src/gui/tristatewidget.cpp

   1 /*
   2  * Bittorrent Client using Qt and libtorrent.
   3  * Copyright (C) 2019  Mike Tzou (Chocobo1)
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18  *
  19  * In addition, as a special exception, the copyright holders give permission to
  20  * link this program with the OpenSSL project's "OpenSSL" library (or with
  21  * modified versions of it that use the same license as the "OpenSSL" library),
  22  * and distribute the linked executables. You must obey the GNU General Public
  23  * License in all respects for all of the code used other than "OpenSSL".  If you
  24  * modify file(s), you may extend this exception to your version of the file(s),
  25  * but you are not obligated to do so. If you do not wish to do so, delete this
  26  * exception statement from your version.
  27  */
  28
  29 #include "tristatewidget.h"
  30
  31 #include <QApplication>
  32 #include <QMouseEvent>
  33 #include <QPainter>
  34 #include <QPaintEvent>
  35 #include <QString>
  36 #include <QStyle>
  37 #include <QStyleOptionMenuItem>
  38
  39 TriStateWidget::TriStateWidget(const QString &text, QWidget *parent)
  40     : QWidget {parent}
  41     , m_closeOnInteraction {true}
  42     , m_checkState {Qt::Unchecked}
  43     , m_text {text}
  44 {
  45     setMouseTracking(true);  // for visual effects via mouse navigation
  46     setFocusPolicy(Qt::TabFocus);  // for visual effects via keyboard navigation
  47 }
  48
  49 void TriStateWidget::setCheckState(const Qt::CheckState checkState)
  50 {
  51     m_checkState = checkState;
  52 }
  53
  54 void TriStateWidget::setCloseOnInteraction(const bool enabled)
  55 {
  56     m_closeOnInteraction = enabled;
  57 }
  58
  59 QSize TriStateWidget::minimumSizeHint() const
  60 {
  61     QStyleOptionMenuItem opt;
  62     opt.initFrom(this);
  63     opt.menuHasCheckableItems = true;
  64     const QSize contentSize = fontMetrics().size(Qt::TextSingleLine, m_text);
  65     return style()->sizeFromContents(QStyle::CT_MenuItem, &opt, contentSize, this);
  66 }
  67
  68 void TriStateWidget::paintEvent(QPaintEvent *)
  69 {
  70     QStyleOptionMenuItem opt;
  71     opt.initFrom(this);
  72     opt.menuItemType = QStyleOptionMenuItem::Normal;
  73     opt.checkType = QStyleOptionMenuItem::NonExclusive;
  74     opt.menuHasCheckableItems = true;
  75     opt.text = m_text;
  76
  77     switch (m_checkState)
  78     {
  79     case Qt::PartiallyChecked:
  80         opt.state |= QStyle::State_NoChange;
  81         break;
  82     case Qt::Checked:
  83         opt.checked = true;
  84         break;
  85     case Qt::Unchecked:
  86         opt.checked = false;
  87         break;
  88     };
  89
  90     if ((opt.state & QStyle::State_HasFocus)
  91         || rect().contains(mapFromGlobal(QCursor::pos())))
  92         {
  93         opt.state |= QStyle::State_Selected;
  94
  95         if (QApplication::mouseButtons() != Qt::NoButton)
  96             opt.state |= QStyle::State_Sunken;
  97     }
  98
  99     QPainter painter {this};
 100     style()->drawControl(QStyle::CE_MenuItem, &opt, &painter, this);
 101 }
 102
 103 void TriStateWidget::mouseReleaseEvent(QMouseEvent *event)
 104 {
 105     toggleCheckState();
 106
 107     if (m_closeOnInteraction)
 108     {
 109         // parent `triggered` signal will be emitted
 110         QWidget::mouseReleaseEvent(event);
 111     }
 112     else
 113     {
 114         update();
 115         // need to emit `triggered` signal manually
 116         emit triggered(m_checkState == Qt::Checked);
 117     }
 118 }
 119
 120 void TriStateWidget::keyPressEvent(QKeyEvent *event)
 121 {
 122     if ((event->key() == Qt::Key_Return)
 123         || (event->key() == Qt::Key_Enter))
 124         {
 125         toggleCheckState();
 126
 127         if (!m_closeOnInteraction)
 128         {
 129             update();
 130             // need to emit parent `triggered` signal manually
 131             emit triggered(m_checkState == Qt::Checked);
 132             return;
 133         }
 134     }
 135
 136     QWidget::keyPressEvent(event);
 137 }
 138
 139 void TriStateWidget::toggleCheckState()
 140 {
 141     switch (m_checkState)
 142     {
 143     case Qt::Unchecked:
 144     case Qt::PartiallyChecked:
 145         m_checkState = Qt::Checked;
 146         break;
 147     case Qt::Checked:
 148         m_checkState = Qt::Unchecked;
 149         break;
 150     };
 151 }