1QLabel(3qt) QLabel(3qt)
2
6 QLabel - Text or image display
7
9 #include <qlabel.h>
10 Inherits QFrame.
12 Public Members
14 QLabel ( QWidget * parent, const char * name = 0, WFlags f = 0 )
15 QLabel ( const QString & text, QWidget * parent, const char * name = 0,
16 WFlags f = 0 )
17 QLabel ( QWidget * buddy, const QString & text, QWidget * parent, const
18 char * name = 0, WFlags f = 0 )
19 ~QLabel ()
20 QString text () const
21 QPixmap * pixmap () const
22 QPicture * picture () const
23 QMovie * movie () const
24 TextFormat textFormat () const
25 void setTextFormat ( TextFormat )
26 int alignment () const
27 virtual void setAlignment ( int )
28 int indent () const
29 void setIndent ( int )
30 bool autoResize () const (obsolete)
31 virtual void setAutoResize ( bool enable ) (obsolete)
32 bool hasScaledContents () const
33 void setScaledContents ( bool )
34 virtual void setBuddy ( QWidget * buddy )
35 QWidget * buddy () const
36 virtual void setFont ( const QFont & f )
37 Public Slots
39 virtual void setText ( const QString & )
40 virtual void setPixmap ( const QPixmap & )
41 virtual void setPicture ( const QPicture & picture )
42 virtual void setMovie ( const QMovie & movie )
43 virtual void setNum ( int num )
44 virtual void setNum ( double num )
45 void clear ()
46 Properties
48 Alignment alignment - the alignment of the label's contents
49 BackgroundMode backgroundMode - the label's background mode (read
50 only)
51 int indent - the label's text indent in pixels
52 QPixmap pixmap - the label's pixmap
53 bool scaledContents - whether the label will scale its contents to fill
54 all available space
55 QString text - the label's text
56 TextFormat textFormat - the label's text format
57 Protected Members
59 virtual void drawContents ( QPainter * p )
60
62 The QLabel widget provides a text or image display.
63 QLabel is used for displaying text or an image. No user interaction
65 functionality is provided. The visual appearance of the label can be
66 configured in various ways, and it can be used for specifying a focus
67 accelerator key for another widget.
68 A QLabel can contain any of the following content types: <center>.nf
70 </center>
72 When the content is changed using any of these functions, any previous
74 content is cleared.
75 The look of a QLabel can be tuned in several ways. All the settings of
77 QFrame are available for specifying a widget frame. The positioning of
78 the content within the QLabel widget area can be tuned with
79 setAlignment() and setIndent(). For example, this code sets up a sunken
80 panel with a two-line text in the bottom right corner (both lines being
81 flush with the right side of the label):
82 QLabel *label = new QLabel( this );
84 label->setFrameStyle( QFrame::Panel | QFrame::Sunken );
85 label->setText( "first line\nsecond line" );
86 label->setAlignment( AlignBottom | AlignRight );
87 A QLabel is often used as a label for an interactive widget. For this
89 use QLabel provides a useful mechanism for adding an accelerator key
90 (see QAccel) that will set the keyboard focus to the other widget
91 (called the QLabel's "buddy"). For example:
92 QLineEdit* phoneEdit = new QLineEdit( this, "phoneEdit" );
94 QLabel* phoneLabel = new QLabel( phoneEdit, "&Phone:", this, "phoneLabel" );
95 In this example, keyboard focus is transferred to the label's buddy
97 (the QLineEdit) when the user presses Alt+P. You can also use the
98 setBuddy() function to accomplish the same thing.
99 [Image Omitted]
101 [Image Omitted]
103 See also QLineEdit, QTextEdit, QPixmap, QMovie, GUI Design Handbook:
105 Label, Basic Widgets, and Text Related Classes.
106
109 Constructs an empty label.
110 The parent, name and widget flag f, arguments are passed to the QFrame
112 constructor.
113 See also alignment, setFrameStyle(), and indent.
115
117 0, WFlags f = 0 )
118 Constructs a label that displays the text, text.
119 The parent, name and widget flag f, arguments are passed to the QFrame
121 constructor.
122 See also text, alignment, setFrameStyle(), and indent.
124
126 const char * name = 0, WFlags f = 0 )
127 Constructs a label that displays the text text. The label has a buddy
128 widget, buddy.
129 If the text contains an underlined letter (a letter preceded by an
131 ampersand, &), and the text is in plain text format, when the user
132 presses Alt+ the underlined letter, focus is passed to the buddy
133 widget.
134 The parent, name and widget flag, f, arguments are passed to the QFrame
136 constructor.
