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 <QApplication>
  29 #include <QPainter>
  30 #include <QPaintEvent>
  31 #include <QRect>
  32 #include <QTimer>
  33 #include <QTimeLine>
  34
  35 SelectionToggle::SelectionToggle(QWidget* parent) :
  36     QAbstractButton(parent),
  37     m_isHovered(false),
  38     m_leftMouseButtonPressed(false),
  39     m_appliedArrowCursor(false),
  40     m_fadingValue(0),
  41     m_margin(0),
  42     m_icon(),
  43     m_fadingTimeLine(0)
  44 {
  45     setFocusPolicy(Qt::NoFocus);
  46     parent->installEventFilter(this);
  47     resize(sizeHint());
  48     setIconOverlay(isChecked());
  49     connect(this, SIGNAL(toggled(bool)),
  50             this, SLOT(setIconOverlay(bool)));
  51     connect(KGlobalSettings::self(), SIGNAL(iconChanged(int)),
  52             this, SLOT(refreshIcon()));
  53 }
  54
  55 SelectionToggle::~SelectionToggle()
  56 {
  57 }
  58
  59 QSize SelectionToggle::sizeHint() const
  60 {
  61     return QSize(16, 16);
  62 }
  63
  64 void SelectionToggle::reset()
  65 {
  66     m_url = KUrl();
  67     hide();
  68 }
  69
  70 void SelectionToggle::setUrl(const KUrl& url)
  71 {
  72     m_url = url;
  73     if (!url.isEmpty()) {
  74         startFading();
  75     }
  76 }
  77
  78 void SelectionToggle::setMargin(int margin)
  79 {
  80     if (margin != m_margin) {
  81         m_margin = margin;
  82         update();
  83     }
  84 }
  85
  86 int SelectionToggle::margin() const
  87 {
  88     return m_margin;
  89 }
  90
  91 KUrl SelectionToggle::url() const
  92 {
  93     return m_url;
  94 }
  95
  96 void SelectionToggle::setVisible(bool visible)
  97 {
  98     QAbstractButton::setVisible(visible);
  99
 100     stopFading();
 101     if (visible) {
 102         startFading();
 103     }
 104
 105 }
 106
 107 bool SelectionToggle::eventFilter(QObject* obj, QEvent* event)
 108 {
 109     if (obj == parent()) {
 110         switch (event->type()) {
 111         case QEvent::Leave:
 112             hide();
 113             break;
 114
 115         case QEvent::MouseMove:
 116             if (m_leftMouseButtonPressed) {
 117                 // Don't forward mouse move events to the viewport,
 118                 // otherwise a rubberband selection will be shown when
 119                 // clicking on the selection toggle and moving the mouse
 120                 // above the viewport.
 121                 return true;
 122             }
 123             break;
 124
 125         default:
 126             break;
 127         }
 128     }
 129
 130     return QAbstractButton::eventFilter(obj, event);
 131 }
 132
 133 void SelectionToggle::enterEvent(QEvent* event)
 134 {
 135     QAbstractButton::enterEvent(event);
 136
 137     if (!m_appliedArrowCursor) {
 138         m_appliedArrowCursor = true;
 139         // Apply the arrow asynchronously. This is required for
 140         // the following usecase:
 141         // 1. Cursor is above the viewport left beside an item
 142         // 2. Cursor is moved above the item, so that the selection-toggle
 143         //    and the item are entered equally.
 144         // In this situation it is not defined who gets the enter-event first.
 145         // As the selection-toggle is above the item, it should overwrite possible
 146         // cursor changes done by the item.
 147         QTimer::singleShot(0, this, SLOT(applyArrowCursor()));
 148     }
 149
 150     // if the mouse cursor is above the selection toggle, display
 151     // it immediately without fading timer
 152     m_isHovered = true;
 153     if (m_fadingTimeLine != 0) {
 154         m_fadingTimeLine->stop();
 155     }
 156     m_fadingValue = 255;
 157     setToolTip(isChecked() ? i18nc("@info:tooltip", "Deselect Item") :
 158                              i18nc("@info:tooltip", "Select Item"));
 159     update();
 160 }
 161
 162 void SelectionToggle::leaveEvent(QEvent* event)
 163 {
 164     QAbstractButton::leaveEvent(event);
 165
 166     if (m_appliedArrowCursor) {
 167         // Reset the cursor asynchronously. See SelectionToggle::enterEvent()
 168         // for a more information.
