src/views/tooltips/tooltipmanager.cpp

   1 /*******************************************************************************
   2  *   Copyright (C) 2008 by Konstantin Heil <konst.heil@stud.uni-heidelberg.de> *
   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 "tooltipmanager.h"
  21
  22 #include "filemetadatatooltip.h"
  23 #include <KIcon>
  24 #include <KIO/PreviewJob>
  25
  26 #include <QApplication>
  27 #include <QDesktopWidget>
  28 #include <QLayout>
  29 #include <QScrollArea>
  30 #include <QScrollBar>
  31 #include <QStyle>
  32 #include <QTimer>
  33
  34 ToolTipManager::ToolTipManager(QWidget* parent) :
  35     QObject(parent),
  36     m_parentWidget(parent),
  37     m_showToolTipTimer(0),
  38     m_contentRetrievalTimer(0),
  39     m_fileMetaDataToolTip(0),
  40     m_toolTipRequested(false),
  41     m_metaDataRequested(false),
  42     m_appliedWaitCursor(false),
  43     m_item(),
  44     m_itemRect()
  45 {
  46     m_showToolTipTimer = new QTimer(this);
  47     m_showToolTipTimer->setSingleShot(true);
  48     m_showToolTipTimer->setInterval(500);
  49     connect(m_showToolTipTimer, SIGNAL(timeout()), this, SLOT(showToolTip()));
  50
  51     m_contentRetrievalTimer = new QTimer(this);
  52     m_contentRetrievalTimer->setSingleShot(true);
  53     m_contentRetrievalTimer->setInterval(200);
  54     connect(m_contentRetrievalTimer, SIGNAL(timeout()), this, SLOT(startContentRetrieval()));
  55
  56     Q_ASSERT(m_contentRetrievalTimer->interval() < m_showToolTipTimer->interval());
  57 }
  58
  59 ToolTipManager::~ToolTipManager()
  60 {
  61     delete m_fileMetaDataToolTip;
  62     m_fileMetaDataToolTip = 0;
  63 }
  64
  65 void ToolTipManager::showToolTip(const KFileItem& item, const QRectF& itemRect)
  66 {
  67     hideToolTip();
  68
  69     m_itemRect = itemRect.toRect();
  70
  71     const int margin = toolTipMargin();
  72     m_itemRect.adjust(-margin, -margin, margin, margin);
  73     m_item = item;
  74
  75     // Only start the retrieving of the content, when the mouse has been over this
  76     // item for 200 milliseconds. This prevents a lot of useless preview jobs and
  77     // meta data retrieval, when passing rapidly over a lot of items.
  78     Q_ASSERT(!m_fileMetaDataToolTip);
  79     m_fileMetaDataToolTip = new FileMetaDataToolTip(m_parentWidget);
  80     connect(m_fileMetaDataToolTip, SIGNAL(metaDataRequestFinished(KFileItemList)),
  81             this, SLOT(slotMetaDataRequestFinished()));
  82
  83     m_contentRetrievalTimer->start();
  84     m_showToolTipTimer->start();
  85     m_toolTipRequested = true;
  86     Q_ASSERT(!m_metaDataRequested);
  87 }
  88
  89 void ToolTipManager::hideToolTip()
  90 {
  91     if (m_appliedWaitCursor) {
  92         QApplication::restoreOverrideCursor();
  93         m_appliedWaitCursor = false;
  94     }
  95
  96     m_toolTipRequested = false;
  97     m_metaDataRequested = false;
  98     m_showToolTipTimer->stop();
  99     m_contentRetrievalTimer->stop();
 100
 101     if (m_fileMetaDataToolTip) {
 102         m_fileMetaDataToolTip->hide();
 103         delete m_fileMetaDataToolTip;
 104         m_fileMetaDataToolTip = 0;
 105     }
 106 }
 107
 108 void ToolTipManager::startContentRetrieval()
 109 {
 110     if (!m_toolTipRequested) {
 111         return;
 112     }
 113
 114     m_fileMetaDataToolTip->setName(m_item.text());
 115
 116     // Request the retrieval of meta-data. The slot
 117     // slotMetaDataRequestFinished() is invoked after the
 118     // meta-data have been received.
