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 }
  48
  49 SelectionToggle::~SelectionToggle()
  50 {
  51 }
  52
  53 QSize SelectionToggle::sizeHint() const
  54 {
  55     return QSize(16, 16);
  56 }
  57
  58 void SelectionToggle::reset()
  59 {
  60     m_url = KUrl();
  61     hide();
  62 }
  63
  64 void SelectionToggle::setUrl(const KUrl& url)
  65 {
  66     m_url = url;
  67     if (!url.isEmpty()) {
  68         startFading();
  69     }
  70 }
  71
  72 KUrl SelectionToggle::url() const
  73 {
  74     return m_url;
  75 }
  76
  77 void SelectionToggle::setVisible(bool visible)
  78 {
  79     QAbstractButton::setVisible(visible);
  80
  81     stopFading();
  82     if (visible) {
  83         startFading();
  84     }
  85
  86 }
  87
  88 bool SelectionToggle::eventFilter(QObject* obj, QEvent* event)
  89 {
  90     if ((obj == parent()) && (event->type() == QEvent::Leave)) {
  91         hide();
  92     }
  93     return QAbstractButton::eventFilter(obj, event);
  94 }
  95
  96 void SelectionToggle::enterEvent(QEvent* event)
  97 {
  98     QAbstractButton::enterEvent(event);
  99
 100     // if the mouse cursor is above the selection toggle, display
 101     // it immediately without fading timer
 102     m_isHovered = true;
 103     if (m_fadingTimeLine != 0) {
 104         m_fadingTimeLine->stop();
 105     }
 106     m_fadingValue = 255;
 107     setToolTip(isChecked() ? i18nc("@info:tooltip", "Deselect Item") :
 108                              i18nc("@info:tooltip", "Select Item"));
 109     update();
 110 }
 111
 112 void SelectionToggle::leaveEvent(QEvent* event)
 113 {
 114     QAbstractButton::leaveEvent(event);
 115     m_isHovered = false;
 116     update();
 117 }
 118
 119 void SelectionToggle::paintEvent(QPaintEvent* event)
 120 {
 121     QPainter painter(this);
 122     painter.setClipRect(event->rect());
 123     painter.setRenderHint(QPainter::Antialiasing);
 124
 125     // draw an alpha blended circle as background
 126     const QPalette& palette = parentWidget()->palette();
 127
 128     const QBrush& backgroundBrush = palette.brush(QPalette::Normal, QPalette::Window);
 129     QColor background = backgroundBrush.color();
 130     background.setAlpha(m_fadingValue / 2);
 131     painter.setBrush(background);
 132
 133     const QBrush& foregroundBrush = palette.brush(QPalette::Normal, QPalette::WindowText);
 134     QColor foreground = foregroundBrush.color();
 135     foreground.setAlpha(m_fadingValue / 4);
 136     painter.setPen(foreground);
 137
 138     painter.drawEllipse(0, 0, width(), height());
 139
 140     // draw the icon overlay
 141     if (m_isHovered) {
 142         KIconEffect iconEffect;
 143         QPixmap activeIcon = iconEffect.apply(m_icon, KIconLoader::Desktop, KIconLoader::ActiveState);
 144         painter.drawPixmap(0, 0, activeIcon);
 145     } else {
 146         if (m_fadingValue < 255) {
 147             // apply an alpha mask respecting the fading value to the icon
 148             QPixmap icon = m_icon;
 149             QPixmap alphaMask(icon.width(), icon.height());
 150             const QColor color(m_fadingValue, m_fadingValue, m_fadingValue);
 151             alphaMask.fill(color);
 152             icon.setAlphaChannel(alphaMask);
 153             painter.drawPixmap(0, 0, icon);
 154         } else {
 155             // no fading is required
 156             painter.drawPixmap(0, 0, m_icon);
 157         }
 158     }
 159 }
 160
 161 void SelectionToggle::setFadingValue(int value)
 162 {
 163     m_fadingValue = value;
 164     if (m_fadingValue >= 255) {
 165         Q_ASSERT(m_fadingTimeLine != 0);
 166         m_fadingTimeLine->stop();
 167     }
 168     update();
 169 }
 170
 171 void SelectionToggle::setIconOverlay(bool checked)
 172 {
 173     const char* icon = checked ? "list-remove" : "list-add";
 174     m_icon = KIconLoader::global()->loadIcon(icon,
 175                                              KIconLoader::NoGroup,
 176                                              KIconLoader::SizeSmall);
 177     update();
 178 }
 179
 180 void SelectionToggle::startFading()
 181 {
 182     Q_ASSERT(m_fadingTimeLine == 0);
 183
 184     const bool animate = KGlobalSettings::graphicEffectsLevel() & KGlobalSettings::SimpleAnimationEffects;
 185     const int duration = animate ? 600 : 1;
 186
 187     m_fadingTimeLine = new QTimeLine(duration, this);
 188     connect(m_fadingTimeLine, SIGNAL(frameChanged(int)),
 189             this, SLOT(setFadingValue(int)));
 190     m_fadingTimeLine->setFrameRange(0, 255);
 191     m_fadingTimeLine->start();
 192     m_fadingValue = 0;
 193 }
 194
 195 void SelectionToggle::stopFading()
 196 {
 197     if (m_fadingTimeLine != 0) {
 198         m_fadingTimeLine->stop();
 199         delete m_fadingTimeLine;
 200         m_fadingTimeLine = 0;
 201     }
 202     m_fadingValue = 0;
 203 }
 204
 205 #include "selectiontoggle.moc"