1/****************************************************************************
2**
3** Copyright (C) 2017 The Qt Company Ltd.
4** Contact: http://www.qt.io/licensing/
5**
6** This file is part of the Qt Quick Controls 2 module of the Qt Toolkit.
7**
8** $QT_BEGIN_LICENSE:LGPL3$
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 http://www.qt.io/terms-conditions. For further
15** information use the contact form at http://www.qt.io/contact-us.
16**
17** GNU Lesser General Public License Usage
18** Alternatively, this file may be used under the terms of the GNU Lesser
19** General Public License version 3 as published by the Free Software
20** Foundation and appearing in the file LICENSE.LGPLv3 included in the
21** packaging of this file. Please review the following information to
22** ensure the GNU Lesser General Public License version 3 requirements
23** will be met: https://www.gnu.org/licenses/lgpl.html.
24**
25** GNU General Public License Usage
26** Alternatively, this file may be used under the terms of the GNU
27** General Public License version 2.0 or later as published by the Free
28** Software Foundation and appearing in the file LICENSE.GPL included in
29** the packaging of this file. Please review the following information to
30** ensure the GNU General Public License version 2.0 requirements will be
31** met: http://www.gnu.org/licenses/gpl-2.0.html.
32**
33** $QT_END_LICENSE$
34**
35****************************************************************************/
36
37#include "qquickfusionknob_p.h"
38
39#include <QtCore/qmath.h>
40#include <QtGui/qpainter.h>
41
42QT_BEGIN_NAMESPACE
43
44QQuickFusionKnob::QQuickFusionKnob(QQuickItem *parent)
45 : QQuickPaintedItem(parent)
46{
47}
48
49QPalette QQuickFusionKnob::palette() const
50{
51 return m_palette;
52}
53
54void QQuickFusionKnob::setPalette(const QPalette &palette)
55{
56 if (palette == m_palette)
57 return;
58
59 m_palette = palette;
60 update();
61}
62
63// extracted from QStyleHelper::drawDial()
64void QQuickFusionKnob::paint(QPainter *painter)
65{
66 const qreal w = width();
67 const qreal h = height();
68 if (w <= 0 || h <= 0)
69 return;
70
71 QColor color = m_palette.color(cr: QPalette::Button);
72 color.setHsv(h: color.hue(),
73 s: qMin(a: 140, b: color .saturation()),
74 v: qMax(a: 180, b: color.value()));
75 color = color.lighter(f: 104);
76 color.setAlphaF(qreal(0.8));
77
78 const qreal sz = qMin(a: w, b: h);
79 QRectF rect(0, 0, sz, sz);
80 rect.moveCenter(p: QPointF(w / 2.0, h / 2.0));
81 const QPointF center = rect.center();
82
83 QRadialGradient gradient(center.x() + rect.width() / 2,
84 center.y() + rect.width(),
85 rect.width() * 2,
86 center.x(), center.y());
87 gradient.setColorAt(pos: 1, color: color.darker(f: 140));
88 gradient.setColorAt(pos: qreal(0.4), color: color.darker(f: 120));
89 gradient.setColorAt(pos: 0, color: color.darker(f: 110));
90
91 painter->setRenderHint(hint: QPainter::Antialiasing);
92 painter->setBrush(gradient);
93 painter->setPen(QColor(255, 255, 255, 150));
94 painter->drawEllipse(r: rect);
95 painter->setPen(QColor(0, 0, 0, 80));
96 painter->drawEllipse(r: rect.adjusted(xp1: 1, yp1: 1, xp2: -1, yp2: -1));
97}
98
99QT_END_NAMESPACE
100

source code of qtquickcontrols2/src/imports/controls/fusion/qquickfusionknob.cpp