1/****************************************************************************
2**
3** Copyright (C) 2016 The Qt Company Ltd.
4** Contact: https://www.qt.io/licensing/
5**
6** This file is part of the examples of the Qt Toolkit.
7**
8** $QT_BEGIN_LICENSE:BSD$
9** Commercial License Usage
10** Licensees holding valid commercial Qt licenses may use this file in
11** accordance with the commercial license agreement provided with the
12** Software or, alternatively, in accordance with the terms contained in
13** a written agreement between you and The Qt Company. For licensing terms
14** and conditions see https://www.qt.io/terms-conditions. For further
15** information use the contact form at https://www.qt.io/contact-us.
16**
17** BSD License Usage
18** Alternatively, you may use this file under the terms of the BSD license
19** as follows:
20**
21** "Redistribution and use in source and binary forms, with or without
22** modification, are permitted provided that the following conditions are
23** met:
24** * Redistributions of source code must retain the above copyright
25** notice, this list of conditions and the following disclaimer.
26** * Redistributions in binary form must reproduce the above copyright
27** notice, this list of conditions and the following disclaimer in
28** the documentation and/or other materials provided with the
29** distribution.
30** * Neither the name of The Qt Company Ltd nor the names of its
31** contributors may be used to endorse or promote products derived
32** from this software without specific prior written permission.
33**
34**
35** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
36** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
37** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
38** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
39** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
42** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
43** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
44** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
45** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
46**
47** $QT_END_LICENSE$
48**
49****************************************************************************/
50
51#include "layoutitem.h"
52
53#include <QGradient>
54#include <QPainter>
55
56//! [0]
57LayoutItem::LayoutItem(QGraphicsItem *parent)
58 : QGraphicsLayoutItem(), QGraphicsItem(parent),
59 m_pix(QPixmap(QLatin1String(":/images/block.png")))
60{
61 setGraphicsItem(this);
62}
63//! [0]
64
65//! [1]
66void LayoutItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
67 QWidget *widget)
68{
69 Q_UNUSED(widget);
70 Q_UNUSED(option);
71
72 QRectF frame(QPointF(0, 0), geometry().size());
73 const QSize pmSize = m_pix.size();
74 QGradientStops stops;
75//! [1]
76
77//! [2]
78 // paint a background rect (with gradient)
79 QLinearGradient gradient(frame.topLeft(), frame.topLeft() + QPointF(200,200));
80 stops << QGradientStop(0.0, QColor(60, 60, 60));
81 stops << QGradientStop(frame.height() / 2 / frame.height(), QColor(102, 176, 54));
82
83 //stops << QGradientStop(((frame.height() + h)/2 )/frame.height(), QColor(157, 195, 55));
84 stops << QGradientStop(1.0, QColor(215, 215, 215));
85 gradient.setStops(stops);
86 painter->setBrush(QBrush(gradient));
87 painter->drawRoundedRect(rect: frame, xRadius: 10.0, yRadius: 10.0);
88
89 // paint a rect around the pixmap (with gradient)
90 QPointF pixpos = frame.center() - (QPointF(pmSize.width(), pmSize.height()) / 2);
91 QRectF innerFrame(pixpos, pmSize);
92 innerFrame.adjust(xp1: -4, yp1: -4, xp2: 4, yp2: 4);
93 gradient.setStart(innerFrame.topLeft());
94 gradient.setFinalStop(innerFrame.bottomRight());
95 stops.clear();
96 stops << QGradientStop(0.0, QColor(215, 255, 200));
97 stops << QGradientStop(0.5, QColor(102, 176, 54));
98 stops << QGradientStop(1.0, QColor(0, 0, 0));
99 gradient.setStops(stops);
100 painter->setBrush(QBrush(gradient));
101 painter->drawRoundedRect(rect: innerFrame, xRadius: 10.0, yRadius: 10.0);
102 painter->drawPixmap(p: pixpos, pm: m_pix);
103}
104//! [2]
105
106//! [3]
107QRectF LayoutItem::boundingRect() const
108{
109 return QRectF(QPointF(0, 0), geometry().size());
110}
111//! [3]
112
113//! [4]
114void LayoutItem::setGeometry(const QRectF &geom)
115{
116 prepareGeometryChange();
117 QGraphicsLayoutItem::setGeometry(geom);
118 setPos(geom.topLeft());
119}
120//! [4]
121
122//! [5]
123QSizeF LayoutItem::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
124{
125 switch (which) {
126 case Qt::MinimumSize:
127 case Qt::PreferredSize:
128 // Do not allow a size smaller than the pixmap with two frames around it.
129 return m_pix.size() + QSize(12, 12);
130 case Qt::MaximumSize:
131 return QSizeF(1000,1000);
132 default:
133 break;
134 }
135 return constraint;
136}
137//! [5]
138

source code of qtbase/examples/widgets/graphicsview/basicgraphicslayouts/layoutitem.cpp