137 See also text, setBuddy(), alignment, setFrameStyle(), and indent.
139
141 Destroys the label.
142
144 Returns the alignment of the label's contents. See the "alignment"
145 property for details.
146
148 This function is obsolete. It is provided to keep old source working.
149 We strongly advise against using it in new code.
150 Returns TRUE if auto-resizing is enabled, or FALSE if auto-resizing is
152 disabled.
153 Auto-resizing is disabled by default.
155 See also setAutoResize().
157
159 Returns this label's buddy, or 0 if no buddy is currently set.
160 See also setBuddy().
162
164 Clears any label contents. Equivalent to setText( "" ).
165
167 Draws the label contents using the painter p.
168 Reimplemented from QFrame.
170
172 Returns TRUE if the label will scale its contents to fill all available
173 space; otherwise returns FALSE. See the "scaledContents" property for
174 details.
175
177 Returns the label's text indent in pixels. See the "indent" property
178 for details.
179
181 Returns a pointer to the label's movie, or 0 if no movie has been set.
182 See also setMovie().
184
186 Returns the label's picture or 0 if the label doesn't have a picture.
187
189 Returns the label's pixmap. See the "pixmap" property for details.
190
192 Sets the alignment of the label's contents. See the "alignment"
193 property for details.
194
196 This function is obsolete. It is provided to keep old source working.
197 We strongly advise against using it in new code.
198 Enables auto-resizing if enable is TRUE, or disables it if enable is
200 FALSE.
201 When auto-resizing is enabled the label will resize itself to fit the
203 contents whenever the contents change. The top-left corner is not
204 moved. This is useful for QLabel widgets that are not managed by a
205 QLayout (e.g., top-level widgets).
206 Auto-resizing is disabled by default.
208 See also autoResize(), adjustSize(), and sizeHint.
210
212 Sets this label's buddy to buddy.
213 When the user presses the accelerator key indicated by this label, the
215 keyboard focus is transferred to the label's buddy widget.
216 The buddy mechanism is only available for QLabels that contain plain
218 text in which one letter is prefixed with an ampersand, &. This letter
219 is set as the accelerator key. The letter is displayed underlined, and
220 the '&' is not displayed (i.e. the ShowPrefix alignment flag is turned
221 on; see setAlignment()).
222 In a dialog, you might create two data entry widgets and a label for
224 each, and set up the geometry layout so each label is just to the left
225 of its data entry widget (its "buddy"), for example:
226 QLineEdit *nameEd = new QLineEdit( this );
228 QLabel *nameLb = new QLabel( "&Name:", this );
229 nameLb->setBuddy( nameEd );
230 QLineEdit *phoneEd = new QLineEdit( this );
231 QLabel *phoneLb = new QLabel( "&Phone:", this );
232 phoneLb->setBuddy( phoneEd );
233 // ( layout setup not shown )
234 With the code above, the focus jumps to the Name field when the user
236 presses Alt+N, and to the Phone field when the user presses Alt+P.
237 To unset a previously set buddy, call this function with buddy set to
239 0.
240 See also buddy(), text, QAccel, and alignment.
242 Examples:
244
246 Sets the font used on the QLabel to font f.
247 Example: menu/menu.cpp.
249 Reimplemented from QWidget.
251
253 Sets the label's text indent in pixels. See the "indent" property for
254 details.
255
257 Sets the label contents to movie. Any previous content is cleared.
258 The buddy accelerator, if any, is disabled.
260 The label resizes itself if auto-resizing is enabled.
262 See also movie() and setBuddy().
264
266 Sets the label contents to plain text containing the textual
267 representation of integer num. Any previous content is cleared. Does
268 nothing if the integer's string representation is the same as the
269 current contents of the label.
270 The buddy accelerator, if any, is disabled.
272 The label resizes itself if auto-resizing is enabled.
274 See also text, QString::setNum(), and setBuddy().
276
278 This is an overloaded member function, provided for convenience. It
279 behaves essentially like the above function.
280 Sets the label contents to plain text containing the textual
282 representation of double num. Any previous content is cleared. Does
283 nothing if the double's string representation is the same as the
284 current contents of the label.
285 The buddy accelerator, if any, is disabled.
287 The label resizes itself if auto-resizing is enabled.
289 See also text, QString::setNum(), and setBuddy().
291
293 Sets the label contents to picture. Any previous content is cleared.
294 The buddy accelerator, if any, is disabled.
296 See also picture() and setBuddy().
298
300 Sets the label's pixmap. See the "pixmap" property for details.
301
303 Sets whether the label will scale its contents to fill all available
304 space. See the "scaledContents" property for details.
305
307 Sets the label's text. See the "text" property for details.
308
310 Sets the label's text format. See the "textFormat" property for
311 details.
