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     setFocusPolicy(Qt::NoFocus);
  40     parent->installEventFilter(this);
  41     resize(sizeHint());
  42     setIconOverlay(isChecked());
  43     connect(this, SIGNAL(toggled(bool)),
  44             this, SLOT(setIconOverlay(bool)));
  45 }
  46
  47 SelectionToggle::~SelectionToggle()
  48 {
  49 }
  50
  51 QSize SelectionToggle::sizeHint() const
  52 {
  53     return QSize(16, 16);
  54 }
  55
  56 void SelectionToggle::reset()
  57 {
  58     m_url = KUrl();
  59     hide();
  60 }
  61
  62 void SelectionToggle::setUrl(const KUrl& url)
  63 {
  64     m_url = url;
  65     if (!url.isEmpty()) {
  66         startFading();
  67     }
  68 }
  69
  70 KUrl SelectionToggle::url() const
  71 {
  72     return m_url;
  73 }
  74
  75 void SelectionToggle::setVisible(bool visible)
  76 {
  77     QAbstractButton::setVisible(visible);
  78
  79     stopFading();
  80     if (visible) {
  81         startFading();
  82     }
  83
  84 }
  85
  86 bool SelectionToggle::eventFilter(QObject* obj, QEvent* event)
  87 {
  88     if ((obj == parent()) && (event->type() == QEvent::Leave)) {
  89         hide();
  90     }
  91     return QAbstractButton::eventFilter(obj, event);
  92 }
  93
  94 void SelectionToggle::enterEvent(QEvent* event)
  95 {
  96     QAbstractButton::enterEvent(event);
  97
  98     // if the mouse cursor is above the selection toggle, display
  99     // it immediately without fading timer
 100     m_isHovered = true;
 101     if (m_fadingTimeLine != 0) {
 102         m_fadingTimeLine->stop();
 103     }
 104     m_fadingValue = 255;
 105     update();
 106 }
 107
 108 void SelectionToggle::leaveEvent(QEvent* event)
 109 {
 110     QAbstractButton::leaveEvent(event);
 111     m_isHovered = false;
 112     update();
 113 }
 114
 115 void SelectionToggle::paintEvent(QPaintEvent* event)
 116 {
 117     QPainter painter(this);
 118     painter.setClipRect(event->rect());
 119     painter.setRenderHint(QPainter::Antialiasing);
 120
 121     // draw an alpha blended circle as background
 122     const QPalette& palette = parentWidget()->palette();
 123
 124     const QBrush& backgroundBrush = palette.brush(QPalette::Normal, QPalette::Window);
 125     QColor background = backgroundBrush.color();
 126     background.setAlpha(m_fadingValue / 2);
 127     painter.setBrush(background);
 128
 129     const QBrush& foregroundBrush = palette.brush(QPalette::Normal, QPalette::WindowText);
 130     QColor foreground = foregroundBrush.color();
 131     foreground.setAlpha(m_fadingValue / 4);
 132     painter.setPen(foreground);
 133
 134     painter.drawEllipse(0, 0, width(), height());
 135
 136     // draw the icon overlay
 137     if (m_isHovered) {
 138         KIconEffect iconEffect;
 139         QPixmap activeIcon = iconEffect.apply(m_icon, KIconLoader::Desktop, KIconLoader::ActiveState);
 140         painter.drawPixmap(0, 0, activeIcon);
 141     } else {
 142         if (m_fadingValue < 255) {
 143             // apply an alpha mask respecting the fading value to the icon
 144             QPixmap icon = m_icon;
 145             QPixmap alphaMask(icon.width(), icon.height());
 146             const QColor color(m_fadingValue, m_fadingValue, m_fadingValue);
 147             alphaMask.fill(color);
 148             icon.setAlphaChannel(alphaMask);
 149             painter.drawPixmap(0, 0, icon);
 150         } else {
 151             // no fading is required
 152             painter.drawPixmap(0, 0, m_icon);
 153         }
 154     }
 155 }
 156
 157 void SelectionToggle::setFadingValue(int value)
 158 {
 159     m_fadingValue = value;
 160     if (m_fadingValue >= 255) {
 161         Q_ASSERT(m_fadingTimeLine != 0);
 162         m_fadingTimeLine->stop();
 163     }
 164     update();
 165 }
 166
 167 void SelectionToggle::setIconOverlay(bool checked)
 168 {
 169     const char* icon = checked ? "list-remove" : "list-add";
 170     m_icon = KIconLoader::global()->loadIcon(icon,
 171                                              KIconLoader::NoGroup,
 172                                              KIconLoader::SizeSmall);
 173     update();
 174 }
 175
 176 void SelectionToggle::startFading()
 177 {
 178     Q_ASSERT(m_fadingTimeLine == 0);
 179
 180     m_fadingTimeLine = new QTimeLine(1500, this);
 181     connect(m_fadingTimeLine, SIGNAL(frameChanged(int)),
 182             this, SLOT(setFadingValue(int)));
 183     m_fadingTimeLine->setFrameRange(0, 255);
 184     m_fadingTimeLine->start();
 185     m_fadingValue = 0;
 186 }
 187
 188 void SelectionToggle::stopFading()
 189 {
 190     if (m_fadingTimeLine != 0) {
 191         m_fadingTimeLine->stop();
 192         delete m_fadingTimeLine;
 193         m_fadingTimeLine = 0;
 194     }
 195     m_fadingValue = 0;
 196 }
 197
 198 #include "selectiontoggle.moc"