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qsgtextnode.cpp
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1// Copyright (C) 2023 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#include "qsgtextnode.h"
5
6QT_BEGIN_NAMESPACE
7
8/*!
9 \class QSGTextNode
10
11 \brief The QSGTextNode class is a class for drawing text layouts and text documents in
12 the Qt Quick scene graph.
13 \inmodule QtQuick
14 \since 6.7
15
16 QSGTextNode can be useful for creating custom Qt Quick items that require text. It is used
17 in Qt Quick by the Text, TextEdit and TextInput elements.
18
19 You can create QSGTextNode objects using QQuickWindow::createTextNode(). The addTextLayout()
20 and addTextDocument() functions provide ways to add text to the QSGTextNode. The text must
21 already be laid out.
22
23 \note Properties must be set before \l addTextLayout() or \l addTextDocument() are called in
24 order to have an effect.
25
26 \note The destruction of QSGTextNode has to be managed with care. In particular, since it
27 references graphics resources, it must be deleted when the Qt Quick scene graph is invalidated.
28 If the node is part of the graph and has the \c OwnedByParent flag set (which is the default),
29 this will happen automatically. However, if the \c OwnedByParent flag is cleared and the node is
30 disposed of manually, care must be taken to do this when the scene graph is invalidated. This
31 can be done by connecting to the \l{QQuickWindow::sceneGraphInvalidated()} signal, or by
32 implementing a slot in the QQuickItem subclass which is named \c{invalidateSceneGraph()}.
33 See also the documentation of QQuickItem for more details.
34 */
35
36/*!
37 \enum QSGTextNode::TextStyle
38
39 This enum type describes styles that can be applied to text rendering.
40
41 \value Normal The text is drawn without any style applied.
42 \value Outline The text is drawn with an outline.
43 \value Raised The text is drawn raised.
44 \value Sunken The text is drawn sunken.
45
46 \sa setTextStyle(), setStyleColor()
47*/
48
49/*!
50 \enum QSGTextNode::RenderType
51
52 This enum type describes type of glyph node used for rendering the text.
53
54 \value QtRendering Text is rendered using a scalable distance field for each glyph.
55 \value NativeRendering Text is rendered using a platform-specific technique.
56 \value CurveRendering Text is rendered using a curve rasterizer running directly on the
57 graphics hardware.
58
59 Select \c NativeRendering if you prefer text to look native on the target platform and do
60 not require advanced features such as transformation of the text. Using such features in
61 combination with the NativeRendering render type will lend poor and sometimes pixelated
62 results.
63
64 Both \c Text.QtRendering and \c Text.CurveRendering are hardware-accelerated techniques.
65 \c QtRendering is the faster of the two, but uses more memory and will exhibit rendering
66 artifacts at large sizes. \c CurveRendering should be considered as an alternative in cases
67 where \c QtRendering does not give good visual results or where reducing graphics memory
68 consumption is a priority.
69
70 \sa setRenderType(), setRenderTypeQuality()
71*/
72
73/*!
74 \fn void QSGTextNode::setColor(QColor color)
75
76 Sets the main color to use when rendering the text to \a color.
77
78 The default is black: \c QColor(0, 0, 0).
79*/
80
81/*!
82 \fn QColor QSGTextNode::color() const
83
84 Returns the main color used when rendering the text.
85*/
86
87/*!
88 \fn void QSGTextNode::setStyleColor(QColor styleColor)
89
90 Sets the style color to use when rendering the text to \a styleColor.
91
92 The default is black: \c QColor(0, 0, 0).
93
94 \sa setTextStyle()
95*/
96
97/*!
98 \fn QColor QSGTextNode::styleColor() const
99
100 Returns the style color used when rendering the text.
101
102 \sa textStyle()
103*/
104
105/*!
106 \fn void QSGTextNode::setTextStyle(QSGTextNode::TextStyle textStyle)
107
108 Sets the style of the rendered text to \a textStyle. The default is \c Normal.
109
110 \sa setStyleColor()
111*/
112
113/*!
114 \fn QSGTextNode::TextStyle QSGTextNode::textStyle()
115
116 Returns the style of the rendered text.
117
118 \sa styleColor()
119*/
120
121/*!
122 \fn void QSGTextNode::setLinkColor(QColor linkColor)
123
124 Sets the color of or hyperlinks to \a linkColor in the text.
125
126 The default is blue: \c QColor(0, 0, 255).
127*/
128
129/*!
130 \fn QColor QSGTextNode::linkColor() const
131
132 Returns the color of hyperlinks in the text.
133*/
134
135/*!
136 \fn void QSGTextNode::setSelectionColor(QColor color)
137
138 Sets the color of the selection background to \a color when any part of the text is
139 marked as selected.
140
141 The default is dark blue: \c QColor(0, 0, 128).
142*/
143
144/*!
145 \fn QColor QSGTextNode::selectionColor() const
146
147 Returns the color of the selection background when any part of the text is marked as selected.
148*/
149
150/*!
151 \fn QColor QSGTextNode::selectionTextColor() const
152
153 Returns the color of the selection text when any part of the text is marked as selected.
154*/
155
156/*!
157 \fn void QSGTextNode::setSelectionTextColor(QColor selectionTextColor)
158
159 Sets the color of the selection text to \a selectionTextColor when any part of the text is
160 marked as selected.
161
162 The default is white: \c QColor(255, 255, 255).
163*/
164
165
166/*!
167 \fn void QSGTextNode::setRenderType(RenderType renderType)
168
169 Sets the type of glyph node in use to \a renderType.
170
171 The default is \l QtRendering.
172*/
173
174/*!