312
314 Returns the label's text. See the "text" property for details.
315
317 Returns the label's text format. See the "textFormat" property for
318 details.
319 Property Documentation
322 This property holds the alignment of the label's contents.
323 The alignment is a bitwise OR of Qt::AlignmentFlags and Qt::TextFlags
325 values. The ExpandTabs, SingleLine and ShowPrefix flags apply only if
326 the label contains plain text; otherwise they are ignored. The DontClip
327 flag is always ignored. WordBreak applies to both rich text and plain
328 text labels. The BreakAnywhere flag is not supported in QLabel.
329 If the label has a buddy, the ShowPrefix flag is forced to TRUE.
331 The default alignment is AlignAuto | AlignVCenter | ExpandTabs if the
333 label doesn't have a buddy and AlignAuto | AlignVCenter | ExpandTabs |
334 ShowPrefix if the label has a buddy. If the label contains rich text,
335 additionally WordBreak is turned on.
336 See also Qt::AlignmentFlags, setBuddy(), and text.
338 Set this property's value with setAlignment() and get this property's
340 value with alignment().
341
343 This property holds the label's background mode.
344 Get this property with backgroundMode().
346 See also QWidget::backgroundMode.
348
350 This property holds the label's text indent in pixels.
351 If a label displays text, the indent applies to the left edge if
353 alignment() is AlignLeft, to the right edge if alignment() is
354 AlignRight, to the top edge if alignment() is AlignTop, and to to the
355 bottom edge if alignment() is AlignBottom.
356 If indent is negative, or if no indent has been set, the label computes
358 the effective indent as follows: If frameWidth() is 0, the effective
359 indent becomes 0. If frameWidth() is greater than 0, the effective
360 indent becomes half the width of the "x" character of the widget's
361 current font().
362 See also alignment, frameWidth, and font.
364 Set this property's value with setIndent() and get this property's
366 value with indent().
367
369 This property holds the label's pixmap.
370 If no pixmap has been set this will return an invalid pixmap.
372 Setting the pixmap clears any previous content, and resizes the label
374 if QLabel::autoResize() is TRUE. The buddy accelerator, if any, is
375 disabled.
376 Set this property's value with setPixmap() and get this property's
378 value with pixmap().
379
381 This property holds whether the label will scale its contents to fill
382 all available space.
383 When enabled and the label shows a pixmap, it will scale the pixmap to
385 fill the available space.
386 This property's default is FALSE.
388 See also scaledContents.
390 Set this property's value with setScaledContents() and get this
392 property's value with hasScaledContents().
393
395 This property holds the label's text.
396 If no text has been set this will return an empty string. Setting the
398 text clears any previous content, unless they are the same.
399 The text will be interpreted either as a plain text or as a rich text,
401 depending on the text format setting; see setTextFormat(). The default
402 setting is AutoText, i.e. QLabel will try to auto-detect the format of
403 the text set.
404 If the text is interpreted as a plain text and a buddy has been set,
406 the buddy accelerator key is updated from the new text.
407 The label resizes itself if auto-resizing is enabled.
409 Note that Qlabel is well-suited to display small rich text documents,
411 i.e. those small documents that get their document specific settings
412 (font, text color, link color) from the label's palette and font
413 properties. For large documents, use QTextEdit in read-only mode
414 instead. QTextEdit will flicker less on resize and can also provide a
415 scrollbar when necessary.
416 See also textFormat, setBuddy(), and alignment.
418 Set this property's value with setText() and get this property's value
420 with text().
421
423 This property holds the label's text format.
424 See the Qt::TextFormat enum for an explanation of the possible options.
426 The default format is AutoText.
428 See also text.
430 Set this property's value with setTextFormat() and get this property's
432 value with textFormat().
433
436 http://doc.trolltech.com/qlabel.html
437 http://www.trolltech.com/faq/tech.html
438
440 Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
441 license file included in the distribution for a complete license
442 statement.
443
445 Generated automatically from the source code.
446
448 If you find a bug in Qt, please report it as described in
449 http://doc.trolltech.com/bughowto.html. Good bug reports help us to
450 help you. Thank you.
451 The definitive Qt documentation is provided in HTML format; it is
453 located at $QTDIR/doc/html and can be read using Qt Assistant or with a
454 web browser. This man page is provided as a convenience for those users
455 who prefer man pages, although this format is not officially supported
456 by Trolltech.
457 If you find errors in this manual page, please report them to qt-
459 bugs@trolltech.com. Please include the name of the manual page
460 (qlabel.3qt) and the Qt version (3.3.8).
461Trolltech AS 2 February 2007 QLabel(3qt)