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