src/selectiontoggle.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2008 by Peter Penz <peter.penz@gmx.at>                  *
   3  *                                                                         *
   4  *   This program is free software; you can redistribute it and/or modify  *
   5  *   it under the terms of the GNU General Public License as published by  *
   6  *   the Free Software Foundation; either version 2 of the License, or     *
   7  *   (at your option) any later version.                                   *
   8  *                                                                         *
   9  *   This program is distributed in the hope that it will be useful,       *
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  12  *   GNU General Public License for more details.                          *
  13  *                                                                         *
  14  *   You should have received a copy of the GNU General Public License     *
  15  *   along with this program; if not, write to the                         *
  16  *   Free Software Foundation, Inc.,                                       *
  17  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  18  ***************************************************************************/
  19
  20 #include "selectiontoggle.h"
  21
  22 #include <kicon.h>
  23 #include <kiconloader.h>
  24 #include <kiconeffect.h>
  25
  26 #include <QPainter>
  27 #include <QPaintEvent>
  28 #include <QRect>
  29 #include <QTimer>
  30 #include <QTimeLine>
  31
  32 SelectionToggle::SelectionToggle(QWidget* parent) :
  33     QAbstractButton(parent),
  34     m_isHovered(false),
  35     m_fadingValue(0),
  36     m_icon(),
  37     m_fadingTimeLine(0)
  38 {
  39     parent->installEventFilter(this);
  40     resize(sizeHint());
  41     setIconOverlay(isChecked());
  42     connect(this, SIGNAL(toggled(bool)),
  43             this, SLOT(setIconOverlay(bool)));
  44 }
  45
  46 SelectionToggle::~SelectionToggle()
  47 {
  48 }
  49
  50 QSize SelectionToggle::sizeHint() const
  51 {
  52     return QSize(16, 16);
  53 }
  54
  55 void SelectionToggle::reset()
  56 {
  57     m_url = KUrl();
  58     hide();
  59 }
  60
  61 void SelectionToggle::setUrl(const KUrl& url)
  62 {
  63     m_url = url;
  64     if (!url.isEmpty()) {
  65         startFading();
  66     }
  67 }
  68
  69 KUrl SelectionToggle::url() const
  70 {
  71     return m_url;
  72 }
  73
  74 void SelectionToggle::setVisible(bool visible)
  75 {
  76     QAbstractButton::setVisible(visible);
  77
  78     stopFading();
  79     if (visible) {
  80         startFading();
  81     }
  82
  83 }
  84
  85 bool SelectionToggle::eventFilter(QObject* obj, QEvent* event)
  86 {
  87     if ((obj == parent()) && (event->type() == QEvent::Leave)) {
  88         hide();
  89     }
  90     return QAbstractButton::eventFilter(obj, event);
  91 }
  92
  93 void SelectionToggle::enterEvent(QEvent* event)
  94 {
  95     QAbstractButton::enterEvent(event);
  96
  97     // if the mouse cursor is above the selection toggle, display
  98     // it immediately without fading timer
  99     m_isHovered = true;
 100     if (m_fadingTimeLine != 0) {
 101         m_fadingTimeLine->stop();
 102     }
 103     m_fadingValue = 255;
 104     update();
 105 }
 106
 107 void SelectionToggle::leaveEvent(QEvent* event)
 108 {
 109     QAbstractButton::leaveEvent(event);
 110     m_isHovered = false;
 111     update();
 112 }
 113
 114 void SelectionToggle::paintEvent(QPaintEvent* event)
 115 {
 116     QPainter painter(this);
 117     painter.setClipRect(event->rect());
 118     painter.setRenderHint(QPainter::Antialiasing);
 119
 120     // draw an alpha blended circle as background
 121     const QPalette& palette = parentWidget()->palette();
 122
 123     const QBrush& backgroundBrush = palette.brush(QPalette::Normal, QPalette::Window);
 124     QColor background = backgroundBrush.color();
 125     background.setAlpha(m_fadingValue / 2);
 126     painter.setBrush(background);
 127
 128     const QBrush& foregroundBrush = palette.brush(QPalette::Normal, QPalette::WindowText);
 129     QColor foreground = foregroundBrush.color();
 130     foreground.setAlpha(m_fadingValue / 4);
 131     painter.setPen(foreground);
 132
 133     painter.drawEllipse(0, 0, width(), height());
 134
 135     // draw the icon overlay
 136     if (m_isHovered) {
 137         KIconEffect iconEffect;
 138         QPixmap activeIcon = iconEffect.apply(m_icon, KIconLoader::Desktop, KIconLoader::ActiveState);
 139         painter.drawPixmap(0, 0, activeIcon);
 140     } else {
 141         if (m_fadingValue < 255) {
 142             // apply an alpha mask respecting the fading value to the icon
 143             QPixmap icon = m_icon;
 144             QPixmap alphaMask(icon.width(), icon.height());
 145             const QColor color(m_fadingValue, m_fadingValue, m_fadingValue);
 146             alphaMask.fill(color);
 147             icon.setAlphaChannel(alphaMask);
 148             painter.drawPixmap(0, 0, icon);
 149         } else {
 150             // no fading is required
 151             painter.drawPixmap(0, 0, m_icon);
 152         }
 153     }
 154 }
 155
 156 void SelectionToggle::setFadingValue(int value)
 157 {
 158     m_fadingValue = value;
 159     if (m_fadingValue >= 255) {
 160         Q_ASSERT(m_fadingTimeLine != 0);
 161         m_fadingTimeLine->stop();
 162     }
 163     update();
 164 }
 165
 166 void SelectionToggle::setIconOverlay(bool checked)
 167 {
 168     const char* icon = checked ? "list-remove" : "list-add";
 169     m_icon = KIconLoader::global()->loadIcon(icon,
 170                                              KIconLoader::NoGroup,
 171                                              KIconLoader::SizeSmall);
 172     update();
 173 }
 174
 175 void SelectionToggle::startFading()
 176 {
 177     Q_ASSERT(m_fadingTimeLine == 0);
 178
 179     m_fadingTimeLine = new QTimeLine(1500, this);
 180     connect(m_fadingTimeLine, SIGNAL(frameChanged(int)),
 181             this, SLOT(setFadingValue(int)));
 182     m_fadingTimeLine->setFrameRange(0, 255);
 183     m_fadingTimeLine->start();
 184     m_fadingValue = 0;
 185 }
 186
 187 void SelectionToggle::stopFading()
 188 {
 189     if (m_fadingTimeLine != 0) {
 190         m_fadingTimeLine->stop();
 191         delete m_fadingTimeLine;
 192         m_fadingTimeLine = 0;
 193     }
 194     m_fadingValue = 0;
 195 }
 196
 197 #include "selectiontoggle.moc"