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 <kglobalsettings.h>
  23 #include <kicon.h>
  24 #include <kiconloader.h>
  25 #include <kiconeffect.h>
  26 #include <klocale.h>
  27
  28 #include <QPainter>
  29 #include <QPaintEvent>
  30 #include <QRect>
  31 #include <QTimer>
  32 #include <QTimeLine>
  33
  34 SelectionToggle::SelectionToggle(QWidget* parent) :
  35     QAbstractButton(parent),
  36     m_isHovered(false),
  37     m_leftMouseButtonPressed(false),
  38     m_fadingValue(0),
  39     m_icon(),
  40     m_fadingTimeLine(0)
  41 {
  42     setFocusPolicy(Qt::NoFocus);
  43     parent->installEventFilter(this);
  44     resize(sizeHint());
  45     setIconOverlay(isChecked());
  46     connect(this, SIGNAL(toggled(bool)),
  47             this, SLOT(setIconOverlay(bool)));
  48     connect(KGlobalSettings::self(), SIGNAL(iconChanged(int)),
  49             this, SLOT(refreshIcon()));
  50 }
  51
  52 SelectionToggle::~SelectionToggle()
  53 {
  54 }
  55
  56 QSize SelectionToggle::sizeHint() const
  57 {
  58     return QSize(16, 16);
  59 }
  60
  61 void SelectionToggle::reset()
  62 {
  63     m_url = KUrl();
  64     hide();
  65 }
  66
  67 void SelectionToggle::setUrl(const KUrl& url)
  68 {
  69     m_url = url;
  70     if (!url.isEmpty()) {
  71         startFading();
  72     }
  73 }
  74
  75 KUrl SelectionToggle::url() const
  76 {
  77     return m_url;
  78 }
  79
  80 void SelectionToggle::setVisible(bool visible)
  81 {
  82     QAbstractButton::setVisible(visible);
  83
  84     stopFading();
  85     if (visible) {
  86         startFading();
  87     }
  88
  89 }
  90
  91 bool SelectionToggle::eventFilter(QObject* obj, QEvent* event)
  92 {
  93     if (obj == parent()) {
  94         switch (event->type()) {
  95         case QEvent::Leave:
  96             hide();
  97             break;
  98
  99         case QEvent::MouseMove:
 100             if (m_leftMouseButtonPressed) {
 101                 // Don't forward mouse move events to the viewport,
 102                 // otherwise a rubberband selection will be shown when
 103                 // clicking on the selection toggle and moving the mouse
 104                 // above the viewport.
 105                 return true;
 106             }
 107             break;
 108
 109         default:
 110             break;
 111         }
 112     }
 113
 114     return QAbstractButton::eventFilter(obj, event);
 115 }
 116
 117 void SelectionToggle::enterEvent(QEvent* event)
 118 {
 119     QAbstractButton::enterEvent(event);
 120
 121     // if the mouse cursor is above the selection toggle, display
 122     // it immediately without fading timer
 123     m_isHovered = true;
 124     if (m_fadingTimeLine != 0) {
 125         m_fadingTimeLine->stop();
 126     }
 127     m_fadingValue = 255;
 128     setToolTip(isChecked() ? i18nc("@info:tooltip", "Deselect Item") :
 129                              i18nc("@info:tooltip", "Select Item"));
 130     update();
 131 }
 132
 133 void SelectionToggle::leaveEvent(QEvent* event)
 134 {
 135     QAbstractButton::leaveEvent(event);
 136     m_isHovered = false;
 137     update();
 138 }
 139
 140 void SelectionToggle::mousePressEvent(QMouseEvent* event)
 141 {
 142     QAbstractButton::mousePressEvent(event);
 143     m_leftMouseButtonPressed = (event->buttons() & Qt::LeftButton);
 144 }
 145
 146 void SelectionToggle::mouseReleaseEvent(QMouseEvent* event)
 147 {
 148     QAbstractButton::mouseReleaseEvent(event);
