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 "circlewidget.h"
52
53#include <QPainter>
54
55#include <stdlib.h>
56
57//! [0]
58CircleWidget::CircleWidget(QWidget *parent)
59 : QWidget(parent)
60{
61 floatBased = false;
62 antialiased = false;
63 frameNo = 0;
64
65 setBackgroundRole(QPalette::Base);
66 setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
67}
68//! [0]
69
70//! [1]
71void CircleWidget::setFloatBased(bool floatBased)
72{
73 this->floatBased = floatBased;
74 update();
75}
76//! [1]
77
78//! [2]
79void CircleWidget::setAntialiased(bool antialiased)
80{
81 this->antialiased = antialiased;
82 update();
83}
84//! [2]
85
86//! [3]
87QSize CircleWidget::minimumSizeHint() const
88{
89 return QSize(50, 50);
90}
91//! [3]
92
93//! [4]
94QSize CircleWidget::sizeHint() const
95{
96 return QSize(180, 180);
97}
98//! [4]
99
100//! [5]
101void CircleWidget::nextAnimationFrame()
102{
103 ++frameNo;
104 update();
105}
106//! [5]
107
108//! [6]
109void CircleWidget::paintEvent(QPaintEvent *)
110{
111 QPainter painter(this);
112 painter.setRenderHint(QPainter::Antialiasing, antialiased);
113 painter.translate(width() / 2, height() / 2);
114//! [6]
115
116//! [7]
117 for (int diameter = 0; diameter < 256; diameter += 9) {
118 int delta = abs((frameNo % 128) - diameter / 2);
119 int alpha = 255 - (delta * delta) / 4 - diameter;
120//! [7] //! [8]
121 if (alpha > 0) {
122 painter.setPen(QPen(QColor(0, diameter / 2, 127, alpha), 3));
123
124 if (floatBased)
125 painter.drawEllipse(QRectF(-diameter / 2.0, -diameter / 2.0, diameter, diameter));
126 else
127 painter.drawEllipse(QRect(-diameter / 2, -diameter / 2, diameter, diameter));
128 }
129 }
130}
131//! [8]
132