summaryrefslogtreecommitdiffstats
path: root/src/declarative/graphicsitems/qdeclarativeflipable.cpp
blob: 1ebbaee29ed61e8fce1c62b613f731e6e8104021 (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
/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtDeclarative module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** 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, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qdeclarativeflipable_p.h"

#include "qdeclarativeitem_p.h"

#include <qdeclarativeinfo.h>

#include <QtGui/qgraphicstransform.h>

QT_BEGIN_NAMESPACE

class QDeclarativeFlipablePrivate : public QDeclarativeItemPrivate
{
    Q_DECLARE_PUBLIC(QDeclarativeFlipable)
public:
    QDeclarativeFlipablePrivate() : current(QDeclarativeFlipable::Front), front(0), back(0) {}

    void updateSceneTransformFromParent();

    QDeclarativeFlipable::Side current;
    QDeclarativeItem *front;
    QDeclarativeItem *back;
};

/*!
    \qmlclass Flipable QDeclarativeFlipable
    \since 4.7
    \brief The Flipable item provides a surface that can be flipped.
    \inherits Item

    Flipable is an item that can be visibly "flipped" between its front and
    back sides. It is used together with Rotation and State/Transition to
    produce a flipping effect.

    Here is a Flipable that flips whenever it is clicked:

    \snippet examples/declarative/flipable/flipable.qml 0

    \image flipable.gif

    The Rotation element is used to specify the angle and axis of the flip,
    and the State defines the changes in angle which produce the flipping
    effect. Finally, the Transition creates the animation that changes the
    angle over one second.
*/

/*!
    \internal
    \class QDeclarativeFlipable
    \brief The Flipable item provides a surface that can be flipped.

    \ingroup group_widgets

    Flipable is an item that can be visibly "flipped" between its front and
    back sides.
*/

QDeclarativeFlipable::QDeclarativeFlipable(QDeclarativeItem *parent)
: QDeclarativeItem(*(new QDeclarativeFlipablePrivate), parent)
{
}

QDeclarativeFlipable::~QDeclarativeFlipable()
{
}

/*!
  \qmlproperty Item Flipable::front
  \qmlproperty Item Flipable::back

  The front and back sides of the flipable.
*/

QDeclarativeItem *QDeclarativeFlipable::front()
{
    Q_D(const QDeclarativeFlipable);
    return d->front;
}

void QDeclarativeFlipable::setFront(QDeclarativeItem *front)
{
    Q_D(QDeclarativeFlipable);
    if (d->front) {
        qmlInfo(this) << tr("front is a write-once property");
        return;
    }
    d->front = front;
    d->front->setParentItem(this);
    if (Back == d->current)
        d->front->setOpacity(0.);
}

QDeclarativeItem *QDeclarativeFlipable::back()
{
    Q_D(const QDeclarativeFlipable);
    return d->back;
}

void QDeclarativeFlipable::setBack(QDeclarativeItem *back)
{
    Q_D(QDeclarativeFlipable);
    if (d->back) {
        qmlInfo(this) << tr("back is a write-once property");
        return;
    }
    d->back = back;
    d->back->setParentItem(this);
    if (Front == d->current)
        d->back->setOpacity(0.);
}

/*!
  \qmlproperty enumeration Flipable::side

  The side of the Flippable currently visible. Possible values are \c
  Front and \c Back.
*/
QDeclarativeFlipable::Side QDeclarativeFlipable::side() const
{
    Q_D(const QDeclarativeFlipable);
    if (d->dirtySceneTransform)
        const_cast<QDeclarativeFlipablePrivate *>(d)->updateSceneTransformFromParent();

    return d->current;
}

// determination on the currently visible side of the flipable
// has to be done on the complete scene transform to give
// correct results.
void QDeclarativeFlipablePrivate::updateSceneTransformFromParent()
{
    Q_Q(QDeclarativeFlipable);

    QDeclarativeItemPrivate::updateSceneTransformFromParent();
    QPointF p1(0, 0);
    QPointF p2(1, 0);
    QPointF p3(1, 1);

    p1 = sceneTransform.map(p1);
    p2 = sceneTransform.map(p2);
    p3 = sceneTransform.map(p3);

    qreal cross = (p1.x() - p2.x()) * (p3.y() - p2.y()) -
                  (p1.y() - p2.y()) * (p3.x() - p2.x());

    QDeclarativeFlipable::Side newSide;
    if (cross > 0) {
       newSide = QDeclarativeFlipable::Back;
    } else {
        newSide = QDeclarativeFlipable::Front;
    }

    if (newSide != current) {
        current = newSide;
        if (current == QDeclarativeFlipable::Back) {
            QTransform mat;
            mat.translate(back->width()/2,back->height()/2);
            if (back->width() && p1.x() >= p2.x())
                mat.rotate(180, Qt::YAxis);
            if (back->height() && p2.y() >= p3.y())
                mat.rotate(180, Qt::XAxis);
            mat.translate(-back->width()/2,-back->height()/2);
            back->setTransform(mat);
        }
        if (front)
            front->setOpacity((current==QDeclarativeFlipable::Front)?1.:0.);
        if (back)
            back->setOpacity((current==QDeclarativeFlipable::Back)?1.:0.);
        emit q->sideChanged();
    }
}

QT_END_NAMESPACE