 169         m_appliedArrowCursor = false;
 170         QTimer::singleShot(0, this, SLOT(restoreCursor()));
 171     }
 172
 173     m_isHovered = false;
 174     update();
 175 }
 176
 177 void SelectionToggle::mousePressEvent(QMouseEvent* event)
 178 {
 179     QAbstractButton::mousePressEvent(event);
 180     m_leftMouseButtonPressed = (event->buttons() & Qt::LeftButton);
 181 }
 182
 183 void SelectionToggle::mouseReleaseEvent(QMouseEvent* event)
 184 {
 185     QAbstractButton::mouseReleaseEvent(event);
 186     m_leftMouseButtonPressed = (event->buttons() & Qt::LeftButton);
 187 }
 188
 189 void SelectionToggle::resizeEvent(QResizeEvent* event)
 190 {
 191     QAbstractButton::resizeEvent(event);
 192     setIconOverlay(isChecked());
 193 }
 194
 195 void SelectionToggle::paintEvent(QPaintEvent* event)
 196 {
 197     QPainter painter(this);
 198     painter.setClipRect(event->rect());
 199
 200     // draw the icon overlay
 201     const QPoint pos(m_margin, m_margin);
 202     if (m_isHovered) {
 203         KIconEffect *iconEffect = KIconLoader::global()->iconEffect();
 204         QPixmap activeIcon = iconEffect->apply(m_icon, KIconLoader::Desktop, KIconLoader::ActiveState);
 205         painter.drawPixmap(pos, activeIcon);
 206     } else {
 207         if (m_fadingValue < 255) {
 208             // apply an alpha mask respecting the fading value to the icon
 209             QPixmap icon = m_icon;
 210             QPixmap alphaMask(icon.width(), icon.height());
 211             const QColor color(m_fadingValue, m_fadingValue, m_fadingValue);
 212             alphaMask.fill(color);
 213             icon.setAlphaChannel(alphaMask);
 214             painter.drawPixmap(pos, icon);
 215         } else {
 216             // no fading is required
 217             painter.drawPixmap(pos, m_icon);
 218         }
 219     }
 220
 221 }
 222
 223 void SelectionToggle::setFadingValue(int value)
 224 {
 225     m_fadingValue = value;
 226     if (m_fadingValue >= 255) {
 227         Q_ASSERT(m_fadingTimeLine != 0);
 228         m_fadingTimeLine->stop();
 229     }
 230     update();
 231 }
 232
 233 void SelectionToggle::setIconOverlay(bool checked)
 234 {
 235     const char* icon = checked ? "list-remove" : "list-add";
 236     const int size = qMin(width() - 2 * m_margin, height() - 2 * m_margin);
 237     m_icon = KIconLoader::global()->loadIcon(icon,
 238                                              KIconLoader::NoGroup,
 239                                              size);
 240     update();
 241 }
 242
 243 void SelectionToggle::refreshIcon()
 244 {
 245     setIconOverlay(isChecked());
 246 }
 247
 248 void SelectionToggle::applyArrowCursor()
 249 {
 250     QApplication::setOverrideCursor(QCursor(Qt::ArrowCursor));
 251 }
 252
 253 void SelectionToggle::restoreCursor()
 254 {
 255     QApplication::restoreOverrideCursor();
 256 }
 257
 258 void SelectionToggle::startFading()
 259 {
 260     Q_ASSERT(m_fadingTimeLine == 0);
 261
 262     const bool animate = KGlobalSettings::graphicEffectsLevel() & KGlobalSettings::SimpleAnimationEffects;
 263     const int duration = animate ? 600 : 1;
 264
 265     m_fadingTimeLine = new QTimeLine(duration, this);
 266     connect(m_fadingTimeLine, SIGNAL(frameChanged(int)),
 267             this, SLOT(setFadingValue(int)));
 268     m_fadingTimeLine->setFrameRange(0, 255);
 269     m_fadingTimeLine->start();
 270     m_fadingValue = 0;
 271 }
 272
 273 void SelectionToggle::stopFading()
 274 {
 275     if (m_fadingTimeLine != 0) {
 276         m_fadingTimeLine->stop();
 277         delete m_fadingTimeLine;
 278         m_fadingTimeLine = 0;
 279     }
 280     m_fadingValue = 0;
 281 }
 282
 283 #include "selectiontoggle.moc"