 149     m_leftMouseButtonPressed = (event->buttons() & Qt::LeftButton);
 150 }
 151
 152 void SelectionToggle::resizeEvent(QResizeEvent* event)
 153 {
 154     QAbstractButton::resizeEvent(event);
 155     setIconOverlay(isChecked());
 156 }
 157
 158 void SelectionToggle::paintEvent(QPaintEvent* event)
 159 {
 160     QPainter painter(this);
 161     painter.setClipRect(event->rect());
 162     painter.setRenderHint(QPainter::Antialiasing);
 163
 164     // draw an alpha blended circle as background
 165     const QPalette& palette = parentWidget()->palette();
 166
 167     const QBrush& backgroundBrush = palette.brush(QPalette::Normal, QPalette::Window);
 168     QColor background = backgroundBrush.color();
 169     background.setAlpha(m_fadingValue / 2);
 170     painter.setBrush(background);
 171
 172     const QBrush& foregroundBrush = palette.brush(QPalette::Normal, QPalette::WindowText);
 173     QColor foreground = foregroundBrush.color();
 174     foreground.setAlpha(m_fadingValue / 4);
 175     painter.setPen(foreground);
 176
 177     painter.drawEllipse(0, 0, width(), height());
 178
 179     // draw the icon overlay
 180     if (m_isHovered) {
 181         KIconEffect iconEffect;
 182         QPixmap activeIcon = iconEffect.apply(m_icon, KIconLoader::Desktop, KIconLoader::ActiveState);
 183         painter.drawPixmap(0, 0, activeIcon);
 184     } else {
 185         if (m_fadingValue < 255) {
 186             // apply an alpha mask respecting the fading value to the icon
 187             QPixmap icon = m_icon;
 188             QPixmap alphaMask(icon.width(), icon.height());
 189             const QColor color(m_fadingValue, m_fadingValue, m_fadingValue);
 190             alphaMask.fill(color);
 191             icon.setAlphaChannel(alphaMask);
 192             painter.drawPixmap(0, 0, icon);
 193         } else {
 194             // no fading is required
 195             painter.drawPixmap(0, 0, m_icon);
 196         }
 197     }
 198 }
 199
 200 void SelectionToggle::setFadingValue(int value)
 201 {
 202     m_fadingValue = value;
 203     if (m_fadingValue >= 255) {
 204         Q_ASSERT(m_fadingTimeLine != 0);
 205         m_fadingTimeLine->stop();
 206     }
 207     update();
 208 }
 209
 210 void SelectionToggle::setIconOverlay(bool checked)
 211 {
 212     const char* icon = checked ? "list-remove" : "list-add";
 213     m_icon = KIconLoader::global()->loadIcon(icon,
 214                                              KIconLoader::NoGroup,
 215                                              qMin(width(), height()));
 216     update();
 217 }
 218
 219 void SelectionToggle::refreshIcon()
 220 {
 221     setIconOverlay(isChecked());
 222 }
 223
 224 void SelectionToggle::startFading()
 225 {
 226     Q_ASSERT(m_fadingTimeLine == 0);
 227
 228     const bool animate = KGlobalSettings::graphicEffectsLevel() & KGlobalSettings::SimpleAnimationEffects;
 229     const int duration = animate ? 600 : 1;
 230
 231     m_fadingTimeLine = new QTimeLine(duration, this);
 232     connect(m_fadingTimeLine, SIGNAL(frameChanged(int)),
 233             this, SLOT(setFadingValue(int)));
 234     m_fadingTimeLine->setFrameRange(0, 255);
 235     m_fadingTimeLine->start();
 236     m_fadingValue = 0;
 237 }
 238
 239 void SelectionToggle::stopFading()
 240 {
 241     if (m_fadingTimeLine != 0) {
 242         m_fadingTimeLine->stop();
 243         delete m_fadingTimeLine;
 244         m_fadingTimeLine = 0;
 245     }
 246     m_fadingValue = 0;
 247 }
 248
 249 #include "selectiontoggle.moc"