summaryrefslogtreecommitdiff
path: root/src/gui/widgets/qcheckbox.cpp
blob: 0759cbec8491fdd32d58637f13fa0c22493d2613 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qcheckbox.h"
#include "qapplication.h"
#include "qbitmap.h"
#include "qicon.h"
#include "qstylepainter.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qevent.h"

#include "private/qabstractbutton_p.h"

QT_BEGIN_NAMESPACE

class QCheckBoxPrivate : public QAbstractButtonPrivate
{
    Q_DECLARE_PUBLIC(QCheckBox)
public:
    QCheckBoxPrivate()
        : QAbstractButtonPrivate(QSizePolicy::CheckBox), tristate(false), noChange(false),
          hovering(true), publishedState(Qt::Unchecked) {}

    uint tristate : 1;
    uint noChange : 1;
    uint hovering : 1;
    uint publishedState : 2;

    void init();
};

/*!
    \class QCheckBox
    \brief The QCheckBox widget provides a checkbox with a text label.

    \ingroup basicwidgets


    A QCheckBox is an option button that can be switched on (checked) or off
    (unchecked). Checkboxes are typically used to represent features in an
    application that can be enabled or disabled without affecting others, but
    different types of behavior can be implemented. For example, a
    QButtonGroup can be used to group check buttons logically, allowing
    exclusive checkboxes. However, QButtonGroup does not provide any visual
    representation.

    The image below further illustrates the differences between exclusive and
    non-exclusive checkboxes.

    \table
    \row \o \inlineimage checkboxes-exclusive.png
         \o \inlineimage checkboxes-non-exclusive.png
    \endtable

    Whenever a checkbox is checked or cleared it emits the signal
    stateChanged(). Connect to this signal if you want to trigger an action
    each time the checkbox changes state. You can use isChecked() to query
    whether or not a checkbox is checked.

    In addition to the usual checked and unchecked states, QCheckBox optionally
    provides a third state to indicate "no change". This is useful whenever you
    need to give the user the option of neither checking nor unchecking a
    checkbox. If you need this third state, enable it with setTristate(), and
    use checkState() to query the current toggle state.

    Just like QPushButton, a checkbox displays text, and optionally a small
    icon. The icon is set with setIcon(). The text can be set in the
    constructor or with setText(). A shortcut key can be specified by preceding
    the preferred character with an ampersand. For example:

    \snippet doc/src/snippets/code/src_gui_widgets_qcheckbox.cpp 0

    In this example the shortcut is \e{Alt+A}. See the \l{QShortcut#mnemonic}
    {QShortcut} documentation for details (to display an actual ampersand,
    use '&&').

    Important inherited functions: text(), setText(), text(), pixmap(),
    setPixmap(), accel(), setAccel(), isToggleButton(), setDown(), isDown(),
    isOn(), checkState(), autoRepeat(), isExclusiveToggle(), group(),
    setAutoRepeat(), toggle(), pressed(), released(), clicked(), toggled(),
    checkState(), and stateChanged().

    \table 100%
    \row
        \o \inlineimage macintosh-checkbox.png Screenshot of a Macintosh style checkbox
        \o A checkbox shown in the \l{Macintosh Style Widget Gallery}{Macintosh widget style}.
    \row
        \o \inlineimage windows-checkbox.png Screenshot of a Windows XP style checkbox
        \o A checkbox shown in the \l{Windows XP Style Widget Gallery}{Windows XP widget style}.
    \row
        \o \inlineimage plastique-checkbox.png Screenshot of a Plastique style checkbox
        \o A checkbox shown in the \l{Plastique Style Widget Gallery}{Plastique widget style}.
    \endtable

    \sa QAbstractButton, QRadioButton, {fowler}{GUI Design Handbook: Check Box}
*/

/*!
    \enum QCheckBox::ToggleState
    \compat

    \value Off  Use Qt::Unchecked instead.
    \value NoChange  Use Qt::PartiallyChecked instead.
    \value On  Use Qt::Checked instead.
*/

/*!
    \fn void QCheckBox::stateChanged(int state)

    This signal is emitted whenever the check box's state changes, i.e.
    whenever the user checks or unchecks it.

