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 "starrating.h"
52
53#include <QtWidgets>
54#include <cmath>
55
56constexpr int PaintingScaleFactor = 20;
57
58//! [0]
59StarRating::StarRating(int starCount, int maxStarCount)
60 : myStarCount(starCount),
61 myMaxStarCount(maxStarCount)
62{
63 starPolygon << QPointF(1.0, 0.5);
64 for (int i = 1; i < 5; ++i)
65 starPolygon << QPointF(0.5 + 0.5 * std::cos(x: 0.8 * i * 3.14),
66 0.5 + 0.5 * std::sin(x: 0.8 * i * 3.14));
67
68 diamondPolygon << QPointF(0.4, 0.5) << QPointF(0.5, 0.4)
69 << QPointF(0.6, 0.5) << QPointF(0.5, 0.6)
70 << QPointF(0.4, 0.5);
71}
72//! [0]
73
74//! [1]
75QSize StarRating::sizeHint() const
76{
77 return PaintingScaleFactor * QSize(myMaxStarCount, 1);
78}
79//! [1]
80
81//! [2]
82void StarRating::paint(QPainter *painter, const QRect &rect,
83 const QPalette &palette, EditMode mode) const
84{
85 painter->save();
86
87 painter->setRenderHint(hint: QPainter::Antialiasing, on: true);
88 painter->setPen(Qt::NoPen);
89 painter->setBrush(mode == EditMode::Editable ?
90 palette.highlight() :
91 palette.windowText());
92
93 const int yOffset = (rect.height() - PaintingScaleFactor) / 2;
94 painter->translate(dx: rect.x(), dy: rect.y() + yOffset);
95 painter->scale(sx: PaintingScaleFactor, sy: PaintingScaleFactor);
96
97 for (int i = 0; i < myMaxStarCount; ++i) {
98 if (i < myStarCount)
99 painter->drawPolygon(polygon: starPolygon, fillRule: Qt::WindingFill);
100 else if (mode == EditMode::Editable)
101 painter->drawPolygon(polygon: diamondPolygon, fillRule: Qt::WindingFill);
102 painter->translate(dx: 1.0, dy: 0.0);
103 }
104
105 painter->restore();
106}
107//! [2]
108

source code of qtbase/examples/widgets/itemviews/stardelegate/starrating.cpp