Text(
  60         TextFrameIndex nLength, ///< length of this portion in the view string
  61         PortionType nType,       /// type of this portion
  62         sal_Int32 nHeight = 0,   /// height of this portion
  63         sal_Int32 nWidth = 0     /// width of this portion
  64         ) = 0;
  65
  66     /** special portion. This method is called for every non-text
  67      * portion. The parameters describe the length of the
  68      * corresponding characters in the view string (often 0 or 1),
  69      * the text which is displayed, and the type of the portion.
  70      */
  71     virtual void Special(
  72         TextFrameIndex nLength, ///< length of this portion in the view string
  73         const OUString& rText, /// text which is painted on-screen
  74         PortionType nType,         /// type of this portion
  75         sal_Int32 nHeight = 0,     /// font height of the painted text
  76         sal_Int32 nWidth = 0,     /// width of this portion
  77         const SwFont* pFont = nullptr /// font of this portion
  78         ) = 0;
  79
  80     /** line break. This method is called whenever a line break in the
  81      * layout occurs.
  82      */
  83     virtual void LineBreak(sal_Int32 nWidth) = 0;
  84
  85     /** skip characters. The SwTextFrame may only display partially
  86      * display a certain paragraph (e.g. when the paragraph is split
  87      * across multiple pages). In this case, the Skip() method must be
  88      * called to inform the portion handler to ignore a certain run of
  89      * characters in the 'view string'. Skip(), if used at all, must
  90      * be called before any of the other methods is called. Calling
  91      * Skip() between portions is not allowed.
  92      */
  93     virtual void Skip(
  94         TextFrameIndex nLength   /// number of 'view string' characters to be skipped
  95         ) = 0;
  96
  97     /** end of paragraph. This method is to be called when all the
  98      * paragraph's portions have been processed.
  99      */
 100     virtual void Finish() = 0;
 101 };
 102
 103 #endif
 104
 105 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */