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