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/JobUiDelegate>
  25 #include <KIO/PreviewJob>
  26
  27 #include <QApplication>
  28 #include <QDesktopWidget>
  29 #include <QLayout>
  30 #include <QScrollArea>
  31 #include <QScrollBar>
  32 #include <QStyle>
  33 #include <QTimer>
  34
  35 ToolTipManager::ToolTipManager(QWidget* parent) :
  36     QObject(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_margin(4),
  44     m_item(),
  45     m_itemRect()
  46 {
  47     if (parent) {
  48         m_margin = qMax(m_margin, parent->style()->pixelMetric(QStyle::PM_ToolTipLabelFrameWidth));
  49     }
  50
  51     m_showToolTipTimer = new QTimer(this);
  52     m_showToolTipTimer->setSingleShot(true);
  53     m_showToolTipTimer->setInterval(500);
  54     connect(m_showToolTipTimer, SIGNAL(timeout()), this, SLOT(showToolTip()));
  55
  56     m_contentRetrievalTimer = new QTimer(this);
  57     m_contentRetrievalTimer->setSingleShot(true);
  58     m_contentRetrievalTimer->setInterval(200);
  59     connect(m_contentRetrievalTimer, SIGNAL(timeout()), this, SLOT(startContentRetrieval()));
  60
  61     Q_ASSERT(m_contentRetrievalTimer->interval() < m_showToolTipTimer->interval());
  62 }
  63
  64 ToolTipManager::~ToolTipManager()
  65 {
  66     delete m_fileMetaDataToolTip;
  67     m_fileMetaDataToolTip = 0;
  68 }
  69
  70 void ToolTipManager::showToolTip(const KFileItem& item, const QRectF& itemRect)
  71 {
  72     hideToolTip();
  73
  74     m_itemRect = itemRect.toRect();
  75
  76     m_itemRect.adjust(-m_margin, -m_margin, m_margin, m_margin);
  77     m_item = item;
  78
  79     // Only start the retrieving of the content, when the mouse has been over this
  80     // item for 200 milliseconds. This prevents a lot of useless preview jobs and
  81     // meta data retrieval, when passing rapidly over a lot of items.
  82     Q_ASSERT(!m_fileMetaDataToolTip);
  83     m_fileMetaDataToolTip = new FileMetaDataToolTip();
  84     connect(m_fileMetaDataToolTip, SIGNAL(metaDataRequestFinished(KFileItemList)),
  85             this, SLOT(slotMetaDataRequestFinished()));
  86
  87     m_contentRetrievalTimer->start();
  88     m_showToolTipTimer->start();
  89     m_toolTipRequested = true;
  90     Q_ASSERT(!m_metaDataRequested);
  91 }
  92
  93 void ToolTipManager::hideToolTip()
  94 {
  95     if (m_appliedWaitCursor) {
  96         QApplication::restoreOverrideCursor();
  97         m_appliedWaitCursor = false;
  98     }
  99
 100     m_toolTipRequested = false;
 101     m_metaDataRequested = false;
 102     m_showToolTipTimer->stop();
 103     m_contentRetrievalTimer->stop();
 104
 105     if (m_fileMetaDataToolTip) {
 106         m_fileMetaDataToolTip->hide();
 107         // Do not delete the tool tip immediately to prevent crashes when
 108         // QCoreApplication tries to deliver an 'Enter' event to it, see bug 310579.
 109         m_fileMetaDataToolTip->deleteLater();
 110         m_fileMetaDataToolTip = 0;
 111     }
 112 }
 113
 114 void ToolTipManager::startContentRetrieval()
 115 {
 116     if (!m_toolTipRequested) {
 117         return;
 118     }
 119
 120     m_fileMetaDataToolTip->setName(m_item.text());
 121
 122     // Request the retrieval of meta-data. The slot
 123     // slotMetaDataRequestFinished() is invoked after the
 124     // meta-data have been received.
