1// Copyright (C) 2016 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4
5#include "qtextlist.h"
6#include "qtextobject_p.h"
7#include "qtextcursor.h"
8#include "qtextdocument_p.h"
9#include <qdebug.h>
10
11QT_BEGIN_NAMESPACE
12
13using namespace Qt::StringLiterals;
14
15class QTextListPrivate : public QTextBlockGroupPrivate
16{
17public:
18 QTextListPrivate(QTextDocument *doc)
19 : QTextBlockGroupPrivate(doc)
20 {
21 }
22};
23
24/*!
25 \class QTextList
26 \reentrant
27
28 \brief The QTextList class provides a decorated list of items in a QTextDocument.
29 \inmodule QtGui
30
31 \ingroup richtext-processing
32
33 A list contains a sequence of text blocks, each of which is marked with a
34 bullet point or other symbol. Multiple levels of lists can be used, and
35 the automatic numbering feature provides support for ordered numeric and
36 alphabetical lists.
37
38 Lists are created by using a text cursor to insert an empty list at the
39 current position or by moving existing text into a new list.
40 The \l{QTextCursor::insertList()} function inserts an empty block into the
41 document at the cursor position, and makes it the first item in a list.
42
43 \snippet textdocument-lists/mainwindow.cpp 0
44
45 The \l{QTextCursor::createList()} function takes the contents of the
46 cursor's current block and turns it into the first item of a new list.
47
48 The cursor's current list is found with \l{QTextCursor::currentList()}.
49
50 The number of items in a list is given by count(). Each item can be
51 obtained by its index in the list with the item() function. Similarly,
52 the index of a given item can be found with itemNumber(). The text of
53 each item can be found with the itemText() function.
54
55 Note that the items in the list may not be adjacent elements in the
56 document. For example, the top-level items in a multi-level list will
57 be separated by the items in lower levels of the list.
58
59 List items can be deleted by index with the removeItem() function.
60 remove() deletes the specified item in the list.
61
62 The list's format is set with setFormat() and read with format().
63 The format describes the decoration of the list itself, and not the
64 individual items.
65
66 \sa QTextBlock, QTextListFormat, QTextCursor
67*/
68
69/*! \internal
70 */
71QTextList::QTextList(QTextDocument *doc)
72 : QTextBlockGroup(*new QTextListPrivate(doc), doc)
73{
74}
75
76/*!
77 \internal
78*/
79QTextList::~QTextList()
80{
81}
82
83/*!
84 Returns the number of items in the list.
85*/
86int QTextList::count() const
87{
88 Q_D(const QTextList);
89 return d->blocks.size();
90}
91
92/*!
93 Returns the \a{i}-th text block in the list.
94
95 \sa count(), itemText()
96*/
97QTextBlock QTextList::item(int i) const
98{
99 Q_D(const QTextList);
100 if (i < 0 || i >= d->blocks.size())
101 return QTextBlock();
102 return d->blocks.at(i);
103}
104
105/*!
106 \fn void QTextList::setFormat(const QTextListFormat &format)
107
108 Sets the list's format to \a format.
109*/
110
111/*!
112 \fn QTextListFormat QTextList::format() const
113
114 Returns the list's format.
115*/
116
117/*!
118 \fn int QTextList::itemNumber(const QTextBlock &block) const
119
120 Returns the index of the list item that corresponds to the given \a block.
121 Returns -1 if the block was not present in the list.
122*/
123int QTextList::itemNumber(const QTextBlock &blockIt) const
124{
125 Q_D(const QTextList);
126 return d->blocks.indexOf(t: blockIt);
127}
128
129/*!