    \a state contains the check box's new Qt::CheckState.
*/

/*!
    \property QCheckBox::tristate
    \brief whether the checkbox is a tri-state checkbox

    The default is false; i.e. the checkbox has only two states.
*/

void QCheckBoxPrivate::init()
{
    Q_Q(QCheckBox);
    q->setCheckable(true);
    q->setMouseTracking(true);
    q->setForegroundRole(QPalette::WindowText);
    setLayoutItemMargins(QStyle::SE_CheckBoxLayoutItem);
}

/*!
    Initializes \a option with the values from this QCheckBox. This method is
    useful for subclasses that require a QStyleOptionButton, but do not want
    to fill in all the information themselves.

    \sa QStyleOption::initFrom()
*/
void QCheckBox::initStyleOption(QStyleOptionButton *option) const
{
    if (!option)
        return;
    Q_D(const QCheckBox);
    option->initFrom(this);
    if (d->down)
        option->state |= QStyle::State_Sunken;
    if (d->tristate && d->noChange)
        option->state |= QStyle::State_NoChange;
    else
        option->state |= d->checked ? QStyle::State_On : QStyle::State_Off;
    if (testAttribute(Qt::WA_Hover) && underMouse()) {
        if (d->hovering)
            option->state |= QStyle::State_MouseOver;
        else
            option->state &= ~QStyle::State_MouseOver;
    }
    option->text = d->text;
    option->icon = d->icon;
    option->iconSize = iconSize();
}

/*!
    Constructs a checkbox with the given \a parent, but with no text.

    \a parent is passed on to the QAbstractButton constructor.
*/

QCheckBox::QCheckBox(QWidget *parent)
    : QAbstractButton (*new QCheckBoxPrivate, parent)
{
    Q_D(QCheckBox);
    d->init();
}

/*!
    Constructs a checkbox with the given \a parent and \a text.

    \a parent is passed on to the QAbstractButton constructor.
*/

QCheckBox::QCheckBox(const QString &text, QWidget *parent)
    : QAbstractButton (*new QCheckBoxPrivate, parent)
{
    Q_D(QCheckBox);
    d->init();
    setText(text);
}

void QCheckBox::setTristate(bool y)
{
    Q_D(QCheckBox);
    d->tristate = y;
}

bool QCheckBox::isTristate() const
{
    Q_D(const QCheckBox);
    return d->tristate;
}


/*!
    Returns the check box's check state. If you do not need tristate support,
    you can also  use \l QAbstractButton::isChecked() which returns a boolean.

    \sa setCheckState() Qt::CheckState
*/
Qt::CheckState QCheckBox::checkState() const
{
    Q_D(const QCheckBox);
    if (d->tristate &&  d->noChange)
        return Qt::PartiallyChecked;
    return d->checked ? Qt::Checked : Qt::Unchecked;
}

/*!
    Sets the check box's check state to \a state. If you do not need tristate
    support, you can also use \l QAbstractButton::setChecked() which takes a
    boolean.

    \sa checkState() Qt::CheckState
*/
void QCheckBox::setCheckState(Qt::CheckState state)
{
    Q_D(QCheckBox);
    if (state == Qt::PartiallyChecked) {
        d->tristate = true;
        d->noChange = true;
    } else {
        d->noChange = false;
    }
    d->blockRefresh = true;
    setChecked(state != Qt::Unchecked);
    d->blockRefresh = false;
    d->refresh();
    if ((uint)state != d->publishedState) {
        d->publishedState = state;
        emit stateChanged(state);
    }
}