175 \fn QSGTextNode::RenderType QSGTextNode::renderType() const
176
177 Returns the type of glyph node used for rendering the text.
178*/
179
180/*!
181 \fn void QSGTextNode::setRenderTypeQuality(int renderTypeQuality)
182
183 If the \l renderType() in use supports it, set the quality to use when rendering the text.
184 When supported, this can be used to trade visual fidelity for execution speed or memory.
185
186 When the \a renderTypeQuality is < 0, the default quality is used.
187
188 The \a renderTypeQuality can be any integer, although limitations imposed by the underlying
189 graphics hardware may be encountered if extreme values are set. The Qt Quick Text element
190 operates with the following predefined values:
191
192 \value DefaultRenderTypeQuality -1 (default)
193 \value LowRenderTypeQuality 26
194 \value NormalRenderTypeQuality 52
195 \value HighRenderTypeQuality 104
196 \value VeryHighRenderTypeQuality 208
197
198 This value is currently only respected by the QtRendering render type. Setting it changes the
199 resolution of the distance fields used to represent the glyphs. Setting it above normal will
200 cause memory consumption to increase, but reduces filtering artifacts on very large text.
201
202 The default is -1.
203*/
204
205/*!
206 \fn int QSGTextNode::renderTypeQuality() const
207
208 Returns the render type quality of the node. See \l setRenderTypeQuality() for details.
209*/
210
211/*!
212 \fn void QSGTextNode::setFiltering(QSGTexture::Filtering filtering)
213
214 Sets the sampling mode used when scaling images that are part of the displayed text to
215 \a filtering. For smoothly scaled images, use \l{QSGTexture::Linear} here.
216
217 The default is \l{QSGTexture::Nearest}.
218
219 \sa filtering()
220*/
221
222/*!
223 \fn QSGTexture::Filtering QSGTextNode::filtering() const
224
225 Returns the sampling mode used when scaling images that are part of the displayed text.
226
227 \sa setFiltering()
228*/
229
230/*!
231 \fn void QSGTextNode::setViewport(const QRectF &viewport)
232
233 Sets the bounding rect of the viewport where the text is displayed to \a viewport. Providing
234 this information makes it possible for the QSGTextNode to optimize which parts of the text
235 layout or document are included in the scene graph.
236
237 The default is a default-constructed QRectF. For this viewport, all contents will be included
238 in the graph.
239*/
240
241/*!
242 \fn QRectF QSGTextNode::viewport() const
243
244 Returns the current viewport set for this QSGTextNode.
245*/
246
247/*!
248 \fn QSGTextNode::addTextLayout(QPointF position, QTextLayout *layout, int selectionStart = -1, int selectionCount = -1, int lineStart = 0, int lineCount = -1)
249
250 Adds the contents of \a layout to the text node at \a position. If \a selectionStart is >= 0,
251 then this marks the first character in a selected area of \a selectionCount number of
252 characters. The selection is represented as a background fill with the \l selectionColor() and
253 the selected text is rendered in the \l selectionTextColor().
254
255 For convenience, \a lineStart and \a lineCount can be used to select the range of \l QTextLine
256 objects to include from the layout. This can be useful, for instance, when creating elided
257 layouts. If \a lineCount is < 0, then the the node will include the lines from \a lineStart to
258 the end of the layout.
259
260 This function forwards its arguments to the virtual function doAddTextLayout().
261
262 \sa clear()
263*/
264
265/*!
266 \fn QSGTextNode::addTextDocument(QPointF position, QTextDocument *document, int selectionStart = -1, int selectionCount = -1)
267
268 Adds the contents of \a document to the text node at \a position. If \a selectionStart is >= 0,
269 then this marks the first character in a selected area of \a selectionCount number of
270 characters. The selection is represented as a background fill with the \l selectionColor() and
271 the selected text is rendered in the \l selectionTextColor().
272
273 This function forwards its arguments to the virtual function doAddTextDocument().
274
275 \sa clear()
276*/
277
278/*!
279 \fn QSGTextNode::doAddTextLayout(QPointF position, QTextLayout *layout, int selectionStart, int selectionCount, int lineStart, int lineCount)
280
281 Virtual function called by addTextLayout(), which converts the contents of \a layout to scene
282 graph nodes and adds them to the current node at \a position.
283
284 If \a selectionStart is >= 0, then this marks the first character in a selected area of
285 \a selectionCount number of characters. The selection is represented as a background fill with
286 the \l selectionColor() and the selected text is rendered in the \l selectionTextColor().
287
288 For convenience, \a lineStart and \a lineCount can be used to select the range of \l QTextLine
289 objects to include from the layout. This can be useful, for instance, when creating elided
290 layouts. If \a lineCount is < 0, then the the node will include the lines from \a lineStart to
291 the end of the layout.
292
293 \sa clear(), addTextLayout()
294*/
295
296/*!
297 \fn QSGTextNode::doAddTextDocument(QPointF position, QTextDocument *document, int selectionStart, int selectionCount)
298
299 Virtual function called by addTextDocument(), which converts the contents of \a document to
300 scene graph nodes and adds them to the current node at \a position.
301
302 If \a selectionStart is >= 0, then this marks the first character in a selected area of
303 \a selectionCount number of characters. The selection is represented as a background fill with
304 the \l selectionColor() and the selected text is rendered in the \l selectionTextColor().
305
306 \sa clear(), addTextDocument()
307*/
308
309/*!
310 \fn QSGTextNode::clear()
311
312 Clears the contents of the node, deleting nodes and other data that represents the layouts
313 and documents that have been added to it.
314
315 \sa addTextLayout(), addTextDocument()
316*/
317
318QSGTextNode::~QSGTextNode() = default;
319
320QT_END_NAMESPACE