 119     m_metaDataRequested = true;
 120     m_fileMetaDataToolTip->setItems(KFileItemList() << m_item);
 121     m_fileMetaDataToolTip->adjustSize();
 122
 123     // Request a preview of the item
 124     m_fileMetaDataToolTip->setPreview(QPixmap());
 125
 126     KIO::PreviewJob* job = KIO::filePreview(KFileItemList() << m_item, QSize(256, 256));
 127
 128     connect(job, SIGNAL(gotPreview(KFileItem,QPixmap)),
 129             this, SLOT(setPreviewPix(KFileItem,QPixmap)));
 130     connect(job, SIGNAL(failed(KFileItem)),
 131             this, SLOT(previewFailed()));
 132 }
 133
 134
 135 void ToolTipManager::setPreviewPix(const KFileItem& item,
 136                                    const QPixmap& pixmap)
 137 {
 138     if (!m_toolTipRequested || (m_item.url() != item.url())) {
 139         // No tooltip is requested anymore or an old preview has been received
 140         return;
 141     }
 142
 143     if (pixmap.isNull()) {
 144         previewFailed();
 145     } else {
 146         m_fileMetaDataToolTip->setPreview(pixmap);
 147         if (!m_showToolTipTimer->isActive()) {
 148             showToolTip();
 149         }
 150     }
 151 }
 152
 153 void ToolTipManager::previewFailed()
 154 {
 155     if (!m_toolTipRequested) {
 156         return;
 157     }
 158
 159     const QPixmap pixmap = KIcon(m_item.iconName()).pixmap(128, 128);
 160     m_fileMetaDataToolTip->setPreview(pixmap);
 161     if (!m_showToolTipTimer->isActive()) {
 162         showToolTip();
 163     }
 164 }
 165
 166 void ToolTipManager::slotMetaDataRequestFinished()
 167 {
 168     if (!m_toolTipRequested) {
 169         return;
 170     }
 171
 172     m_metaDataRequested = false;
 173
 174     if (!m_showToolTipTimer->isActive()) {
 175         showToolTip();
 176     }
 177 }
 178
 179 void ToolTipManager::showToolTip()
 180 {
 181     Q_ASSERT(m_toolTipRequested);
 182     if (m_appliedWaitCursor) {
 183         QApplication::restoreOverrideCursor();
 184         m_appliedWaitCursor = false;
 185     }
 186
 187     if (m_fileMetaDataToolTip->preview().isNull() || m_metaDataRequested) {
 188         Q_ASSERT(!m_appliedWaitCursor);
 189         QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 190         m_appliedWaitCursor = true;
 191         return;
 192     }
 193
 194     const QRect screen = QApplication::desktop()->screenGeometry(QCursor::pos());
 195
 196     // Restrict tooltip size to current screen size when needed.
 197     // Because layout controlling widget doesn't respect widget's maximumSize property
 198     // (correct me if I'm wrong), we need to let layout do its work, then manually change
 199     // geometry if resulting widget doesn't fit the screen.
 200
 201     // Step #1 - make sizeHint return calculated tooltip size
 202     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetFixedSize);
 203     m_fileMetaDataToolTip->adjustSize();
 204     QSize size = m_fileMetaDataToolTip->sizeHint();
 205
 206     // Step #2 - correct tooltip size when needed
 207     if (size.width() > screen.width()) {
 208         size.setWidth(screen.width());
 209     }
 210     if (size.height() > screen.height()) {
 211         size.setHeight(screen.height());
 212     }
 213
 214     // m_itemRect defines the area of the item, where the tooltip should be
 215     // shown. Per default the tooltip is shown centered at the bottom.
 216     // It must be assured that:
 217     // - the content is fully visible
 218     // - the content is not drawn inside m_itemRect
 219     const int margin = toolTipMargin();
 220     const bool hasRoomToLeft  = (m_itemRect.left()   - size.width()  - margin >= screen.left());
 221     const bool hasRoomToRight = (m_itemRect.right()  + size.width()  + margin <= screen.right());
 222     const bool hasRoomAbove   = (m_itemRect.top()    - size.height() - margin >= screen.top());
 223     const bool hasRoomBelow   = (m_itemRect.bottom() + size.height() + margin <= screen.bottom());
 224     if (!hasRoomAbove && !hasRoomBelow && !hasRoomToLeft && !hasRoomToRight) {
 225         return;
 226     }
 227
 228     int x, y;
 229     if (hasRoomBelow || hasRoomAbove) {
 230         x = qMax(screen.left(), m_itemRect.center().x() - size.width() / 2);
 231         if (x + size.width() >= screen.right()) {
 232             x = screen.right() - size.width() + 1;
 233         }
 234         if (hasRoomBelow) {
 235             y = m_itemRect.bottom() + margin;
 236         } else {
 237             y = m_itemRect.top() - size.height() - margin;
 238         }
 239     } else {
 240         Q_ASSERT(hasRoomToLeft || hasRoomToRight);
 241         if (hasRoomToRight) {
 242             x = m_itemRect.right() + margin;
 243         } else {
 244             x = m_itemRect.left() - size.width() - margin;
 245         }
 246         // Put the tooltip at the bottom of the screen. The x-coordinate has already
 247         // been adjusted, so that no overlapping with m_itemRect occurs.
 248         y = screen.bottom() - size.height() + 1;
 249     }
 250
 251     // Step #3 - Alter tooltip geometry
 252     m_fileMetaDataToolTip->setFixedSize(size);
 253     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetNoConstraint);
 254     m_fileMetaDataToolTip->move(QPoint(x, y));
 255     m_fileMetaDataToolTip->show();
 256
 257     m_toolTipRequested = false;
 258 }
 259
 260 int ToolTipManager::toolTipMargin() const
 261 {
 262     const int margin = m_parentWidget->style()->pixelMetric(QStyle::PM_ToolTipLabelFrameWidth);
 263     return qMax(4, margin);
 264 }
 265
 266 #include "tooltipmanager.moc"