130 \fn QString QTextList::itemText(const QTextBlock &block) const
131
132 Returns the text of the list item that corresponds to the given \a block.
133*/
134QString QTextList::itemText(const QTextBlock &blockIt) const
135{
136 Q_D(const QTextList);
137 int item = d->blocks.indexOf(t: blockIt) + 1;
138 if (item <= 0)
139 return QString();
140
141 QTextBlock block = d->blocks.at(i: item-1);
142 QTextBlockFormat blockFormat = block.blockFormat();
143
144 QString result;
145
146 const int style = format().style();
147 QString numberPrefix;
148 QString numberSuffix = u"."_s;
149
150 // the number of the item might be offset by start, which defaults to 1
151 const int itemNumber = item + format().start() - 1;
152
153 if (format().hasProperty(propertyId: QTextFormat::ListNumberPrefix))
154 numberPrefix = format().numberPrefix();
155 if (format().hasProperty(propertyId: QTextFormat::ListNumberSuffix))
156 numberSuffix = format().numberSuffix();
157
158 switch (style) {
159 case QTextListFormat::ListDecimal:
160 result = QString::number(itemNumber);
161 break;
162 // from the old richtext
163 case QTextListFormat::ListLowerAlpha:
164 case QTextListFormat::ListUpperAlpha:
165 {
166 // match the html default behavior of falling back to decimal numbers
167 if (itemNumber < 1) {
168 result = QString::number(itemNumber);
169 break;
170 }
171
172 const char baseChar = style == QTextListFormat::ListUpperAlpha ? 'A' : 'a';
173
174 int c = itemNumber;
175 while (c > 0) {
176 c--;
177 result.prepend(c: QChar::fromUcs2(c: baseChar + (c % 26)));
178 c /= 26;
179 }
180 }
181 break;
182 case QTextListFormat::ListLowerRoman:
183 case QTextListFormat::ListUpperRoman:
184 {
185 // match the html default behavior of falling back to decimal numbers
186 if (itemNumber < 1) {
187 result = QString::number(itemNumber);
188 } else if (itemNumber < 5000) {
189 QString romanNumeral;
190
191 // works for up to 4999 items
192 QLatin1StringView romanSymbols;
193 if (style == QTextListFormat::ListLowerRoman)
194 romanSymbols = "iiivixxxlxcccdcmmmm"_L1;
195 else
196 romanSymbols = "IIIVIXXXLXCCCDCMMMM"_L1;
197
198 int c[] = { 1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000 };
199 int n = itemNumber;
200 for (int i = 12; i >= 0; n %= c[i], i--) {
201 int q = n / c[i];
202 if (q > 0) {
203 int startDigit = i + (i+3)/4;
204 int numDigits;
205 if (i % 4) {
206 // c[i] == 4|5|9|40|50|90|400|500|900
207 if ((i-2) % 4) {
208 // c[i] == 4|9|40|90|400|900 => with subtraction (IV, IX, XL, XC, ...)
209 numDigits = 2;
210 }
211 else {
212 // c[i] == 5|50|500 (V, L, D)
213 numDigits = 1;
214 }
215 }
216 else {
217 // c[i] == 1|10|100|1000 (I, II, III, X, XX, ...)
218 numDigits = q;
219 }
220
221 romanNumeral.append(s: romanSymbols.sliced(pos: startDigit, n: numDigits));
222 }
223 }
224 result = std::move(romanNumeral);
225 } else {
226 result = u"?"_s;
227 }
228
229 }
230 break;
231 default:
232 Q_ASSERT(false);
233 }
234 if (blockIt.textDirection() == Qt::RightToLeft)
235 return numberSuffix + result + numberPrefix;
236 else
237 return numberPrefix + result + numberSuffix;
238}
239
240/*!
241 Removes the item at item position \a i from the list. When the last item in the
242 list is removed, the list is automatically deleted by the QTextDocument that owns
243 it.
244
245 \sa add(), remove()
246*/
247void QTextList::removeItem(int i)
248{
249 Q_D(QTextList);
250 if (i < 0 || i >= d->blocks.size())
251 return;
252
253 QTextBlock block = d->blocks.at(i);
254 remove(block);
255}
256
257
258/*!
259 Removes the given \a block from the list.
260
261 \sa add(), removeItem()
262*/
263void QTextList::remove(const QTextBlock &block)
264{
265 QTextBlockFormat fmt = block.blockFormat();
266 fmt.setIndent(fmt.indent() + format().indent());
267 fmt.setObjectIndex(-1);
268 const_cast<QTextDocumentPrivate *>(QTextDocumentPrivate::get(block))->setBlockFormat(from: block, to: block, newFormat: fmt, mode: QTextDocumentPrivate::SetFormat);
269}
270
271/*!
272 Makes the given \a block part of the list.
273
274 \sa remove(), removeItem()
275*/
276void QTextList::add(const QTextBlock &block)
277{
278 QTextBlockFormat fmt = block.blockFormat();
279 fmt.setObjectIndex(objectIndex());
280 const_cast<QTextDocumentPrivate *>(QTextDocumentPrivate::get(block))->setBlockFormat(from: block, to: block, newFormat: fmt, mode: QTextDocumentPrivate::SetFormat);
281}
282
283QT_END_NAMESPACE
284
285#include "moc_qtextlist.cpp"
286

source code of qtbase/src/gui/text/qtextlist.cpp