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_text {text}
  42 {
  43     setMouseTracking(true);  // for visual effects via mouse navigation
  44     setFocusPolicy(Qt::TabFocus);  // for visual effects via keyboard navigation
  45 }
  46
  47 void TriStateWidget::setCheckState(const Qt::CheckState checkState)
  48 {
  49     m_checkState = checkState;
  50 }
  51
  52 void TriStateWidget::setCloseOnInteraction(const bool enabled)
  53 {
  54     m_closeOnInteraction = enabled;
  55 }
  56
  57 QSize TriStateWidget::minimumSizeHint() const
  58 {
  59     QStyleOptionMenuItem opt;
  60     opt.initFrom(this);
  61     opt.menuHasCheckableItems = true;
  62     const QSize contentSize = fontMetrics().size(Qt::TextSingleLine, m_text);
  63     return style()->sizeFromContents(QStyle::CT_MenuItem, &opt, contentSize, this);
  64 }
  65
  66 void TriStateWidget::paintEvent(QPaintEvent *)
  67 {
  68     QStyleOptionMenuItem opt;
  69     opt.initFrom(this);
  70     opt.menuItemType = QStyleOptionMenuItem::Normal;
  71     opt.checkType = QStyleOptionMenuItem::NonExclusive;
  72     opt.menuHasCheckableItems = true;
  73     opt.text = m_text;
  74
  75     switch (m_checkState)
  76     {
  77     case Qt::PartiallyChecked:
  78         opt.state |= QStyle::State_NoChange;
  79         break;
  80     case Qt::Checked:
  81         opt.checked = true;
  82         break;
  83     case Qt::Unchecked:
  84         opt.checked = false;
  85         break;
  86     };
  87
  88     if ((opt.state & QStyle::State_HasFocus)
  89         || rect().contains(mapFromGlobal(QCursor::pos())))
  90         {
  91         opt.state |= QStyle::State_Selected;
  92
  93         if (QApplication::mouseButtons() != Qt::NoButton)
  94             opt.state |= QStyle::State_Sunken;
  95     }
  96
  97     QPainter painter {this};
  98     style()->drawControl(QStyle::CE_MenuItem, &opt, &painter, this);
  99 }
 100
 101 void TriStateWidget::mouseReleaseEvent(QMouseEvent *event)
 102 {
 103     toggleCheckState();
 104
 105     if (m_closeOnInteraction)
 106     {
 107         // parent `triggered` signal will be emitted
 108         QWidget::mouseReleaseEvent(event);
 109     }
 110     else
 111     {
 112         update();
 113         // need to emit `triggered` signal manually
 114         emit triggered(m_checkState == Qt::Checked);
 115     }
 116 }
 117
 118 void TriStateWidget::keyPressEvent(QKeyEvent *event)
 119 {
 120     if ((event->key() == Qt::Key_Return)
 121         || (event->key() == Qt::Key_Enter))
 122         {
 123         toggleCheckState();
 124
 125         if (!m_closeOnInteraction)
 126         {
 127             update();
 128             // need to emit parent `triggered` signal manually
 129             emit triggered(m_checkState == Qt::Checked);
 130             return;
 131         }
 132     }
 133
 134     QWidget::keyPressEvent(event);
 135 }
 136
 137 void TriStateWidget::toggleCheckState()
 138 {
 139     switch (m_checkState)
 140     {
 141     case Qt::Unchecked:
 142     case Qt::PartiallyChecked:
 143         m_checkState = Qt::Checked;
 144         break;
 145     case Qt::Checked:
 146         m_checkState = Qt::Unchecked;
 147         break;
 148     };
 149 }