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