 125     m_metaDataRequested = true;
 126     m_fileMetaDataToolTip->setItems(KFileItemList() << m_item);
 127     m_fileMetaDataToolTip->adjustSize();
 128
 129     // Request a preview of the item
 130     m_fileMetaDataToolTip->setPreview(QPixmap());
 131
 132     KIO::PreviewJob* job = new KIO::PreviewJob(KFileItemList() << m_item, QSize(256, 256));
 133     job->setIgnoreMaximumSize(m_item.isLocalFile());
 134     if (job->ui()) {
 135         job->ui()->setWindow(qApp->activeWindow());
 136     }
 137
 138     connect(job, SIGNAL(gotPreview(KFileItem,QPixmap)),
 139             this, SLOT(setPreviewPix(KFileItem,QPixmap)));
 140     connect(job, SIGNAL(failed(KFileItem)),
 141             this, SLOT(previewFailed()));
 142 }
 143
 144
 145 void ToolTipManager::setPreviewPix(const KFileItem& item,
 146                                    const QPixmap& pixmap)
 147 {
 148     if (!m_toolTipRequested || (m_item.url() != item.url())) {
 149         // No tooltip is requested anymore or an old preview has been received
 150         return;
 151     }
 152
 153     if (pixmap.isNull()) {
 154         previewFailed();
 155     } else {
 156         m_fileMetaDataToolTip->setPreview(pixmap);
 157         if (!m_showToolTipTimer->isActive()) {
 158             showToolTip();
 159         }
 160     }
 161 }
 162
 163 void ToolTipManager::previewFailed()
 164 {
 165     if (!m_toolTipRequested) {
 166         return;
 167     }
 168
 169     const QPixmap pixmap = KIcon(m_item.iconName()).pixmap(128, 128);
 170     m_fileMetaDataToolTip->setPreview(pixmap);
 171     if (!m_showToolTipTimer->isActive()) {
 172         showToolTip();
 173     }
 174 }
 175
 176 void ToolTipManager::slotMetaDataRequestFinished()
 177 {
 178     if (!m_toolTipRequested) {
 179         return;
 180     }
 181
 182     m_metaDataRequested = false;
 183
 184     if (!m_showToolTipTimer->isActive()) {
 185         showToolTip();
 186     }
 187 }
 188
 189 void ToolTipManager::showToolTip()
 190 {
 191     Q_ASSERT(m_toolTipRequested);
 192     if (m_appliedWaitCursor) {
 193         QApplication::restoreOverrideCursor();
 194         m_appliedWaitCursor = false;
 195     }
 196
 197     if (m_fileMetaDataToolTip->preview().isNull() || m_metaDataRequested) {
 198         Q_ASSERT(!m_appliedWaitCursor);
 199         QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 200         m_appliedWaitCursor = true;
 201         return;
 202     }
 203
 204     const QRect screen = QApplication::desktop()->screenGeometry(QCursor::pos());
 205
 206     // Restrict tooltip size to current screen size when needed.
 207     // Because layout controlling widget doesn't respect widget's maximumSize property
 208     // (correct me if I'm wrong), we need to let layout do its work, then manually change
 209     // geometry if resulting widget doesn't fit the screen.
 210
 211     // Step #1 - make sizeHint return calculated tooltip size
 212     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetFixedSize);
 213     m_fileMetaDataToolTip->adjustSize();
 214     QSize size = m_fileMetaDataToolTip->sizeHint();
 215
 216     // Step #2 - correct tooltip size when needed
 217     if (size.width() > screen.width()) {
 218         size.setWidth(screen.width());
 219     }
 220     if (size.height() > screen.height()) {
 221         size.setHeight(screen.height());
 222     }
 223
 224     // m_itemRect defines the area of the item, where the tooltip should be
 225     // shown. Per default the tooltip is shown centered at the bottom.
 226     // It must be assured that:
 227     // - the content is fully visible
 228     // - the content is not drawn inside m_itemRect
 229     const bool hasRoomToLeft  = (m_itemRect.left()   - size.width()  - m_margin >= screen.left());
 230     const bool hasRoomToRight = (m_itemRect.right()  + size.width()  + m_margin <= screen.right());
 231     const bool hasRoomAbove   = (m_itemRect.top()    - size.height() - m_margin >= screen.top());
 232     const bool hasRoomBelow   = (m_itemRect.bottom() + size.height() + m_margin <= screen.bottom());
 233     if (!hasRoomAbove && !hasRoomBelow && !hasRoomToLeft && !hasRoomToRight) {
 234         return;
 235     }
 236
 237     int x, y;
 238     if (hasRoomBelow || hasRoomAbove) {
 239         x = qMax(screen.left(), m_itemRect.center().x() - size.width() / 2);
 240         if (x + size.width() >= screen.right()) {
 241             x = screen.right() - size.width() + 1;
 242         }
 243         if (hasRoomBelow) {
 244             y = m_itemRect.bottom() + m_margin;
 245         } else {
 246             y = m_itemRect.top() - size.height() - m_margin;
 247         }
 248     } else {
 249         Q_ASSERT(hasRoomToLeft || hasRoomToRight);
 250         if (hasRoomToRight) {
 251             x = m_itemRect.right() + m_margin;
 252         } else {
 253             x = m_itemRect.left() - size.width() - m_margin;
 254         }
 255         // Put the tooltip at the bottom of the screen. The x-coordinate has already
 256         // been adjusted, so that no overlapping with m_itemRect occurs.
 257         y = screen.bottom() - size.height() + 1;
 258     }
 259
 260     // Step #3 - Alter tooltip geometry
 261     m_fileMetaDataToolTip->setFixedSize(size);
 262     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetNoConstraint);
 263     m_fileMetaDataToolTip->move(QPoint(x, y));
 264     m_fileMetaDataToolTip->show();
 265
 266     m_toolTipRequested = false;
 267 }
 268
 269 #include "tooltipmanager.moc"