/*!
    \reimp
*/
QSize QCheckBox::sizeHint() const
{
    Q_D(const QCheckBox);
    if (d->sizeHint.isValid())
        return d->sizeHint;
    ensurePolished();
    QFontMetrics fm = fontMetrics();
    QStyleOptionButton opt;
    initStyleOption(&opt);
    QSize sz = style()->itemTextRect(fm, QRect(), Qt::TextShowMnemonic, false,
                                     text()).size();
    if (!opt.icon.isNull())
        sz = QSize(sz.width() + opt.iconSize.width() + 4, qMax(sz.height(), opt.iconSize.height()));
    d->sizeHint = (style()->sizeFromContents(QStyle::CT_CheckBox, &opt, sz, this)
                  .expandedTo(QApplication::globalStrut()));
    return d->sizeHint;
}


/*!
    \reimp
    \since 4.8
*/
QSize QCheckBox::minimumSizeHint() const
{
    return sizeHint();
}

/*!
    \reimp
*/
void QCheckBox::paintEvent(QPaintEvent *)
{
    QStylePainter p(this);
    QStyleOptionButton opt;
    initStyleOption(&opt);
    p.drawControl(QStyle::CE_CheckBox, opt);
}

/*!
    \reimp
*/
void QCheckBox::mouseMoveEvent(QMouseEvent *e)
{
    Q_D(QCheckBox);
    if (testAttribute(Qt::WA_Hover)) {
        bool hit = false;
        if (underMouse())
            hit = hitButton(e->pos());

        if (hit != d->hovering) {
            update(rect());
            d->hovering = hit;
        }
    }

    QAbstractButton::mouseMoveEvent(e);
}


/*!
    \reimp
*/
bool QCheckBox::hitButton(const QPoint &pos) const
{
    QStyleOptionButton opt;
    initStyleOption(&opt);
    return style()->subElementRect(QStyle::SE_CheckBoxClickRect, &opt, this).contains(pos);
}

/*!
    \reimp
*/
void QCheckBox::checkStateSet()
{
    Q_D(QCheckBox);
    d->noChange = false;
    Qt::CheckState state = checkState();
    if ((uint)state != d->publishedState) {
        d->publishedState = state;
        emit stateChanged(state);
    }
}

/*!
    \reimp
*/
void QCheckBox::nextCheckState()
{
    Q_D(QCheckBox);
    if (d->tristate)
        setCheckState((Qt::CheckState)((checkState() + 1) % 3));
    else {
        QAbstractButton::nextCheckState();
        QCheckBox::checkStateSet();
    }
}

/*!
    \reimp
*/
bool QCheckBox::event(QEvent *e)
{
    Q_D(QCheckBox);
    if (e->type() == QEvent::StyleChange
#ifdef Q_WS_MAC
            || e->type() == QEvent::MacSizeChange
#endif
            )
        d->setLayoutItemMargins(QStyle::SE_CheckBoxLayoutItem);
    return QAbstractButton::event(e);
}

#ifdef QT3_SUPPORT
/*!
    Use one of the constructors that doesn't take the \a name
    argument and then use setObjectName() instead.
*/
QCheckBox::QCheckBox(QWidget *parent, const char* name)
    : QAbstractButton (*new QCheckBoxPrivate, parent)
{
    Q_D(QCheckBox);
    setObjectName(QString::fromAscii(name));
    d->init();
}

/*!
    Use one of the constructors that doesn't take the \a name
    argument and then use setObjectName() instead.
*/
QCheckBox::QCheckBox(const QString &text, QWidget *parent, const char* name)
    : QAbstractButton (*new QCheckBoxPrivate, parent)
{
    Q_D(QCheckBox);
    setObjectName(QString::fromAscii(name));
    d->init();
    setText(text);
}

#endif


/*!
    \fn void QCheckBox::setNoChange()
    \compat

    Use setCheckState() instead.
*/

/*!
    \fn void QCheckBox::setState(ToggleState state)
    \compat

    Use setCheckState() instead.
*/

/*!
    \fn QCheckBox::ToggleState QCheckBox::state() const
    \compat

    Use checkState() instead.
*/

QT_END_NAMESPACE